Wu Qixian, Gao Huijun, Zhang Zhengke, Li Taotao, Qu Hongxia, Jiang Yueming, Yun Ze
Center of Economic Botany, Core Botanical Gardens, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences, Guangzhou 510600, China.
Metabolites. 2020 Mar 14;10(3):108. doi: 10.3390/metabo10030108.
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 HO, 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.
红光照射可有效延长多种水果的货架期。然而，关于红光诱导的代谢物和酶活性却知之甚少。在本研究中，火龙果果实经100勒克斯红光处理24小时。红光照射显著减弱了衰老特征的变化趋势，如总可溶性固形物（TSS）和TSS/酸度（可滴定酸度，TA）比值的降低、TA的增加以及呼吸速率。此外，还测定了活性氧（ROS）相关特征、初级代谢物谱和挥发性化合物谱。通过气相色谱-质谱联用（GC-MS）共检测并成功鉴定出71种初级代谢物和67种挥发性化合物。红光照射在采后贮藏早期增强了糖酵解、三羧酸（TCA）循环、醛类代谢和抗氧化酶活性，导致H₂O₂、可溶性糖、有机酸以及C-6和C-7醛类减少。在采后贮藏后期，红光处理的火龙果果皮中诱导产生了大量与抗性相关的代谢物和酶活性，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-苦基肼（DPPH）自由基清除能力、还原力、脂肪酸和挥发性香气。
