Unit 4 Microbes used in food industry - PSRU

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Food Microbiology_Katekan Dajanta 1

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Microbes used in food industry

Nature uses microorganisms to carry out fermentation processes, and for thousands of years

Fermentation in food processing is the conversion of carbohydrates to alcohols and carbon dioxide or organic acids using yeast bacteria or a combination under aerobic or using yeast, bacteria, or a combination under aerobic or anaerobic conditions

Carbohydrates(sugar)

Alcohols + Organic acids + CO2

microbes

aerobic/anaerobic

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Microflora in fermented foods

Bacteriao Lactic acid bacteria : Leuconostoc mesenteroides, Lactobacillus

brevis, Pediococcus and Streptococcus sp.o Other bacteria : Bacillus, Acetobacter

Mould o Aspergillus, Rhizopus, Mucor, Actinomucor, Amylomyces, Neurospora

and Monascus

Yeast o Saccharomyces

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Benefits of fermentation

Preservation of food: some microbes could be produced antimicrobial substances (organic acid, ethanol, bacteriocin) against spoilage and pathogenic microorganisms

Fermentation to peel seed coat (eg. cocoa, coffee, pepper) with natural microorganisms (lactic acid bacteria, acetic acid bacteria and yeast)

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Benefits of fermentation

Biological enrichment:

o Probiotic bacteria/lactic bacteria

o Essential amino acids, vitamins, essential fatty acidsy

Enrichment of the diet through development of a diversity of flavors, aromas, and textures in food substrates into new product

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Fermentation

http://academic.pgcc.edu/~kroberts/Lecture/Chapter%205/fermentation.html6

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Type of fermentation

Alcohol fermentation

Acetic acid fermentation

Lactic acid fermentationLactic acid fermentation

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8 http://www.uic.edu/classes/bios/bios100/lectures/respiration.htm


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Acetic fermentation

Alcohol + O2 + Acetobacter spp. acetic acid + H2Oacetification

orGluconobacter

10 http://www.uic.edu/classes/bios/bios100/lectures/respiration.htm

Lactic acid fermentation

11ที่มา : http://porpax.bio.miami.edu/~cmallery/150/makeatp/c8.9x18b.lactic.acid.jpg

Lactic acid fermentation

Homofermenterso 85-90% of sugar were converted into lactic acid eg. Streptococcus faecalis,

Pediococcus cerevisiae

Heterofermenterso 50% of sugar were converted into lactic acid, 25% were converted into

d d h l d 2 % d COacetic acid and ethanol, and 25% were converted into CO2

o Leuconostoc mesenteroides, Leu. fermenti, Lactobacilli

o Foods : Yoghurt, fermented milk, cheese, fermented meat and vegetable

Facultative heterofermenterso Some species of Lactobacillus could display both of homo- and

heterofermenters

o Lb. plantalum, Lb. casei and Lb. sake

o Food: wine12

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Ferment-inhibiting substances Production of organic acids and decreasing of pH

Bacteriocins against other relative bacteria

o nisin (Lactococcus lactis)

Hydrogen peroxide (H2O2) Hydrogen peroxide (H2O2)o Aerobic fermentation: LAB produce H2O2 as electron acceptoro Anaerobic fermentation: small content of H2O2 were produced

by LABo Raw milk: H2O2 act as co-factor in Lactoperoxidase system

(lactoperoxidase+ H2O2 + thiocyanate)

Ethanol in the heterofermenter at anaerobic condition

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Pickled fruits and vegetables

LAB change sugar in fruit and vegetable to lactic acid

Microbes involved in the fermentation process: Lactobacteriaceae (Streptococcus, Pediococcus, Diplococcus, Leuconostoc and Lactobacillus)

Fermentation :o First stage of fermentation: LAB produce organic

acidso Last stage of fermentation: aciduric yeasts

and moulds

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Pickled fruits and vegetables

Change in appearance, texture, flavor, taste

Factors affecting the quality of pickled fruits and vegetableo pHo Oxygeno Fermenting temperatureo Salt concentrationo Starter microorganisms

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Kimchi

Kimchi is a traditional fermented Korean side dish made of vegetables with a variety of seasoning

Use different vegetable eg. cabbage, radish, cucumber, scallion

• Microbes involved in the fermentation process:

o Leuconostoc sp. : Leu. mesenteroides, Leu. kimchi

o Lactobacillus : Lb. plantarum, Lb. brevis

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Change in LAB in fermented kimchi

Leu. mesenteroides + vegetable + brine + ingredients(Facultative anaerobic condition)

lactic acid + acetic acid + CO2 + ethanol (pH = 4.6-4.9)

Growth of Lb. plantarum, Pediococcus cerevisiae,

Lb. brevis, Lb. fermentum

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Sauerkraut

Sauerkraut = sour cabbage

Finely cut cabbage fermented by various LAB: Leuconostoc, Lactobacillus, Pediococcus

Salt plays an important role in initiating the sauerkraut p y p gprocess and affects the quality of the final producto withdraw juice from the cabbage o Adjust anaerobic conditiono Inhibit undesired microorganismso making a more favourable environment for development of the

desired bacteriao contribute to the firmness

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Microbes involved in the fermentation process of Sauerkraut

Anaerobic LAB o Production of lactic acid, acetic acid, formic acid,

succinic acid causing pH to decrease and inhibited spoilage aerobic bacteriaspoilage aerobic bacteria

Facultative anaerobic LAB Leu. Mesenteroides grow rapidly at low pH value,

produce large contents of lactic and acetic acids

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Microbes involved in the fermentation process of Sauerkraut

Homofermentative lactobacilliGrowing of Lactobacilli (Lb. plantarum, Lb. sakei, Lb.

curvatus) and cocci (streptococci and pediococci) Converting of sugar (glucose, fructose, sucrose) into Converting of sugar (glucose, fructose, sucrose) into

lactic acid

Heterofermentative lactobacilli the last stage of sauerkraut fermentation ferment pentose sugar (arabinose, xylose)

into lactic acid

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Wine

Wine is an alcoholic beverage made from fermented

grapes or other fruits

Production process:

Grape (crushing) + S. cerevisiae alcohol fermentationp ( g) f

Packaging aging/maturation malolactic fermentation(clarification)

(sugar) Bacterial fermentation

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Wine

Source of fermenting microbials:o Starter: usually use S. cerevisiaeo Grape : yeast, mould, LAB, AABo Equipment

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Malolactic fermentation

L-malic acid L-lactic acidLeuconostoc oenos fermentation

Decaboxylationecabo y at o

CO2

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Vinegar

Vinegar is a liquid consisting mainly of acetic acid and water

The acetic acid is produced by the

fermentation of ethanol b acetic acid fermentation of ethanol by acetic acid

bacteria

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Vinegar: 2 step of fermentation

acetic acid bacteria (Aectobacterspp., Gluconobacter, A. pasteurianus)

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Acetification

Alcohol + Acetobacter spp. aldehydes

Alcohol dehydrogenase

Acetic acid

Aldehydedehydrogenase

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Miso (Japanese)

Also called Chiang (Chinese), Jang (Korean)

Various types

rice miso barley miso soybean miso

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Miso fermentation

Polished rice

Soaked

Cooked

IncubatedK

oji m

akin

g p

roce

ss

Seed mold

Whole soybean

Soaked

Cooked

Salt

Aspergillus oryzae

Koji

KB

rine

ferm

enta

tion

pro

cess

YeastLactic acid bacteria

Mixed

Fermented

Aged

Mashed

Miso

Saccharomyces rouxii, Zygosaccharomyces spp.

Lb. acidophilus, Lb. delbrueckii, Pediococcus

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Koji

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Tempeh Tempeh is a fungal fermented soybean

food originating from Indonesia The fungal enzyme activity causes

significant decomposition of polymeric components, as well as a

id bl difi ti f b considerable modification of soybean flavonoids.

Usually used Rhizopus oligosporus, other such as R. oryzae, R. stolonifer

Tempeh offers a number of proven health benefits including excellent digestibility and protection against diarrhea and chronic degenerative diseases.

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Tempeh

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Tempeh

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Potential Strains Selected for Improvement of Active Substances in Tempeh fermentation

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Sufu

Su-fu (Chinese cheese) or tao-hu-yi in Thailand

Sufu originated in China but is also prepared in other Asian countries where variations of sufu exist.

Sufu is consumed as an appetizer and a side dish, e.g. with breakfast rice or steamed-bread.

Sufu is a highly flavoured, creamy cheese-like product, so it would be expected to be suitable for use in western countries as a healthy, non-cholesterol food from plant origin.36

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Sufu Most sufu products are produced by a similar principle, which involves four main steps:(1) Preparation of tofu(2) Preparation of pehtze(3) Salting ( ) g(4) Ripening

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Sufu

According to the colour and flavour, sufu can be classified into four types

Red sufu -mainly consists of salt, angkak (Monascus-fermented rice), alcoholic beverage, sugar, flour (or soybean) paste and some spices.

White sufu - similar ingredients as red sufu in the dressing mixture but without angkak

Grey sufu - contains the soy whey left over from making tofu, salt and some spices.

Other types - made by adding various ingredients to the dressing, including vegetables, rice, bacon, and even higher concentrations of alcohol

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Sufu

According to fermenting microbes, sufu can be classified into four types:

1) Mould-fermented sufu – used Mucor racemosus, M. hiemalis and Actimomucor elegans in the pizi production

2) Naturally fermented sufu - used natural microbes in the piziproduction

3) Bacteria-fermented sufu – inoculated bacteria eg. Bacillus sp. or Micrococcus sp. into maturation process

4) Enzymatically ripened sufu

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Thua Nao/Natto Thua Nao (Thai)/Natto (Japanese) are

Bacillus-fermented soybean

Bacillus subtilis and related bacilli (i.e., B. licheniformis and B. pumilus) are usually found to be dominant microflora of the found to be dominant microflora of the fermented soybeans

A major activity in the fermentation is the hydrolysis of proteins to peptides and amino acids which are responsible for the typical ‘umami’ taste in fermented soybeans

Thua Nao

Natto40

Traditional Natto Process

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Traditional Thua Nao Fermentation

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Thua Nao VS Natto Production

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Thua Nao

Thua Nao Kab Roasted Thua Nao Mer Steamed Thua Nao Mer

Nam Ngearw Curry Chilli paste

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Natto

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Natto Foods

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Thua Nao/Natto

The utilisation of soybean protein by bacteria leads to free amino acids formation

Typical characteristics of traditional fermented soybeans are distinct ammoniacal smell, brownish colour, palatable taste and seed covered

ith b t with mucous substance.

Isoflavones are phytoestrogens that are abundant in soy-fermented foods and have been related to several health benefits.

Pharmacological and antioxidant properties of soy isoflavones are involved in prevention of breast cancer, antihypertensive effect, reduced risk of cardiovascular diseases, improvement of bone health, reduced menopause symptoms, antimutagenic effects and antidiabeticeffects.47

Improvement of Thua Nao Production

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Starter culture/Thua Nao powder

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Fermented ground pork (Nham) Nham is an uncooked, fermented semi-dry Thai

sausage

It is made from fresh lean pork, pork skins, cooked rice, fresh garlic and eye bird chillies

The sausage is wrapped in banana leaves or g ppsynthetic casings and fermented for 3-5 days

Rice act as a source of carbohydrates for lactic acid production during fermentation

LAB fermentation :o early stage of fermentation usually found Pediococcus

cerevisiae, hetrofermentative LAB

o last stage - Lb. plantarum and Lb. brevis fermentation

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Improved Nham Fermentation

Pure starter culture for fermenting Nham : o Lb. plantarum

o Lb. curvatus

o Pediococcus pentosaceuso Pediococcus pentosaceus

o Ped. acidilactici

Mixed 3 microbes:o Lb. plantarum

o Pediococcus serevisiae

o Micrococcus varians

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Salami Salami is cured sausage, fermented and

air-dried meat

Ingredients included pork or meat, minced fat, red wine, garlic, spices

LAB fermentation LAB fermentation

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Fish sauce

Fish sauce is a clear, amber to reddish brown liquid with a predominantly salty taste and characteristic aroma.

It is obtained from the hydrolysis of fish with salt through natural fermentation for 6–12 months

Fish sauce is well recognized as a food flavoring by the people in Southeast Asia for many centuries.

Hydrolysis of fish protein results in small-molecule peptides, nitrogen compounds, and amino acids.

Fish sauce contains about 20 g/L of total nitrogen, of which 80% is in the form of amino acids.

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Local Names of Fish Sauce in Different Countries

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Fermented milk

Dairy starter cultures are microorganisms that are intentionally added to milk in order to create a desired outcome

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in the final product, most often through their growth and “fermentation” processes.

Fermented milk

Fermented milk products such as yogurt, kefir, buttermilk, and acidophilus milk are gaining increasing attention.

F d lk

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Fermented milks containing probiotics could be used to prevent and/or cure some important diseases (such as intestinal- and immune-associated diseases).

Fermented milk

The most common use of starter cultures is for the production of lactic acid from lactose (milk sugar), which in most cases causes or assists in the coagulation of milk protein by lowering its pH value.

C l h d l d ll f d

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Cultures that produce lactic acid are generally referred to as “lactic acid bacteria” (LAB) such as Lactobacillus, Lactococcus and Leuconostoc.

Milk + LAB Lactic acid + Acetic acid + CO2 + (lactose) Flavor compounds (diacetyl,

acetaldehyde)

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Fermented milk

The fermentation process increases the shelf-life of the product, while enhancing the taste and improving the digestibility of milk.

Starter organisms can also influence flavor and texture of cultured and/or aged products through the

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of cultured and/or aged products through the breakdown of proteins, fats and other milk constituents in addition to the pH effect.

The lower pH of cultured products can be inhibitory to certain spoilage organisms, although inhibition is also associated with other by-products of growth with some starters.

Fermented milk

Probiotic cultures are organisms that have some claimed health benefit for those that consume them, e.g., better digestion, anti-cancer compounds, and prevention of heart disease.

Probiotic cultures may be added as adjuncts or they may

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Probiotic cultures may be added as adjuncts or they may be directly involved in the fermentation process.

Lactic acid bacteria Lactic acid production: Streptococcus lactis, S. cremoris

and S. thermophilus

Flavour production : S. diacetilactis and Leuconostoccitrovorum

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Fermented milk usually use mixed starter culture

o Starter D: S. cremoris+ S. lactis +S. diacetilactis

o Starter DL: S. cremoris +S. lactis+ S. diacetilactis +Leuconostoccitrovorum

o Starter L: S. cremoris +S. lactis+ Lb. citrovorum

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Dairy Starter Cultures

Major Function Product UseMesophilic starters

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Dairy Starter Cultures

Major Function Product UseThermophilic starters

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Type of fermented milk

Mesophilic starter fermented milk

Butter milko Fermented pasteurized skim milk with mesophilic LAB

eg. Lactococcus and Leuconostoc at 19-22C for 15-20 h

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Sour creamo Fermented milk butter with Streptococcus and Leuconostoc at 20-

22C until pH decreased at 4.5

Fermented milko Langfilo Filmjolko Ymer

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Mesophilic and thermophilic starter fermented milk

Yoghurto Fermented milk with Strep. thermophilus (mesophilic) and

Lb. bulgaricus (thermophilic) (ratio 1:1)

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Yakulto Fermented skim milk with Lb. casei at 37C for 4 days

Bulgarian butter milko High acid fermented butter milk, fermented by 2% Lb. bulgaricus

at 38 – 42 C for 10-12 h


Mesophilic and thermophilic starter fermented milk

Acidophilus milk o Fermented sterilized milk with 2-5% Lb. acidophilus at 38C for

18-24 h

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Probiotic fermented milko Fermented milk with LAB (Lb. acidophilus, Lb. casei) and

probiotic (Bifidobacterium) acidophilus at 38C for 18-24 h


Alcohol-lactic fermentation

Kefir o Fermented milk with LAB (Lactococci, Leuconostoc, Lactobacilli)

and yeast (Candida, Kluyveromyces, Saccharomyces) at 20-25C and 8 10C

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8-10C

Kumisso Russian fermented milk, fermented with Lb. bulgaricus and

Candida kefir at 18-20C and 4-6C

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Health benefit microorganisms

Usually according “probiotic ” (meaning “for life)

Probiotics are live microorganisms, which when administered in adequate amounts, confer a health benefit on the host

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Prebiotic a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-being and health

Prebiotic = oligofructose, fructooligosaccharides, inulin and polyfructose

Probiotics

Lactobacillus species Bifidobacterium species Other

L. acidophilus B. bifidum Bacillus cereus

L. casei B. longum Eschericia coli

L. reuteri B. breve Saccharomycescerevisiae

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L. bulgaricus B. infantis Saccharomycesboulardii

L. plantarum B. lactis Enterococcus faecalis

L. johnsonii B. adolescentis Strep. thermophilus

L. lactis Trichuris suis

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Mechanisms of Action of Probiotics

Produce antimicrobial substances (organic acids or bacteriocins)

Upregulate immune response to possible pathogens or to vaccines

Downregulate inflammatory response

Assist in early programming of the immune system to result in a

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y p g g ybetter balanced immune response and reducing risk ofdevelopment of allergy

Improve gut mucosal barrier function

Enhance stability or promote recovery of commensal microbiota

Deliver functional proteins (eg, lactase) or enzymes

Decrease pathogen adhesion

Health benefits

Prevention and treatment of diarrhea

Treatment of chronic inflammatory bowel disease

Treatment of ischemic bowel disease and bacterial infections in children born prematurely

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The immune system of the body

Treatment of allergies

Prevention of colon cancer

Treatment of fungal vaginitis

Reduces blood cholesterol levels

Unit 4 Microbes used in food industry - PSRU

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