Schmelzer J M, Hartel R W
Pillsbury Co., Minneapolis, MN 55414, USA.
J Dairy Sci. 2001 Feb;84(2):332-44. doi: 10.3168/jds.S0022-0302(01)74482-7.
The objectives of this study were to provide a better understanding of the effects of triacylglycerol (TAG) and non-TAG components (minor lipids) of milk fat on phase and crystallization behavior of binary mixtures of palm kernel oil (PKO) and the physical properties of corresponding compound coatings. Binary mixtures of a fractionated PKO with the different milk fats were examined for melting profiles, crystallization kinetics, and crystalline microstructures, and polymorphic changes during storage. Compound coatings were made with equivalent binary fat mixtures and measured for hardness and bloom formation. Milk fat and milk fat fractions affected crystallization rates of fractionated PKO, depending on the melting point of the fat. High-melting components resulted in more rapid crystallization, whereas the original milk fat and low-melting components inhibited crystallization. The crystal structure (e.g., number, size, shape) of the PKO crystals was influenced significantly by the addition of milk fat fractions and was influenced by the presence or absence of the minor lipids in milk fat. Milk fat and milk fat fractions had a softening effect on fractionated PKO, which was apparent in the binary mixtures as well as the compound coatings. In general, as the solid fat content (at 25 degrees C) of the binary mixtures increased, the hardness of the respective coatings increased. This also was related to an increased rate of bloom formation during storage.
本研究的目的是更深入了解乳脂肪的三酰甘油（TAG）和非TAG成分（微量脂质）对棕榈仁油（PKO）二元混合物的相行为和结晶行为以及相应复合涂层物理性质的影响。对分馏PKO与不同乳脂肪的二元混合物进行了熔点曲线、结晶动力学、晶体微观结构以及储存期间多晶型变化的研究。用等量的二元脂肪混合物制备复合涂层，并测量其硬度和起霜情况。乳脂肪和乳脂肪组分影响分馏PKO的结晶速率，这取决于脂肪的熔点。高熔点成分导致结晶更快，而原始乳脂肪和低熔点成分则抑制结晶。PKO晶体的晶体结构（如数量、大小、形状）受乳脂肪组分添加的显著影响，并且受乳脂肪中微量脂质存在与否的影响。乳脂肪和乳脂肪组分对分馏PKO有软化作用，这在二元混合物以及复合涂层中都很明显。一般来说，随着二元混合物在25℃时的固体脂肪含量增加，相应涂层的硬度增加。这也与储存期间起霜速率增加有关。
