Application of Pulsed Electric Field to promote peelability on Peponids and Drupes: Understanding the effects on cells and the physical properties of fruits

Pulsed Electric Field (PEF) is an emerging non-thermal technology with the potential to improve peeling processes in the fruit and vegetable industry. This study investigated the impact of thermal (blanching) and non-thermal (PEF) treatments on the peeling ability and structural integrity of mangoes (Mangifera indica) and red bell peppers (Capsicum annuum). PEF treatments were applied at 1 kV/cm using two specific energy levels for each product: 1.1 and 4.6 kJ/kg for mangoes, and 3.4 and 10.3 kJ/kg for bell peppers. Conventional blanching (94°C for 1 and 3 min for mangoes, and 1 and 2 minutes for red bell pepper) served as the reference method. Key parameters evaluated peeling force and losses, firmness, color, and microstructure. In mangoes, PEF at 4.6 kJ/kg effectively reduced peeling force by 50% and minimized losses by 40%, performing better than 3-minute blanching, which reduced peeling losses by 30%. Microstructure analysis confirmed structural changes in parenchyma and collenchyma tissues, facilitating easier peel removal. Additionally, PEF treatments resulted better color retention than blanching; in contrast, red bell pepper samples didn't show any improvement in peeling ability after PEF treatment, due to their waxy nature skin that created a significant barrier. Although blanching for 2 minutes reduced firmness by up to 50%, microstructure analysis showed cell shrinkage and thickened cell walls, with no significant impact from PEF on peel detachment. These results demonstrate that PEF shows promising potential for improving mango peeling while preserving quality, but its effectiveness on red bell peppers appears limited, likely due tovariations in tissue structure and morphological characteristics.