33A-7 |
|
Y.-H. Chang1, J.-H. LIN1, C.-L. Pan1, and T.-J. Lu2. (1) Department of Food and Nutrition, Providence University, 200 Chung-Chi Rd., Shalu, Taichung, 43301, Taiwan, (2) Graduate Institute of Food Science and Technology, National Taiwan University, P.O. Box 23-14, Taipei, 106, Taiwan Acid hydrolysis of starch in alcohol solution has high recovery of treated starch and uses less amount of acid. For further understanding the effects of acid-alcohol treatment on starch, rice starch was treated in anhydrous methanol with different types and concentrations of acid. The result indicated that different acids had distinct effects on the molecular weight distribution and solubility of starch treated in methanol. The changes on molecular weight distribution and solubility of starch treated with HCl were more profound than that of starch treated with other acids. Effects of different types and concentrations of acid on molecular weight distribution and solubility of starches treated with different types of acid were realized. Rice starch (25 g, d.b.) was treated in anhydrous methanol (100mL) with 1mL of different types (HCl, HNO3, H2SO4 and H3PO4) and concentrations (2.5, 5.0, 7.5 and 10.0N) of acid at 45°C for 1h, the molecular weight distribution of starches was then examined by high performance size exclusion chromatography, and the solubility of starch was also determined. Results showed the content of F1 (amylopectin) fraction for all treated starches were lower than that of native starch. The F1 content of starch treated with HCl decreased with increasing concentration. Starch treated with 2.5 to 7.5N H2SO4 showed similar content of F1, whereas F1 content for starch treated with 10N H2SO4 obviously decreased. The F1 contents of starches treated with HNO3 and H3PO4 decreased slightly, and no obvious difference among starches treated with different concentrations was found. Solubility of starch showed increasing tendency after treated with acid, and was negatively correlated (r2>0.80) with the F1 content of starch. Starch treated with HCl showed decreasing on F1 content and increasing on solubility, and the changes of F1 content and solubility of starch depended on the concentration. The decrease of F1 content and increase of solubility of starch after treated with 10N H2SO4 was more obvious than treated with 2.5-7.5N H2SO4. Starch treated in HNO3 and H3PO4 showed less changes on the F1 content and solubility.
Session 33A, Carbohydrate: General
|