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Effect of processing conditions on microstructure of milk fat fraction/sunflower oil blends
Author(s) -
Martini S.,
Herrera M. L.,
Hartel R. W.
Publication year - 2002
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-002-0604-5
Subject(s) - crystallization , sunflower oil , materials science , crystal (programming language) , microstructure , mass fraction , ice crystals , fraction (chemistry) , optical microscope , analytical chemistry (journal) , sunflower seed , sunflower , composite material , chemical engineering , chemistry , chromatography , scanning electron microscope , optics , mathematics , biochemistry , physics , computer science , engineering , programming language , combinatorics
The effect of processing conditions on the crystallization of blends of a high‐melting milk fat fraction and sunflower oil was investigated. Two cooling rates were selected for all studies: 0.1°C/min (slow rate) and 5.5°C/min (fast rate). Blends were crystallized in two conditions: (i) with agitation in an 80‐mL crystallizer (dynamic), and (ii) on a microscope slide without agitation (static). The selected crystallization temperatures were 25, 30, and 35°C for both cooling rates. Photographs of the development of crystals with time were taken in both static and dynamic conditions, and the crystal size distribution was determined at the moment that the laser signal reached its peak. Photographs showed that when samples were cooled slowly, crystals had a more regular boundary, appeared to be more densely arranged, and were larger. In dynamic conditions, crystal sizes were smaller and the background contained numerous small crystals, which were not found in statically crystallized samples. All images showed that crystals were not single crystals, but grew by accretion.