Specific wavelength LED light pulses modifies Vitamin C and organic acids content in raspberries and blackberries fruit during postharvest

Abstract

Raspberries and blackberries produce extremely perishable fruit with a high market value for its flavor and nutritional qualities. Light Emitting Diodes (LED) recently emerged as a no polluting and energy-saving technology in fruit postharvest. The aim of this work was to evaluate the effect of different LED light pulses during raspberries´ and blackberries´ postharvest under cold storage. Fruit of both species were placed in clamshells and exposed to short light pulses of 15 min every 2 h for 7 and 14 d of storage at 4 ºC. The treatments were darkness, Green, Blue, Red, and Red+Blue LED light. Internal breakdown increased in darkness with a concomitant decrease in the respiration rate in raspberry fruit, but light did not improve the fruit quality of blackberries. Green and Blue treatments promoted an advance in the raise of the ascorbic acid content at d 7 and maintained higher levels of citric acid 14 d after cold storage in raspberries, while in blackberries, there was a significant decrease in ascorbic and citric acid contents. Different patterns organic acids synthesis and catalysis between species suggest that fruits have different strategies for maturation and ripening, interacting with light during postharvest. Overall, these results showed that short LED light pulses can extend the postharvest life of raspberries, decreasing the fruit internal breakdown and increasing the content of ascorbic acid.