草酸处理对锦橙采后风味品质及乙醇代谢的影响

Effects of postharvest application of oxalic acid on flavor quality and ethanol metabolism in Citrus sinensis L.Osbeck cv.Jincheng

目前柑橘消费市场对果实品质要求高,但采后果实风味和感官接受度不断下降。为探究保持柑橘采后风味品质的方法,该研究以不同质量浓度的草酸处理锦橙,运用气相色谱-质谱和实时荧光定量PCR技术,测定锦橙采后挥发性香气物质和乙醇的含量及乙醇代谢相关基因转录水平。结果表明,草酸(oxalic acid,OA)处理能够有效维持锦橙果实感官品质、保持果肉中较高的挥发性香气物质含量和较低的乙醇含量,其中以质量浓度为1 g/L的草酸(OA2)处理效果最佳。贮藏120 d时,OA2组挥发性香气物质含量为226.48μg/g,为CK组的145.23%;乙醇含量为52.85μg/g,为CK组的7.14%。OA2处理诱导乙醇代谢相关基因PDC、ADH表达水平显著降低。另外,OA2处理后果实可溶性固形物、抗坏血酸含量增加,抑制了果实的呼吸强度。综上,锦橙采后草酸处理能够有效改善果实风味品质,降低异味产生和感知。该研究为柑橘采后风味品质保持技术和天然保鲜剂研发提供了理论依据。

At present,the consumption market of citrus has higher requirements on fruit quality,but the flavor and sensory acceptability of postharvest fruits decline continuously.To explore the approaches to maintain fruit postharvest flavor quality,Citrus sinensis L.Osbeck cv.Jincheng was treated with different oxalic acid concentrations.GC-MS was used to test the contents of aroma volatiles and ethanol in postharvest fruits.The expression levels of genes involved in ethanol metabolism were tested by real-time quantitative PCR(qRT-PCR).The results showed that oxalic acid treatment could maintain higher sensory quality,aroma volatiles content and lower ethanol content in Jincheng fruits,and the 1 g/L(OA2)oxalic acid treatment showed the best effects.After storage for 120 days,the aroma volatiles content of OA2 treated group was 226.48μg/g,which was 145.23%of CK group.And the ethanol content was 52.85μg/g,which was 7.14%of CK group.After OA2 treatment,the expression levels of PDC and ADH genes involved in ethanol metabolism were significantly decreased.In addition,the soluble solids and ascorbic acid contents of Jincheng fruits were increased,and the fruit respiratory intensity was inhibited after OA2 treatment.These results suggested that postharvest application of oxalic acid could effectively improve Jingcheng fruit quality and reduce the off-flavors generation and perception.This study provides a theoretical basis for the research of citrus postharvest flavor quality maintenance technology and natural preservative.