Submitted to: Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/8/2010
Publication Date: 1/1/2011
Citation: Jin, P., Wang, S.Y., Wang, C.Y., Zheng, Y. 2011. Effect of cultural system and storage temperature on antioxidant capacity and phenolic compounds in strawberries. Food Chemistry. 124:262-270. Interpretive Summary: The demand for organic food products has increased rapidly during recent years. However, research findings comparing the nutritive values of organically produced foods with those of conventionally grown foods have been inconclusive. We evaluated fruit quality, antioxidant activity, and flavonoid content of organically and conventionally grown strawberries. We found that strawberries produced organically contained significantly higher amounts of phytonutrients than those produced in conventional culture. Thus, the organically grown strawberries may provide greater benefit to human health than conventionally grown strawberries. This research contributes to the knowledge on the effect of cultural practices on quality and antioxidant activity in fruits. Information obtained from this study will benefit the consumer and other scientists.
Technical Abstract: The effects of cultural systems and storage temperatures on antioxidant enzyme activities and nonenzyme antioxidant components in two cultivars (‘Earliglow’ and ‘Allstar’) of strawberries were investigated. Fruit samples were hand-harvested from organic and conventional farms in Maryland, USA, and were stored at 10, 5 and 0 °C. Results from this study showed that strawberries grown from organic culture exhibited generally higher activities in glutathione reductase (GR), glutathione peroxidase (G-POD), ascorbate peroxidase (AsA-POD), guaiacol peroxidase (G-POD), catalase (CAT), superoxidase dismutase (SOD), monodehydroascorbate reducatase (MDAR), and dehydroascorbate reductase (DHAR). Moreover, the organic culture also produced fruit with higher level of glutathione (GSH), ascorbate acid (AsA), total phenolics, total anthocyanins and individual flavonoids contents. In addition, strawberries grown from organic culture had higher antioxidant capacities (ORAC, •OH, DPPH scavenging capacities) than those grown from conventional culture. Antioxidant capacities in strawberries were also influenced by storage temperature. Fruit stored at higher temperature (10 °C) had higher activities of antioxidant enzymes and antioxidant capacities than those stored at lower temperatures (0 or 5 °C) in both organic and conventional cultural systems. No significant difference was found between 5 and 0 °C storage. In conclusion, strawberries produced from organic culture contained significantly higher activities of antioxidant enzymes and higher amount of non-enzyme antioxidant components than those produce from conventional culture, and even though low storage temperatures helped maintain quality, they also retarded the increase in antioxidant activities.