Influence of processing conditions on the physicochemical properties of complex fat systems Article uri icon

abstract

  • Three blends of soybean oil (SBO), coconut oil (CO), and palm stearin (PS) were crystallized at different shear rates (100 and 1,000 rpm) and processing temperatures (low and high) in a scraped surface heat exchanger. The SBO/CO/PS proportions (w/w) tested were 50/0/50 %25, 33/33/33 %25, and 16.7/16.7/66.6 %25. The physicochemical properties of the blends were analyzed by differential scanning calorimetry, texture analysis, microscopy, and the released oil (Ro) technique. The blends crystallized at 100 rpm developed two endotherms, which were associated with β and co-crystallized β′. In contrast, only the β′ polymorph was observed in blends processed at 1,000 rpm. After 28 days, the presence of β crystals and medium-chain TAG in the blends appeared to stimulate a transition of phase from β′ to β. In general, the hardness of the blends was directly related to the concentration of PS. The systems that were crystallized at 1,000 rpm demonstrated higher hardness, adhesiveness, and crystalline stability than those crystallized at 100 rpm. At both processing temperatures investigated, the blends with the highest Ro and permeability were obtained at 1,000 rpm. These characteristics were associated with the agglomeration of saturated TAG and were promoted by the initial crystallization conditions and migration of TAG during storage. At shear rates of 1,000 rpm and a PS concentration range of 50-66.6 %25, the Ro of the blends was 2-10 %25 with a lower solid fraction, an important signal of good stability. © 2014 AOCS.

publication date

  • 2014-01-01