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Allergenicity, trypsin inhibitor activity and nutritive quality of enzymatically modified soy proteins.

De La Barca AM, Wall A, López-Díaz JA

Departamento de Nutrición Humana, Centro de Investigación en Alimentación y Desarrollo, Hermosillo, Sonora, México. amc@cascabel.ciad.mx

Two ultrafiltered soy flour protein fractions were evaluated; the first was obtained by hydrolysis (0.5-3 kDa, F(0.5-3)), and the second was an enzymatically methionine-enriched fraction (1-10 kDa, F(1-10)E). Amino acid profiles, protein quality, allergenicity (against soy-sensitive infant sera) and trypsin inhibitor activity were determined. Fraction F(1-10)E fulfilled amino acid requirements for infants, whereas the F(0.5-3) fraction was methionine deficient. Both fractions were similar in net protein utilization, and F(1-10)E digestibility was comparable with casein and higher (P?<?0.05) than F(0.5-3) or soy isolate. Allergenicity of SF was reduced to 21.5% with the hydrolysis in F(1-10)E and it was not detected in F(0.5-3.) Residual trypsin inhibitor activity with respect to soy flour was 8.1%, 3.3% and 1% for hydrolysate, F(1-10)E and F(0.5-3), respectively. Both fractions presented high nutritive quality and reduced or null allergenicity. The trypsin inhibitor activity decreased along processing and could be a useful indicator for production of hypoallergenic proteins.

Published 12 July 2005 in Int J Food Sci Nutr, 56(3): 203-11.
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