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, visual 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 combined effects 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 eight weeks. The quality parameters examined included weight loss, firmness, colour, visual appearance and overall marketability, as well as nutritional properties, including total phenolic content, total flavonoid content and antioxidant capacity. Packaging and temperature both significantly affected fruit marketability. Fruit stored at RT quickly lost quality in all packaging types. Fruit stored at 4 °C retained firmness, colour, total phenolic content, flavonoid content and antioxidant capacity better than fruit stored at 25 °C or 8 °C; however, chilling injury and fungal growth developed at 4 °C, with approximately 20% of the fruit in each packaging treatment deemed unsaleable by Week 8. At 8 °C, no chilling injury, visible fungal growth or shrivelling was observed. Although approximately 60% of fruit in cardboard clamshells and net bags were classified as unsaleable because of loss of freshness, 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 among the combinations of packaging type and storage temperature examined in this study.