The objective of this study was to determine the effect of phytosanitary X-ray irradiation on the physicochemical properties and sensory attributes of early- and late-harvest ‘Bartlett’ pears (Pyrus communis L.) during ripening under simulated commercial conditions. Irradiation delayed ripening, which in turn affected respiration rate, ethylene production, and firmness. Irradiation decreased ethylene production in early- and late-harvest pears and maintained firmness as compared with the control pears. In the early-harvest pears, irradiation did not affect respiration rate, weight loss, or total soluble solids. However, in the late-harvest pears, irradiation resulted in an increase in respiration rate and weight loss and a decrease in total soluble solids. The appearance for irradiated early-harvest pears was rated lower by consumers, but there were no significant differences in the rest of the attributes. Consumers rated the irradiated late-harvest pears lower (P < 0.05) than the non-treated pears for overall liking, texture, and flavor on a 9-point hedonic scale. Consumers perceived the late-harvest irradiated pears to be less sweet than the control (P < 0.05), which correlated with total soluble solids of 12.4% for treated pears vs. 13.2% for the control. Our results show that there were significant differences between the early- and late-harvest pears in their responses to irradiation. Although some sensory attributes were negatively affected, the delay in ripening helped reduce bruising and mold development in irradiated pears during the retail display simulation.
Sokrith Sea, Cyril Rakovski and Anuradha Prakash
Jonathan Tong, Cyril Rakovski and Anuradha Prakash
The objective of this study was to monitor the effects of irradiation on the quality of blueberries and grapes treated at phytosanitary dose levels. Blueberry varieties ‘Star’, ‘Jewel’, and ‘Snowchaser’ and grape varieties ‘Sugraone’ and ‘Crimson Seedless’ were irradiated at a target dose of 400 Gy (range of 400–590 Gy for blueberries and 400–500 Gy for grapes) and stored for 3 and 18 days under refrigeration, plus 3 days at ambient temperatures and evaluated for quality. Storage affected quality of both fruit more than irradiation treatment and there were significant differences among varieties. Irradiated ‘Star’ blueberries maintained their firmness and sensory scores and resisted decay. Alternatively, irradiated ‘Jewel’ blueberries decreased in firmness but sensory scores for overall liking were higher than the control following 3 weeks of storage. ‘Snowchaser’ blueberries were harvested late in the blueberry season and were not as affected by treatment or time due to their initial compromised nature. Firmness was the primary attribute affected by irradiation for both varieties of grapes, but sensory testing showed that consumers did not have a preference for control or irradiated fruit. With respect to other attributes such as color, weight loss, and soluble solids concentration (SSC)/titratable acidity (TA), there were differences among fruit varieties but treatment effects were not significant. Our results show that both, blueberries and grapes, have a high tolerance for phytosanitary irradiation and that storage affects their quality more than irradiation treatment.