大豆油和菜籽油中游离脂肪酸与烟点的数学关系研究

Establishment of the Mathematical Model Between Free Fatty Acid and Smoke Point in Soybean Oil and Rapeseed Oil

随着食用植物油适度精炼理念的提出和被广泛认可,现行产品质量标准中用以反映油脂脂肪酸组成及非甘三酯组分在加热过程中呈现的与油脂热稳定性相关的感观数值之一——烟点,其范围设定的科学性研究就十分迫切和必要。然而,作为与烟点最为密切的油脂中游离脂肪酸含量与烟点的数学拟合方程均是基于现行国标酸值≤0.2 mgKOH/g油范围内,且未考虑油中磷、甘一酯、甘二酯等组分的影响。故本文以在不同批次一级大豆油和一级菜籽油中反添加油酸或亚油酸的方式,获得不同酸值的样品,在此基础上,研究适用于不同批次大豆油及菜籽油的酸值与烟点间的数学关系。最终利用SPSS软件的相关性分析和回归方程建立得到,一级大豆油体系和一级菜籽油体系中,游离脂肪酸含量(x,%)与烟点降低百分比(y,%)间满足y=9.879 8lnx+32.976(R^2=0.975 3)和y=11.039lnx+32.058(R^2=0.899 5)的数学关系,从而为适度精炼理念下,食用油质量标准制修订和指标增减提供有用的试验数据支撑。

As the widely acceptance of moderate refining, it was urgent to study the scientific of the set of the scope of smoke point, a sensory indicator in the current vegetable oil quality standard, which was related to the heat stability and reflected the compositions such as fatty acids and the non -triglyceride compounds. However, the existing mathematical equations between acid value and smoke point were based on the statistics below the acid value of 0.2 mgKOH/g oil, corresponded to the current national standard. Furthermore, the existing mathematical equations did not consider the effects of other ingredients, including phosphorus, monoglyceride and diglyceride. Therefore in this study, we collected different batches of grade one soybean oil and rapeseed oil, and then obtained vegetable oils with varying acid values by adding oleic acid or linoleic acid. According to the results of correlation analysis and regression equation, we established a mathematical equation between the increase percentage of free fatty acid （x, % ） and the decrease percentage of smoke point （y, % ）, corresponding to y = 9. 879 81nx ＋ 32. 976 （R2 = 0.975 3 ） for soybean oil and y = 11. 0391nx ＋ 32. 058 （R2 = 0. 899 5 ） for rapeseed oil, respectively. This study provided a theoretical support for the set of the indicators and revision of the scope in the quality standards that were suitable for moderate