Ellagic acid, vitamin C, and total phenolic contents and radical scavenging capacity affected by freezing and frozen storage in raspberry fruit

The ellagic acid, total phenolic, and vitamin C contents in four raspberry cultivars (Heritage,Autumn Bliss, Rubi, and Zeva) grown in Spain were detec ted and quantified by HPLC in fresh, just frozen, and stored fruits at -20 degreesC for a one year period. Ellagic acid [207-244 mg kg(-1) of fresh we ight (fw)], total phenolic (137-1776 mg kg(-1) of fw), and vitamin C (221-3 12 mg kg(-1) of fw) contents in raw material were higher in the late cultiv ars Zeva and Rubi than in the early cultivars Autumn Bliss and Heritage. Th e freezing process slightly affected the values of extracted ellagic acid, total phenolic, and vitamin C content. At the end of long-term frozen stora ge (12 months), no significant change of total phenolic content extracted w as observed, but significant decreases of 14-21% in ellagic acid and of 33- 55% in vitamin C were quantified. Free radical scavenging capacity measured as antiradical efficiency (AE) depends on the seasonal period of harvest. Late cultivars, Rubi (6.1 x 10(-4)) and Zeva (10.17 x 10(-4)), showed highe r AE than early cultivars, Heritage (4.02 x 10(-4)) and Autumn Bliss (4.36 x 10(-4)). The freezing process produced a decrease of AE values in the fou r cultivars ranging between 4 and 26%. During the frozen storage, the AE va lues reached after the freezing process remained unchanged.