Effects of storage temperature and packaging type on the postharvest quality of finger lime (Citrus australasica)

Finger lime (Citrus australasica F.Muell) is a native Australian citrus species with increasing commercial value because of its unique sensory and nutritional properties. However, like other citrus species, it is highly perishable and susceptible to postharvest quality deterioration. Despite its growing importance, limited research has examined how commercial packaging and storage temperature affect its quality. Therefore, this study investigated the cumulative impact of three commonly used types of packaging (net bags, recycled polyethylene terephthalate (rPET) punnets, and moulded cardboard clamshells) and three storage temperatures (room temperature ((RT), ~25 °C), 8 °C, and 4 °C) on finger lime quality over 56 days. Quality parameters, including weight loss, firmness, colour, visual appearance and overall marketability, total phenolic content, total flavonoid content and antioxidant capacity, were examined. Packaging and temperature both significantly affected fruit marketability. At room temperature, no visible fungal growth was observed; however, all fruit became unsaleable after approximately 10 days due to shrivelling and desiccation. Fruit stored at 4 °C retained firmness, colour, contents of phenolics and flavonoids, and antioxidant capacity better than fruit stored at 25 or 8 °C; however, chilling injury and fungal growth developed and approximately 20% of the fruit in each packaging treatment were unsaleable by week 8. At 8 °C, no chilling injury, visible fungal growth, or shrivelling was observed, but approximately 60% of fruit in cardboard clamshells and net bags were classified as unsaleable due to loss of freshness, whereas approximately 80% of fruit in punnets remained saleable until the end of the trial. Overall, storage at 8 °C in rPET punnets provided the best balance between quality retention and marketability compared to the other combinations of packaging types and storage temperatures examined in this study.