Red light irradiation can effectively prolong the shelf-life of many fruit. However, little is known about red light-induced metabolite and enzyme activities. In this study, pitaya fruit was treated with 100 Lux red light for 24 h. Red light irradiation significantly attenuated the variation trend of senescence traits, such as the decrease of total soluble solid (TSS) and TSS/acidity (titratable acidity, TA) ratio, the increase of TA, and respiratory rate. In addition, the reactive oxygen species (ROS) related characters, primary metabolites profiling, and volatile compounds profiling were determined. A total of 71 primary metabolites and 67 volatile compounds were detected and successfully identified by using gas chromatography mass spectrometry (GC-MS). Red light irradiation enhanced glycolysis, tricarboxylic acid (TCA) cycle, aldehydes metabolism, and antioxidant enzymes activities at early stage of postharvest storage, leading to the reduction of H₂O₂, soluble sugars, organic acids, and C-6 and C-7 aldehydes. At a later stage of postharvest storage, a larger number of resistance-related metabolites and enzyme activities were induced in red light-treated pitaya peel, such as superoxide dismutase (SOD), ascorbate peroxidase (APX), 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging, reducing power, fatty acids, and volatile aroma.

中文翻译：

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采后红光辐照后火龙果皮代谢途径的研究

红光照射可以有效地延长许多水果的保质期。然而，关于红光诱导的代谢产物和酶活性知之甚少。在这项研究中，用100 Lux红光对火龙果果实进行了24小时的处理。红光辐照显着减弱了衰老性状的变化趋势，例如总可溶性固形物（TSS）和TSS /酸度（可滴定酸度，TA）的降低，TA的增加和呼吸频率。此外，还确定了与活性氧（ROS）相关的特征，主要代谢物谱和挥发性化合物谱。通过气相色谱质谱法（GC-MS）总共检测到71种主要代谢物和67种挥发性化合物。红光照射增强了糖酵解，三羧酸（TCA）循环，₂ O ₂，可溶性糖，有机酸以及C-6和C-7醛。在采后贮藏的后期，在红光处理的火龙果皮中诱导了大量与抗性相关的代谢产物和酶活性，例如超氧化物歧化酶（SOD），抗坏血酸过氧化物酶（APX），1，1-二苯基-2 -苦味酚酰肼（DPPH）清除自由基，降低能量，脂肪酸和挥发性香气。