Osmotic Dehydrated Raspberries: Changes in Physical Aspects and Bioactive Compounds

Raspberries are very labile fruits that have a short postharvest life; therefore, there is a need to develop alternative storage and processing methods for extending their shelf-life. The effect of wet (WI) and dry (DI) sucrose infusions (aw = 0.85) on color and bioactive compounds of raspberries has been studied. Additives were included: citric acid, sodium bisulfite, or both. Moisture content decreased from 85% (w/w) for control fruit to approximately 51% (w/w) for infused samples. The shrinkage of fruits was approximately 27% and 46% after WI and DI, respectively. No major color changes occurred, except for WI-bisulfite treatment. Although the total polyphenols and anthocyanin content were significantly reduced in fruits during osmotic dehydration, mainly due to the dilution effect to the medium, 100 g serving of processed raspberries would supply, in some cases, over 50% of polyphenols provided by a glass of wine. The proposed infusion dehydration methods may be considered an alternative to produce shelf-stable products based on raspberries, with an improved quality in terms of appearance.