采后BTH处理对厚皮甜瓜磷脂代谢及香气释放的影响分析

发布时间：2018-08-26 17:20

【摘要】：“玉金香”甜瓜(Cucumis melo L.cv.Yujinxiang)是呼吸跃变型果实,BTH处理可诱导其抗病性,影响果实香气物质等次生代谢。磷脂是果实细胞膜的主要构成组分,磷脂酶作用下可水解为脂肪酸、甘油、磷酸和氨基醇等,进而参与香气等次生代谢。采后BTH处理“玉金香”甜瓜果实,贮藏期间监测PLA2、PLC和PLD活性及其基因表达特性,分析BTH诱抗处理对磷脂代谢底物、产物以及代谢酶活的影响,确定磷脂代谢与果实香气释放的相关性,探讨采后BTH诱抗处理对甜瓜果实细胞膜磷脂代谢和香气释放的影响机理。结果显示:1、采后BTH处理可抑制磷脂组分PC、PI降解,降低磷脂代谢产物PA和脂肪酸的含量,但在贮藏后期BTH处理组脂肪酸不饱和度高于对照。2、采后BTH处理降低PLA2、PLC和PLD的基因相对表达量和酶活性。3、采后BTH处理减少了样品亚油酸代谢的C6、C9香气组分释放量,抑制了亚麻酸代谢的C6、C9醇醛类和油酸代谢的含有丁基、戊基的香气组分及其大部分衍生酯类的释放,促进了乙酸(Z)-3-己烯酯、乙酸3,6-壬二烯酯、乙酸异丁酯酯类物质的释放。4、果实脂肪酸代谢香气物质总量与乙烯释放的相关性系数较磷脂代谢大,呈极显著正相关(P0.01),与PLA2活性呈显著正相关(P0.05)、与PI呈显著负相关(P0.05),其它因素与其相关性不显著。乙烯释放与脂肪酸代谢香气物质总量的相关性高于乙烯释放与磷脂代谢,且高于磷脂代谢与脂肪酸代谢香气总量的相关性。PLA2、磷脂代谢产物不饱和脂肪酸与香气组分释放相关性分别呈显著正相关和负相关(P0.05)。BTH处理后削弱乙烯释放、磷脂代谢与香气物质之间的相关性。综上所述,采后BTH处理可通过抑制磷脂组分降解、磷脂酶活性及其基因相对表达量减少产物磷脂酸和不饱和脂肪酸的生成,进而抑制不饱和脂肪酸代谢的香气物质的释放;由乙烯释放与脂肪酸代谢香气组分释放的相关性高于磷脂代谢,可推断脂肪酸代谢香气组分的前体物质代谢—磷脂代谢对脂肪酸代谢香气组分释放的影响度可能小于后期的LOX代谢,乙烯是影响脂肪酸代谢香气组分的关键因素。采后BTH处理降低了乙烯释放、磷脂代谢与香气物质的相关性,削弱了乙烯释放与磷脂代谢对香气物质释放的影响。
[Abstract]:"Yujinxiang" muskmelon (Cucumis melo L.cv.Yujinxiang is a kind of fruit with respiratory jump, which can induce its disease resistance and affect the secondary metabolism of aroma substances. Phospholipid is the main component of fruit cell membrane. Phospholipase can be hydrolyzed into fatty acid, glycerol, phosphoric acid and amino alcohol, and then participate in the secondary metabolism of aroma. Postharvest BTH was used to treat muskmelon fruits. During storage, the activities of PLA2,PLC and PLD and their gene expression were monitored, and the effects of BTH induced resistance treatment on the activities of phospholipid metabolites, metabolites and enzymes were analyzed. To determine the relationship between phospholipid metabolism and aroma release, and to explore the mechanism of the effect of postharvest BTH induced treatment on lipid metabolism and aroma release of muskmelon fruit cell membrane. The results showed that BTH treatment after harvest could inhibit the degradation of phospholipid component PC,PI and decrease the content of PA and fatty acid, the metabolite of phospholipid. However, the unsaturation of fatty acids in the BTH treatment group was higher than that in the control group at the late stage of storage. The relative expression and enzyme activity of PLA2,PLC and PLD were decreased in postharvest BTH treatment, and the release of C6C9 aroma components of linoleic acid metabolism in the samples was decreased by postharvest BTH treatment. The aroma components of Ding Ji, pentyl group and most of their derivative esters were inhibited by the metabolism of linolenic acid, such as C _ 6C _ 9 alcoholaldehyde and oleic acid metabolism, which promoted the release of (Z) -3-hexene acetate and 3nylenediene acetate. The correlation coefficient between the total amount of fatty acid metabolic aroma and ethylene release was higher than that of phospholipid metabolism. There was a significant positive correlation (P0.01), a significant positive correlation with PLA2 activity (P0.05), a significant negative correlation with PI (P0.05), and no significant correlation between other factors. The correlation between ethylene release and fatty acid metabolic total aroma substance was higher than that of ethylene release and phospholipid metabolism. And higher than that of phospholipid metabolism and total aroma of fatty acid metabolism. PLA2. The relationship between unsaturated fatty acid and aroma component release was significantly positive and negative correlation (P0.05). BTH treatment weakened ethylene release. The correlation between phospholipid metabolism and aroma substances. In conclusion, BTH treatment after harvest can inhibit the degradation of phospholipid components, reduce the production of phosphatidic acid and unsaturated fatty acids by phospholipase activity and the relative expression of their genes, and then inhibit the release of aroma substances from unsaturated fatty acid metabolism. The correlation between ethylene release and aroma component release of fatty acid metabolism was higher than that of phospholipid metabolism. It can be concluded that the effect of metabolism of phospholipid on the release of aroma components of fatty acid metabolism may be less than that of LOX in the later stage. Ethylene is the key factor affecting the aroma component of fatty acid metabolism. Postharvest BTH treatment decreased ethylene release, the correlation between phospholipid metabolism and aroma substances, and the effect of ethylene release and phospholipid metabolism on aroma release.
【学位授予单位】：甘肃农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TS255.3

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