Faculty of Food Science and Technology, Univ. Putra Malaysia, Serdang, Selangor 43400 UPM, Malaysia.
J Food Sci. 2011 Jan-Feb;76(1):C21-30. doi: 10.1111/j.1750-3841.2010.01922.x. Epub 2010 Dec 1.
The ability of palm oil (PO) to crystallize as beta prime polymorph has made it an attractive option for the production of margarine fat (MF). Palm stearin (PS) expresses similar crystallization behavior and is considered one of the best substitutes of hydrogenated oils due to its capability to impart the required level of plasticity and body to the finished product. Normally, PS is blended with PO to reduce the melting point at body temperature (37 °C). Lipid phase, formulated by PO and PS in different ratios were subjected to an emulsification process and the following analyses were done: triacylglycerols, solid fat content (SFC), and thermal behavior. In addition, the microstructure properties, including size and number of crystals, were determined for experimental MFs (EMFs) and commercial MFs (CMFs). Results showed that blending and emulsification at PS levels over 40 wt% significantly changed the physicochemical and microstructure properties of EMF as compared to CMF, resulting in a desirable dipalmitoyl-oleoyl-glycerol content of less than 36.1%. SFC at 37 °C, crystal size, crystal number, crystallization, and melting enthalpies (ΔH) were 15%, 5.37 μm, 1425 crystal/μm(2), 17.25 J/g, and 57.69J/g, respectively. All data reported indicate that the formation of granular crystals in MFs was dominated by high-melting triacylglycerol namely dipalmitoyl-oleoyl-glycerol, while the small dose of monoacylglycerol that is used as emulsifier slowed crystallization rate. Practical Application: Most of the past studies were focused on thermal behavior of edible oils and some blends of oils and fats. The crystallization of oils and fats are well documented but there is scarce information concerning some mechanism related to crystallization and emulsification. Therefore, this study will help to gather information on the behavior of emulsifier on crystallization regime; also the dominating TAG responsible for primary granular crystal formations, as well as to determine the best level of stearin to impart the required microstructure properties and body to the finished products.
棕榈油（PO）能够结晶为β'变体，这使其成为人造黄油脂肪（MF）生产的有吸引力的选择。棕榈硬脂（PS）表现出相似的结晶行为，由于其能够赋予成品所需的塑性和稠度，因此被认为是氢化油的最佳替代品之一。通常，PS 与 PO 混合以降低体温（37°C）下的熔点。PO 和 PS 以不同比例形成的脂质相经过乳化过程，然后进行以下分析：三酰基甘油、固体脂肪含量（SFC）和热行为。此外，还测定了实验性人造黄油（EMF）和商业人造黄油（CMF）的微观结构特性，包括晶体的大小和数量。结果表明，与 CMF 相比，PS 水平超过 40wt%的混合和乳化显著改变了 EMF 的理化和微观结构特性，导致二棕榈酰-油酰-甘油的含量低于 36.1%。37°C 时的 SFC、晶体尺寸、晶体数量、结晶和熔化焓（ΔH）分别为 15%、5.37μm、1425 个晶体/μm(2)、17.25J/g 和 57.69J/g。所有报告的数据表明，MF 中颗粒状晶体的形成主要由高熔点三酰基甘油即二棕榈酰-油酰-甘油主导，而作为乳化剂使用的少量单酰基甘油则减缓了结晶速度。实际应用：过去的大多数研究都集中在食用油的热行为和一些油脂的混合上。油脂的结晶已有详细的记录，但关于与结晶和乳化有关的某些机制的信息却很少。因此，本研究将有助于收集有关乳化剂对结晶状态的影响的信息；还确定了负责初级颗粒状晶体形成的主要 TAG，以及确定赋予成品所需的微观结构特性和稠度的最佳硬脂含量。
