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Effect of sulphydryl reagents on the heat stability of whey protein isolate
- Wijayanti, Heni B., Bansal, Nidhi, Sharma, Ranjan, Deeth, Hilton C.
- Food chemistry 2014 v.163 pp. 129-135
- glutathione, heat stability, lactalbumin, whey protein isolate
- The effects of sulphydryl (–SH) reagents on protein aggregation reactions in heated whey protein isolate (WPI) and pure α-lactalbumin (α-La) were investigated. In contrast to its previously reported effect with pure β-Lg, dihydrolipoic acid (DHLA) markedly reduced the heat stability of WPI, especially the α-La component, which aggregated much more readily in the presence of DHLA than in WPI alone. Whilst pure α-La is quite stable to heat, it is much less stable in the presence of DHLA. An effect similar to DHLA was observed with reduced glutathione (GSH). N-ethylmaleimide (NEM), and to a lesser extent, dithio(bis)-p-nitrobenzoate (DTNB), improved the heat stability of WPI; these reagents had little effect on α-La.