Effects of freezing and oven drying of Romanian wild and cultivated red raspberries on total anthocyanins and total antioxidant capacity

This study was conducted to investigate the content of some antioxidant phytochemicals (anthocyanins, phenolics) in five different red raspberry fresh samples grown in Romania, the anthocyanin profile through direct ESI-IT-MS/MS and the influence of traditional preservation methods on total anthocyanins and total antioxidant capacity. The results showed a high level of these bioactives in wild fresh samples compared to cultivated ones (Heritage and The Latham cvs.). The anthocyanin profiles of the crude extracts peformed by direct ESI-IT-MS/MS without previous HPLC-DAD, showed a higher content of glycosylated anthocyanins in The Latham cv. Freezing at - 18 degrees C and oven-drying at 60 degrees C and 80 degrees C of red raspberries in relation to the retention of anthocyanin pigments and total antioxidant capacity have been studied. Frozen wild red raspberries maintained a good total anthocyanins content during 7-months storage at - 18 degrees C, while The Latham and Heritage cvs. showed an increase in the level of these pigments. The content was decreased in case of the two garden-grown samples (7-24 % decrease). Fresh red raspberries reported higher content of total anthocyanins than dried products. Oven-drying technology showed good retention of total anthocyanins and of antioxidant potential up to 5 hours of drying at 60 degrees C, but high temperatures degraded these thermolabile compounds.