Composition of Granules in Evaporated Milks Stored at Low Temperatures

Reviews of the progress of Dairy Science: Frozen concentrated milk

“…This product had received severe heat treatments both during fore warming and during sterilization and as a result the whey protein was completely denatured. However, Fox et al (1967) have reported the formation of granules during prolonged refrigerated storage (at + 2 to +4°C).…”

“…Further independent evidence supports the hypothesis that crystallization is the rate-controlling factor in destabilization of frozen concentrated milk. For example, when the disaceharide lactose is hydrolysed to glucose and galactose by the enzyme /?-galactosidase the rate of precipitate formation is greatly reduced (Stimpson, 1954;Tumerman et al 1954;Johnson & Tumerman, 1962;Guy et al 1974;Andresen & Barfoed, 1978;Guy, 1982). The relation between the extent of hydrolysis and the shelf life at -9-4 °C for three-fold concentrated milk is shown in Fig.…”

“…This saltiness is a well-known phenomenon in full-cream evaporated milk where phosphate is added as a stabilizer, but in that case it is masked by the cooked flavour which results from processing. More seriously, there is evidence of other defects associated with oxidation of fat during prolonged storage (Guy, 1982). Polyphosphate addition seems to promote destabilization of the fat emulsion during frozen storage of concentrated milk and the liberated free fat is then rendered accessible to oxidative deterioration (Leviton et al 1966).…”

“…However, it is only in the last 5 or 6 years that /?-galactosidases suitable for food use have become available at a commercially viable price. For this reason, the recent paper by Guy (1982) gives the only detailed report of the application of lactose hydrolysis to a practical process. Guy's work refers to goat milk concentrates but there is no doubt that it would be equally applicable to bovine milk.…”

Influence of surfactants on the conformation of β‐lactoglobulin B using circular dichroism

“…15 Following ammonium sulfate precipitation, the dialyzed sample was lyophilized and stored a t 2°C until used. The yield was 6.1 from 8 L of fresh whole milk.…”