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P. Linko, Y.-Y. Cheng, and M. Milner. Copyright 1960 by the American Association of Cereal Chemists, Inc. Changes in the soluble carbohydrates of wheat embryos as affected by storage at temperature and moisture values pertinent to conditions which produce germ-damaged ("sick") wheat in commercial grain were investigated chromatographically. From the total sugar content of 28.6% in commercial wheat germ, raffinose (38.1%) and sucrose (55.9%) are the major components, with fructose (2.8%), glucose (2.1%), and melibiose (1.1%) present in smaller quantities. Storage for 8 days at various moisture contents from 8.9 to 25%, and temperatures from 29 to 50 C., produced characteristic increases of reducing sugars, at the expense of the nonreducing. Browning, as indicated by fluorescence, increased with moisture content and temperature, but only after discoloration was visually apparent, and particularly at moisture values beyond 15%. A decrease in nonreducing sugars, as well as an increase in reducing carbohydrates which apparently form browning intermediates with available free amino acids, preceded marked increases in fluorescence. At moisture levels related to practical storage conditions, several unknown sugarlike compounds appeared quickly in stored commercial germ. These compounds disappeared later as fluorescence values rose. However, only one of these unknowns appears in intact viable wheat grains when sufficient moisture permits germination. |
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