Effect of pasteurisation on the chemical composition of liquid whole egg. II.—Comparison of the protein fractionation patterns of raw and pasteurised liquid whole egg

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Abstract
Samples of commercial raw and pasteurised whole egg were re‐examined after 41 weeks' storage under frozen conditions. As well as differences between the two samples, the protein fractionation patterns revealed marked differences from the original unstored material. A second comparison of commercial raw and pasteurised egg indicated that considerable differences could occur in the protein fractionation patterns of raw egg. This was confirmed in subsequent experiments.Two experiments on egg white showed that pasteurisation for 2 1/2 min at 135°F caused no change in the fractionation pattern of the proteins, and provided sound evidence for the reproducibility of the fractionation procedure.The separate influences of time and temperature of heating on liquid whole egg were studied in a series of laboratory‐scale pasteurisation experiments. It appeared that time was a more important factor than temperature and that a heating time of 5 minutes, which is approximately the time that the bulk of the egg is held at the pasteurising temperature in commercial plants, caused significant changes in the fractionation patterns of both soluble and insoluble proteins.When pasteurisation was carried out for 2 1/2 min at 148–152°F, and also when time was varied at 150°F, the thiol and disulphide concentrations of the soluble proteins were not altered by any of the pasteurisation conditions studied.A short study was made of the distribution of α‐amylase activity during the fractionation of the soluble proteins of raw whole egg.Preliminary experiments on gel filtration of the insoluble protein portions indicated that this technique is capable of revealing changes in molecular weight distribution resulting from pasteurisation and gave support to the view that heat treatment of whole egg results in aggregation or association of some of the proteins.