Authors: ZALA ZORENC, ROBERT VEBERIC, FRANCI STAMPAR, DARINKA KORON, MAJA MIKULIC-PETKOVSEK
Abstract: As blueberries ripen successively and are commercially harvested over a period of several weeks, their composition may be altered during the harvest. The aim of this study was to compare blueberry fruit composition during the entire harvest season. Fully ripe fruits of two northern highbush blueberry cultivars (Bluecrop and Jersey) were harvested weekly at two different locations. Additionally, the Earliblue cultivar was monitored at a single location. Most of the examined characteristics changed during the harvest season and were cultivar-dependent, with smaller differences observed between sampling locations. Fruit weight of all cultivars decreased with the time of harvest. Levels of total sugars generally increased and total organic acids decreased, making the berries sweeter at the end of the growing period. Moreover, berries harvested later in the season generally contained more total anthocyanins. Total phenolic content generally decreased with successive harvests, mostly due to decreasing contents of total hydroxycinnamic acid derivatives and flavonol glycosides. The results indicate that blueberries harvested at later periods are smaller and contain comparable or increased levels of selected metabolites than larger fruits collected at the beginning of the harvest season.
Keywords: Anthocyanins, fruit weight, primary metabolites, phenolics, seasonal variation, Vaccinium
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