EXTRACTION OF DEFATTED SOYBEAN FLOURS AND FLAKES WITH AQUEOUS ALCOHOLS - EVALUATION OF FLAVOR AND SELECTED PROPERTIES

One of the chief obstacles to the acceptance of soy protein products for food use is flavor. Treatment with organic solvents, primarily aqueous alcohols, has been shown by previous workers to improve color and flavor of soy proteins. In this study, three alcohols (ethanol, methanol, and isopropyl alcohol) at various aqueous concentrations were used to extract defatted soy flours and flakes at temperatures ranging from 30 to 75 °C. The odors and flavors of the extracted flours and flakes were evaluated when the products were initially prepared and also after 6 and 12 months of storage at 25 °C. After 6 months of storage at 25 °C, there were few signs of deterioration in either flavor or odor scores of the stored samples. However, after 12 months of storage at 25 °C, four samples were scored significantly lower for odor than were their unaged controls. These four samples were those (1) extracted with 70% ethanol at 30 °C, (2) extracted with 87.7% isopropyl alcohol at 30 °C, (3) extracted with 50% methanol at 45 °C, (4) extracted with 92.7% ethanol at 60 °C. Of these four samples, 1 through 3 above also scored significantly lower for flavor. © 1979, American Chemical Society. All rights reserved.