Blue Light-Emitting Diode (LED) illumination and ascorbic acid synergistically delay browning symptoms and maintain abiu (Pouteria caimito) fruit quality during storage

Abiu is a tropical fruit that often develops browning symptoms on its peel and pulp, which leads to a short shelf life. This study evaluated the effect of exogenous ascorbic acid treatment on browning and the postharvest quality of abiu fruit stored under blue light emitting diodes (LED) light. The abiu fruit was immersed in an ascorbic acid solution at concentrations of 0 and 10 mM for 10 min, air-dried, and then exposed to blue LED light at a temperature of 28 ± 2 °C and 80 ± 3% relative humidity for 18 days. Four treatments were applied to the postharvest abiu fruit: (1) Control (0 mM ascorbic acid, no blue LED exposure); (2) AA10 (10 mM ascorbic acid, no blue LED exposure); (3) Blue LED (0 mM ascorbic acid, blue LED exposure); (4) AA10 + Blue LED (10 mM ascorbic acid, blue LED exposure). The results indicated that the AA10 + blue LED treatment maintained a low browning index of 9% for the peel and 15% for the pulp of the abiu fruit throughout the 18-day storage period. This combination treatment effectively suppressed the oxidation of phenolic compounds, inhibited the increase in polyphenol oxidase (PPO) enzyme activity, and reduced malondialdehyde (MDA) levels during storage. The AA10 + blue LED treatment also minimized weight loss, lowered respiration rates and ethylene production, and preserved firmness, sugar, acidity, and vitamin C content. Therefore, the AA10 + blue LED treatment is an effective method for delaying browning and maintaining the quality of abiu fruit.