The Effects of Storage and Harvesting Method on Anthocyanin Content of Southern Highbush Blueberries (Vaccinium corymbosum L.), Poster Board #034

Secondary plant metabolites, like flavonoids, have been shown to have beneficial effects on human health. Anthocyanidins, a class of flavonoids, have been linked with decreasing cancer risks and improving cardiovascular health. Blueberries (Vaccinium spp.) are a rich source of multiple types of anthocyanins. Anthocyanin levels within blueberry fruit may be influenced by horticultural production practices as well as postharvest storage conditions. The objective of this study was to determine the effects of two different harvesting techniques and four different storage durations on six blueberry cultivars and advanced selections. Six genotypes (Sweetcrisp, Farthing, Meadowlark, Scintilla, Star, and FL 01-248) grown in Florida were either hand or machine harvested. After manual sorting, the fruit were stored at 0–1°C and 90–95% relative humidity. Two clamshells of fruit were removed every week for three weeks after harvest and analyzed either immediately or after three days at room temperature. The total anthocyanin measurements were made by identifying the concentrations of cyanidin, delphinidin, malvinidin, peonidin, and petunidin, the predominant anthocyanins found in blueberries. Anthocyanin measurement was performed using HPLC. Genotype and harvest method were the two most significant factors affecting anthocyanidin content. Genotypes FL 01-248 and Scintilla averaged 112 mg/100g and 88 mg/100g fresh weight, respectively, over the duration of the study while cultivars Farthing and Star had concentrations of 65 mg/100g and 60 mg/100g fresh weight, respectively. Machine harvested fruit generally had 20% less total anthocyanins than the hand harvested fruit. The storage duration did not affect anthocyanidin content; however, time spent at room temperature did. Fruit left at room temperature for 3 days after removal from storage had about 10% higher levels of anthocyanins than fruit analyzed immediately after removal from storage. Hand harvesting may result in the selective harvest of fruit at the optimum stage of harvest while mechanical harvesting typically results in the non-selective removal of fruit at various stages of ripening. The variability in the stage of ripening may partly explain the differences in anthocyanidin content between the two methods of harvesting. Additionally, mechanical impact sustained during mechanical harvesting may reduce the amount of anthocyanins produced and enhance the production of other defense or repair-related compounds. Room temperature incubation following removal from low temperature storage may result in the induction of anthocyanin production leading to the higher content of these compounds. Together, data from this study indicate that harvesting method, genotype, and storage protocol can affect anthocyanidin content in blueberry.