Encapsulation of proteins and peptides in milkfat: encapsulation efficiency and temperature and freezing stabilities

Encapsulation of aqueous protein solution was most efficient when the butter and protein solution emulsion was at 58 degrees C before dispersion into water, although encapsulation efficiencies were high between 46 and 66 degrees C. Capsules could be produced with no emulsifiers and an emulsion temperature of 66 degrees C but no capsules were formed when emulsion temperature was lowered to 38 degrees C. Capsules with encapsulated beta-casein peptides and with proteose peptone had similar low-temperature stabilities with a loss of about 10 per cent of the peptides after 24 h at 4 degrees C. However, capsules with beta-casein peptides were slightly more stable above 26 degrees C. Little diffusion of the haemoglobin from capsules occurred at less than 20 degrees C but above 32 degrees C capsules destabilized and the haemoglobin diffused out of the capsules. Capsules were stable after freezing at -90 degrees C and -18 degrees C and could be thawed and redispersed; a 15-25 per cent loss of capsules was observed during freezing. Concentrating capsules by removing all or one-half of the dispersion fluid did not increase stability to freezing.