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ABSTRACT

Flours and protein concentrates, prepared from defatted soybean flakes steamed up to 20 min before or after extraction with hexane:ethanol azeotrope 82/18 v/v, were presented to a 15-member trained taste panel. Flavors and odors were described and rated for intensity on a scale of 1 to 10 where 1 is strong and 10 is bland. Azeotropic extraction for 6 hr by itself significantly affected flavor of flours and of concentrates so that they scored 7.4 and 6.8, respectively, compared to 4.0 for raw, hexane-defatted, soy flour. Toasting after azeotropic extraction raised flavor scores of flours and protein concentrates to 7.9, a value which compares favorably with 8.1 for wheat flour. Toasting is also necessary to inactivate trypsin inhibitors and other antinutritional factors in azeotropio-extracted soybean flakes. A protein isolate from toasted, azeotropio-extracted flakes scored 7.3 compared to 8.0 for sodium caseinata Yields of protein isolates are good if the heatprocessed fiakes are extracted with hot water at 74°C and pH 7.2.