[Nutritional value and acceptibility of soy proteins in human diet]

These studies on textured soya protein (TSP) were directed towards the evaluation of its acceptability and nutritional value in man. ACCEPTABILITY. In the beginning, the reaction of adults to the incorporation of 40 g TSP in their daily diet was studied. After a three-week period, no intolerance or fatigue with the regim was shown. In a following study, observations made on young children's attitudes along with quantitative measurements of their food intake were noted during four one-wekk periods: -- period of "imposed diet", without TSP; -- period of imposed diet", with TSP; -- period of "free diet", without TSP; -- period of "free diet", with STP; During the periods of "imposed diets", children could eat only the proposed quantities of foodstuffs. During periods of "free diets", children were able to choose the quantity and sort of food they preferred from the proposed menu. Total protein ingested (differentiating between that of animal and vegetable origin) was calculated for each child from his daily food record. Results show that only one of the twenty-four children systematically refuse soya-containing preparations. Average consumption of soya protein during "free diet" periods was close to the desired level and not significantly different to levels achieved in the "imposed diet" period. The acceptance of TSP by the children was therefore evident. NUTRITIONAL VALUE. The following studies were designed to determine the effects of the replacement of animal protein by TSP (at the maximal levels of its tolerability) in a normal diet. In the first nitrogen balance study, with 10 convalescent subjects, the following protocol was developed: -- the habitual caloric and protein intakes of the subjects was established; -- following a four-day adaptation period, the subjects entered consecutively: a control period at established levels of calories and protein, and a test period in which 20 g of soya protein replaced an equivalent quantity of animal protein. The average nitrogen balances for control and test periods were + 4.49 g and 3.62 g. The difference not being significant at a probability of 5 p. 100. In a second study with 12 adults in good health (6 males and 6 females) soya protein replaced 34-39 p. 100 of the daily protein intake (according to the menu) and the average nitrogen balances in control and test periods were + 0.16 g and 0.91 g. These studies confirm the TSP replacement of animal protein in the normal diet does not affect nitrogen balance and that TSP can make a contribution to the fulfilment protein requierements in man.