18A-19 |
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C. YU, Dept. of Food Science and Biotechnology, Kyung Hee Univ., 1 Seochun, Yongin, 449-701, South Korea, H.-W. Choi, Starches and Sweetener Division/R&D Center, Daesang Corp., 125-8, Pyokyo-ri, Majang-myun, Ichon, 467-813, South Korea, D.-S. Kim, Dept. of Food Science, Milyang National Univ., 1025-1 Nae 2 Dong, Miryang, 627-130, South Korea, N.-Y. Hur, Dept. of Food and Culinary Art, Osan College, 17, Chunghak-Dong, Osan, 447-749, South Korea, B.-Y. Kim, Dept. of Food Science & Technology, Kyung Hee Univ., Seochun 1, Yongin, South Korea, and M.-Y. Baik, Dept. of Food Science and Technology, Kyung Hee Univ., Seochun 1, Yongin, 449-701, South Korea. Starch is one of the most widely used ingredients in the food industry. There is a limitation on native starch for special uses. Chemical modification of starch is an alternative way to produce tailor-made product. Cross-linking provides heat, acid, and shear resistance by making chemical bonds between molecules in the granule. On the other hand, hydroxypropylation provides shelf-stability, freeze-thaw stability, and cold storage stability by weakening the internal hydrogen bond strength. Although physicochemical properties of modified starch are well established, they are focused on single modification and limited information is available on cross-modified starches. The objective of this work is to investigate the physicochemical properties of cross-modified starch, which focused on the effect of hydroxypropylation on cross-linked rice starch. Rice starch was cross-linked using phosphorous oxychloride (0.005%, 0.02%). Cross-linked rice starches were then hydroxypropylated using propylene oxide (2%, 6%, 12%). Physicochemical properties of cross-modified (cross-linked and hydroxypropylated, CLHP) rice starches were investigated using RVA and DSC. Swelling power of CLHP rice starches increased at relatively lower temperature than native rice starch. CLHP rice starches showed lower solubility than native rice starch and solubility increased with increasing the amount of propylene oxide. For RVA characteristics, peak viscosity of CLHP rice starches were lower than native starch and holding strength and final viscosity higher than native starch. DSC thermal transitions of CLHP rice starches were shifted to lower temperature than native rice starch as the degree of hydroxypropylation increased. Overall, physicochemical properties of cross-modified rice starch was highly dominated by first modification and second modification showed relatively small impact. However, second modification could not be negligible since it also changes the physicochemical properties of single modified starches. This work provides the basic and scientific information on the physicochemical properties of cross-modified (CLHP) rice starch.
Session 18A, Carbohydrate: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |