Sweet potato starch (SPS) has limited uses in the Philippines, but modification of its properties may make it more suitable for use in traditional products that normally use other types of starch. Heat-moisture treatment was applied to native SPS (HMTSPS), which was used as a substrate and composite with maize starch (MS) to produce bihon-type starch noodles. Preliminary quality scoring showed that acceptability scores of raw starch noodles, plain boiled, and sautéed noodles made from 100% HMTSPS and 50% HMTSPS:50% MS were not significantly different from the commercial bihon. However, consumer testing is recommended to further validate acceptability of the sweet potato for bihon.

Cereal Chem. 74(5):681-686Sweetpotato flours vary widely in color depending on genotype, and when used in wheat-based composite flours, they will impart characteristic colors which may be favorable or unfavorable for particular food products. Sweetpotato flour (SPF) was prepared from 44 genotypes and analyzed for proximate composition and biochemical properties. The Hunter Color L*, a*, b* values of the dry SPF and their modified Pekar slicks (PS) with water and with alkali were measured. Polyphenol oxidase activity, α-amylase activity, and total sugar were significantly correlated to L* values of dry SPF and of their PS tests with water and with alkali. The yellow pigment level was significantly correlated to the yellowness (b*) of the dry flour and of the PS test with water, but less cor-related to b* of the PS test with alkaline. The results indicated a complex biochemical basis to SPF color, and no single biochemical factor examined was adequate to predict the color of a food product made from SPF. However, the PS color parameters were highly correlated with the color of dough sheets for white-salted and yellow-alkaline noodles made from wheat and sweetpotato composite flour (75:25). Thus, the simple modified PS test could be used in screening of genotypes for color stability and suitability for a specific end-use. SPF genotypes conferred a wide range of colors on composite flour dough preparations. Some colors, particularly the range of greens and bright orange, may be useful in specialty product development.

Beef, pork and lamb roasts were cooked by two 2450 MHz microwave ranges, one operated at 220V (1054W cooking power) and one at 1lSV (492W cooking uower) and by a conventional gas oven (163 f 3°C). The only significant effect related to power level of micrdwave ranges was retention of thiamine, riboflavin and niacin which was less in meat cooked by the micro\lave 115V than by the other two methods. There was a trend toward less retention of sodium, chloride, phosphorus and iron in meat cooked by microwaves than by the conventional method. Also, microwave cooking resulted in less formation of free amino acids than conventional cooking but total protein did not differ significantly.

Market samples of frozen peas were cooked with and without water in a domestic microwave oven (115V, 550 watts cooking power) and in an institutional microwave oven (220V, 1150 watts cooking power). Total ascorbic acid, as determined by the 2,4‐dinitrophenylhydrazine method, was higher in peas cooked without water regardless of cooking appliance. Microwave cooked peas tend to have greater retention of total ascorbic acid than those cooked conventionally.

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