DETBA VALUE AND HEXANAL PRODUCTION WITH THE COMBINATION OF UNSATURATED FATTY-ACIDS AND EXTRACTS PREPARED FROM SOYBEAN SEEDS LACKING 2 OR 3 LIPOXYGENASE ISOZYMES

Hydroperoxide and n-hexanal production by lipoxygenase action is an im portant problem in the effective use of soybean seeds for food ingredi ents. We examined here the additional effect of unsaturated fatty acid s on the 1,3-diethyl-2-thiobarbituric acid (DETBA) value (index for hy droperoxide production) and n-hexanal product-ion with two normal soyb ean cultivars; three mutants partially lacking lipoxygenase and contai ning only L-l, L-2, or L-3; and one mutant completely lacking lipoxyge nase (Lo). Among the soybeans tested, the Lo soybean had the lowest le vels of both DETBA value and n-hexanal production. The low DETBA value s were maintained over a wide range of pH (4-10) and temperature (4-70 degrees C) and were not influenced by the addition of unsaturated fat ty acids. These results suggest that the Lo soybean could be an excell ent soybean source for making soybean products with a combination of s oybean and other food ingredients.