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S. ARORA, J. N. Alviola, and R. D. Waniska. Dept. of Soil & Crop Sciences, Texas A&M Univ., 370 Olsen Blvd. Heep Ctr., 2474 TAMU, College Station, TX 77843-2474 Tortillas are increasingly becoming popular across the world. Since dry milling of wheat damages starch and wheat flour is the predominant ingredient in tortillas, the effect of damaged starch on tortilla processing and quality needs to be investigated. Amylases are normally added to wheat flour to moderate the effect of damaged starch and optimize flour quality. The objectives were to study the effects of starch damage on dough and tortilla properties and to determine if bacterial amylase could moderate the effects of damaged starch. Wheat flour was mechanically damaged for 0.5, 1, 4 and 8 hr using a conical-shaped stone, rotating grinder. Tortillas were prepared using pilot-scale, commercial tortilla equipment. Bacterial amylase (0, 0.05, 0.1 and 1 au/kg flour) was added to hydrolyze damaged starch. Subjective and objective properties for dough and tortillas were evaluated. Iodine absorbance increased linearly with starch damage (r=0.99), which increased from 5.4% to 12.6%. Flour with 9.7 or 12.6% damaged starch had significantly higher dough water absorption, toughness and press rating. Objective dough compression values supported subjective ratings. Tortillas made there from had smaller diameters and lower opacities, but improved shelf stability. All levels of bacterial amylase decreased ratings for dough smoothness and dough toughness of flours with 9.7 or 12.6% damaged starch. Tortillas prepared using damaged starch and bacterial amylase had properties similar to control. Wheat flours for tortillas should have low levels of starch damage since moderate to high levels of starch damage lowers all other tortilla qualities but improves tortilla shelf life. Bacterial amylase overcame the negative effects of higher levels of damaged starch. Further research is needed to understand how starch damage influences tortilla quality.
Session 93, Carbohydrate: General
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