我国代表性油种脂肪酸组成分析及热稳定性研究
发布时间:2018-06-10 11:01
本文选题:植物油 + 脂肪酸 ; 参考:《湖南农业大学》2013年硕士论文
【摘要】:不同油种具有不同脂肪酸组分及含量,油脂经过加热之后,其脂肪酸组分和含量也会发生巨大变化。脂肪酸是评价食用油品质的重要指标之一,其组成、含量和比例在很大程度上决定了食用油的营养价值。本试验通过比较不同升温程序和气体流速等色谱参数条件下脂肪酸甲酯混合标准品以及反式脂肪酸甲酯标准品的分离情况,优化分离效果的色谱参数。在气相色谱条件优化的前提下,从我国10个地区以及网上商城采集了11个品种共计141个样品的植物油,利用气相色谱法检测各植物油的脂肪酸组分,分析我国代表性植物油的脂肪酸特点,并且选择富含n-6脂肪酸的玉米油,富含n-9脂肪酸的茶油,富含n-3脂肪酸的亚麻籽油进行加热试验。得到以下结果: 1.选用CP-sil88毛细管气相色谱柱(100mx0.25mm id×0.2μm),进样口和检测器温度分别为250℃,260℃;流速和柱流速分别为68.8ml/min,0.65ml/min;线速率为14.3cm/s;吹扫流量为3.0ml/min;分流比为100:1;进样量为1ul时,可使各脂肪酸组分达到基线分离。该方法的精密度试验和加标回收率结果良好,适合植物油的脂肪酸检测尤其是反式脂肪酸的检测。 2.食用植物油中花生油的饱和脂肪酸含量最高,为18.54g/100g;菜籽油和核桃油的饱和脂肪酸含量均低于其他植物油种,低于8g/100g。茶油和橄榄油富含单不饱和脂肪酸,分别为78.02g/100g和73.88g/100g;核桃油单不饱和脂肪酸含量最低,为7.70g/100g。核桃油和亚麻籽油富含多不饱和脂肪酸,含量分别为68.38g/100g、64.37g/100g。核桃油中多不饱和脂肪酸主要为n-6脂肪酸,含量为59.56g/100g;亚麻籽油中多不饱和脂肪酸主要为n-3脂肪酸,含量为47.90g/100g。市售桶装植物油中,橄榄油不含反式脂肪酸,其他植物油中都含有微量的反式脂肪酸。不同种类植物油各脂肪酸比例存在较大差异,采集的植物油中饱和脂肪酸/单不饱和脂肪酸/多不饱和脂肪酸的比值范围为1:1.5~8.6:0.5~8.9,n-6/n-3的比值范围为0.3~317.1:1。 3.低温以及短时间的加热对植物油的影响比较小,高温、长时间的加热会明显影响植物油的脂肪酸组分和含量。在同一加热温度下,随着加热时间的延长,三种试验油的各脂肪酸与时间均具有相关性。与未加热试验油相比,随着加热时间的延长以及加热温度的升高,加热后试验油的过氧化值,茴香胺值和总氧化值均出现明显增加。
[Abstract]:Different kinds of oil have different fatty acid composition and content. After heating, the fatty acid composition and content of oil will change greatly. Fatty acid is one of the important indexes to evaluate the quality of edible oil. Its composition, content and proportion determine the nutritive value of edible oil to a great extent. The chromatographic parameters of separation effect were optimized by comparing the separation of mixed standard and trans fatty acid methyl ester under different temperature program and gas flow rate. On the premise of optimizing the gas chromatography conditions, the vegetable oils of 11 varieties and 141 samples were collected from 10 regions and online shopping malls in China, and the fatty acid components of each vegetable oil were detected by gas chromatography. The fatty acid characteristics of typical vegetable oils in China were analyzed, and the heating test was carried out with corn oil rich in n-6 fatty acids, tea oil rich in n-9 fatty acids and flaxseed oil rich in n-3 fatty acids. The results are as follows: 1. A CP-sil88 capillary gas chromatographic column (100mx 0.25mm id 脳 0.2 渭 m) was used, the injection port and detector temperature were 250 鈩,
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