Effect of Compost Socks System On Antioxidant Capacity, Flavonoid Content, and Fruit Quality of Strawberries

The effect of cultivation practices on fruit quality, antioxidant capacity, and flavonoid content in strawberries var. Allstar and Chandler (Fragaria x ananassa Duch.) was evaluated. Strawberry fruit used in this study were from plants grown in soils which had prior history of black root rot and red stele, caused by Phytophthora fragariae Hickman, and had not been fumigated during the seven years prior to the study. Results from this study showed that different cultural systems (matted row, black plastic mulch and compost socks) significantly affected total anthocyanins and total phenolics in strawberries. Fruit from plants grown in compost socks had significantly higher oxygen radical absorbance capacity than fruit from black plastic mulch or matted row systems. Individual flavonoids and anthocyanins were also higher in strawberries grown in compost socks than those grown in black plastic mulch or matted row systems. Higher levels of ellagic acid, ellagic acid glucoside, p-coumaroyl-glucose, quercetin 3-glucoside and quercetin 3-glucuronide, kaempferol 3-glucoside and kaempferol 3-glucuronide were also found in fruit grown from compost sock than those from other systems. Strawberry plants grown in compost socks also produce fruit with significantly higher soluble solids content, titratable acid, total sugars, fructose, glucose, sucrose, and citric acid than fruits produced in the two other culture systems. In general, cv. Chandler surpassed cv. Allstar in content of sugars, acids and flavonoids regardless of pre-planting vinegar drenching and various culture treatments. However, pre-planting vinegar treatment increased acidity, and cyanidin-based and pelargonidin-based anthocyanins, but decreased sugar content in fruit of both cultivars.