Changes of flavonoid content and antioxidant capacity in blueberries after illumination with UV-C

• Published in: Food chemistry Vol. 117; no. 3; pp. 426 - 431
• Main Authors: Wang, Chien Y., Chen, Chi-Tsun, Wang, Shiow Y.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.12.2009; [Amsterdam]: Elsevier Science; Elsevier
• Subjects: Anthocyanins; antioxidant activity; Biological and medical sciences; blueberries; flavonoids; food analysis; Food industries; food processing; food processing quality; Fruit and vegetable industries; fruit composition; fruit quality; Fundamental and applied biological sciences. Psychology; Phenolics; Phytochemicals; Postharvest; ultraviolet radiation; Vaccinium corymbosum; Postharvest; Vaccinium corymbosum; Anthocyanins; Phytochemicals; Phenolics; Anthocyanin; Fruit; Berry; Antioxidant; Flavonoid; Polyphenol; Dicotyledones; Blueberry; Angiospermae; Pigments; Phenols; Illumination; Spermatophyta; Ericaceae
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2009.04.037

The levels of flavonoids in blueberries ( Vaccinium corymbosum L.) were found to increase after illumination with UV-C. Phytochemicals affected included resveratrol, myricetin-3-arabinoside, quercetin-3-galactoside, quercetin-3-glucoside, kaempferol-3-glucuronide, delphinidin-3-galactoside, cyanidin-3-galactoside, delphinidin-3-arabinoside, petunidin-3-galactoside, petunidin-3-glucoside, petunidin-3-arabinoside, malvidin-3-galactoside, malvidin-3-arabinoside, and chlorogenic acid as analyzed by HPLC. Significantly higher antioxidant capacity was detected in fruit treated with 2.15, 4.30, or 6.45 kJ m −2 compared to the control fruit. UV-C dosage of 0.43 kJ m −2 also increased phenolics and anthocyanins, but to a lesser extent. The optimum doses of UV-C for enhancing phytochemical content in blueberries were 2.15 and 4.30 kJ m −2. These data suggest that proper use of UV-C illumination is capable of modifying the phytochemical content of blueberries. Time course measurements of the effects of UV-C revealed that the strongest responses of fruit to UV-C treatment occurred instantly after the illumination and the effects diminished with time. Therefore, even though residual effects were evident following UV-C exposure, the best results were obtained immediately after the treatment.