Department of Food Science and Experimental Nutrition, University of São Paulo, São Paulo, SP, Brazil.
Department of Food Science and Experimental Nutrition, University of São Paulo, São Paulo, SP, Brazil; Food Research Center (FoRC), São Paulo, Brazil.
Food Res Int. 2020 May;131:108975. doi: 10.1016/j.foodres.2019.108975. Epub 2020 Jan 3.
Papayas undergo fast postharvest changes triggered by the plant hormone ethylene. Some important pathways have been analyzed in limited studies (transcriptomics and targeted metabolomics); however, broad use of proteomics or untargeted metabolomics have not yet been used in papayas. In this study, two groups of green papayas (150 days after anthesis-physiological maturity for papayas) were treated with ethylene at different times (6 and 12 h) and their metabolic changes in fruit pulp were evaluated with untargeted metabolomics (general metabolites and volatile compounds) and proteomics. Polar metabolites exhibited distinct patterns, especially with regard to some amino and fatty acids during stimulated ripening. In particular, glutamate increased through a possible gamma aminobutyric acid (GABA) shunt and/or proteases activity. Moreover, the stimulated ripening altered the volatile compounds and the protein profiles. The results suggest that changes in membrane breakdown and the resulting oxidative processes could be responsible for volatile compound production, altering some sensorial qualities of papayas, such as pulp softening and the specific papaya linalool volatile compound increment. Thus, GABA levels could also be a strong biological marker for papaya development and ripening stages. This study applied two "omic" techniques that provided insight into how the plant hormone ethylene could influence papaya postharvest quality.
番木瓜在植物激素乙烯的作用下，会迅速发生采后变化。一些重要的途径已经在有限的研究中进行了分析（转录组学和靶向代谢组学）；然而，蛋白质组学或非靶向代谢组学的广泛应用尚未在番木瓜中使用。在这项研究中，两组绿木瓜（授粉后 150 天-木瓜生理成熟）在不同时间（6 小时和 12 小时）用乙烯处理，并通过非靶向代谢组学（一般代谢物和挥发性化合物）和蛋白质组学评估果肉的代谢变化。极性代谢物表现出不同的模式，特别是在一些氨基酸和脂肪酸方面在刺激成熟过程中。特别是谷氨酸通过可能的γ-氨基丁酸（GABA）分流和/或蛋白酶活性增加。此外，刺激成熟改变了挥发性化合物和蛋白质图谱。结果表明，膜破裂和由此产生的氧化过程的变化可能是挥发性化合物产生的原因，改变了木瓜的一些感官特性，如果肉软化和特定的木瓜芳樟醇挥发性化合物的增加。因此，GABA 水平也可能是番木瓜发育和成熟阶段的一个强有力的生物学标志物。本研究应用了两种“组学”技术，深入了解植物激素乙烯如何影响番木瓜的采后品质。
