Pulsed light influences several metabolic routes, delaying ripening and improving the postharvest quality of acerola

Abstract

• Pulsed light reduced acerola climacteric respiration and delayed ethylene peak. • Pulsed light-treated acerola was firmer and lost less weight. • Pulsed light enhanced polyamines by stimulating synthesis and inhibiting degradation. • Pulsed light increased vitamin C by reducing degradation and improving recycling. This study investigated how pulsed light (PL) postharvest treatment influences acerola ripening physiology and quality, thus physiologically mature acerola ‘Okinawa’ were treated with PL (0.6 J.cm −2 ) and stored for 16 days at 10 °C. Compared to untreated, PL-treated acerola showed a 5% reduction in climacteric respiration with 78.65 mol CO 2 kg −1 h −1 and a one-day delay in ethylene peak of 2.65 µL C 2 H 4 kg −1 h −1 . PL-treated acerola also showed 13% lower weight loss and was 12% firmer probably due to the enhanced antioxidant enzymes that reduced hydrogen peroxide content with lower membrane lipid peroxidation, in addition to inhibition of cell wall hydrolysis. The higher polyamine levels induced by PL may be explained by the greater synthesis, inhibition of degradation, and enhancement of back-conversion reactions. PL treatment would have increased the total vitamin C by 33% as a result of lower degradation and more efficient recycling reactions, while polyphenols would have increased 10% by reducing oxidation and enhancing synthesis. Although the storage period exerted the main influence on ‘Okinawa’ acerola, results indicate that PL delayed ripening and promoted quality as an elicitor of antioxidant metabolism thus representing a hormetic phenomenon. Proposed mode of action of pulsed light (0.6 J.cm −2 ) on the physiology of ‘Okinawa’ acerola.