Author: Jellal, Younes Title: Physical, Sensory, and ... · foods are rapidly increasing. This...

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Author: Jellal, Younes

Title: Physical, Sensory, and Microbial Attributes of Reduced-Sodium All-Beef

Frankfurters

The accompanying research report is submitted to the University of Wisconsin-Stout,

Graduate School in partial completion of the requirements for the

Graduate Degree/ Major: MS Food and Nutritional Sciences

Research Adviser: Eun Joo Lee, Ph.D.

Submission Term/Year: Spring, 2013

Number of Pages: 55

Style Manual Used: American Psychological Association, 6th

edition

I understand that this research report must be officially approved by the

Graduate School and that an electronic copy of the approved version will be made

available through the University Library website

I attest that the research report is my original work (that any copyrightable

materials have been used with the permission of the original authors), and as such,

it is automatically protected by the laws, rules, and regulations of the U.S.

Copyright Office.

My research adviser has approved the content and quality of this paper.

STUDENT:

NAME Younes Jellal DATE: May 15, 2013

ADVISER:

NAME Eun Joo Lee DATE: May 15, 2013

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Jellal, Younes. Physical, Sensory, and Microbial Attributes of Reduced-Sodium All-Beef

Frankfurters

Abstract

The average sodium consumption in the American diet (3,400 mg/day) exceeds the

recommended intake (2,300 mg/day) and consumers’ demands to reduce sodium from processed

foods are rapidly increasing. This study’s objective was to evaluate the physical, sensory, and

microbial properties of reduced-sodium all-beef frankfurters. The effects of three sodium

substitutes (potassium chloride, natural flavor enhancer (NFE), and a KCl/potassium citrate

blend) were compared with two controls, positive (100% NaCl) and negative (70% NaCl). The

sodium substitutes were incorporated into emulsified beef frankfurter formulations at 30%

sodium reduction. Cook yield, pH, internal color, texture, total plate count, and consumer

sensory properties were evaluated. No significant difference was observed in texture attributes

and cook yield (88.1-89.5%) between treatments. The pH of raw beef was 5.8 but that of final

products ranged from 6.2 to 6.3. Internal color was similar for all TRTs except for the b* values

of NFE treatment. All samples showed minimal (<1000 CFU/g) microbial growth while the

negative control had 2,000 CFU/g. Sensory evaluation demonstrated that panelists preferred the

KCl treatment. Results indicated that 30% sodium reduction in frankfurters can be achieved by

using sodium substitutes without significantly impacting the quality and sensory characteristics

of the final product.

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Acknowledgements

This project was made possible not only through my own efforts, but through the

guidance and support of the mentors I’ve been lucky enough to encounter during my time at the

University of Wisconsin-Stout.

First of all, I would like to thank my thesis advisor Dr. Eun Joo Lee for helping me

throughout the entire process. My gratitude goes out to Dr. Naveen Chikthimmah for not only

teaching me so much of what I know, but for being a good friend as well. My thanks are

extended to Dr. Cynthia Rohrer for her mentorship during my journey through the Food Science

Master’s program. Appreciation also goes out to Connie Galep and Vicki Weber for their

assistance during different phases of this project. I am grateful to UW-Stout Research Services

for awarding me with a grant to help fund my research. And finally, my unwavering gratitude

goes out to Dr. Jeff Sindelar of UW-Madison for the mentorship he offered to me which helped

make the success of this project possible.

To my family — you made me into the man I am today. Without you, I would be

nothing. And to my son, Jonah — the light you’ve brought into my life makes every moment

count. Thank you.

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Table of Contents

Abstract ...................................................................................................................................... 2

List of Tables .............................................................................................................................. 6

List of Figures ............................................................................................................................. 7

Chapter I: Introduction ................................................................................................................ 8

Problem Statement......................................................................................................... 10

Purpose of the Study ...................................................................................................... 10

Objectives of the Study .................................................................................................. 10

Definition of Terms ....................................................................................................... 11

Assumptions of the Study .............................................................................................. 11

Limitations of the Study ................................................................................................ 11

Methodology ................................................................................................................. 12

Chapter II: Literature Review .................................................................................................... 13

Key Ingredients in Frankfurters ..................................................................................... 13

Functions of Sodium in Foods ....................................................................................... 17

Health Effects of Salt ..................................................................................................... 21

Strategies to Reduce Sodium in Foods ........................................................................... 22

Chapter III: Methodology .......................................................................................................... 29

Product Manufacture ..................................................................................................... 29

Physical Properties ........................................................................................................ 32

Microbial Analysis (Total Plate Count) .......................................................................... 34

Sensory Analysis ........................................................................................................... 35

Data Analysis ................................................................................................................ 36

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Chapter IV: Results and Discussion .......................................................................................... 37

Cook Yield Measurements ............................................................................................. 37

Instrumental Color Measurements ................................................................................. 39

Texture Profile Analysis ................................................................................................ 40

Microbial Analysis (Total Plate Count) .......................................................................... 42

Sensory Analysis ........................................................................................................... 43

Chapter V: Conclusions ............................................................................................................ 47

Recommendations ......................................................................................................... 48

References ................................................................................................................................ 49

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List of Tables

Table 1: Sodium Levels (mg/100 g) in Standard and Reduced Salt Foods...……….……………19

Table 2: Formulation of Frankfurters….………………………………………………………...30

Table 3: Mean Values for cooking yield, pH 24 hours after manufacture and pH four months

after for emulsified frankfurters……………..………………………………………….…39

Table 4: Mean Values for Objective Internal Color Measurements in Emulsified

Frankfurters..…………………………………….……..……………………......………40

Table 5: Mean Values for Hardness, Cohesiveness, Springiness, and Chewiness of Emulsified

Frankfurters……………………..………………………..……………………...………41

Table 6: Total Plate Count Numbers for the Different Frankfurter Treatments…………...……43

Table 7: Mean Ratings for Sensory Attributes of Emulsified Frankfurters Using a 7-point

Hedonic Scale (1=none, 3=moderate, 7=very strong) with Consumer Panelists…...…..45

Table 8: Mean Ratings for Consumers’ Liking and Intent to Purchase Using a 9-point Hedonic

Scale (1=dislike extremely, 5=neither like or dislike, 9=like very much) for Emulsified

Frankfurters………………………………………………...……………………...…….46

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List of Figures

Figure 1: Scale diagram of taste perception as concentration increases…………………………24

Figure 2: Diagram of the committee’s approach to identify strategies to reduce sodium intake of

U.S. population. ……………………………………….…………..…………………27

Figure 3: Sodium chloride reduction using SoMinus PCM, potassium chloride, and natural flavor

enhancer………………………………………………………………………………..31

Figure 4: Panelists’ consumption frequency of frankfurters.……..…...…………………………46

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Chapter I: Introduction

In 1969, the White House Conference on Food, Nutrition, and Health underlined the

direct association of sodium to hypertension. This marked the starting point of numerous public

health initiatives which addressed the high levels of sodium intake among the U.S. population

(Institute of Medicine, 2010). Later, in January 2009, the Institute of Medicine (IOM)

Committee on Strategies to Reduce Sodium Intake was summoned for the first time.

However, the American average daily intake of sodium continues to exceed 3,400 mg

(equivalent to about 1.5 teaspoons of salt), which is well over the maximum intake level of 2,300

mg/d sodium (one teaspoon of salt) established by the 2005 Dietary Guidelines for Americans

(Institute of Medicine, 2010).

A contributing factor to this trend lies in the consumption of processed foods that contain

high levels of sodium. The food industry relies heavily on the flavor of processed foods because

they are readily consumed by Americans. Failed efforts to reduce the sodium intake in an

average diet stem from the desirable taste of salt found in many of these foods (Institute of

Medicine, 2010).

In processed meats such as frankfurters, salts are used not only for their organoleptic

properties, but for their functional properties as well (Antonios & MacGregor, 1997). Therefore

reducing salt levels will require some adjustment within the food itself to ensure that the same

degree of both preservation and flavor is maintained.

Salt affects many aspects of food, so this process can be complicated. The microbial

stability, flavor, water holding capacity, and overall safety of a food is determined in part by the

amount of salt in a product (Hand, Terrell & Smith, 1982). Salt is an important element in meat

products in particular because it creates binding agents by solubilizing structural proteins. These

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binding agents make up the texture of a meat product, alongside other factors such as fat

retention and water binding capacity (Gelabert, Gou, Guerrero & Arnau, 2003).

The difficulty of sodium reduction in processed meat products is that every aspect that

goes into a meat product affects all others. The water binding capacity for meat, for example,

increases along with the pH of the product (Shuming, 2006). It can then be assumed that low-

salt meat products with poor texture can be improved by increasing its pH, and therefore

increasing its water binding capacity (Shuming, 2006). While the question of poor texture in

low-sodium meat products has now been addressed, another problem rises in its wake: reduced

salt levels paired with high pH levels put the safety of the meat product at risk, which creates

another issue to replace the former. Equally, if one was to lower pH levels for the purpose of

stunting bacterial growth, the texture of the meat product is put in jeopardy because water loss

would then increase.

Reducing salt could also decrease shelf-life. Although it will not affect the number or

species of bacteria initially present in a food, it may augment the bacteria’s growth rate and

chances of survival (Barry-Ryan, Bourke, & Gutierrez, 2008).

Beyond the purposes of texture and food safety, salt is also a popular flavor enhancer.

Although preferences differ among people, the sodium ion that brings about a salty taste has

become a staple of the American diet. Because of its negative health effects, the National Salt

Reduction Initiative hopes to lower sodium intake by 20% by means of a gradual reduction over

the period of five years (Institute of Medicine, 2010). Salt receptors on the tongue become more

sensitive when salt intake is reduced in small amounts, therefore small changes may be more

acceptable to consumers than large decreases in salt levels of foods (Kim, Lopetcharat, Gerard &

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Drake, 2012). This does not mean, however, that consumers would prefer a lower-sodium taste

to its higher-sodium counterpart.

Due to the complex and multifaceted role of salt in meat products, reducing sodium

levels safely should involve modifying processing conditions to reduce the overall need for salt.

Shelf-life adjustment may be necessary in this situation. Salt can also be replaced by another

chloride, or substituted with additives containing low or no sodium.

Problem Statement

Considering its association with pertinent health issues like high blood pressure and

cardiovascular diseases, it is important to reduce the sodium content of processed foods such as

frankfurters while still maintaining their physical properties, sensory attributes, and safety.

Purpose of the Study

The purpose of this study was to evaluate the physical, sensory, and microbial properties

of reduced-sodium frankfurters, respectively, through a texture profile analysis, sensory

evaluation, and a total microbial count. The experiment was conducted at the Food & Nutrition

Department (University of Wisconsin-Stout) in collaboration with the Meat Science Department

(University of Wisconsin-Madison) during Fall 2012.

Objectives of the Study

The objectives of this study were to:

1. Determine the physical properties including cook yield, pH, internal color, and texture in

reduced-sodium frankfurters.

2. Determine the microbial properties including total plate count in reduced-sodium

frankfurters.

3. Investigate the sensory attributes in reduced-sodium frankfurters.

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Definition of Terms

The following terms are relevant to this research. They are defined as such:

Flavor. Defined as the combination of taste and aroma which combined produce a

distinct sensory impression of an ingested food or substance.

Organoleptic properties. Refers to the feel produced by any substance interfering with

an individual’s touch, taste, or smell, as well as with the whole organism.

Sodium chloride. Ionic compound (NaCl) also referred to as salt or table salt is

considered the cheapest and most food preservative universally used.

Total plate count. “(Also referred to as aerobic plate count or standard plate count) can

provide a general indication of the microbiological quality of a food. A standard plate count

will not differentiate between the natural microflora of a food, spoilage microorganisms, and

organisms added to fermented foods or pathogenic microorganism” (NSW Food Authority, p.5,

2009).

Assumptions of the Study

Excessive intake of sodium has been linked to hypertension and increased risk of strokes.

The main source of sodium in the average diet is sodium chloride. It affects flavor, texture, and

shelf life of meat products such as frankfurters. A particular problem with reduced-sodium

frankfurters would be not only the perceived flavor, but also acceptable physical properties and a

reasonable shelf life.

Limitations of the Study

The main limitations of this study were related to the sensory analysis. First, it was

complicated to develop a questionnaire that would allow the most precise description of each

sample due to the panelists’ varied preferences. Moreover, this study lacked trained panelists.

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Students and staff from UW-Stout participated in the sensory analysis and were not trained as

professional panelists, which may have biased the overall results.

Methodology

All the samples of frankfurters (regular and reduced-sodium) were analyzed for their

physical properties, sensory attributes, and their total plate count.

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Chapter II: Literature Review

The recommended daily intake of sodium provided by the 2005 Dietary Guidelines for

Americans for people over the age of two years is a maximum of 2,300 mg. However, most

Americans consume approximately two times that amount (Henney, Taylor, & Boon, 2010).

This increased salt intake has been linked to health concerns such as hypertension and

cardiovascular disease. As a result, in April 2010, the Institute of Medicine recommended that

sodium be reduced in food (Institute of Medicine, 2010).

However, sodium reduction is difficult for the meat industry in particular as processed

meats such as ham, bacon, sausage, bologna, and frankfurters include high levels of sodium. Salt

provides functionality characteristics in meat products such as food safety and increased shelf

life, as well as enhances its flavor. Other preservatives, additives, flavoring agents, or processing

techniques may be needed if salt levels were reduced. This will ensure both microbial safety and

quality.

The purpose of this study was to evaluate the physical, sensory, and microbial properties

of reduced-sodium frankfurters. Consequently, the sections to be addressed in this chapter are

the key ingredients in frankfurters including sodium, functions of sodium in food products,

health effects of sodium, and some strategies to reduce sodium in foods.

Key Ingredients in Frankfurters

The major ingredients of frankfurters are meat and salt. Plus, meat is mostly composed

of water, protein, and fat.

Water. The water content of lean meat can be up to 70%. It is the largest component

with about 3.5 to 7.7 times the amount of protein present. Also, it represents about 5 to 8% of

the fat tissue. Water has a major effect on the texture of frankfurters because of its role in

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emulsions. In addition, water activity is very critical for the safety and shelf-life of food

products in general and frankfurters in particular. “The water activity (aw) of a food is the ratio

between the vapor pressure of the food itself, when in a completely undisturbed balance with the

surrounding air media, and the vapor pressure of distilled water under identical conditions”

(FDA, 1984, Chapter 39). For instance, a food product is defined as safe if its water activity is

controlled to 0.85 or less, which does not provide enough moisture needed for microbial growth.

Protein. Three groups of proteins exist: myofibrillar proteins which are salt soluble,

sarcoplasmic (water soluble), and connective tissue proteins which are not soluble in salt. These

protein groups have different properties that would affect processed meats in many different

ways.

The myofibrillar proteins, responsible for the contraction ability of living muscles, are

found inside the muscle cell. The ability of these proteins to become solubilized, in the presence

of salts, makes them very valuable in processed meats manufacturing. For example, their

solubilization makes the glue that holds boneless products together (Montana Meat Processors

Convention, 2001). Also, salt soluble proteins are very important to the water holding capacity

and contribute to the firmness of products.

The sarcoplasmic proteins are found inside the muscle cell, which is where energy

protein synthesis takes place. One form of sarcoplasmic protein, myoglobin, has significant

importance in processed meats because it gives meat its color.

The connective tissue proteins are responsible for contraction movements in the body

muscles. Collagen is the major protein of this category with varying content between different

muscles and even within the same muscle (Montana Meat Processors Convention, 2001). This

protein group is important to processed products because if present in large quantities, it has a

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detrimental impact on the finished product texture (Montana Meat Processors Convention,

2001).

Fat. The importance of fat resides on the fact that it directly affects the flavor, texture

and shelf life of processed meats. Triglycerides which are glycerol molecules attached to three

fatty acids are considered the main constituent of animal lipids. But, there is more than just

triglycerides, fatty acids are numerous and differ by the number of Carbons as well as the

number of unsaturated bonds in the carbon chains. The greater the number of unsaturated carbon

chains, the more susceptible meat fat is to oxidation. Once oxidized fatty acids double bonds

break and produce new compounds such as aldehydes and ketones (Montana Meat Processors

Convention, 2001) which impart off-odors and flavors known as rancidity.

Salt. Salt is the major ingredient for the curing process of meats. It prevents spoilage by

inhibiting bacterial growth through alteration of the osmotic pressure, then dehydration of

microbial cells (Davidson, 2001). However, salt if used alone for curing, produces harsh, dry,

and dark unattractive colored meat product that is not palatable (Montana Meat Processors

Convention, 2001). Besides, sodium chloride is indispensable in processed meats. Sahoo,

Sajala, and Kumar (2004) have cited the following functions of sodium in processed meats. It

produces a desired flavor by enhancing saltiness, preserves foods by lowering the water activity,

it solubilizes meat proteins which improves the emulsion meat-moisture-fat therefore desirable

texture, increases the water binding capacity and hydration of proteins, as well as the viscosity

which enables the incorporation of fat into batters.

Recently, due to the association of salt to some health issues, meat processors are trying

to reduce sodium levels in most meat products. Thus, other chloride-containing and non-sodium

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salts are being tested such as potassium chloride. Unluckily, these salts produce a bitter

undesirable after taste (Montana Meat Processors Convention, 2001).

Sweeteners. The main function of sugars is to unstiffen salt based cured meats. Also,

sugars are essential for the maillard browning reaction which produces a brown color and

enhances the flavor of cooked cured meats. A reducing sugar reacts to amino groups in proteins

and many desirable compounds are produced. But, sometimes a more pronounced reaction

would expose several undesirable results such as burned flavors and dark unpleasant colors

(Montana Meat Processors Convention, 2001).

Gums. Carrageenan is gum that’s used the most in meat products. It is a water soluble

hydrocolloid, therefore retains water under heating conditions and forms gel water systems

(Montana Meat Processors Convention, 2001).

During meat processing, water escapes from the meat which is referred to as cook loss.

The addition of carrageenan helps reducing this cook loss. It forms a gel in the product which

enhances consistency and stability (Montana Meat Processors Convention, 2001).

In the presence of salt, carrageenan becomes insoluble in water and does not form a gel, it

only scatters in the system. Hence, it should be incorporated after salt so it does not swell before

it integrates the meat (Montana Meat Processors Convention, 2001).

Starches. Long chains of glucose (100’s) with the ability to hold water and swell under

heating conditions are called starches. When added to processed meats, they help the coating of

the product but they are not to exceed 2% (Montana Meat Processors Convention, 2001).

Flavoring agents. Spice extracts are mostly used for the purpose of flavor enhancement

in processed meats. Commonly, these spices can be mixed with dextrose in order to increase

their water solubility and penetration into the meat.

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Armstrong named the baker’s dozen of spices used in the meat industry in the Montana

Meat Processors Convention (2001) as follows: coriander, mustard, fennel, garlic, cumin, sage,

paprika, chili, nutmeg, mace, red, black, and white pepper. These spices make up to 99% of the

flavor of meat products in the US.

Functions of Sodium in Foods

Salt (sodium chloride) is used to enhance the flavor, improve texture, and extend the shelf

life of meat products.

Flavor. Sodium is one of the only cations that can present a rudimentary salty taste

which can be identified by the human tongue (other than lithium, which can be lethal if

consumed in large doses). While some minerals like calcium and potassium have a component

of saltiness to their taste, other flavors dwarf the predominant salty flavoring and are perceived

as metallic.

Salt further affects the taste of foods by masking bitter flavors and enhancing more

favorable ones. Roughly 25% of the population are unresponsive to ordinary levels of bitter

compounds and are known as nontasters. On the other end of the spectrum, about 25% are very

sensitive to bitter compounds and are known as supertasters (Kilcast & den Ridder, 2007).

Therefore, the perception of bitterness is genetically controlled in humans to some degree.

Decreasing the salt levels in foods by a large amount may then make the foods undesirable to a

fourth of consumers—the supertasters. It must be taken into account however that flavor is not

the only aspect which governs the acceptability of a meat product. Its functional properties are

also determining factors (Herrero et al., 2008).

Texture. The texture of a food is affected when sodium chloride interacts with other

foremost components in the food itself before, during, or after processing.

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Sodium activates proteins in meat products which induces them to bind more water

molecules. Matulis, McKeith, Sutherland, and Brewer (1995) found that lowering salt levels to

less than 1.3% in frankfurters resulted in incomplete protein extraction and allowed water to

escape. The protein extraction with the use of salt is important in the meat industry to obtain

desirable textural properties. Salt changes the ionic strength and allows the proteins to be

exposed within a meat batter. The hydrophilic ends of the protein bind to water, whereas the

hydrophobic ends of the protein bind with fat stabilizing an emulsion.

Water-holding capacity, break strength, bind strength, and cook loss are also influenced

by the amount of salt-soluble proteins present in a food product, which in turn affects the overall

texture of that product. Break strength is measured by breaking meat products. The force

needed to break a meat patty is positively related to the bind within the product. Thus, break

strength evaluation provides information in regards to the amount of bind strength between the

meat particles and fat within a product (Herrero et al., 2008). If bind strength is weakened,

particles within meat products crumble, which is detrimental in further processing.

Besides the bind strength, the water-holding capacity and cook loss affect texture as well.

A reduced water-holding capacity and an increased cook loss in meat products produce an

undesirable texture with dry meat and a reduced overall palatability. Gelabert, Gou, Guerrero,

and Arnau (2003) demonstrated that water-holding capacity increased with salt inclusion, while

cook loss is reduced in meat when salt is added (Huffman, Am Ly, & Cordray, 1981).

Preservation. Historically, salt was added to food predominantly for purposes of

preservation. However, due to the emergence and popularity of advanced food preservation

practices such as refrigeration, the necessity to use salt specifically as a preservative is not as

significant as it once was. Salt levels in processed foods, however, are still holding steady at

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high levels, which may affect the long-term health of consumers. Table 1 illustrates the sodium

level in commonly consumed products.

Table 1

Sodium Levels (Mg/100 G) in Standard and Reduced Salt Foods

(Data from www.nal.usda.gov/fnic/foodcomp/search, In Doyle, 2008)

Food Standard Reduced Sodium

Frankfurter 1090 311

Beef Bologna 1080 682

Salami, pork and beef 2010 623

Bacon, cooked 2310 1030

Ham, extra lean, roasted 1385 681

Bread, commercial white 681 27

Soup, condensed tomato (Campbell’s) 573 427

Cheese, Swiss 192 14

Cheese, Parmesan 1602 63

Soy sauce 5637 3333

Salt can greatly reduce the water activity in foods, which is the amount of unbound water

present and accessible for microbial growth. Due to its reduction properties for water activity,

sodium works well as an effective preservative. Its ability to retard water activity in foods stems

from the sodium and chloride ions’ ability to correlate with water molecules (Fennema, 1996;

Potter & Hotchkiss, 1995).

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Most foodborne bacteria such as Listeria monocytogenes, Clostridium botulinum, E. coli,

Salmonella spp., and Pseudomonas spp cannot grow below a water activity of 0.92. There are a

few types of bacteria, however, that are able to tolerate lower water activities. These species

include some spoilage yeasts (0.62), spoilage lactic acid bacteria (0.90), and Staphylococcus

aureus (0.83). Molds (Aspergillus and Penicillium) tolerate lower water activities than most

bacteria. The water activity levels these molds can tolerate range from 0.80 to 0.83 (Betts,

Everis, & Betts, 2007; Christian, 2000). In response to high salt levels, other microbes such as

L.monocytogenes synthesize specific stress proteins which help them to thrive (Duché,

Trémoulet, Glaser, & Labadie, 2002).

As an additive to foods, salt can cause osmosis shock, or the loss of water in cells through

osmosis (Davidson, 2001). Salt may also reduce the rate of growth by forcing cells to use energy

to exclude sodium ions from their cells, as well as reduce the oxygen solubility that restricts

cellular enzymes (Shelef & Seiter, 2005).

Food products are oftentimes preserved by using a multifaceted approach to control

microbial growth known as a multiple hurdle method (Leistner, 2000). A number of factors

affect the amount of sodium needed to inhibit pathogens. Temperature, pH, and oxygen levels,

as well as fat and additive presence all contribute to microbial growth. To extend product shelf

life and augment food safety, different preservation techniques are combined to create a number

of ‘hurdles’ a pathogen must overcome to remain active in a food product. This method can also

create supplementary benefits, such as reducing the severity of processing in a food. Another

added advantage is the improvement of nutritional quality through the use of less salt by

attaining microbial safety with lower levels of sodium (Leistner & Gould, 2005).

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Health Effects of Salt

Generalities. Sodium is essential for the human body as it regulates cells’ plasma

volume, and contributes in the transport of some molecules across cell walls. Further, 98% of

the dietary sodium ingested gets absorbed at the intestine level while kidneys purge any excess

sodium in the body. However, as humans age, they tend to experience a decreased kidney

function, hence a decreased excretion of excess sodium. Therefore, the cells’ plasma volume

may increase which would induce hypertension directly associated to heart diseases and stroke.

Hypertension. Clinical studies have been limited on how to explain the impact of a

person’s diet on blood pressure. One instance was a study that looked at three different levels of

salt intakes to see if salt reduction in the diet correlated directly with a drop in blood pressure

(He & MacGregor, 2003). There was a consistent pattern visible throughout all the subjects

when salt was reduced within the range of 12 to 3 g/d. A decrease in blood pressure of 3.6 to

5.6/1.9 to 3.2 mm Hg (systolic/diastolic) in hypertensives and 1.8 to 3.5/0.8 to 1.8 mm Hg in

normotensives was present with a sodium reduction of 3 g/d in the subject’s diet. This same

pattern was consistent throughout—the effects doubled with a 6 g/d reduction and tripled with a

9 g/d reduction.

Cardiovascular diseases. The Coronary Heart Disease (CHD) Policy Model was used

by Domingo et al. (2010) to quantify the benefits of reductions in dietary salt in a large

population. This model projected that the reduction of salt of up to 3 g per day (1200 mg of

sodium per day) would reduce the number of new heart disease cases by up to 120,000, stroke by

up to 66,000, and total number of deaths per year by 92,000. Thus, Domingo et al. concluded

that this achievable reduction in dietary sodium would considerably lower the number of

cardiovascular diseases’ cases.

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Bone disease. Calcium metabolism has been shown to be linked strongly with sodium

intake. Studies have shown that a diet high in salt may have an adverse effect on the body’s

ability to retain calcium, which in turn affects bone density. An increase in urinary losses of

calcium has been shown to correlate with diets high in sodium; there is additional 20–60 mg

calcium excreted in urine for every 2300 mg of sodium the body ingests (Teucher et al., 2008).

It is difficult for the body to compensate for this loss of calcium through increased dietary

absorption caused by additional 2.3g sodium per day (Heaney, 2006). What’s more, studies have

also shown that high levels of sodium in the body can lead to a reduction in blood pH, resulting

in low-grade metabolic acidosis which also increases calcium loss and bone resorption (Frings-

Meuthen, Baecker & Heer, 2008).

Strategies to Reduce Sodium in Foods

Sodium restricted diet. The simplest way to reduce sodium intake is to expect

consumers to adjust their eating habits accordingly once they are informed that they consume

dangerous amounts of salt. However, diets which restrict sodium can be challenging to maintain

for a number of reasons. A study conducted by Kim, Lopetcharat, Gerard, and Drake (2012)

entitled “Consumer Awareness of Salt and Sodium Reduction and Sodium Labeling” was

designed to gain data surrounding the attitudes consumers consistently had towards dietary

sodium in foods. The study featured consumers (n=489) who participated in a quantitative

internet study about their attitudes toward various parts of food labels. The results of the study

showed that the amount of sodium in a product that is found on the food label panel did not

influence a consumer’s view on that product either negatively or positively. What consumers did

find pleasing, however, was the addition of a nutrient such as fiber or whole grain. The study

23

also showed that a “reduced” claim was more appealing to consumers than a “free” claim for

“unhealthy” nutrients like sugar, sodium, and fat.

Consumers are actively encouraged to choose low-salt foods which are not offered

readily in their stores (Hooper, Bartlett, Smith, & Ebrahim, 2002). Going forward, food

processors should be expected to reduce the sodium content of their products while maintaining

desirable flavors instead of calling for reducing sodium intake by advice alone (Dotsch, Busch,

Batenburg, Liem, Tareilus, Mueller, & Meijer, 2009).

Salt substitutes. There is no one ultimate substitute to salt. The idea is to find an

ingredient that produces a well perceived saltiness when consumed. Besides, the uniqueness of

sodium and the saltiness it elicits, can be explained by its unique ability to stimulate the

epithelial sodium channels ENaC’s situated on the taste receptor cells (Chandrashekar, Kuhn,

Oka, Yarmolinsky, Hummler, Ryba, & Zuker, 2010). The perception of saltiness starts with the

sodium activating the ENaC’s which send an afferent signal to the gustatory regions of the brain.

Furthermore, the saltiness cannot be fully perceived unless the concentration is high enough to

stimulate ENaC’s, as well as to produce electrical impulses transmitted to the brain and decoded

in order to determine the salty taste quality (Keast & Roper, 2007). The following figure

describes briefly the effect of sodium concentration on its perception (Keast & Roper, 2007).

24

Figure 1. Scale diagram of taste perception as concentration increases (adopted from (Keast &

Roper, 2007).

Other chloride salts. Chloride salt alternative ingredients such as potassium chloride

(KCl), magnesium chloride (MgCl2), and calcium chloride (CaCl2) have been used to replace

various levels of sodium in products. The crystalline structure of KCl is similar to that of NaCl,

and is therefore the most common replacement option of sodium in processed foods (Dötsch et

al., 2009). This sodium alternative is limited, however, and not recommended as a replacement

at levels no higher than 50% due to its propensity toward a bitter, metallic, or chemical aftertaste

(Hutton 2002; Tarver 2010). Similarly, CaCl2 and MgCl2 possess a sour, bitter flavor which also

limits their usefulness as replacement options. Furthermore, another downfall to the substitution

of KCl for NaCl is that excess of potassium can also contribute to a number of kidney problems

(Tarver 2010). Whiting and Jenkins (1981) investigated the partial substitution of NaCl by KCl

in frankfurters. The results of their study showed that KCl was a viable option when it came to

reducing NaCl content up to a usage level of 50%. Hand and others (1982) also investigated the

25

effects of chloride salts in emulsified beef and pork frankfurters. They concluded that a 35%

replacement of NaCl by KCl may be the most viable Na reduction option for frankfurters as off-

flavor was slightly greater than the control, but was not different across all storage periods.

Bitter blockers. Due to the aforementioned bitter and metallic taste found in the

substitution of K salts for Na salts, the use of masking agents such as bitter blockers can help

increase the appeal of a product to consumers. Bitter compounds along with Na salts interact in

a way where the bitterness is suppressed while the perceived saltiness remains unaffected

(Kilcast & den Ridder 2007). Keast and Breslin (2002) studied oral pharmaceuticals and its

ability to suppress bitterness with the anions and cations of salts. These particular tests

predominantly studied adenosine monophosphate (AMP) and monosodium glutamate (MSG).

The authors of the study adjusted the intensity of bitterness in each sampling because of the

variability among individuals in their bitter-tasting ability. The adjustments were dependent

upon other substances present, which allowed the authors to determine if the masking agent was

effective for all participants rather than those sensitive to bitter flavors. Through the use of

professional sensory panelists, it was determined that MSG and AMP successfully inhibited

bitterness by a significant amount. This supports the hypothesis that substances containing

glutamate can have a significant impact in NaCl reduction by making alternatives more

appealing to consumers.

Natural flavor enhancer. Natural Flavor Enhancer (NFE) is a modified soy sauce

designed to bring intensity the umami flavor in foods. It is made with the same ingredients as

soy sauce—water, wheat, soybeans, and NaCl—but in vastly different proportions. The most

significant difference is that NFE contains a higher percentage of wheat than soybeans, which

also leads to a lighter color in NFE than soy sauce (Sato et al., 2010). Furthermore, NFE has less

26

NaCl than its soy sauce counterpart. NFE is known for its natural umami taste (Kremer et al.,

2009), which refers to a palatable meaty, brothy, or savory flavor. Many studies have shown that

umami substances can enhance saltiness as well as other tastes and flavors. Yamaguchi (1987)

investigated the relationship between saltiness and umami in various Asian dishes. He

conducted a sensory evaluation using samples with different levels of umami substances and

NaCl. Yamaguchi then concluded that the inclusion of umami substances allows for a 30%

sodium reduction without negatively impacting consumer acceptability. McGough et al. (2011)

conducted a study that investigated consumer sensory and quality impacts associated with the

partial replacement of NaCl using NFE in processed meat. The results of the study suggested

that a complex relationship may exist between KCl and NFE, where a combination of these

particular ingredients can create a palatable product without NaCl. This also points to potential

for greater KCl utilization without the product being negatively impacted by the bitter taste KCl

is known for. The study suggests that NFE may have the ability to enhance the saltiness already

present in a product without increasing the levels of NaCl or negatively impacting quality and

sensory characteristics.

The Institute of Medicine (IOM) strategy. The Institute of Medicine was established in

1970 to act under the responsibility of the National Academy of Sciences, as an adviser to the

federal government. Its main mission was to identify medical, research and education issues. In

2008, at the request of Congress, a 14 member committee was assembled and given the mission

of planning for reducing the sodium intake amongst Americans. Later, the committee insisted on

the combination of actions by food industrials, government, and education of the public as well

as professionals. Figure 2 illustrates the committee’s approach to reduce sodium intake of the

U.S. population.

27

Figure 2. Diagram of the committee’s approach to identify strategies to reduce sodium intake of

U.S. population (Institute of Medicine, 2010).

~(Chapter 1): Examine pest Uld pruent govemment and public heall.h inil.iataves/ goal tet.Ling

~Chaplor:l): Conridet unique challengu

~Chapters 4. j, 6, &nd 7. .nd Appendixes) : Examine the c:onteXI.

~(Chapter It): Coruidor options and uninlend.ed c:orwequenees:

Co.nuniltte's Ta.sk

+

Consume~: EdU(&tio~otivation

Public H••llll ~Food Induotty: Voluntary-Sodium Reduction• Initiatives

.Provision ofPoint-of.Pu:rchue lnformat.ion RegardingSodium Contt:n1

~ SaltT .. te/Fl•vor y Ubiquity in Food Supply

OU\er Roles ofSodiu-m Sodium Intake and Sowces The Food Environment The RegulalOJy £nvi:ronmenl l.at.emat.ional Experiences

Consum.ett: Educa.t.ion/Motival.ion • SLatus Quo ~Foocllndwt.ry: VotuntvySodium. Rtduct.iont

Provision ofPoint..of.Pwdlastt Information Regarding Sodium Content

• &:onomie lneenlives • Te.chnolo gical.Advances • Leverage From Food Pl'o c:uremenl. 61\.d Assist«l.ce Program$ • RegulatoryOptlon• • Role ofConswneu

• I Monitori.ng and Swveilletlce I

RECOMMENDED ____., Next Steps and S1RATEOffiS Reuo.rch Need$

(Chapt.,.9) (Chapttr 10)

28

In order for the committee to achieve such goals and implement their approach, a lot of

data gathering and food supply data analysis will be necessary. Such a path needs continuous

monitoring of the effects of each stage. The committee then highlighted three major areas where

research would be required (Institute of Medicine, 2010). These areas include how salty taste

likings develop throughout an individual’s lifespan, how to reduce sodium content safely and

effectively, and what specific factors affect consumers’ awareness and behavior in relation to

sodium reduction.

29

Chapter III: Methodology

The sections to be addressed in this chapter include product manufacture, physical

properties, microbial analyses, sensory evaluation, and data analysis.

Product Manufacture

Frankfurter samples were created in ready-to-eat form by mixing 50% of (90% lean/10%

fat) fresh beef trim and 50% of (50/50) fresh beef trim acquired from the UW-Provision in

Middleton, WI. The meat was coarse ground using a meat grinder (Hobart Model 4732, Hobart

Corporation, Troy, OH) with a 4.76 mm (3/16”) plate and then separated into 18 batches. The

batches were made up of 11 lbs. of meat product each. The 18 batches were assigned at random

to six treatments (TRT 1, 2, 3, 4), a negative control (C-) and a positive control (C+), with three

replications per each treatment.

Frankfurter formulas are shown in Table 2. The positive control was comprised of the

following: 40.1% (90/10) beef, 40.1% (50/50) beef, 16.0% water and ice mix (50/50), 2.0% salt

from flake salt (2.5% of the meat block), 1.4% salt free seasoning*** (Product 6020023 V1,

[sugar and spice extractives], Saratoga Food Specialties, Bolingbrook, IL), 0.3% sodium

phosphates, 156 ppm curing salt (Product 0490000 Sure Cure – 6.25% sodium nitrite, [salt,

sodium nitrite, FD&C Red #3, sodium silica aluminate] Excalibur Seasoning Company, Pekin,

IL), and 547 ppm sodium erythorbate.

30

Table 2

Formulation of Frankfurters

Formulation C+ C- TRT-1 TRT-2 TRT-3 TRT-4

90/10 Beef Trim 40.1% 40.4% 39.0% 40.1% 39.9% 39.5%

50/50 Beef Trim 40.1% 40.4% 39.0% 40.1% 39.9% 39.5%

Water/Ice (50/50 mix) 16.0% 16.2% 15.6% 16.1% 16.1% 15.8%

Salt (NaCl) 2.0% 1.4% 1.0% 1.4% 1.1% 0.8%

SoMinus PCM - - 3.9% - - -

KaliSel KCl - - - 0.6% 0.3% -

NFE - - - - 1.3% 2.7%

Salt Free Seasoning*** 1.4% 1.4% 1.4% 1.4% 1.4% 1.4%

Sodium Phosphates 0.3% 0.3% 0.3% 0.3% 0.3% 0.3%

Sodium Erythorbate 547 ppm 547 ppm 547 ppm 547 ppm 547 ppm 547 ppm

Curing Salt (6.25% nitrite) 156 ppm 156 ppm 156 ppm 156 ppm 156 ppm 156 ppm

Totals 100% 100% 100% 100% 100% 100%

All treatments contained 1.4% salt free seasoning*** (Product 6020023 V1, [sugar and

spice extractives], Saratoga Food Specialties, Bolingbrook, IL), 0.3% sodium phosphates, 156

ppm curing salt (Product 0490000 Sure Cure – 6.25% sodium nitrite, [salt, sodium nitrite, FD&C

Red #3, sodium silica aluminate] Excalibur Seasoning Company, Pekin, IL), and 547 ppm

sodium erythorbate. The negative control (C-) was a 30% salt reduction, with 40.4% (90/10)

beef, 40.4% (50/50) beef, 16.2% water and ice mix (50/50) and 1.4% salt from flake salt; TRT-1

was a 30% salt reduction, with 39.0% (90/10) beef, 39.0% (50/50) beef, 15.6% water and ice

31

mix (50/50), 1.0% flake salt and 3.9% SoMinus PCM (10% NaCl and 90% others including

potassium chloride, potassium citrate, and natural flavoring) from Van Hees Inc. (Cary, NC);

TRT-2 was a 30% salt reduction, with 40.1% (90/10) beef, 40.1% (50/50) beef, 16.1% water and

ice mix (50/50), 1.4% flake salt and 0.6% KaliSel KCl (99.1% KCl) from (Morton Salt Inc.,

Chicago, IL); TRT-3 was a 30% salt reduction, with 39.9% (90/10) beef, 39.9% (50/50) beef,

15.9% water and ice mix (50/50), 1.1% flake salt, 1.3% salt from NFE modified soy sauce

(22.5% NaCl, Kikkoman USA, Walworth, WI) and 0.3% KaliSel KCl; TRT-4 was a 30% salt

reduction, with 39.5% (90/10) beef, 39.5% (50/50) beef, 15.8% water and ice mix (50/50), 0.8%

flake salt and 2.7% salt from NFE (22.5% NaCl, Kikkoman USA, Walworth, WI).

Figure 3. Sodium chloride reduction using SoMinus PCM, Potassium Chloride and Natural

Flavor Enhancer.

Emulsions were produced using techniques described by Rust (1987). The emulsified

frankfurters were manufactured using a bowl chopper (Krämer & Grebe 67-225, Krämer &

Grebe GmbH & Co. KG., Biendenkopf-Wallau, Germany). The coarse ground beef (90/10) was

100% NaCl

70% NaCl

50% NaCl

70% NaCl 55%

NaCl 40% NaCl

20% NaCl from

SoMinus PCM

30% KCl

15% NaCl from

NFE 30%

NaCl from NFE

30% SoMinus PCM 15%

KCl

C+ C- TRT-1 TRT-2 TRT-3 TRT-4

32

chopped with all ingredients added (except for salt free seasoning), and half of the water/ice mix

until a temperature of 2.2°C was achieved. The ground beef (50/50), salt free seasoning and

remainder of the water/ice were added and the bowl chopper was scraped to ensure complete

mixing and chopping. The mixture was chopped until a temperature of 21.1°C was achieved.

After the completion of chopping, the emulsion was transferred to a rotary-vane vacuum filler

with a linking attachment (Handtmann VF 608 Plus vacuum filler, Handtmann CNC

Technologies Inc., Buffalo Grove, IL) and stuffed into 27 mm cellulose casings (Viscofan USA

Inc., Montgomery, AL) with 80 grams per link.

All treatments were hung on smokehouse sticks, placed on a smokehouse truck and

showered with cold water prior to the onset of cooking. Cooking was accomplished in a single

truck smokehouse (Alkar Model 450 MiniSmoker, Alkar Engineering Corp., Lodi, WI) using a

standard frankfurter smokehouse schedule with the target internal temperature of 71.1°C. After

the completion of thermal processing, the frankfurters were immediately chilled until the internal

temperatures were below 4.4°C. Thermal processing and cooling data was recorded using a data

logger (TempTale®4, Sensitech, Beverly, MA, U.S.A.). After cooling, the cellulose casings

were removed and frankfurters were placed in barrier bags (Flavorseal Vacuum Pouch, Carroll

Manufacturing and Sales, Avon, OH) for vacuum packaging (Ultravac 2100-C Vacuum

Packager, Koch Equipment, Kansas City, MO). Samples were stored at 2°C until further

analysis.

Physical Properties

Cook yield measurements. Cooking yields were determined for the frankfurters by

taking a raw weight of the whole batch prior to thermal processing and reweighing the product

33

after thermal processing and cooling. Cook yield was determined by the following equation:

(McGough et al., 2012): Cook yield = (cooled weight / raw weight) x 100

PH measurements. PH levels were measured using methods described by Sebranek et

al. (2001). The pH samples were blended in a 1:9 ratio of sample to distilled, de-ionized water

(DDW) and were homogenized with a Polytron Mixer (P10-35GTT, Dispersing Aggregate PTA-

20/2W, Kinematica, AG, Lucerne, Switerzland) at setting 7 for 45 seconds. Whatman #1 filter

paper was folded and pushed into the 150 ml beaker slurry to allow the fat free solution to come

through the paper. The tip of the electrode was placed into the solution and pH was measured

with a pH meter (Accumet Basic AB15 Plus pH Meter, Fisher Scientific, Fair Lawn, NJ.)

equipped with an electrode (Accument combination pH electrode with Ag/AgCl reference Model

13-620-285, Fisher Scientific, Fair Lawn, NJ) calibrated with 4.00 and 7.00 phosphate buffers

(Testo 206, Testo AG, Lenzkirch, Germany). Measurements were made in triplicates per

replication per treatment.

Instrumental color measurements. Color was measured using a Minolta Chromameter

(Model CR-300, Minolta Camera Co., Ltd., Osaka, Japan; 1 cm aperture, illuminant C, 2°

observer angle). The Minolta Chromameter was standardized by placing the same vacuum

packaging bags that were used to package the frankfurters over the white standardization tile.

Values for the white standard tile were L* = 97.06, a* = -0.14, b* = 1.93

(Y = 93.7, x = 0.3163, and y = 0.3324).

Commission Internationale de l’Eclairage (CIE) L* (lightness), a* (redness) and b*

(yellowness) internal color measurements were taken 24 hours after manufacture. Frankfurters

were sliced lengthwise and placed into vacuum bags and measurements were taken immediately

34

after the frankfurters were sliced. Measurements for the interior color were taken at two

randomly selected locations on each of the samples (McGough et al., 2012).

Texture profile analysis. The texture profile analysis was conducted using methods

described by Wenther (2003) and Bourne (1978). The TA-HDi Texture Analyzer (Texture

Technologies Corp., Scarsdale, NY) equipped with a 25 mm diameter cylinder (TA-25) was used

to determine the texture profile analysis of samples by a two-compression test. The TA-HDi

Texture Analyzer was calibrated with a 10 kg weight and Texture Expert software was used. A

texture profile analysis was conducted on frankfurter samples 24 hours post manufacture using a

core of frankfurter (1.6 cm diameter, 1.9 cm high). The test was performed at 3.3 mm/second for

both a two-cycle 50% compression and a two-cycle 72% compression. One measurement was

taken per core, with two cores taken from four links per replication in each treatment, resulting in

24 measurements for both compression sets. The following equations were used for textural

measurements:

Hardness = the peak force during the first compression (72% compression)

Springiness = the height the sample recovered during the time that elapses

between the end of the first bite and start of the second bite (50% compression)

Cohesiveness = the ratio of the positive force area during the second compression

(50%) to that during the first compression (50%), calculated as:

((Area 2/Area 1) x 100)

Chewiness = the product of (hardness x cohesiveness x springiness)

Microbial Analysis (Total Plate Count)

Total plate counts of each of the samples were completed using the AOAC Official

Method 990.12. Each sample was diluted to five different dilutions and then analyzed in

35

triplicates. The entire analysis was done in a laminar air flow chamber. Frankfurters samples

were ground using the stomacher, and different dilutions were created (10-1, 10-2, 10-3, 10-4 and

10-5) using a buffer solution. The diluted samples were then transferred to petrifilms (3M Co.,

St. Paul, MN) and incubated for 24 hours at 37 ºC. The colony forming units CFUs were

counted using a colony count meter.

Sensory Analysis

The sensory analysis was done through a total of 100 panelists at the University of

Wisconsin-Stout Sensory Analysis Laboratory (Menomonie, WI) over two days (four hours per

day; three treatments per day) to collect data from a minimum of 100 panelists per treatment.

The panelists were comprised mostly of students enrolled in the food science program, faculty,

and staff. Panelists were asked to evaluate four textural properties: salt intensity, meat flavor

intensity, hardness, juiciness, and the overall desirability of each sample tasted. Demographic

questions were also asked regarding gender, intent to purchase each sample, and the average

frequency of frankfurter consumption.

The samples were heated in crockpots for 1 hour at high temperature (80 ºC) and then

kept at (60 ºC) throughout the sensory time. Frankfurters were then cut into 7 mm pieces with

the ends being discarded and then placed into pre-labeled sample dish as panelists were arriving.

Each panelist was given three samples in an individual booth under incandescent lighting and

DDW to cleanse the palate between samples. Samples were coded with a random three digit

number and presented in random order. All the textural properties were scored on a seven point

hedonic scale where one being very low, four being moderate, and seven being very high. Data

was collected by using a computerized sensory scoring system (COMPUSENSE five, v 4.4,

Compusense, Inc., Guelph, Ontario, Canada).

36

Data Analysis

The experimental design was a randomized complete block using a mixed effects model.

Statistical analysis was performed for all measurements using the Statistical Analysis System

(version 9.3, SAS Institute Inc., Cary, NC) Mixed Model procedure (SAS Inst. 2003). The

model included the fixed main effects of treatment (TRTs 1-4, C- and C+) and replication (n=3)

resulting in 18 observations. All least significant differences were found using the Tukey-

Kramer pairwise comparison method. Significance levels were determined at P < 0.05.

37

Chapter IV: Results and Discussion

Different salt replacers were investigated as a means to substitute and reduce sodium

chloride in frankfurters. The following sections will address the results obtained with specific

information on cook yield, pH measurements, instrumental color measurements, texture profile

analysis data, microbiological data (total plate count), and sensory evaluation.

Cook Yield Measurements

Cook yields of frankfurter samples using different salt substitutes are shown in Table 3.

The cook yield values were not significantly different (P > 0.05) between TRTs, C- (negative

control), and C+ (positive control). This indicated that a 30% sodium reduction using SoMinus

PCm, KCl and NFE did not affect or reduce the emulsion formation and water holding capacity

of frankfurters and were comparable to the 100% sodium chloride formula (C+). A research

conducted by Sofos (1983) determined that frankfurters formulated with 2.5% NaCl produced

stable emulsions with high cook yields. Likewise, Matulis, McKeith, Sutherland, and Brewer

(1995) found that lowering salt levels to less than 1.3% in frankfurters resulted in incomplete

protein extraction and allowed water to escape. It can be concluded that a salt contents between

1.3% and 2.5% would not greatly affect the protein extraction. In this experiment all treatments

(30% sodium reduction), other than C+, had 1.4% salt contents. Protein extraction with the use

of salt is important in the meat industry to obtain desirable textural properties. Salt changes the

ionic strength and allows the proteins to be exposed within a meat batter. The hydrophilic ends

of the protein bind to water, whereas the hydrophobic ends of the protein bind with fat stabilizing

an emulsion (Herrero et al., 2008).

38

PH Measurements

The pH values for the frankfurters made with the varying treatments are shown in Table

3. TRT-1 had significantly (P < 0.05) higher pH than all TRTs which may be attributed to the

presence of potassium citrate, usually used as a buffering agent in foods. TRT-3 and TRT-4

containing NFE had the lowest pH values, and were even lower than C+, which concurs with

McGough et al. (2011). Their results revealed a negative correlation between pH and NFE

amounts. The pH values decreased alongside an increase of NFE. Such a trend is consistent

with the expected results, as the pH of the NFE used during the experiment had a low pH value

of 5.30. The pH values 24 hours and four months after manufacture were not significantly

different (P>0.05) for each of the TRTs. The pH mean values of the raw beef 90/10 and 50/50

trimmings were 5.84 and 5.80, respectively, which is within the ideal range of pH (5.6-6.0) for

products where good water binding is required (FAO, 2007). For that reason a relatively high

pH is desired in lean meat as it provides a better water holding capacity (FAO, 2007). The

water-holding capacity is the lowest at the isoelectric point, where the number of positively and

negatively charged groups of the myofibrillar proteins is equal. Thus, the charges cancel out and

no charge is available to hold water (Gault, 1985). The inclusion of phosphates (pH>7.0) in all

treatments helped increase the water-holding capacity by raising the pH (FAO, 2007). On the

other hand, salt increased the product’s water-holding capacity by shifting the isoelectric point

(IEP) to a lower pH (Gault, 1985). Thus, the differences on moisture content values between

treatments could be attributed to what extent each of the salt substitutes has played this IEP

shifting role in the formulations.

39

Table 3

Mean Values for Cooking Yield, PH 24 Hours After Manufacture and PH Four Months After for

Emulsified Frankfurters

TRTs Cooking Yield % pH 24Hrs after manufacture pH 4 months after

manufacture

C+ 89.48a 6.22cd 6.20cd

C- 88.09a 6.28b 6.28b

1 88.82a 6.35a 6.35a

2 88.58a 6.24c 6.24bc

3 88.57a 6.21d 6.21cd

4 88.88a 6.18e 6.18d

C-: negative control; C+: positive control; 1: SoMinus PCM; 2: KCl; 3: KCl+NFE; 4: NFE

Values with different letters within the same column are significantly different (p≤0.05)

Instrumental Color Measurements

Internal color measurements were conducted and the least square means are displayed in

Table 4. Internal color values for CIE L, a*, and b* were affected by different sodium chloride

substitutes in frankfurters. L* values were grouped into three significantly (P < 0.05) different

sets. However, the L* means’ values were comparable and ranged between 64.6 (C-, the darkest

internal color) and 65.8 (TRT-2, the lightest). Internal a* values were not significantly different

(P > 0.05), signifying that NaCl’s substitutes did not affect the internal redness of frankfurters.

Internal b* values were significantly (P < 0.05) higher for TRTs containing NFE compared to

other TRTs. This suggests yellowness values increase along with increasing NFE, which was

yellow in color to begin with, as it contains a higher percentage of wheat than soybeans, which

gives it a lighter color than soy sauce (Sato et al., 2010). These results concur with McGough

40

et al. (2011), which NaCl substitutes affected the internal color L* and b* values, while a*

values remained unchanged between all TRTs.

Table 4

Mean Values for Objective Internal Color Measurements in Emulsified Frankfurters

TRTs L* a* b*

C+

C-

1

2

3

4

64.95ab

64.57b

65.35ab

65.82a

65.76a

64.70ab

16.85a

17.03a

16.88a

16.93a

16.70a

16.66a

9.18c

9.25c

9.15c

9.52bc

9.90b

10.59a



Texture Profile Analysis

Table 5 shows the means for the texture profile analysis (TPA). No significant

differences were observed between all TRTs in terms of hardness of the samples. The hardness

values ranged from 92 Newton to 94.9 N. The negative control (C-) was the most cohesive

(P<0.05) followed by TRTs 2, 3 and 4. However, despite the absence of statistical differences

between TRTs 3 and 4, TRT-4 showed a slightly lower cohesiveness than TRT-3, which concurs

with McGough et al. (2011) who observed that cohesiveness decreased as a result of increasing

NFE contents. The C- displayed the highest (P<0.05) springiness value (11.22 mm), while TRT-

4 showed the lowest (P<0.05) value (10.97 mm). It might be concluded that springiness

decreased accordingly with increasing NFE content as obtained by McGough et al. (2011). The

41

TPA also revealed that all TRTs were significantly (P < 0.05) chewier than C+. Despite TRT-3

not being significantly different from TRT-4, its chewiness value (619.66 N*mm) is slightly

higher than TRT-4 (613.35 N*mm). This result concurs with McGough et al. (2011) who

observed that chewiness decreased with increasing NFE amounts. However, McGough et al.

(2011) utilized varying levels of a liquid natural flavor enhancer (NFE) and flake salt in the

manufacture of emulsified frankfurters (manufactured with 90% lean fresh beef knuckles and

42% lean pork trimmings), while in our study we used a 70% salt with varying levels of

substitutes in all-beef frankfurters.

Overall, although NaCl substitutes clearly affected the cohesiveness, springiness, and

chewiness of frankfurters, the values were comparable. The hardness was the same for all TRTs.

Table 5

Mean Values for Hardness, Cohesiveness, Springiness, and Chewiness of Emulsified

Frankfurters

TRTs Hardness (N) Cohesiveness (%) Springiness (mm) Chewiness (N*mm)

C+

C-

1

2

3

4

92.0a

92.3a

94.7a

95.7a

92.9a

94.9a

58.5b

60.0a

58.5b

59.5ab

59.9ab

59.2ab

11.15ab

11.22a

11.16ab

11.19a

11.13ab

10.97b

600.15b

620.19ab

614.30ab

640.67a

619.66ab

613.35ab



42

Microbial Analysis (Total Plate Count)

Total plate count (TPC) numbers for the different frankfurter treatments are shown in

Table 6. The positive control, as expected, showed the lowest value (133 CFUs/g), yet was not

significantly different from TRT-1(467 CFUs/g), TRT-2(667 CFUs/g), TRT-3 (200 CFUs/g),

and TRT-4 (333 CFUs/g). They all expressed less than 1000CFUs/g which is below the

Recommended Microbiological Norm (104 CFUs/g) in processed ready-to-eat meats (Food

Administration Manual, 1995). The combination of KCl with NFE in TRT-3 had a very similar

antimicrobial effect to C+. TRT-2 containing 30% KCl was in the lower end of the antimicrobial

effect which concurs with Terrell et al. (1983) who observed that a replacement of salt (2.5%) in

ground pork with KCl or CaCl did not influence growth of the spoilage organisms Micrococcus

or Moraxella and only slightly increased Lactobacillus counts in refrigerated conditions. On the

other hand, the negative control showed the highest value (1933 CFUs/g) (P<0.05) compared to

all the other TRTs. Such a trend was expected as the C- would have a higher water activity and

thus a higher microbial growth. Bidlas & Lambert (2008) led a study using a small range of

pathogenic bacterial species (Aeromonas hydrophila, Enterobacter sakazakii, Shigella flexneri,

Yersinia enterocolitica and 3 strains of Staphylococcus aureus). They found that potassium

chloride has an equivalent antimicrobial effect on these organisms when calculated on a molar

basis, which might explain the low CFUs in TRTs 1, 2 and 3. Also, Lee, Cesario, Owens,

Shanbrom & Thrupp (2002) evaluated citrate salt for antibacterial activity against a sample of

common pathogens. Their study showed that citrate salt actively reduced gram-positive species

and Candida albicans. These results concur with the low CFUs in TRT-1 containing potassium

citrate along with KCl. On the other hand, while no studies have been conducted on the

antibacterial effects of NFE, Kataoka (2005) mentioned in a review paper that soy sauce

43

possesses antimicrobial activity against bacteria such as Staphylococcus aureus, Shigella

flexneri, Vibrio cholera, Salmonella enteritidis, and pathogenic E. coli O157:H7.

Table 6

Total Plate Count Numbers for the Different Frankfurter Treatments



Sensory Analysis

The sensory analysis results are presented in Tables 7 and 8. For salt intensity using a 7-

point hedonic scale (1=none, 3=moderate, and 7=very strong) with consumer panelists, all TRTs

were significantly perceived as less salty (2.85-3.87) than the positive control (C+, 4.53) at

P<0.05 (Table 7). Among the treatment samples, TRT-2 (KCl) was the highest saltiness (3.87),

which was better than the negative control and TRT-4 (NFE) was the lowest saltiness (2.85).

These results coincided with the preference of saltiness using a 9-point hedonic scale (1=dislike

extremely, 5=neither like or dislike, 9=like extremely) (Table 8). Consumer’s first preference of

saltiness was the positive control sample (6.03) and second was TRT-2 (KCl, 5.83), which was

similar trend with salt intensity. These results indicated that TRT-2 (NaCl:KCl=7:3) formulation

TRTs CFUs/g

C- 1933a

C+ 133b

1 467b

2 667b

3 200b

4 333b

44

was optimal sodium reduction formula to keep similar salt intensity with 100% sodium chloride

formula.

In terms of meat flavor, the C+ and TRT-2 scored greater (P<0.05) than all other TRTs.

It was noted that TRT-1 scored the lowest for meat flavor intensity (3.88). Conversely, TRT-4

meat flavor intensity was the least liked (4.37), while TRT-1 scored the same as TRT-3 (5.31 and

5.27, respectively) and yet was less than C+ and TRT-2.

Further, all TRTs were perceived as being moderately hard in texture (P>0.05), with C+

slightly harder (4.33) (P<0.05). The panelists also equally liked the hardness level (5.59-5.89),

only except TRT-4 (5.16). For the juiciness attribute, C+, TRTs 2, and 3 were perceived as

moderately juicy, yet juicier (P<0.05) than TRT-1, TRT-4 and C- in the order given. The

panelists preferred all TRTs for their juiciness over TRT-4’s, which was neither liked nor

disliked as evident by the rating of 4.76.

The overall liking of the samples was affected by the salt substitute used. Based on this

panel, the C+ (positive control) and TRT-2 (KCl) were liked the most, having overall liking

ratings of 4.76 and 4.91, respectively (P<0.05), followed by the negative control (4.52). Both

TRT-1 and TRT-3 were neither liked nor disliked as evidenced by the ratings of 4.04 and 4.15.

However, TRT-4, containing NFE, was disliked by the panelists (3.42), in disagreement with

McGough et al. (2011) who observed that all treatments containing NFE were liked more than

the control.

The panelists did not show a clear intention in buying any of the products. TRTs 1 and 4

were the least probable to be purchased based on this panel. This tendency might be explained

by the panelists’ low consumption of frankfurters as 55% of them consume frankfurters

occasionally (Figure 4). Also, 75% of the panelists were females and 25% males. Bartoshuk,

45

Duffy, and Miller (1995) led a study on the anatomy, psychophysics, and gender effects on

tastes’ perception. They concluded that women are often supertasters, which they supported

with anatomical data; women have more fungiform papillae and more taste buds. These findings

could explain the divergences between our results and other studies such as McGough et al.

(2011). McGough et al. (2011) concluded that NFE has the ability to increase consumer sensory

overall liking, salty taste perception, and overall taste intensity based on a panel of 52% males

and 48% females. However in this study, NFE containing TRT-4 scored the lowest for most of

the attributes and was the least probable to be purchased, while the panelists’ first preference of

saltiness was C+ (6.03) followed by TRT-2 (KCl, 5.83).

Table 7

Mean Ratings for Sensory Attributes of Emulsified Frankfurters Using a 7-Point Hedonic Scale

(1=None, 3=Moderate, 7=Very Strong) with Consumer Panelists

TRTs Salt Intensity Meat Flavor Hardness Juiciness

C+

C-

1

2

3

4

4.53a

3.23c

3.11c

3.87b

3.62b

2.85c

4.43a

4.23b

3.88c

4.41a

4.03c

4.21b

4.33a

4.00b

4.28b

4.28b

4.21b

4.08b

4.08a

3.64b

3.18b

4.18a

3.98a

3.13b



46

Table 8

Mean Ratings for Consumers’ Liking and Intent to Purchase Using a 9-Point Hedonic Scale

(1=Dislike Extremely, 5=Neither Like Or Dislike, 9=Like Very Much) for Emulsified

Frankfurters

TRTs Salt Intensity

Liking

Meat Flavor

Liking

Hardness

Liking

Juiciness

Liking

Overall

Liking

Intent to

Purchase

C+

C-

1

2

3

4

6.03a

5.68b

5.02c

5.83a

5.62b

4.72c

5.93a

5.80a

5.31b

5.99a

5.27b

4.37c

5.89a

5.73a

5.59ab

5.84a

5.74a

5.16b

5.75a

5.69a

4.80c

5.75a

5.46b

4.76b

4.76a

4.52ab

4.04b

4.91a

4.15b

3.42c

3.37a

3.02ab

2.55c

3.32a

2.90b

2.38c



Figure 4. Panelists’ consumption frequency of frankfurters.

Never 11%

Occasionally 55%

Monthly 26%

Weekly 7%

Daily 1%

47

Chapter V: Conclusions

The industrial application of any salt replacer in order to reduce sodium in emulsified

frankfurters must take into consideration potential textural effects and color impacts. However,

only a few quality differences existed from NaCl reduction. The cook yield values were not

significantly different between all treatments (TRTs) including two controls, positive (C+) and

negative control (C-). This indicate that a 30% sodium reduction using SoMinus PCm, KCl and

NFE did not affect or reduce the emulsion formation and water holding capacity of frankfurters

and were comparable to the 100% sodium chloride formula (C+). TRT-1 had significantly

higher pH than all TRTs, which may be attributed to the presence of potassium citrate, usually

used as a buffering agent in foods. TRT-3 and TRT-4 containing NFE had the lowest pH values,

and were even lower than C+. Among internal color values (CIE L, a*, and b*), b* values were

significantly higher for TRTs containing NFE compared to other TRTs. This suggests

yellowness values increase along with increasing NFE, which was yellow in color to begin with,

as it contains a higher percentage of wheat than soybeans, which gives it a lighter color than soy

sauce. No significant differences were observed between all TRTs in terms of hardness in the

frankfuter samples. Springiness and chewiness value were significantly decreased accordingly

with increasing NFE contents.

Total plate count (TPC) numbers for the different frankfurter treatments expressed less

than 1000 CFUs/g, which is below the Recommended Microbiological Norm (104 CFUs/g) in

processed ready-to-eat meats. The combination of KCl with NFE in TRT-3 had a very similar

antimicrobial effect to C+. TRT-2 containing 30% KCl was in the lower end of the antimicrobial

effect. On the other hand, the negative control (C-) showed the highest value (1933 CFUs/g)

compared to all the other TRTs.

48

In the sensory analysis results, although all TRTs were significantly perceived as less salt

intensity and saltiness preference than the positive control, TRT-2 (KCl) was the highest

saltiness and preference among TRTs. These results indicated that TRT-2 (NaCl:KCl=7:3)

formulation was optimal sodium reduction formula to keep similar salt intensity with 100%

sodium chloride formula. In terms of meat flavor, the C+ and TRT-2 (KCl) scored greater than

all other TRTs. Further, C+ and TRT-2 (KCl) were perceived as being moderately hardness and

juiciness in texture and the panelists also equally liked the hardness and juiciness level following

by those intensities, only except TRT-4 (NFE). The overall liking and intent to purchase of the

samples was affected by the salt substitute used. The C+ (positive control) and TRT-2 (KCl)

were liked the most, but TRT-4 (NFE) was disliked the most by the panelists. In the conclusion,

30% sodium reduction in frankfurters can be achieved by using sodium substitutes without

significantly impacting the quality and sensory characteristics of the final product.

Recommendations

Further studies are needed in order to test other combinations of Na/NaCl reduction, NFE

usage, and other salt reduction systems to provide a reduced Na/NaCl product with desirable

sensory and quality attributes. Future research should also be completed to determine the effect

of Na/NaCl reduction on the growth of specific organisms. Likewise, more experimentation

should include a wider subset of processed meat products.

49

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