COMPARISON OF THE PROTEIN NUTRITIONAL VALUE OF TVP, METHIONINE ENRICHED TVP AND BEEF AT TWO LEVELS OF INTAKE FOR HUMAN ADULTS

Abstract

SUMMARY— The objective of the study was to compare the protein nutritive value for adult men of beef, an extruded soybean product resembling beef (TVP) and a 1% DL‐methionine‐fortified TVP product at two levels of nitrogen intake. Experimental diets were maintained adequate in calories, vitamins and minerals. Mean nitrogen balances of subjects fed 8.0g nitrogen per subject per day from beef, TVP or methionine‐fortified TVP were +0.74, +0.78 and +0.72g nitrogen per day, respectively, indicating that at this level of protein intake all three sources equaled or exceeded the protein requirements of adult men. Mean nitrogen balances of subjects fed 4.0g nitrogen per subject per day from beef, TVP or methionine‐fortified TVP were ‐0.30, ‐0.70 and ‐0.45g nitrogen per day, respectively. While none of the test protein sources fully met the protein needs of the subjects at this level of nitrogen intake, beef was superior to TVP on the basis of nitrogen balance data. DL‐methionine fortification at the 1% level of the TVP was demonstrated to be partially effective in improvement in nitrogen balance.