Peanut stearins(PeS),the winterisation product of peanut oil in the plant,were used as raw ma-terials to study their properties and to solve the problems of insufficient research,limited application and low added value of PeS.The physicochemical properties of the three PeS were analysed,and their thermo-dynamic properties,crystal polymorphism and crystal micromorphology were investigated by differential scanning calorimetry(DSC),X-ray diffraction and polarized light microscopy.The major fatty acids of PeS determined by gas chromatography were oleic(O,31.56％-35.77％),linoleic(L,33.40％-35.98％)and palmitic(P,11.94％-14.11％)acids,followed by stearic(St,7.00％-8.83％),behenic(Be,4.69％-6.27％),arachidic(Ad,2.74％-3.52％),lignoceric(1.31％-1.89％)and eicosenoic(0.44％-0.59％)acids,and the iodine values(Ⅳs)of PeS were in the range of 85.33-93.53 g/100 g.PeS is mainly composed of tri-unsaturated triglycerides and mono-saturated di-unsaturated triglycerides.Due to the high content of unsaturated triglycerides,PeS had relativelly low SFC and crystallized slowly.In the range of 0-25℃,SFCs of PeS increased with the saturated fatty acids increasing at a given temperature.The slip melting points of PeS increased with Ⅳ decreasing and ranged from 22.1℃ to 26.3℃.The results of the thermal analysis exhibited that PeS showed two strong and wide endothermic peaks in the range of-30-0℃ and 0-25℃ in the melting process while presenting one wide exothermic peak in the range of-20-20℃ during the crystallization process.Two distinct diffraction peaks close to 4.10 and 3.70 Å presen-ted in PeS were attributed to the β′ form crystal.The crystal cluster of PeS with lower Ⅳ was feather blade-like and the aggregates of the clusters of them were rosette-like.However,PeS with higher Ⅳ showed cloud-like morphology.PeS exhibited one-step crystallization with various lag periods at 15℃.PeS could be used as base stock in plastic fat preparation through blending or interesterification with other hard fats.
万方数据
维普
