Effect of canopy position on rind biochemical properties of ‘Marsh’ grapefruit during postharvest non-chilling cold storage was evaluated on fruit harvested from different production regions. Inside canopy (IC) and outside canopy (OC) fruit were harvested at commercial maturity from two commercial farms located at KwaZulu-Natal (KZN) and Limpopo (LMP), South Africa during two seasons. Rind biochemical analyses including colour indices, total phenolic concentration and sugars were performed on harvested grapefruit after week 0, 3, 6 and 9 of cold storage at 7.5 ± 0.5 °C. Canopy position showed high significant (p < 0.001) effect on rind biochemicals while significant (p < 0.05) influence of production region were observed on same parameters. Reducing sugars were more concentrated in IC fruit harvested from both production region than OC fruit at weeks 0 and 3 but inverse results occurred at weeks 6 and 9. Production region significantly (p < 0.001) influenced vitamin C (14.4 - 14.8 g/ kg-1) and (12.3 - 16.1 g/ kg-1) of fruit rind at weeks 0, 3, 6, and 9 from KZN and LMP, respectively. This study revealed that canopy position can influence rind biochemical properties of ‘Marsh’ grapefruit during non-chilling postharvest cold storage.

Keywords: Citrus, Physiological rind disorder, Radical-scavenging activities, Sugars, Vitamin C.