Elevated O2 alleviated anaerobic metabolism in postharvest winter jujube fruit by regulating pyruvic acid and energy metabolism

Over-accumulation of anaerobic metabolites is a typical characteristic of postharvest senescence in winter jujube fruit. Here, elevated O2 was applied during cold storage to investigate its regulation on anaerobic respiration. The results found 60 % O2 was the optimal concentration to inhibit anaerobic respiration, which showed 83.82 % lower acetaldehyde and 57.13 % lower ethanol compared with control. Elevated O2 maintained energy status by activating succinate dehydrogenase and cytochrome C oxidase, with 1.11-fold higher energy charge observed as compared with the control. In addition, activated aerobic respiration also accelerated the consumption of pyruvic acid, and pyruvic acid content was reduced by 63 % in elevated O2-treated fruit. Sufficient energy supply and reduced pyruvic acid content in elevated O2-treated fruit induced the alleviation of anaerobic respiration, leading to attenuating the accumulation of ethanol and acetaldehyde as a result. The study proved elevated O2 repressed anaerobic metabolism by regulating pyruvic acid level and energy metabolism.