基于GC和GC-MS技术检测果酒中的脂肪酸

Determination of Fatty Acids in Fruit Wine by GC and GC-MS Technologies

摘要:

脂肪酸对于果酒的风味具有重要意义。为建立一种准确分析果酒中脂肪酸的方法，采用有机溶剂液-液萃取法提取果酒中的脂肪酸，用硫酸-甲醇法进行甲酯化处理，优化了前处理条件，比较了两种前处理方法，确定了脂肪酸甲酯化最佳温度为80 ℃、最佳甲酯化时间为40 min。采用GC-MS配合标准品对8种果酒中的脂肪酸进行定性分析，以内标法结合外标法用GC进行定量分析，共检出脂肪酸组分28种，各果酒中所含脂肪酸的种类相近，其中，软脂酸的含量相对较高，其含量在各果酒脂肪酸总量中所占比例皆在25%左右。桑椹酒中检出的脂肪酸总量在8种果酒中最高，达78.21 mg/L。研究表明，该方法分析各脂肪酸含量的RSD均在5.0%以下，回收率均大于87%，该方法有较好的准确度及精密度，满足分析要求。

Abstract:

The fatty acids (FAs) play a significant role in the flavor of fruit wine. In order to establish an accurate analysis method for them, organic solvent liquid-liquid extraction was utilized to extract the fatty acids in fruit wine followed by methyl esterification with sulfuric acid-methanol. After comparing with two different pretreatment conditions, the optimum temperature for methyl esterification was set at 80 ℃ for 40 min. Eight types of fruit wine were qualitatively characterized based on the standard fatty acid samples with GC-MS and quantitatively tested via internal and external standard method. 28 kinds of FAs were discovered, which varied little among different wines. Palmitic acid was the most abundant in all kinds of wines, reaching round 25% of the total FAs. Mulberry wine was demonstrated to contain the highest FAs concentration of 78.21 mg/L among 8 types of wines. The RSD of all FAs concentrations obtained by this method was below 5%. In addition, this method showed more than 87% recycling efficiency, high accuracy and precision of the analysis.