FOOD CHEMISTRY

Module 7. Food additives

Lesson 17
VITAMINS, AMINO ACIDS, MINERALS

17.1 Introduction

A food additive is a substance (or a mixture of substances) which is added to food and is involved in production, processing, packaging and/or storage of foods without being a major ingredient. Additives or their degradation products generally remain in food, but in some cases they may be removed during processing. Food additives are defined in various ways:

17.2 Definition

Food additives may be defined as chemical substances which are deliberately added to foods, in known and regulated quantities, for the purpose of assisting in the processing of foods, preservation of foods or in improving the flavor and texture or appearance of foods.

17.2.1 Definition according to PFA

As per PFA Act food additive is defined as any substance not normally used as a typical ingredient of foods whether or not it has nutritional value; the intentional addition of which to food for technological Including organoleptic purpose in the manufacturing, processing, preparation; treatment, packing, packaging, transport or holding of food results in it or its ingredients becoming a component or otherwise affecting characteristics of such foods.

17.3 Functions of Food Additives

Different food additives perform several useful functions in the interest of manufacturer and consumer of the food and food products. Some important functions are listed below:

1. Enhances the shelf life of food.
2. Improves and maintains the nutritive value of food.
3. Reduces the wastage and improves yield of the product.
4. Facilitates the processing/preparation of food.
5. Improves colour and appearance of food.
6. Improves body and texture of food.
7. Improves aroma and taste of food.
8. Enhance the consumer’s acceptability of the food.

17.4 Classification of Food Additives

They are classified into two ways

(A) Intentional Food Additives

These are those substances added to food intentionally to improve product quality and sensory properties. These are generally added to foods selectively in carefully controlled conditions during processing and in small permissible amounts necessary to achieve the desired effects e.g. Preservatives, antioxidants, emulsifying agents, stabilizers, flavorings, colourants, nutrient supplements etc.

(B) Unintentional Food Additives - contaminants

These are those additives which are not deliberately added to foods but gain entry as a result of operations inherent to production, storage, processing or marketing. They find their way in food accidentally. Some of the incidental additives are pesticides, toxic metals, anti nutrients, heavy metals etc. It may cause health hazard and may also spoil the food.

17.5 Food Additives are Further Classified Based on Source

They are natural, synthetic and nature identical

1. Natural

They are derived from natural sources like animals, plants, micro-organisms etc.

2. Synthetic

They are chemically synthesized in laboratory

3. Nature Identical

They chemically identical to those obtained from natural sources but synthesized artificially

17.6 Various Categories of Food Additives

1. Preservatives
2. Antioxidants
3. Appearance control agents – BVO, ester gum, waxes, polishes etc
4. Coloring agents
5. Flavour enhancers
6. Emulsifiers and Stabilizers(Thickening agents)
7. Humectants – moisture control agents
8. Sugar substitutes and artificial agents
9. Nutrients supplement (vitamins, amino acids, minerals, etc.)
10. Buffers – pH control agents – acids, alkalis and salts
11. Leavening agents – yeast and chemicals
12. Propellants and gases
13. Oxidizing and reducing agents
14. Sequestering agents and chelating agents
15. Firming agents
16. Masticating substances
17. Anti-stick (release) and Anti-caking (free- flowing) agents
18. Tracers
19. Anti-freeze agents
20. Bulking agents
21. Clarifying agents
22. Bleaching & maturing agents
23. Acidulants
24. Foaming (aerating) and Antifoaming agents

17.7 Considerations Required in use of Food Additives

The following criteria/guidelines are required to be taken care of before the use of any additives.

1. It must be ascertained that the real need exists for the use.
2. It does not cause any adverse physiological and harmful effects even upon regular consumption for a prolong period i.e. the food additives must be safe/ harmless.
3. It should not reduce/destroy the nutritive value of food.
4. It should confirm the agreed specifications, where possible legislation should define permissible maximum quantities of a given additive.

Any food additive should be used at minimum level necessary to produce the desired effect, additives or their degradation products generally remain in food but in some cases they may be removed during processing. The limit of addition should be established based on the following factors:

1. The estimated level of the consumption of food for which an additive is proposed.
2. Minimum level which in animal studies exhibit minimum deviation from the normal physiological behaviour.
3. An adequate margin of safety to reduce to a minimum any hazard to health in all groups of consumers.

17.8 Safety Aspects of Food Additives

It is necessary to know in advance how safe the food additive is before permitting its use in food products.

ADI of Food Additives

The ADI (Acceptable Daily Intake) is the amount that can be consumed on a daily basis for a life time without appreciable risk. Its unit is mg/kg body weight / day.

GRAS substances

GRAS – Generally Recognized as Safe

It is a device which US FDA has adopted to give endorsement to those substances which have had many years of use and for which there is no evidence of any harmful effects.

17.9 Vitamins

Many food products are enriched or fortified with vitamins to adjust for processing losses or to increase the nutritive value. Such enrichment is important, particularly for fruit juices, canned vegetables, flour and bread, milk, margarine and infant food formulations. Table given below provides an overview of vitamin enrichment of food. Several vitamins have some desirable additional effects. Ascorbic acid is a dough improver, but can play a role similar to tocopherol as an antioxidant. Carotenoids and riboflavin are used as coloring pigments, while niacin improves the color stability of fresh and cured and pickled meat.

Table 17.1 Examples of vitamin fortification of food products

Vitamin	Food products
B1	Cocoa powder and its products, beverages and concentrates, confectionary and other baked products
B2	Baked products, beverages
B6	Baked and pasta products
B12	Beverages, etc.
Pantothenic acid	Baked products
Folic acid	Cereals
C	Fruit drinks, desserts, dairy products, flour
A	Skim milk powder, breakfast cereals (flakes), beverage concentrates, margarine, baked products, etc.
D	Milk, milk powder, etc.
E	Various food products, e. g. Margarine

17.10 Amino Acids

The biological value of a protein (g protein formed in the body/100 g food protein) is determined by the absolute content of essential amino acids, by the relative proportions of essential amino acids, by their ratios to nonessential amino acids and by factors such as digestibility and availability. Since food is not available in sufficient quantity or quality in many parts of the world, increasing its biological value by addition of essential amino acids is gaining in importance. The best example of use of amino acid as additive is fortification of rice with L-lysine and L-threonine, supplementation of bread with L-lysine and fortification of soya and peanut protein with methionine. Synthetic amino acids are used also for chemically defined diets which can be completely absorbed and utilized for nutritional purposes in space travel, in pre-and post-operative states, and during therapy for maldigestion and malabsorption syndromes.

17.11 Minerals

Food is usually an abundant source of minerals. Fortification is considered for iron, which is often not fully available, and for calcium, magnesium, copper and zinc. Iodization of salt is of importance in iodine deficient areas.

Iodized salt is produced as a preventive measure against goiter, a disease of the thyroid gland. It contains 5 mg/kg of sodium-, potassium- or calcium iodide. Nitrite salts are used for pickling and dry curing of meat. They consist of common salt and sodium nitrite (0.4–0.5%), with or without additional potassium nitrate.

17.11.1 Fortification

It is the practice of deliberately increasing the content of an essential micronutrient, i.e. Vitamins and Minerals (including trace elements) in a food, so as to improve the nutritional quality of the food supply and provide a public health benefit with minimal risk to health.