Effects of Using Lime Juice and UV-B Irradiation as Pretreatments on the Quality Characteristics of Hot-air Dried Kiwifruit Slices

Background and Objectives: Use of appropriate pretreatments before drying process can greatly improve quality characteristics of the final dried products. In this study, effects of UV-B irradiation and lime juice as pretreatments on the quality characteristics of dried kiwifruit slices was investigated using hot-air method.  Materials & Methods: Spray machine was used to spray lime juice at time intervals (0, 2.5, 5, 7.5 min) and UV-B pretreatment was used at various time intervals (zero, 60, 120 min). Results: Results showed that use of UV-B and lime juice as pretreatments significantly decreased shrinkage, color change and firmness and increased rehydration. Total phenolic compounds, antioxidant capacity and acidity in samples pretreated with UV-B and lime juice increased, compared to the control sample. Simultaneous use of lime juice and UV-B caused significant increases in vitamin C of the samples, which increased from 4.51 mg/100 g in the control sample to 36.01 mg/100 g in the treated sample for 7 min with lime juice and 1 h for UV-B. Results of the sensory evaluation showed that use of UV-B and lime juice as pretreatments resulted in significant improvement in acceptability of the sensory characteristics of dried kiwifruit slices. Conclusion: Based on the findings of this study, UV-B and lime juice as pretreatments included favorable effects on the quality characteristics of dried kiwifruit samples, which could be used as appropriate pretreatments for hot-air drying fruits.