The objective of this study was to investigate the effect of freezing/thawing and microwave-assisted
drying on the quality of blueberries and energy consumption of drying. The structure collapse, reduction
in sample volume, mechanical resistance and thickness of the skin during freezing/thawing facilitated
heat and moisture transfer during drying of blueberries. Freezing/thawing significantly reduced
drying time (by up to 29%) and specific energy consumption of drying (by up to 27%) in comparison with
drying without initial pretreatment. Nevertheless, the combination of freezing/thawing and drying
adversely affected the quality of the final product, generating harder, more chewy and gummy fruits
compared with those dried without initial pretreatment. Microwave-assisted drying of raw berries,
which included hot air drying at 80 C until the achievement of moisture content of 1.95 ± 0.05 kg$kg1
d.w. (dry weight), promoted most efficient drying in terms of enhanced product quality (determined by
hardness, chewiness, gumminess, porosity, density and shrinkage) and reduced energy consumption.