| Summary: | Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item. Includes bibliographical references. Five sorghum varieties, Dorado, Malisor 84-7, Tortillero, ATx630*R3338, and ATx623*SC1 03 were malted according to standard procedures and monitored for malting quality and starch modification during a 5 day malting period. Dry matter losses (DML) and (x-and B-amylase activities increased with longer germination time. After 5 days of malting, ot-and B-amylase activities were highest in Dorado and lowest in Malisor 84-7. (x-Amylase activity in Dorado was 70% and B-amylase activity was 65% of a commercial barley malt reference. Starch decreased and enzyme susceptible starch increased with longer germination time. Apparent starch loss was highly correlated with DML and a-and B-amylase activities. The amount of soluble amylopectin at 850C decreased during malting for all varieties. The amount of soluble amylopectin at 1200C decreased for all normal endosperm varieties during germination. Malting increased the proportion of starch soluble at 1200 and 850C. Dextrins (MW 3.0 X 1 03 to 6.1 X 103 ) developed during malting in all varieties. After 5 days of malting, dextrin content ranged from 19.5% (Dorado) to 5.1% (Malisor 84-7) Dextrin development was delayed in Malisor 84-7 and Tortillero until germination day 1 or 2. ATx630*R3338 produced significantly more dextrins during the germination period. Dextrin content of the commercial barley malt was 15.6%. Total sugars (DP 1 to DP 6) increased during malting. After 5 days of malting, ATx623*SC1 03 had the highest amount of sugars (1 1.6%) and Malisor 847 had the lowest amount of sugars (6.6%). A commercial barley malt sample contained 10.6% sugars. Sucrose and glucose were the predominant sugars detected in malt. Enzyme activity, endosperm composition (normal versus waxy), and endosperm hardness affect the modification of starch during malting. Few changes in the starch profile were seen in Malisor 84-7 during malting possibly due to low enzyme activities. ATx623*SC1 03 (soft, normal endosperm) and ATx630*R3338 (intermediate, waxy endosperm) were able to mobilize starch and accumulate lower molecular weight carbohydrates more efficiently than Dorado although enzyme activities were not as high.
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