气调贮藏对猕猴桃抗坏血酸-谷胱甘肽代谢的影响

Effect of Controlled-atmosphere Storage on Ascorbate-glutathione Metabolism in Kiwifruit

摘要:

为探讨气调贮藏调控猕猴桃采后衰老的可能机理。以空气比例（20.9%O2+0.04%CO2）为对照，研究了不同气体成分[CA1 （2%O2+3%CO2）、CA2（2%O2+6%CO2）、CA3（5%O2+3%CO2）、CA4（5%O2+6%CO2）]对采后‘红阳’猕猴桃可溶性固形物（SSC）、可溶性总糖、淀粉、可滴定酸（TA）、抗坏血酸（ASA）和谷胱甘肽（GSH）含量，自由基（DPPH、超氧阴离子）清除能力及抗坏血酸-谷胱甘肽循环相关酶活性的影响。结果表明：较普通冷藏和其它气体成分相比，CA1（2%O2+3%CO2）处理可抑制果实SSC、可溶性总糖含量的增加，减缓淀粉、TA含量的下降。另外，CA1、CA2和CA3处理可提高猕猴桃的谷胱甘肽和抗坏血酸含量，减缓果实自由基清除能力和抗坏血酸-谷胱甘肽循环相关酶活性的下降，其中CA1处理的效果最明显。因此，2%O2+3%CO2对‘红阳’猕猴桃衰老的抑制作用与其维持果实中较高的ASA和GSH有关。

Abstract:

Potential mechanisms underlying the effects of controlled-atmosphere (CA) storage on the senescence of the kiwifruit cultivar Hongyang were studied. The effect of different gas compositions [CA1 (2% oxygen + 3% carbon dioxide), CA2 (2% oxygen + 6% carbon dioxide), CA3 (5% oxygen + 3% carbon dioxide), and CA4 (5% oxygen + 6% carbon dioxide), with CK (20.9% oxygen + 0.04% carbon dioxide) as control] was investigated on soluble solid (SSC), total soluble sugar, starch, titratable acid (TA), ascorbic acid (AsA), and glutathione (GSH) content; scavenging capacities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide anions; and the activities of enzymes involved in the ascorbate-glutathione cycle in postharvest kiwifruit. The results showed that treatment with CA1 inhibited the increase in SSC and total soluble sugar content, as well as alleviated the decrease in starch and TA content compared with CK and the other CA treatments. In addition, treatment with CA1, CA2, and CA3 increased AsA and GSH content in kiwifruit as compared to that with CA4 and CK. Moreover, treatment with CA1, CA2, and CA3 alleviated the decrease in superoxide anion- and DPPH-scavenging rates as well as the activities of enzymes involved in the ascorbate-glutathione cycle in kiwifruit, of which CA1 treatment showed the strongest effect. Therefore, senescence inhibition in the kiwifruit cultivar Hongyang by CA1 treatment was associated with higher AsA and GSH content.