Effects of Storage Temperatures and Durations on Acidity and Sourness of Winter Harvested ‘Gilis’ Passion Fruit

“Gilis” is a hybrid passion fruit cultivar valued for its large size, excellent aroma, attractive purple peel and self-compatibility. Summer harvested “Gilis” fruit have a balanced taste, however, winter harvested fruit in cold locations consist lower total soluble solids (TSS) and higher acidity levels resulting in a sourer flavor. To address this issue, we examined the effects of different storage temperatures (10, 21, and 25°C) and storage durations (7, 10, and 14 days) on TSS and acidity levels, sourness and flavor acceptance, alongside with postharvest quality parameters, including fruit shrinkage and decay incidence. Overall, we conducted three independent experiments with winter harvested “Gilis” fruit, and found that storage at a low temperature of 10°C maintained postharvest quality but did not reduce acidity or improve flavor. In contrast, storage at a moderate temperature of 21°C for 10–14 days reduced acidity levels by 0.6–1.0%, decreased perception of sourness, and improved flavor acceptance, without causing major deterioration. Storage at a higher temperature of 25°C further reduced acidity by 0.7–1.2% but led to unacceptable levels of 50–55% shrinkage and 25–37% decay. It is concluded that postharvest storage at 21°C for 10–14 days may provide an effective strategy to reduce acidity and sourness of winter grown “Gilis” passion fruit while maintaining overall fruit quality.