Effect of thermal treatment on the protein profile of whey from ovine and caprine milk throughout lactation

The independent and combined effects of temperature, heating period and stirring rate on the extent of precipitation of each of the major proteins in ovine and caprine acid wheys at various stages of lactation were studied using two-level, replicated, complete factorial designs. Evaluation of the extent of precipitation was based on the quantitative results obtained by gel permeation chromatography. Statistical analyses indicated that temperature is the most important factor in the precipitation of u-lactalbumin and /I-lactoglobulin from acid whey from both ovine and caprine milks. The magnitude of the independent effects of heating time and stirring rate on the precipitation of B-lactoglobulin and a-lactalbumin from ovine whey reached local maxima as lactation elapsed, but such effects were rather small for caprine whey.