米糠蜡对稻米油基凝胶油形成的影响及动力学

以三级稻米油为基料油,研究了米糠蜡(rice bran wax,RBW)添加量对凝胶油形成特性的影响及凝胶油结晶形成的动力学参数。结果表明:在25℃时,RBW添加量为4%时便可形成凝胶油。随着RBW添加量的增加,凝胶油的硬度明显增加,贮藏30 d后凝胶油硬度变化不显著。凝胶油的固体脂肪含量也随RBW添加量的增加呈增多趋势,凝胶油主要为β′晶体。4%和7%RBW添加量凝胶油晶体为絮状,添加量为10%时凝胶油晶体转变为长枝晶状且密度增大。该凝胶油仅有一个结晶峰,采用Avrami方程模型拟合出的直线具有良好的线性关系(R~2=0.934 31),说明Avrami方程能较好地适用于稻米油基凝胶油结晶过程的研究,得到Avrami指数n为1.396 83,表明该凝胶油的晶体成核为均相瞬时成核并按照一维与二维混合结晶方式生长。

Effect of Rice Bran Wax on the Formation of Oleogel and Its Kinetics

In this paper, the effect of addition of rice bran wax (RBW) to third-grade rice bran oil (RBO) on the formation and crystallization kinetic parameters of oleogel was studied. The results showed that addition of 4% RBW showed gelling behavior in RBO at 25 ℃. The hardness of oleogels showed an increasing trend with the increase of RBW content and was not changed significantly after 30 days of storage. With the increase of RBW content, solid fat content of oleogels increased. And the crystal structure of oleogels mainly consisted of β’ crystal. The crystals of oleogels with 4% and 7% RBW were formed in floc shape. When the content of RBW was increased to 10%, the crystal of oleogels changed into a long dendritic shape and the spatial distribution density increased. As the oleogels had only one crystal peak, the Avrami equation model was used to study the crystallization kinetics and a good linear relationship was obtained (R2 = 0.934 31), indicating that Avrami equation could be applied to simulate the crystallization process of oleogels. The Avrami exponent n obtained by fitting the data was 1.396 83, suggesting the simultaneous occurrence of instantaneous nucleation and one-dimensional and two-dimensional crystal growth.