Sweetpotato starch and flour research in Thailand.
1992
Maneepun S. | Reungmaneepaitoon S. | Yunchalad M.
Thirty-four sweetpotato varieties were grown in 1990 to study their chemical composition. The results were in the range of 57-71 moisture content, 3.19-12.06 dry weight, 4.96-12.83 fiber, 1.37-4.15 ash, and 28.6-43.1 dry matter. Based on these varieties, analysis of dry matter could be classified into three groups low, medium and high. Five varieties had below 31 for low; 19 varieties had 31-36 for medium; and ten varieties had over 36 for high. The starch content was below 20 for the low group (four varieties); 20-25 for the medium group (19 varieties); and over 25 for the high group (11 varieties). Starch extraction yield was in the range of 47.17-61.90. The amylase content of sweetpotato starch ranged from 25.45-3.48. Fractionated amylase was tested from the high amylase variety, Mae-Jo. Successful separation of amylase from sweetpotato starch was obtained by forming an amylase complex with 1-BuOH and diluted HCl. This mixture of starch and solvent was heated to 85 gradesC for 35 min, then cooled to room temperature and kept for 24 hrs. The fractionated yield was 36.16 and contained 49.07 amylase. The fractionated amylase was also characterized by the Scanning Electron Microscopy (SEM). Three were shredded and dried in a cabinet air dryer at 50 gradesC. The shreds dried sufficiently in about four hrs. Weight change, moisture content, and yield were analyzed. The percentage of yields after drying, based on whole roots, was 20.7-21.52. This uncooked flour was substituted (up to 40) for rice flour in snackfood processed by using a cooker extruder and village texturizer. These processing experiments have a promising potential for developement at the commercial level.
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