Enhancing hydroxycinnamic acids and flavan-3-ol contents by pulsed electric fields without affecting quality attributes of apple.

Pulsed electric fields (PEF) have arisen as a promising tool for enhancing plant-based food bioactive compounds, although side effects on quality attributes might compromise consumer acceptance. This work was aimed at filling the gap in the understanding of whole effects of PEF on apple phenolic compounds profile and quality parameters. Treatment specific energy was a critical factor affecting phenolic profile and quality attributes, which in turn varied from 0 to 24 h after treatment. Treatments at 1.8 and 7.3 kJ kg-1 (140 and 260 μs total treatment times, respectively) induced important quality changes, mainly discoloration and firmness loss, while overall phenolic contents decreased, except those of flavonols. However, 24 h after treatment at 0.01 kJ kg-1 (20 μs total treatment time), the main apple phenolic compounds as determined by HPLC-DAD-MS had enhanced contents (28% 5-caffeoylquinic acid; 35% procyanidin B2). Accordingly, total phenolics and total flavan-3-ols contents increased (26% and 35%, respectively), while physicochemical quality attributes were not affected. Therefore, 0.01 kJ kg-1 PEF treatment is proposed for obtaining apples with optimal quality and enhanced functional value.