دانلود رایگان مقاله بررسی ترکیب تری اسیل گلیسرول و ساختار اولئیک روغن کلزا

ABSTRACT

The composition of fatty acids in triacylglycerides (TAGs) and their position on the glycerol backbone determine the nutritional value of vegetable oil. In this study, gas chromatography and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) were used to analyze the composition and distribution of fatty acids in TAGs of different rapeseed oils. Our results show the content of oleic acid in high-oleic-acid rapeseed oil to be about 80%. In terms of the number of acyl carbon atoms (CN), TAGs with CN52–C54 were most abundant, with a maximum concentration at CN54 (80%). The main type of TAG was oleic-oleic-oleic (OOO), accounting for 71.75%, while oleic-oleic-linoleic (OOL) accounted for 7.56%, oleic-oleic-linolenic (OOLn) accounted for 4.81%, and stearic-oleic-oleic (SOO) accounted for 4.74%. Oleic acid in high-oleic-acid rapeseed oil was distributed in the following order of preference: sn-2 > sn-1/3. In high-erucic-acid rapeseed oil, however, oleic acid was enriched at the sn-1/3. These data show that the content of oleic acid can be as high as about 80% in high-oleic-acid material. This finding suggests that high-oleic-acid rapeseed oil has high nutritional value.

3. Results

3.1. Fatty-acid composition of rapeseed oil Table 1 presents the composition of fatty acids and their relative percentages in the six tested samples. The results showed the oleic acid content to be 85.31% and 74.67% in samples 1 and 2, respectively, while in samples 3 and 4, the oleic acid content was 60.48% and 64.90%, respectively. The oleic acid content was 23.05% and 24.07% in samples 5 and 6, respectively. The content of erucic acids and eicosenoic acids was rich in samples 5 and 6. 3.2. The number of acyl carbon atoms in the fatty acids of TAGs in rapeseed oil The total carbon number (CN value) of the acyl chains in the fatty acids of TAGs in the six samples of rapeseed was analyzed using a VF-5ht capillary column with GC-FID detection. The results showed that the CN values of the TAGs in samples 1–4 were 52 and 54, while samples 5 and 6 had a wide range of CN values (from 52 to 62), as shown in Table 2.