Hot water dipping: Impact on postharvest quality, individual sugars, and bioactive compounds during storage of 'Sonata' strawberry

Soluble sugars plays an important role in the ripening of strawberry fruit and whether hot water (HW) treatment has a significant impact on sugar content is yet unclear. This study investigated the impact of hot water treatment (35 and 45 degrees C) and dipping duration of 5 or 10 min on the physicochemical quality, individual sugars, antioxidant activity and visual quality of freshly harvested 'Sonata' strawberries stored in open packaging trays at 4 degrees C for 9 days and then transferred to 16 degrees C for 3 days. Hot water treatment and duration had significant impact on measured quality attributes of strawberries (p < 0.05). Hot water dip induced an initial sharp increase in transpiration rate (TR). Calculated TR for 'Sonata' strawberries ranged from 11.4 to 63.1 mu g kg(-1) s(-1) across all treatments during storage. An initial decline in colour parameters chroma (61.3 +/- 6.7) and hue angle (41.2 +/- 5.4) was observed until day 6 and thereafter, they increased until the end of storage, across all treatments. A significant increase in total soluble solids and titratable acidity was observed. Concentration of sucrose declined sharply and significantly from 131.9 to 28.7 mmol L-1 during the storage period, followed by glucose and fructose. Percentage relative concentration decrease in sucrose, glucose and fructose was in the range of 60-78%, 10-20%, and 1-10%, respectively, at the end of storage. At the end of storage, antioxidant capacity was better retained in samples dipped at 45 degrees C for 5 and 10 min (14.3 and 14.5 mu mol g(-1) Trolox Equivalent, respectively). Overall, HW-treatment of 45 degrees C for 5 min had no detrimental effects and best maintained quality attributes of strawberries and prevented incidence of decay. (C) 2016 Elsevier B.V. All rights reserved.