Chemicals in Food
During processing of food, a number of chemicals are added to it to increase its shelf life and also to make it more attractive. Main categories of food additives are as follows:
(i) Food colours
(ii) Flavours and sweeteners
(iii) Antioxidants
(iv) Fat emulsifiers and stabilizing agents
(v) Flour improvers
(vi) Preservatives
(vii) Nutritional supplements such as vitamins, minerals, etc.
Except for nutritional supplements none of the above food additives has any nutritive value.
In this section we will learn about preservations and sweeteners.
1. Food preservatives
Food items containing moisture get spoiled due to growth of micro-organisms. Growth of micro-organisms in a food material can be inhibited by adding food preservatives. Food preservatives are classified into two groups – Class I and Class II. Class I preservatives include table salt, sugar and vegetable oils. The Class II preservatives are chemical preservatives. The chemical substance which is used as food preservative should not be harmful to the human beings. Such chemical substances which are added to food materials to prevent their spoilage are known as chemical preservatives. In our country, two chemical preservatives which are permitted for use are:
(i) Benzoic acid (or sodium benzoate)
(ii) Potassium metabisulphite or sodium metabisulphite.
Benzoic acid or its sodium salt, sodium benzoate is commonly used for the preservation of food materials. For the preservation of fruits, fruit juices, squashes and jams sodium benzoate is used as preservative because it is soluble in water and hence easily mixes with the food product. 0.06% to 0.1% concentration of sodium benzoate is sufficient for the preservation of fruit juices and squashes. Sodium benzoate is metabolized by conversion to hippuric acid, C6H5CONHCH2COOH which is finally excreted in the urine.
Potassium metabisulphite or sodium metasulphite is used for the preservation of colourless food materials such as fruit juices, squashes, apples, lichies and raw mango chutney. These are not used for preserving coloured food materials because sulphur oxide produced from these chemicals is a bleaching agent. These preservatives on reaction with acid of the juice liberate sulphur dioxide which is very effective in killing the harmful micro-organisms present in the food and thus prevents it from getting spoiled.
2. Artificial sweetening agents
Sugar or sucrose is the natural sweetening agent. However, excess consumption of sugar leads to many diseases such as obesity, diabetes, coronary heart disease. Many artificial sweetening agents have been isolated which are much sweeter than sugar. These artificial sweetening agents are non-nutritive in nature and are used as substitutes for sugar in foods and beverages especially soft drinks. Some examples of artificial sweetening agents are saccharin, cyclamates. Saccharin (Ortho-sulphobenzimide) is about 550 times sweeter than cane sugar or sucrose.
The use of cyclamates as sweetening agent has been banned in many countries in view of suspected carcinogenic effects.
Aspartame is another artificial sweetener. It is methyl ester of the dipeptide aspartyl phenylalanine. It is about 100 times sweeter than sucrose.
Aspartame is unstable to heat and therefore, it can be used as a sugar substitute in cold drinks and cold foods only.
Alitame is another artificial sweetening agent. It is about 2000 times sweeter than sucrose. It is more stable to heat than aspartame. Since Alitame is a high potency sweetener, it is difficult to control sweetness of food while using this sweetener.
Sucralose is a trichloroderivative of sucrose. It is about 600 times sweeter than sucrose. It is stable at cooking temperature.
Services: - Chemicals in Food Homework | Chemicals in Food Homework Help | Chemicals in Food Homework Help Services | Live Chemicals in Food Homework Help | Chemicals in Food Homework Tutors | Online Chemicals in Food Homework Help | Chemicals in Food Tutors | Online Chemicals in Food Tutors | Chemicals in Food Homework Services | Chemicals in Food