基于GC-MS分析短波紫外线处理采后香蕉挥发性组分

GC-MS analysis of volatile components in postharvest banana treated with UV-C

应用正交试验优化顶空固相微萃取(HS-SPME)萃取条件,研究经UV-C处理的采后香蕉挥发性组分的变化。通过单因素测定合适的萃取头、萃取前的超声时间、样品量和萃取温度,再利用正交试验获得SPME最佳的萃取参数。在此基础上,测定和鉴定UV-C处理组和对照组香蕉果肉的挥发性化合物,比较两者挥发性成分的差异,评价UV-C处理采后香蕉的香气效果。结果表明,最佳萃取参数为:超声时间20 min、样品量4.0 g、萃取温度50℃,在此条件下鉴定出两组香蕉果肉挥发性组分共169个,主要由酯、醛、酮、醇和其他组成,其中酯类有58个、醛类有34个、酮类有27个、醇类有17个、其他类有33个,UV-C组的总酯含量(76.61%±0.25%)高于对照组的总酯含量(75.98%±0.39%)。两组香蕉的差异代谢挥发性组分共有38个,其中含量下调的有34个,含量上调的有4个。综上分析,采后香蕉经UV-C处理,其挥发性组分会受到影响,但其特征酯类和总酯含量略有提高。香蕉的香气主要源于酯类,UV-C处理进行香蕉贮藏保鲜不仅不会造成香蕉香气下降,反而会使其香气略有增强。

The extraction conditions of headspace solid phase microextraction(HS-SPME) were optimized by orthogonal experiment to study the changes of volatile components in postharvest bananas with UV-C treated.Suitable extraction head, ultrasonic time before extraction, sample weight and extraction temperature were determined by single factor, and the best extraction parameters for SPME were obtained using orthogonal experiment.Under these conditions, the volatile compounds in banana pulp of UV-C treated group and control group were determined and identified, and the differences of volatile components between the two groups were compared to evaluate the aroma effect of postharvest banana treated by UV-C.The results showed that the optimal extraction parameters were as follows: ultrasonic time 20 min, sample weight 4.0 g, extraction temperature 50 ℃.Under these conditions, 169 volatile components were identified in banana pulp of the two groups, which were mainly composed of esters, aldehydes, ketones, alcohols and others, including 58 esters, 34 aldehydes, 27 ketones, 17 alcohols and 33 others.The total ester content in UV-C group(76.61%±0.25%) was higher than that in control group(75.98%±0.39%).There were 38 differential metabolic volatile components of bananas in the two groups, including 34 down-regulated and 4 up-regulated.In conclusion, the banana treated with UV-C affected its volatile components, but their characteristic esters and total esters were slightly improved.The aroma of bananas is mainly derived from esters.UV-C treatment for postharvest bananas storage and preservation will not cause the decline of banana aroma, but will make its aroma slightly enhanced.