Quality and Biochemical Changes of ‘Grand Nain’ Bananas during Shelf Life

Abstract

. Quality attributes, antioxidant compounds, free radical scavenging capacity (FRSC, DPPH IC50 value) and enzymes activities of ‘Grand Nain’bananas were investigated during shelf life at 20±2oC and 60-70% RH for 7 days. Weight loss, peel color and browning indices increased while, pulp firmness, titratable acidity (TA), pH and membrane stability index (MSI) decreased during shelf life. Total soluble solid (TSS) concentration increased up to day five then remained stable whereas, vitamin C increased ranged from 5.8 to 8.2 mg 100g-1 fresh weight (FW) during the first two days and then decreased. Total phenols concentration in both peel and pulp increased ranged from 0.19 to 1.64 gkg-1 and 0.17 to 0.59 gkg-1 FW, respectively during shelf life. Total flavonoids firstly increased, remained stable until day five then, decreased in both peel and pulp. It ranged from 0.05 to 0.21 gkg-1 FW and 0.03 to 0.19 gkg-1 FW in peel and pulp, respectively. Both total phenols and flavonoids concentrations were higher in peel than pulp. FRSC in peel remained stable until day five then, sharply decreased (higher DPPH IC50 values) and ranged from 3.83 to 19.43 IC50 values. While, in pulp it decreased (higher DPPH IC50 values) during shelf life and ranged from 4.1 to 13.3 IC50 values. Polyphenoloxidase (PPO), peroxidase (POD), polygalacturornase (PG), xylanase and ?-amylase activities in peel and pulp greatly varied during shelf life.