33A-3 |
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K.-J. Lee1, Y.-R. Kim2, and J. SHIM1. (1) Food and Bio Technology, Hankyong National University, 67 Sukjong dong, Ansung city, Kyonggi-do, South Korea, (2) Food Science and Technology, Seoul National University, San 56-1 Shilim dong, Kwanak gu, Seoul, South Korea Dry-heating of starch could be a possible method for convenient modification of starch. Moreover, it could induce the interaction between starch and charged polymers (Lim et al, 2002). Incorporation of soy protein into starch-based foods could be beneficial in the nutritional aspect. Based on these, in this research, the feasibility of starch modification using dry-heat treatment with soy protein was examined and the properties of the modified starch gels were characterized. Our objective was to investigate the effect of soy protein addition and dry-heat treatment on the pasting and gelling properties of corn starch Dry-heated samples were prepared by, first, drying the corn starch solutions with 3% soy protein isolate (SPI) at 40°ĘC and then heating them at 130°ĘC for 4 hrs. The pasting properties of the starch samples and the textural properties of the starch gels were measured using a Rapid Visco-Analyzer and Texture Analyzer, respectively. The effect of SPI and dry heating on the retrogradation and microstructure of gel samples were also investigated by DSC and SEM, respectively. Pasting and textural properties of corn starch samples and their gels were modified by dry-heating with SPI, suggesting the possible occurrence of interactions between starch and protein. Pasting viscosity was significantly higher for dry heated samples compared to unheated samples, and at pH8 compared to at pH6. Dry-heat treatment increased elastic modulus and decreased fracture stress and strain of starch gels containing SPI. During storage, retrogradation of starch gel was retarded by addition of SPI. There was no significant effect of dry-heat treatment and pH on the retrogradation of starch gels. Addition of SPI retarded starch retrogradation and modified the properties of starch gels with increased nutritional value. Dry-heat treatment with SPI could be a possible method for starch modification.
Session 33A, Carbohydrate: General
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