Evolution of Quality Parameters and Bioactivity of Actinidia chinensis cv. Sungold (Kiwifruit) Slices Subjected to Different Drying Conditions Storage for 4 Months

The present study aimed to investigate the impact on nutritional and functional properties of dried kiwifruit (Actinidia chinensis cv. Sungold) slices during conservation for 120 days in sealed containers in the dark at 25 °C. For this purpose, kiwifruits slices were dried at two different temperatures, 40 and 55 °C, for 30 and 25 h, respectively. Fresh and dried kiwi slices were analyzed for their pH, activity water, total solid soluble (TSS), color, titratable acidity, total phenols (TPC) and flavonoids content (TFC), organic acids, and radical scavenging activities. Analysis carried out on the dehydrated samples showed a good aptitude of kiwi material towards the drying process. Particularly, it has been observed that the drying treatment at low temperature helped to preserve the nutraceutical properties of the fruits. In fact, samples treated at 40 °C (KLT) showed at day 0 (T0) the highest TPC and TFC with values of 979.42 Gallic Acid Equivalents (GAE)/100 g of dried weight (dw) and 281.84 mg catechin equivalents (CTE)/100 g dw even if compared with fresh kiwi slices sample (FKF). Moreover, KLT also exhibited the highest values of antioxidant activity (1657 mmol Trolox/100 g dw). After 120 days storage, all dried samples showed a high ascorbic acid content (429–339 mg/100 g dw fruits) and only a slight variation of physicochemical parameters. Textural Parameters (hardness, springiness, cohesiveness, gumminess, and chewiness), apart from resilience results, showed significant differences between kiwifruit dried at 55 °C and at 50 °C (KLT and KHT, respectively). Color and aroma intensity were the main sensory descriptors with higher scores.