分光光度法测定一级大豆油色泽的研究

COLOR DETERMINATION OF FIRST-GRADE BEAN OIL BY SPECTROPHOTOMETRY

以一级大豆油为研究对象,分析了分光光度法与罗维朋比色法在固定黄值、不固定黄值时测定结果之间的关系.固定黄值的结果表明：分光光度法在430~480 nm之间的吸光度和X轴所围面积与罗维朋比色法的测定结果具有较好的相关性,对于浅色一级大豆油,黄值固定为3,判定系数r2为0.789 0,对于颜色较深的一级大豆油,黄值固定为10,r2为0.944 7.不固定黄值的测定结果表明：对同一种色泽的大豆油,分光光度法的测定结果唯一,不存在罗维朋比色法因操作者不同造成的较大误差,还可以根据等高线在底面的投影分布严格划分油脂色泽等级;并且得出了普通市售一级大豆油黄、红值与积分面积三者的对应关系.

Selecting first-grade bean oil as object,we studied the relationship between the determination results of spectrophotometry and Lovibond colorimetric method under the conditions of fixing yellow value and not fixing yellow value. For fixed yellow value,the results showed that the absorbance and area surrounded by the X axis of the spectrophotometry had good correlation with that of the Lovibond colorimetric method in 430 to 480 nm;the yellow value was set to 3,and the determination coefficient r2 was 0.789 0 for light-color first-grade bean oil;and the yellow value was set to 10,and the determination coefficient r2 was 0.944 7 for deep-color first-grade bean oil. For unfixed yellow value, the results showed that the determination result of spectrophotometry was unique;however,the Lovibond colorimetric method had large error caused by different operators;the color grade of the oils can be strictly classified according to the projection distribution of contour lines on the bottom surface;and the corresponding relationship between yellow value,red value and integral area of the common commercial first-grade bean oil was obtained.