Submitted to: Acta Horticulturae
Publication Type: Proceedings
Publication Acceptance Date: 8/1/2003
Publication Date: 12/1/2003
Citation: GONG, Y., MATTHEIS, J.P. EFFECTS OF LOW OXYGEN ON ACTIVE OXYGEN METABOLISM AND INTERNAL BROWNING IN 'BRAEBURN' APPLE FRUIT. ACTA HORTICULTURAE 628:533-539. 2003.
Technical Abstract: 'Braeburn' apple fruit were held in low oxygen (0.5kPa O2 +0.05kPa CO2) controlled atmosphere (CA) at 0 deg C or sealed in polyethylene bags (PA) at 20 deg C to obtain anaerobic conditions. Control fruit (CK) were stored in air. Activity of xanthine oxidase (XOD), NADH and NADPH oxidase, superoxide dismutase (SOD) and the incidence of physiological disorders were investigated. The activities of XOD, NADH- and NADPH oxidase were highest in apples from the CA and PA treatments. SOD activity was similar in CA and CK fruit, but lower in PA apples. Acetaldehyde (AA) treatment (120 ppm, at 0 deg C for 24 hr) prior to CA or addition of AA (1 ml of a 1% solution) to polyethylene bags stimulated NAD(P)H oxidase activity. AA pre-treatment resulted in lower SOD activity, and this response was detectable through two months storage in CA. The physiological disorder, internal browning, occurred in apples stored in CA or PA, and the disorder development was enhanced by AA treatments. The results suggest that development of internal browning in 'Braeburn' apples may be associated with superoxide accumulation due to enhanced activity of XOD and NAD(P)H oxidase with reduced SOD activity under low oxygen or anaerobic conditions.