A food ingredient is any substance that is added to a food to achieve a desired effect. The term “food ingredient” includes food additives, which are substances added to foods for specific technical and/or functional purposes during processing, storage or packaging.
There are two types of food additives—direct and indirect. Direct food additives are used in foods to impart specific technological or functional qualities. Stabilisers which are used to help prevent separation of nutrients in fortified milk products, come under this category. Wherein, indirect additives are not intentionally added to food, but may be present in trace amounts as a result of processing, packaging, shipping or storage.
Direct stabilisers yield gel networks, when incorporated in dairy products leading to firm texture, and consequently problem of syneresis in yoghurt is reduced. Addition of relatively minimum amount of stabilisers in ice cream provides desired body and textural characteristics.
Most of the stabilisers are primarily aimed to enhance the shelf life of food product by preventing them from microbial attack. They are called food grade stabilisers.
Alginic acid (C6H8O6) is a popular food stabiliser that is derived from brown algae. It is extensively used in ice cream and syrups, and used as toppings on desserts. Similarly, carrageenan is an anionic hydrocolloid and classified as adsorbing polysaccharides used in different dairy products.
Agar Agar obtained from red algae and is widely used as thickener in foods. Guar gum is a naturally existing as polysaccharide, extracted from the seeds of a leguminous plant Cyamopsis tetragonoloba (L.) containing of 1, 4-ß-D-mannose backbone and 1, 6-a-D-galactose side chain, with 1:2 ratio of galactose:mannose. It is used as thickening and stabilising agent having highly viscous colloidal dispersion property especially in acidic products like yoghurt.
Carboxymethylcellulose (CMC) is a polysaccharide hydrocolloid compound of ß-1-4- glucose polymers with extensive application in dairy product. Gelatin is a natural stabiliser derived from collagen, widely obtained from pigskin, cattle hides, or cattle bones (called ossein). It is best gelling/thickening agent that related to the yoghurt rheology and imparts good resistance to the syneresis. Aqueous extraction of edible plant material (usually citrus fruits or apples) is used to obtain pectin (C6H10O7), a purified water-soluble colloidal carbohydrate product. It is applied as stabilisers in dairy products.
These stabilisers are excellently utilised to hold fortified components from unintentional reactions with nutrients and other compounds. They prevent the nutrients from sedimenting and keep them in suspension state.
Stabilisers provide excellent suspending capabilities for cocoa, impart homogenous appearance and texture to chocolate milk, and provide excellent flavour release. In short, by using stabilisers or thickeners high-rheology product of excellent texture and body, appearance, consistency, mouthfeel, extending shelf life can be formulated.
Furthermore, a perspective understanding of the chemical and physical interactions of these stabilisers with the proteins, caseins, fats and water in the milk is important in the development of innovative flavoured and functional dairy products.
A single stabiliser or a combination/blend of stabilisers is used to manufacture the yoghurt and many other products. The objective of using stabilisers blend is to achieve a particular function, or in most of the cases, to overcome one of the limiting properties related with a particular compound.
A single stabiliser may be suitable while producing fruit flavoured yoghurt but may not be appropriate to manufacture other types of high rheology products. Thus, the selection of a specific type of stabiliser for specific type of product depends upon many factors such as effect or mode of action of the stabiliser and functional properties and optimum concentration of the stabilisers to be used.
Fortification of milk with micronutrients play a major role in releaving nutritional deficiency problems in humans. It can improve the palatability and sensory of the products. The studies prove that wide use of fortified milk products in the world improve the health condition of people in geographically specific areas. Fortification of milk and milk products with addition of iron, iodine, all sorts of vitamins, fish oil, probiotics, conjugated linoleic acid, casinate and fibre has been done so far to improve the quality of life to some extent.
The range of foods that are fortified with calcium has steadily grown over the years as it became increasingly clear that intakes were low in many populations. The more soluble calcium salts, such as the citrate malate or the gluconate, are generally used to fortify juices and other beverages. Tribasic calcium phosphate, and sometimes calcium carbonate or lactate, is used to fortify milk, to which gums (e.g. carrageenan, guar gum) must also be added to prevent the calcium salt from sedimenting. Yoghurt and cottage cheese can also be fortified with these calcium compounds.
In industrialised nations and in some Asian countries, soya beverages are marketed as a replacement for cow’s milk in which case these too should be fortified with calcium. Stabilisers such as sodium hexametaphosphate or potassium citrate can improve the quality of soya beverages fortified with calcium gluconate or lactogluconate. The addition of calcium salts to some foods can cause undesirable changes in colour, texture and stability by increasing the cross-linking of proteins, pectins and gums. Calcium fortificants can also darken the colour of chocolate beverages.
Consumer demand for more natural and ‘clean label’ formulations are steadily increasing. Global food industries are already on the lookout for ‘healthier alternatives’ for stabilisers that help its purpose in fortified dairy products to fulfil consumers’ satisfaction and requirement.
(Raajeswari is assistant professor (SG) and Pragatheeswari is Ph D scholar, Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore. They can be reached at raajraajeswari@gmail.com)