THE BIOCHEMISTRY AND TECHNOLOGY OF THE PROTEINS OF SOME LEAFY VEGETABLES OF WESTERN NIGERIA

Abstract

The nutrient composition of six edible leafy vegetables in Nigeria have been determined, and the effect of the age of the plants and of the season of growth on the nutrient levels have also been determined. The crude protein in these vegetables was found to be appreciably high, and the protein was extracted from them by means of the IBP Protein extraction machine recently manufactured at Bothamated Experimental Station, Herts., England. The ease of extraction of the leaf proteins were found to be dependent on the species of plants. The effect of the age of plants and of seasonal variation on the extractability and yield of the extracted leaf protein have also been investigated. The bulk leaf proteins that were extracted have been separated into their various components by none electrophoresis on paper and starch-gel, and their electrophoretic patterns were compared with that of the human serumproteins. An attempt was also made at identifying the various protein fractions constituting the bulk leaf proteins in these vegetables. The changes taking place in the protein fractions as the vegetable plants increased in age were also investigated electrophoretically during two different growing seasons. The amino acid composition of the leaf protein concentrates have been deduced, and their patterns compared with that of the FAO reference protein. The results of the chemical analyses were examined biologically and biochemically with reference to growth of young albino rats fed with diets containing the leaf protein isolates at 10% level. The True Digestibility, Protein efficiency Ratio, Net Protein Utilization, and Biological Values of the vegetables 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. The nutritional qualities of the proteins were compared with those of fortifiedsoya bean protein in a standard Soya/Girl Diet of proven nutritional quality.

The changes in the nutritional values of each of the protein concentrates, brought about by cooking the vegetables, have also been determined from analyses of the proteins extractedfrom both raw and cooked vegetables.