|Maas, John - RETIRED ARS EMPLOYEE|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 25, 2003
Publication Date: May 30, 2003
Citation: Wang, S.Y., Bunce, J.A., Maas, J. 2003. Elevated carbon dioxide increases contents of antioxidant compounds in field-grown strawberries. Journal of Agricultural and Food Chemistry. 51:4315-4320. Interpretive Summary: Strawberries are good sources of natural antioxidants. In addition to the usual nutrients such as vitamins and minerals, strawberries are also rich in anthocyanins, flavonoids and phenolic acids. Elevated CO2 concentration in the atmosphere enhances vegetative growth, carbohydrate accumulation, and fruit productivity in strawberry. However, no information is available on the effect of CO2 concentration on flavonoid content and free radical scavenging capacity of field-grown strawberry fruit. We increased CO2 levels in the chambers of strawberry plants and studied the effect of elevated CO2 concentrations on nutritional quality of fruit. We found that strawberry plants grown under CO2 enrichment conditions had increased phytonutrient content and antioxidant capacity in the fruit. This research increased our knowledge on the impact of environmental factors on nutritional quality of fruit. This information will be useful to strawberry growers interested in selecting the best conditions for maximizing phytonutrient content and antioxidant capacity in strawberry fruit.
Technical Abstract: The effects of elevated CO2 concentrations on the antioxidant capacity and flavonoid content in strawberry fruit (Fragaria x ananassa Duch.) were studied under field conditions. Increased CO2 concentrations resulted in increases in ascorbic acid (AsA), glutathione (GSH), and ratios of AsA to dehydroascorbic acid (DHAsA) and GSH to oxidized glutathione (GSSG); and a decrease in DHAsA in strawberry fruit. High anthocyanin and total phenolic content were also found in fruit of CO2 treated plants. Growing strawberry plants under CO2 enrichment conditions significantly enhanced fruit p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside and quercetin 3-glucuronide contents, as well as cyanidin 3-glucoside, pelargonidin 3-glucoside, and pelargonidin 3-glucoside-succinate content. Fruit of strawberry plants grown in the CO2 enrichment conditions also had high oxygen radical absorbance activity against active oxygen species.