FOOD ADDITIVES

Food additives are any substance not naturally present in a food but added during its preparation and remaining in the finished product. Food additives are all substances added to basic food products. They include anything added during the production, processing, treatment, packaging, transport & storage of a food. Food additives are used to decrease the risk of contamination by certain microbes, maintain and improve nutritional quality, enhance appearance, increase self-life, reduce waste, or contribute to convenience. The PFA gives the definition and list of permissible additives along with the amount permitted. The substance to be used as food additive should be of good grade and must meet the PFA or B-S specifications. With the present degree of urbanization, it would be impossible to maintain food distribution without the processing and packaging with which many additives are involved. The convenience food revolution would not be possible without food additives.

PRESERVATIVES

Chemicals such as salt, alcohol and acetic acid have been used for several hundred years for preserving meat and vegetables and the pickling of food. These processes rely on reducing the water activity or the pH in the food to inhibit the growth of pathogenic organisms.

Food preservatives

 COLOURS

Colour additive is any dye. pigment or substance that can impart colour when added or applied to a food, drug, cosmetic or to the human body.

 • Dyes dissolve in water and are manufactured as powders, granules, liquids, or other special purpose forms. They can be used in beverages, dry mixes, baked goods, confectionary, dairy' products, pet foods and a variety of other products.

 • Lakes are the water-insoluble form of the dye. Lakes are more stable than dyes and are ideal for colouring products containing fats and oils or items lacking sufficient moisture to dissolve dyes. Typical uses include coated tablets, cake and doughnut mixes, hard candies and chewing gums.

Originally many colour additives are natural pigments. They gave place to synthetic dyes obtained from coal tar.

NATURAL COLOURANTS

• Anthocyanins: The anthocyanins comprise a diverse group of glycosidic derivatives of the 2- phenyl benzopyrylium structure. Anthocyanins impart blue, violet and certain red colours to many edible fruits and vegetables.

• Carotenoids and xanthophyl: The carotenoids. Aliphatic and alicyclic unsaturated terpenes composed of eight isoprene units are the most widespread of natural colours in both the plant and animal kingdoms. Carotenoids are oil-soluble colours.

• xanthophyl comprise a group of yellow carotenoid pigments closely related to the carotenes but having keto and/or hydroxy substituents. The most important commercial carotenoids are β-carotene

• Bixa Orellana which contains bixin as the main component; saffron which contains crocetin, (J- carotene and zeaxanthin; paprika extract which contains capsanthin and capsorubin; Xanthophyll extracts from leaves; carrot extracts with (5 and a-carotenes; canthaxanthin from the pink edible mushroom; Cantharellus Nectria cinnabarina; and red palm oil with lycopene and lutein. No adverse effects have been observed with natural colourants.

• Butacaines: The red beet root. Beta vulgarus contains red and yellow pigments of the class betalaines. Red violet betacyanin and yellow betaxanthins are water soluble, quaternary ammonium derivatives of 4-vinyl-5. 6-dihydropyridine-2, 6-dicarboxylic acid.

• Caramel: It is a complex polysaccharide of unidentified chemical structure prepared by heating a food grade carbohydrate like, glucose, sucrose, or starch in the presence of a catalyst—acetic sulphurous or citric acids or bases such as ammonium, calcium, and sodium hydroxides.

• Curcumin: Turmeric, a yellow brown substance widely used as a spice and a natural colourant is derived from the rhizome of curcuma Ionian L. It contains about 1-5 per cent of curcumin as the principal colourant.

PLANT TISSUE CULTURE

In vitro pigment production is an alternative to colour synthesis. Plant tissue culture is a means of growing plant cells in a supportive environment outside of the organism and it can be used to produce useful chemicals such as pigments. Extractions are simple and strong flavours can be eliminated

• Annatto: It is a yellow carotenoid preparation obtained from the seeds of the plant Bixa Orellana. The pigment in annatto is a mixture of bixin. the mono-methyl ester of a dicarboxylic carotenoid compound and norbixin, the dicarboxylic derivative of the same carotenoid as in bixin. Annatto has been used in foods especially dairy products. The presence of two carboxylic acid groups allows the preparation of both water and oil-soluble preparations. The cis forms are redder in colour than the yellow transforms and the degradation compound, so a series of yellow to red colours are available.

• Saffron: Dicarboxylic carotenoid. crocetin is found in saffron together with its digestiobioside ester crocin. Saffron is obtained from the stigma as of the flowers of crocus sativus. Saffron provides both colour and flavour. • Cochineal and related pigments: The term cochineal refers to red colouring material enaminic acid, is the colourant in cochineal. It is extracted from the dried crushed bodies of female D. Coccus just prior to egg-laying time. The pigment may constitute as much as 22 per cent of their dry weight.

• Carmine can be used in powder form to colour a variety of foods. It can be used in a solution of ammonia to colour foodstuffs such as baked products, jams etc. From kermes insect, aglycone kermesic acid is extracted. This also gives like cochineal red.

• Alkanet is a related pigment extracted with alcohol from the roots of Alkanna tinctoria Tausch. The red pigment is only slightly soluble in water but readily soluble in organic solvents. It is used in ice-cream.

• Monascus: Yellow to red colourants from microbial species offer considerable advantages since they can be produced in any quantity and are not subject to the vagaries of nature like cochineal.

• Biliproteins from algae: It is divided into two main groups—red phycoerythrin and the blue phycocyanins. The bilin portion of both groups is an open tetrapyrrole containing a skeleton system similar to chlorophyll and haemoglobin. It is soluble in either water or alcohol used is used in chewing gum.

The following synthetic colours are permitted to be used in foods under PFA rules.

• These colours shall be pure and free from harmful substances, so all food colours and colour preparations shall be sold only under BIS certification mark.

• The synthetic colours are permitted to be used only in certain foods with declaration on the label. The maximum quantity permitted is 200 mg/kg. Some of the foods in which colour is permitted are ice-cream, biscuits, cakes, sugar, boiled confectionery, sweets and savouries, fruit syrup, fruit squash fruit drink and beverage, soft drink, soft drink concentrate, jam, carbonated water and non-carbonated ready to serve beverages and synthetic syrup.

• The pink dye Rhodamine B, Orange RN II and Blue VRS are carcinogenic and causes pathological lesions of vital organs like kidney, spleen, and liver. Metanil yellow causes degeneration of reproductive organs, sterility, stomach trouble and cancer. Hence, these dyes are prohibited.

FLAVOURING AGENTS

The flavours of most fruits and vegetables are produced by very complex mixtures of aldehydes and esters of organic alcohols and acids, with a range of essential oils with complex terpenoid structures.

Many of the synthetic compounds used are ‘nature-identical’, that is. they occur naturally in foods or are formed in cooking processes. A closely related group of additives are called flavour enhancers of which the best known is monosodium glutamate

SWEETENERS

Sweeteners are added to foods for flavoring. Sweeteners other than sugar are added to keep the food energy (calories) low, or because they have beneficial effects for diabetes mellitus and tooth decay and diarrhoea.

Artificial sweeteners:

Are used in food industry as a small concentration of these substances is required to sweeten the product. An ideal sweetener is as sweeter than sucrose, has a pleasant taste with no after taste, is colourless, odourless, readily, soluble, functional, and economically feasible. It also is non-toxic, does not promote dental cavities and is either metabolised normally or excreted from the body unchanged without contributing to any metabolic abnormalities. Ideal is multiple sweetener approach. When multiple sweeteners are used together, they have a synergistic effect. They reduce the cost and improve the product taste and stability, since the combination often overcomes the limitations of the individual sweeteners.

EMULSIFIERS AND STABILISERS

The texture of many processed foods depends on the fact that they are emulsions or foams and if they are to retain these textural properties they must be stabilised in someway. The additives used for this purpose are surfactants, amphipathetic molecules which act at the interfaces of the two phases in the food. The most commonly used emulsifiers are mono and diglycerides and phospholipids such as lecithin.

Stabilisers are usually macromolecules which form a dispersed matrix or gel into which other smaller molecules can be incorporated. Substances used as stabilisers and thickeners are polysaccharides, are given in Table.

Chelating agents or Sequestestrants: These are compounds that form complexes with metal ions. When metallic ions are released due to hydrolytic or other degradative reactions, they are free to participate in reactions that lead to discolouration, oxidative rancidity, turbidity, and flavour changes in foods. Addition of chelating agents results in the complexing of these metal ions and thereby the stabilisation of foods. Citric acid and its derivatives, phosphates, and salts of Ethylene Diamine Tetra Acetic Acid (EDTA) arc the most popular chelating agents used in foods. Chelating agents are not antioxidants, they serve as scavengers of metals which catalyse oxidation. They, however, are antioxidant synergists.

ANTIOXIDANTS

One of the most important types of deterioration that can occur in a foodstuff is the oxidation of the fats to produce unpleasant odours which can be detected at low levels by the human senses. The details of antioxidants are discussed in chapter on “Food Presents".

FLOUR IMPROVERS: - These are a group of additives which are added to flours used in bread making either to improve the elasticity of the dough and lead to greater volume of loaf or because they improve the stability of the crumb and slow the process of staling.

Government Regulations

The use of food additives is subjected to government regulation throughout the world. These regulations prescribe the food in which specific additive may be safely used, a specified maximum limit the manner of addition, directions on labelling, packaging requirements. The central government in the ministry of health has a central committee for food standards which reviews from time to time the situation regarding additives based on available scientific data.