Frozen fruit presents additional temperature-related challenges.
Cryo-SEM was used to evaluate the structure of wild blueberries that had been frozen using three different methods, stored at three different temperatures, and held in frozen storage for 5 months. Microstructural data were then compared with quality measures, which included changes in percentage drip, damaged berries, and anthocyanin leakage, to explore relationships between structural changes and observed quality changes. Cryo-SEM results indicated that microstructural changes observed in frozen blueberry samples are characteristic of their temperature history. Quality measurements and microstructural data are in agreement that improvement of frozen blueberry quality resulted from faster freezing rates and lower temperatures of storage than are used presently in standard production methods. This study indicates that cryo-SEM can be a valuable tool in assessing frozen blueberry quality and developing optimal conditions for freezing wild blueberries.