Postharvest quality and shelf-life of new mandarin hybrids under cold storage conditions

Mandarins and mandarin hybrids are consumed as fresh fruit as they are particularly appreciated for their taste and peelability. During the last years new seedless triploid mandarins were released by Council for Agricultural Research and Economics (CREA), some characterized by anthocyanin pigmentation. However, little is known about their postharvest behaviour. Cold storage represents a useful method to preserve fruit quality, increase anthocyanin content and extend fruit shelf-life, avoiding postharvest issues such as rots and weight loss. This study aimed to assess cold storage aptitude of selected mandarins and the effect of low temperature on fruit postharvest quality. Fruits of the hybrids A145, Sweet Sicily, Early Sicily, C6925, Mandared, D871 were harvested at ripening. Hybrids were evaluated at harvest (T0) and after 10 (T10), 20 (T20), 30 (T30), 40 (T40) days of storage at 5±1°C and 85-90% relative humidity (RH), followed by 7 days at 20±2°C and 75% RH (simulated shelf-life) for each interval (T10+7, T20+7, T30+7, T40+7). Fruit weight loss, physiological disorders (chilling injury, ageing), decay incidence, quality attributes changes, and sensory analysis were evaluated during storage and shelf-life. Afourer mandarin was used as reference. Results showed variability among hybrids regarding decay incidence and physiological disorders, starting from T30, with the highest values at T40+7. A145 showed the highest chilling injury, requiring adjusted storage conditions. Weight loss increased during storage for all the hybrids tested, with values below 5% until T10. All pigmented hybrids showed an increase in anthocyanins during storage. The hybrids that better retained postharvest quality at the end of cold storage were Mandared and D871, although Mandared showed the highest incidence of rots. These hybrids resulted tolerant to physiological disorders, maintained the firmness and the most relevant qualitative traits, and showed the best fruit external appearance during shelf-life.