Abstract:In order to determine the differences in the quality between the fresh blueberries and the blueberries thawed by four different methods (microwaving, ultrasound, warm water bath, natural thawing), this study took blueberry as the research object and explored the best thawing method through the comparison of the juice yield, pH, titratable acid, soluble solids, viscosity, water-soluble pectin, anthocyanin, total phenol, ORAC, PPO and POD of blueberries. The results showed that the TSS, pH and titratable acid content of the blueberry thawed by microwaving were insignificantly different from those of the fresh blueberry, with the highest number (11 species) of monomeric anthocyanins and highest total anthocyanin content (62.45 mg/100 g). Microwave thawing exhibited the least damage to anthocyanins in blueberries and offered the greatest preservation on the nutrients, leading to the highest total phenolic content (2.27 mg/g) and antioxidant capacity (46.88 μmol/g) in the thawed blueberry. The thawed blueberries by microwaving had the lowest PPO content (105.99 u/g·min) and a lower POD content (compared to that in the blueberries thawed by warm water bath), thus, were not easily oxidized and browned. Accordingly, microwave thawing is superior to the other three thawing methods.
