Bicarbonate-assisted extraction of pomegranate peel (Punica granatum L.) to obtain extracts with new low molecular weight phenols and enriched in total tannins and ellagic acid

Pomegranate peel is a by-product rich in ellagitannins, characterized by high molecular weight and low bioavailability. Working on several peel samples, we aimed to propose a single-step bicarbonate-assisted extraction to produce dry extracts with new phenol profiles rich in hydrolyzed tannins with potentially higher bioavailability. Compared to decoction, 0.6% sodium bicarbonate (NaHCO3) for 1 h extraction allowed 3.5-6.5-fold and 5.6-11.3-fold increase in ellagic acid and gallic acid, respectively, with total phenols ranging from 28.3% to 35.1% w/w. Simple pomegranate peel extraction with bicarbonate can be applied to prepare botanical extracts suitable for the food supplement market, thus increasing the value of this by-product.