Structural, rheological and emulsifying properties of RG-I enriched pectins from sweet and sour cherry pomaces

Abstract

RG-I enriched pectins exhibit distinct biological functions such as antioxidant, anti-inflammatory and regulating the intestinal flora environment. Understanding their processing properties helps realize their applications in food and pharmaceuticals. In this study, pectin was extracted from Prunus cerasus pomace (RPC) and Prunus avium pomace (RPA) by mild acid extracting method. RPC and RPA were low-methoxylated branched semicrystalline polymers, with high contents of RG-I and HG (47.7 and 40.5 mol% for RPC; 51.2 and 36.2 mol% for RPA). They had comparable protein contents (1.6–1.9%), phenolic contents (1.2–2.0%), Mw (>2000 kDa), branching degrees, and monosaccharide compositions. RPA had a lower GalA contentand bigger side chains attached to RG-I ((Ara + Gal)/Rha: 11.7 for RPA and 9.5 for RPC). Both were rheology modifiers and emulsifiers with similar and good thermal stability. RPA is a more effective emulsifier, whilst RPC suits more gel formation. For aqueous solutions at 1% and 2%, RPA had higher viscosity. At 4%, RPA solution showed liquid-like character whilst RPC solution behaved like elastic solid-like material. Overall, cherries are a novel source of RG-I enriched pectin, which can potentially be used as natural emulsifiers and rheology modifiers in the food industry or cosmetics.