Treatment with exogenous salicylic acid maintains quality, increases bioactive compounds, and enhances the antioxidant capacity of fresh goji (Lycium barbarum L.) fruit during storage

Abstract

Goji fruit is susceptible to rot and deterioration after harvest, but drying results in the loss of functional components. To explore the effects of salicylic acid (SA) on fruit quality, bioactive compounds, and antioxidant capacity during storage, fresh goji fruit was treated with SA (1, 2, and 3 mmol L−1) and stored at 0 °C or ambient temperature. Compared to the control, SA repressed disease at both treatment temperatures. During storage at 0 °C, SA decreased respiration intensity and ethylene production and resulted in higher color values, firmness, total soluble solids (TSS), and TSS-to-titratable acidity ratio compared to the control. Meanwhile, the SA-treated fruits showed lower weight loss, lower titratable acidity, and better sensory quality. Treated fruit stored at 0 °C also showed higher hydrophilic and lipophilic total antioxidant activities compared to the control, which was attributed to the higher contents of hydrophilic bioactive components (e.g., ascorbic acid, total phenolics, and total flavonoids) and lipophilic bioactive components (e.g., total carotenoids). Among the tested SA concentrations, 2 mmol L−1 SA had the strongest effects. The results demonstrate that SA can delay ripening and senescence, retain fruit quality, promote the accumulation of bioactive compounds, and enhance the antioxidant capacity of fresh goji fruit during storage.