Changes in protein and fat structure in whipped cream caused by heat treatment and addition of stabilizer to the cream

摘要

Whipping cream, at 36/100 fat, was high temperature short time pasteurized (75deg.C, 16 s), or ultra-high temperature sterilized (l40deg.C, 4 s), with and without added stabilizer. Maximum overrun foams were stored for 24 h (5deg.C) for comparison of fresh and aged foams. Electrophoresis results showed no significant change in protein composition on the milk fat globule membrane because of heat treatment. Freeze-substitution and transmission electron microscopy showed that partial coalescence can be a two stage process, small globules coalesce and then these larger globules partially coalesce. Partially coalesced fat became part of the air/ serum interface and added viscosity to the serum phase. The network of protein in the serum phase of whipped cream was found to deteriorate more in UHT heat treated whipped cream during storage than in foams prepared from HTST heat treated creams. This may account for the lack of stability in UHT sterilized and whipped cream.