Pectic oligosaccharides (POS) have been proposed as a new class of prebiotics due to their ability to regulate microbiota in human intestine, their anti-oxidant properties compared to other commercial oligosaccharides or their anti-inflammatory and anti-obesity effects1. POS are commonly obtained by partial (acid and/or enzymatic) hydrolysis of pectin. However, the growing demand of POS as functional additives for the pharma and food industries requires new sources and greener extraction strategies. In this sense, onion skin wastes (OSW) can offer great potential, since every year more than 450,000 t of OSW are discarded2, whereas subcritical water (SubW) emerges as an interesting and environmentally friendly technique to recover different valuable compounds from natural solid matrices.
