Pre-storage calcium chloride and aloe vera gel coatings mitigate internal browning and senescence scald in ‘Conference’ pears

Abstract

Physiological disorders pose significant challenges to the quality and shelf life of ‘conference’ pears. This study investigates the efficacy of calcium chloride (CaCl2) and aloe vera (AV) gel treatments in reducing internal browning and senescence scald in ‘Conference’ pears. Four groups were evaluated: a control, individual 2 % CaCl2, 15 % AV gel treatments, and a combined CaCl2 and AV gel treatment. Pears having following maturity indices (TSS 12 %, ho 90, and Firmness 67 N) were then stored at 2 ± 1 °C, 85±5 % RH for 180 d The fruits were removed from cold storage to room temperature and kept at 20±3 °C and 65±5 % RH followed by physicochemical and sensory analyses. The combined treatment proved most effective in preserving quality and reducing internal browning and senescence scald. Treated pears displayed reduced respiration rates, ethylene production, internal browning, senescence scald, and weight loss. Moreover, the combined treatment resulted in higher TA and lower TSS compared to the control after 180 d of storage. The reduction in internal browning and senescence scald can be attributed to enzyme activity modulation. The combined treatment increased catalase (CAT) and superoxide dismutase (SOD) activity, reducing oxidative stress. This, in turn, minimized oxidative reactions leading to internal browning. Furthermore, the treatment inhibited polyphenol oxidase (PPO) and peroxidase (POD) activity, enzymes responsible for browning reactions. Lower PPO and POD activity contributed to reduced internal browning and senescence scald. The combined actions of enhanced antioxidant enzymes and decreased browning-related enzymes synergistically reduced internal browning. In conclusion, the combined CaCl2 and AV gel treatment effectively mitigated internal browning and senescence scald in pears and also received the highest score in sensory analysis. Enhanced antioxidant enzyme activity (CAT and SOD) and reduced PPO and POD activity collectively contributed to this reduction. This eco-friendly approach presents a sustainable strategy for extending shelf life and enhancing pear quality, providing an alternative to traditional chemical interventions for managing physiological disorders.