Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6397778 | Food Research International | 2013 | 8 Pages |
Abstract
Freezing processing is widely used in food industry, but some key scientific issue is still unclear. In this paper, the effects of freeze-thaw cycles on the molecular weight, radius of gyration, free amino group content, free sulphydryl group content and molecular conformation of gluten were investigated by size-exclusion chromatography in conjunction with multi-angle laser light scattering (SEC-MALLS), spectrophotometry and atomic force microscopy (AFM). The results showed that during the freeze-thaw cycles (frozen at â 18 °C with cycling to 0 °C for 12 h and then back to â 18 °C per 10 days) the molecular weight and radius of gyration of the gluten proteins decreased with the increase in freeze-thaw cycles, implying a depolymerisation in the high-molecular-weight fraction of the gluten. The free amino group content changed only slightly, and the free sulphydryl group content of the gluten increased from 9.8 μmol/g for the control to 13.87 μmol/g for the gluten stored for 120 days and submitted to 12 times freeze-thaw cycling, indicating that the depolymerisation of the gluten during freeze-thaw cycling was due to the breakage of disulphide bonds. AFM images showed that the gluten chain formed a fibril-like branched network which was weakened with increasing freeze-thaw cycles storage time. Some aggregation of the gluten chains was also observed in the AFM images.
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Authors
Lei Zhao, Lin Li, Guo-qin Liu, Ling Chen, Xingxun Liu, Jie Zhu, Bing Li,