Metabolic response of vitamin C and phenolic compounds in fresh-cut pineapple induced by pulsed electric fields

Abstract

The loss of nutritional quality is the main factor associated with the perishability of minimally processed foods. In this sense, the application of pulsed electric field (PEF) as an abiotic elicitor to induce stress responses in the metabolism of vitamin C and phenolic compounds in minimally processed pineapple tissues was evaluated. The samples were subjected to treatment with PEF (5 pulses – 3.5 kV m⁻¹) and subsequently stored under refrigeration (10 ± 2°C and 90 ± 5% RH) for a period of 7 days. Pulsed electric field treatment increased total vitamin C (AsA) levels by up to 4.32% up to the third day of storage compared to the control and kept oxidized AsA levels low. This is advocated by the incitement of AsA biosynthesis initiated by the more prominent action of l-galactone-1,4-lactone dehydrogenase—GalLDH and the reusing chemicals (Monodehydroascorbate reductase—MDHA and Dehydroascorbate reductase—DHA) in the ascorbate–glutathione cycle. In the metabolism of phenolic compounds, an increase of 25.26%, 21.48%, and 25.44% was observed for polyphenols, flavonoids, and antioxidant activity in samples treated with PEF in relation to the control, respectively, until the third day of storage. These results were corroborated by the higher phenylalanine ammonia-lyase (PAL) – PAL synthesis activity and lower polyphenoloxidase—PPO degradative action, which can be seen in the absence of dark spots on the tissues during storage. Considering the consumption and nutritional potential of minimally processed pineapple, the use of PEF is an important technology to increase/preserve the antioxidant potential, ensuring food safety and the visual appearance of the final product.