The increase in levels of free fatty acids (FFA) in morning and afternoon milk after 48 h cold storage at 5 °C was determined at two stages of lactation in milk from 96 cows. Lipolysis was positively correlated to day of lactation (r = 0-6, P < 0-001), while the correlations between lipolysis and milk yield and fat content respectively were due to these factors being related to day of lactation. In afternoon milk the level of FFA increased almost three times above that in morning milk. Lipolysis was closely related to the Hpoprotein lipase (LPL) activity associated with the cream fraction (r = 0-8, P < 0-001). Afternoon milk had higher LPL activity in the cream fraction than morning milk. Lipase activity in the cream increased with increasing stage of lactation. Cooling of milk increased LPL activity associated with the fat phase. This effect was greater in afternoon milk from late lactation than in morning milk from early lactation. When heparin was added to milk the LPL activity associated with the fat increased substantially; again, this effect was greater in afternoon milk from late lactation than in morning milk from early lactation. Lipolysis was higher in heparinized milk than in normal milk, and there was a close correlation between lipolysis and LPL activity associated with the fat (r = 0-82, P < 0-001). Characteristics of the milk fat globule influencing the attraction of LPL were found to be fundamentally important to lipolysis.

BADGE-based epoxy resins have been commercially available for more than 40 years. They are extremely versatile, finding applications in many fields in both thermal and ambient cure applications. The present review focuses on their use in the food industry as surface coatings for food and beverage cans, and in particular on their chemical stability in relation to their toxicology and sensorial effects on foods. The implications of these properties of epoxy resins for prospective EU legislation on plastic coatings for food contact is discussed.

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[Hydrogen-3] glycerol ether and [carbon-14] hexadecanol were infused into the mammary gland or jugular vein of cows in colostral or full phases of lactation to determine their relative rates of synthesis and degradation. Neutral alkylglycerols were both synthesized and cleaved in the bovine gland. Oxidation of fatty alcohols and cleaving of neutral alkylglycerol ethers was faster during the milk than the colostral phase of lactation. In the colostral phase, both increased rate of synthesis and decreased cleavage contributed to increased neutral alkylglycerol concentration; however, synthesis changes were greater. Disappearance of [carbon-14] fatty alcohol and [hydrogen-3] alkylglycerol ether from the blood was the magnitude of fatty acid disappearance in previous studies, but uptake by the mammary gland was slower. Alkylglycerols were taken up from the blood and secreted intact into both colostrum and milk.

The concentrations of dihydroxyacetone phosphate (DHAP), glycerol-3-phosphate (GP), glucose and alkylglycerols were measured in bovine colostrum and milk. Concentrations of GP were higher in colostrum than in milk, and corresponded to intracellular concentrations at the onset of lactation. This suggests that GP equilibrates over the apical membrane at onset of lactation, which is believed to occur also in full lactation. The ratio of DHAP to GP showed a peak in colostrum that was more than twice that in milk, indicating that concentration changes in colostrum/milk were not caused by dilution. DHAP was positively correlated to metabolical compounds such as glucose and alkylglycerols. As DHAP is a required precursor for alkylglycerol synthesis, the positive correlation suggests that DHAP may be limiting for alkylglycerol synthesis and thus could explain the elevated levels of alkylglycerols found in colostrum.