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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Healthy Processed Foods Research » Research » Publications at this Location » Publication #314521

Title: Glycation inhibits trichloroacetic acid (TCA)-induced whey protein precipitation

item YI, JIANG - Jiangnan University
item Zhang, Yuzhu
item Yokoyama, Wallace - Wally
item LIANG, FANG - Jiangnan University
item ZHONG, FANG - Jiangnan University

Submitted to: European Food Research and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2014
Publication Date: 12/2/2014
Citation: Yi, J., Zhang, Y., Yokoyama, W.H., Liang, F., Zhong, F. 2014. Glycation inhibits trichloroacetic acid (TCA)-induced whey protein precipitation. European Food Research and Technology. 240(4)847-852. doi: 10.1007/s00217-014-2391-9.

Interpretive Summary: The first stage of Maillard reactions is the glycation reaction between free amino groups from proteins and reducing sugars. Maillard reactions are important in flavor studies and in studies aimed at understanding the processing effects on the allergenicity of food allergens. This study used “dry heating” to produce whey protein isolate (WPI) complexes with reducing saccharides under conditions that have been widely used to study Maillard reactions. The effects of glycation with different reducing saccharides on WPI stability and solubility were studied. Glycation increased the denaturation temperature of the WPI and glycation with polysaccharides also protected inhibited trichloroacetic acid induced WPI precipitation.

Technical Abstract: Four different WPI saccharide conjugates were successfully prepared to test whether glycation could inhibit WPI precipitation induced by trichloroacetic acid (TCA). Conjugates molecular weights after glycation were analyzed with SDS-PAGE. No significant secondary structure change due to glycation was detected. Glycation decreased the apparent denaturation enthalpy and increased denaturation temperature (Td). The TCA-induced WPI precipitation profiles were shown to be U-shaped. The attachment of maltodextrin and dextran increases WPI solubility against TCA-induced precipitation. However, similar effects were not observed when WPI was glycated with monosaccharide (mannose) and disaccharide (maltose), even though the degrees of glycation were significantly higher, compared to WPI-maltodextrin or WPI-dextran conjugates. The effects against precipitation depended on the molecular weight of saccharides, while the effects of the degrees of glycation were not pronounced. Steric hindrance may be the reason to inhibit TCA-induced protein precipitation after glycation. The information of this study provided may extend our knowledge about TCA-induced protein precipitation mechanism.