Appropriate harvest maturity for exploitation of wild black raspberry (Rubus sp.) fruits during shelf life period from Rawalakot, Azad Jammu and Kashmir

Black raspberries (Rubus sp.) are abundantly grown and distributed widely in temperate regions of Pakistan which shows rich plant diversity of fruit species. In this study wildly grown black raspberry fruits were harvested from Rawalakot at three different maturity stages and investigated for physical, biochemical and antioxidant properties. Random samples of wild black raspberry fruits from each maturity stage [turning (75% red, 25% green), full red (100% red), black (100% black)] were stored at room temperature (22 ± 2 °C, 46% RH) for maximum 7 days and analysed on alternate days. Results showed that fruit weight, total soluble solids, pH, vitamin C, total flavonoids, total phenols, total antioxidants and total anthocyanins increased whereas fruit firmness and titratable acidity levels decreased as maturity progressed from turning to black stage. During shelf life period, total soluble solids and pH increased, while fruit weight, firmness, total anthocyanins, total flavonoids and total phenols significantly decreased with shelf life period. Moreover, titratable acidity and vitamin C decreased by advancement in shelf life period. It is advisable that wild black raspberry fruits should be harvested at black stage if used for immediate consumption. However, raspberries can be harvested at full red stage to extend storage period without compromising on fruit quality.