Authors: A Bazmi Perla Relkin
Publish Date: 2006/04/03
Volume: 84, Issue: 1, Pages: 99-104
Abstract
We studied thermal transitions and physical stability of oilinwater emulsions containing different milk fat compositions arising from anhydrous milk fat alone AMF or in mixture 21 mass ratio with a high melting temperature AMF–HMT or a low melting temperature AMF–LMT fraction Changes in thermal transitions in bulk fat and emulsion samples were monitored by differential scanning calorimetry DSC under controlled cooling and reheating cycles performed between 50 and –45°C 5°C min–1 Comparison between bulk fat samples and emulsions indicated similar values of melting completion temperature whereas initial temperature of fat crystallization Tonset seemed to be differently affected by storage temperature depending on triacylglycerols TAG composition After storage at 4°C Tonset values were very similar for emulsified and nonemulsified AMF–HMT blend whereas they were lower by approx 6°C for emulsions containing AMF or mixture of AMF–LMT fraction After storage at –30°C Tonset values of recrystallization were higher in emulsion samples than in bulk fat blends whatever the TAG fat composition Light scattering measurements and fluorescence microscopic observations indicated differences in fat droplet aggregationcoalescence under freezethaw procedure depending on emulsion fat composition It appeared that under quiescent freezing emulsion containing AMF–LMT fraction was much less resistant to fat droplet aggregationcoalescence than emulsions containing AMF or AMF–HMT fraction Our results indicated the role of fat droplet liquidsolid content on emulsion stability
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