| Abstract
| - Whey powders have attracted attention for use in the food industry. The Maillard reaction is amajor deteriorative factor in the storage of these and other dairy food products.The objective of thepresent work was to further study the Maillard reaction as related to the physical structure of thematrix, either porous or mechanically compressed, or to storage above the Tg of anhydrous wheysystems. Sweet whey (W), reduced minerals whey (WRM), whey protein isolate (WPI), and wheyprotein concentrate (WPC) were stored in ovens at selected temperatures. Colorimetric measurementswere performed with a spectrocolorimeter, thermal analyses (TGA) by means of a thermobalance,and glass transition temperature studies by DSC. The browning order in the vials and in thecompressed systems followed the order W > WRM> WPC > WPI. kw2, the slope of the second linearsegment of the TGA curve, was related to the loss of water due to nonenzymatic browning (NEB).Browning development was in good relationship with this loss of weight. In the glassy state, thecompressed systems developed higher rates of browning and weight loss (assigned to NEB reactions)than the porous systems. Reaction rates in both (porous and compressed) systems became similaras (T − Tg) increased. Keywords: Browning; whey powder; glass transition; compression
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