Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


In-vivo and in-vitro studies were conducted to measure bioavailability of iron from beef and beef-soy mixtures. The effects of cooking temperature and method of cooking were investigated. Animals absorbed non-heme iron better than heme forms and utilized iron contained in beef-soy diets as efficiently as that contained in beef diets. Colorimetric iron values of 17.18, 6.0, and 9.02% were obtained in raw, broiled and microwaved beef samples, respectively. A similar trend was observed in beef-soy mixtures when analyzed raw (11.03), broiled (6.32) or microwaved (2.21). Iron contained in beef-soy flour mixtures was dialyzed in a larger proportion (16.60%) as compared to mixtures containing soy concentrate (4.66%) or isolate (1.99%). The amount of beef present in the mixture also affected colorimetric iron. Non-heme iron content of beef increased from 3.20 (mu)g/g in raw samples to 5.51 (mu)g/g and 7.79 (mu)g/g in microwaved and broiled samples, respectively. A significant correlation (P < 0.05) was found between non-heme iron and cooking temperature. Distinct electrophoretic patterns were observed in raw, broiled and microwaved beef samples, as well as, for beef-soy flour mixtures. Microwaving resulted in a larger number of more clearly defined colored bands. A low molecular weight protein fraction was always present in microwaved samples. No correlation were found between non-heme iron determined in vitro, and either cystine, glycine or histidine. Method of cooking and type of soy product affected the amount of several individual amino acids and total amino acids contained in beef-soy mixtures.