Food Chemistry

Lecture Notes – Introduction to food analysis Part 1

You are working in a food laboratory and have been given a series of samples including foods, beverages and ingredients. You are required to analyse the food components. So where do you start and what do you do?

The first question“What is the purpose of the analysis?” It is important to clarify this because the answer will affect the method we choose and the way we do an analysis.

Uses of dataIt is also important to recognize that the primary role of laboratory analytical data is invariably to allow someone to make a decision.

Reliability of dataIt follows then that a suitable level of reliability is needed if the correct decision is to be made. Another way to say this is that your boss or the person making a decision based upon the data could make an inappropriate decision if the data from your analysis is not right.

Reasons for analyzing food componentsThere are many possible reasons. Examples for analysis of food components include:

1) Legal or regulatory issuesThere are standards which must be met. In Australia these are set by Food Standards Australia New Zealand and can be found in the Australia New Zealand Food Standards Code. Whenever there is a figure in these regulations they are written as either maximum or minimum values.Examples would be: the dietary fibre content must be more than 10g per kg. or The sugar content must not exceed 15g per kg.

1

If you are doing this sort of analysis then the results might be used for deciding whether the food meets the legal requirements. If it does not then it should not be sold and the manufacturer/seller can be fined for selling the product.

2) Food labellingUnder current Australian standards the packaging on most foods must include at least some analytical data in the form of a nutrient information panel. The required form is as follows:

Nutrition InformationServings per package: 1

Serving size: 210g

Quantity per serving Quantity per 100g

Energy 2121kJ 1010kJ

Protein 19.1g 9.1g

Fat, total

- saturated

25.2g

12.6g

12.0g

6.0g

Carbohydrate

- sugars

51.0g

5.5g

24.3g

2.6g

Sodium 1008mg 480mg

The quality of analyses and calculations carried out for labeling purposes are also really critical. Firstly, consumers are making decisions (will I buy and eat this product). Secondly if the analyses on the label are clearly incorrect then they will be very embarrassing. There may also be the expense of replacing the large amount of packaging/labels.

2

3) Food compositional dataAnalyses of foods are used to compile comprehensive published tables. Some of these are in book form and others are now available on the world wide web. Again these primarily assist consumers to choose foods to meet their specific needs. They generally have a nutritional basis and are used by nutritionists and dieticians as the basis of advising consumers.

4) Analyses for research purposesMost companies are constantly involved in research and development activities in an effort to provide innovative and appealing products in a cost effective manner. In this case no-one outside the company will necessarily see the data and the analyses used might be quite different from some of those used for the purposes described above.

5) Analyses for quality control/assuranceHere we are testing raw ingredients to establish whether they are within our company’s specifications. The company may use the results to decide that this delivery of flour is suited to biscuit manufacture or to some alternative end use.

Analysis results might also be used as the basis for decisions as to whether some final product meets the specifications used by the company as quality criteria.

3

Comparisons of food analysis data

Following on from the various purposes of analysis, there are two common ways in which we might choose to compare our own laboratory data for food products and ingredients.

Food composition data Food regulations

4

Further issues on comparisons of analysis data

Firstly, there are now many sources of food compositional data. A comprehensive bibliography is provided on the Food Chemistry website (folder bibliographies).

5

6