NUTRITIONAL CHANGES IN SOME NIGERIAN FOODS DURING DIETARY PREPARATION AND THEIR EFFECTS ON THE MAMMALIAN BODY

Abstract

Starting with a comprehensive review of the research already done in the related field of nutrition, the chemical composition of 20 Nigerian food materials which are used in the preparation of six common local diets has been investigated. The diets were prepared using accepted recipes and commonly used methods of preparation. Simultaneously, the same amounts of food materials, as used for cooked diets, were mixed raw to correspond to each cooked diet. The changes in the nutritional value of each of these diets, which were brought about by cooking, have been determined from the analyses of the raw mixed and cooked diet. The effects of feeding these diets to rats have been studied by measurement of the growth of these animals and of various protein constituents of the blood. The digestibility, nitrogen balances, and biological values of the food proteins have been determined using a specially designed battery of wire net cages in which it is possible to collect faeces and urine of the rats separately. A method has also been described for the quantitative estimation of various amino acids in food proteins using an automatic amino acid analyzer. The amino acid patterns of these diets have been deduced and compared with the known requirements of various amino acids for rat growth. A comparison of the amino acid patterns of these diets and the FAO provisional pattern of amino acid requirements has also been made. The results of the chemical analysis are examined with references to growth of rats when these diets are fed to them.