Changes in Anthocyanin and Antioxidant Contents during Maturation of Australian Highbush Blueberry (Vaccinium corymbosum L.) Cultivars

Abstract

The Australian blueberry industry is worth over $300 million, but there is limited information on factors influencing their chemical composition, particularly their ripeness and harvest stage. This pilot study investigated changes in total monomeric anthocyanin content (TMAC; measured using the pH-differential method) and total antioxidant capacity (TAC; measured with the cupric reducing antioxidant capacity assay) of four Australian highbush blueberry cultivars (Denise, Blue Rose, Brigitta and Bluecrop) at four time points and three maturity stages (unripe, moderately ripe and fully ripe). The TAC of most cultivars decreased by 8–18% during ripening, although that of the Blue Rose cultivar increased markedly. However, the TAC of ripe fruit from this cultivar also fluctuated markedly throughout the harvest season (between 1168–2171 mg Trolox equivalents 100 g−1). The TMAC increased sharply between the medium-ripe and fully ripe maturity stages, with the Blue Rose cultivar showing the highest TMAC values (211 mg 100 g−1, compared to 107–143 mg 100 g−1 for the remaining varieties). The TMAC of ripe fruit from this cultivar also rose steadily throughout the harvest season, in contrast to most other cultivars where the TMAC fell slightly over time. These results indicate that the levels of health-benefitting compounds in Australian-grown highbush blueberries may depend not only on the cultivar, but also upon the time of harvest.

Opportunities to Improve Effectiveness of Pollination of Blueberry CV. ‘Bluecrop’

“…Among the cultivars of the genus Vaccinium, highbush blueberry is the most noteworthy because, compared to other species of blueberries, its yield is the highest and ranges from 5 to 17 t/ha [7,32]. Because of their high content of phenolic acids and flavonoids, blueberries are considered a health-promoting fruit [33,34].…”

Phenolic Compound Content and the Antioxidant and Antimicrobial Activity of Wild Blueberries (Vaccinium stenophyllum Steud.) Fruits Extracts during Ripening

“…For example, fruits of the variety 'Blue Rose' showed a trolox equivalent antioxidant capacity measured by the DPPH method of 2.11 mg of trolox equivalent per gram of fresh weight [9], while fruits of Vaccinium meridionale Sw., reached 143.68 µg of trolox equivalent per gram of dry weight [10]. On the other hand, studies on Vaccinium floribundum Kunth.…”