Antioxidant mechanism of a continuous microenvironment regulation system for prolonging the shelf-life of red grapes.

Red grapes (Vitis vinifera L.) have a high sugar content, thin skins, and relatively short shelf-life after harvesting. We developed polylactic acid/polybutylene succinate film, prepared by extrusion of polylactic acid and polybutylene succinate, that significantly prolonged the shelf-life of red grapes from 8 to 12 days by delaying the loss of weight, loss of hardness, and reduction in soluble solid content after harvesting. Further mechanistic study showed that this modified atmosphere film delayed the senescence of harvested red grape, the phenomenon that was highly related to the lower active oxygen species production and higher antioxidant enzyme activity compared to the non-packaged grape. The proposed continuous and dynamic microenvironment regulation system is a promising method to study the mechanisms of respiratory metabolism in fruit and extends food shelf-life while reducing food waste. PRACTICAL APPLICATION: In this study, we designed a means to microenvironmental regulatory packaging that directly creates a continuous, dynamic, and monitorable microenvironment. To ensure that the fruit inside the package underwent coordinated aerobic and anaerobic respiration, we melt-extruded polylactic acid (PLA) and polybutylene succinate (PBS) to form a homogeneous biodegradable film. We demonstrated that the best preservation results were achieved with a film comprising an 80/20 PLA-to-PBS ratio. This film can prolong the shelf-life of fruits by regulating respiratory metabolism.