Irradiation and storage influence on bioactive components and quality of early and late season ‘Rio Red’ grapefruit (Citrus paradisi Macf.)

Irradiation as an alternative quarantine treatment has been under consideration by the International Consultative Group on Food Irradiation. This study was conducted on early and late season ‘Rio Red’ grapefruit to investigate the effects of harvest date, storage, and low dose irradiation on functional constituents, and quality. Fruit was treated with 0, 70, 200, 400 and 700 Gy and then stored under simulated storage conditions by subjecting the fruit to 10 ◦C for 4 weeks followed by 1 week at 20 ◦C with 90–95% relative humidity. Flavanones (naringin and narirutin), terpenoids (limonin 17-d-glycopyranoside, -carotene and lycopene) and quality (ascorbic acid content, soluble solids (%), titratable acidity) were evaluated immediately following irradiation treatment and storage. Results demonstrated that the response of fruit to irradiation depended on harvest time. Lower doses (at or below 200 Gy) of irradiation coupled with 35 days of storage were useful in enhancing health promoting compounds in early season grapefruit. Higher doses of irradiation (400 and 700 Gy) and 35 days of storage had detrimental effects on quality of early season grapefruit, however, no significant effect was observed on the quality of the late season fruit. © 2004 Elsevier B.V. All rights reserved.