Physicochemical, structural and functional properties of water-soluble polysaccharides extracted from Egyptian agricultural by-products

One of the successful strategies for the improvement of the sustainable food chain is to achieve economic success while improving environmental performance. For this point of view, water-soluble polysaccharides (WSP) were extracted from some agricultural by-products (potato peel (PoP), pea peel (PeP) and taro peel (TP) as Egyptian agro-waste products). Furthermore; Physicochemical parameters, structural, antioxidant and functional properties of the extracted polysaccharides were investigated via High-Performance Liquid Chromatography (HPLC), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR) spectroscopy, Thermo Gravimetric Analysis (TGA) as well as DPPH radical and ABTS radical assays. The most predominant sugar(s) content in PoP were glucose and stachyose (50.12 and 20.68 g/100 g), in PeP was sucrose (34.34 g/100 g) and in TP were stachyose and glucose (47.4, 35.73 g/100 g). FTIR analysis confirmed the presence of different polysaccharides functional groups (OH, CH, CH₂ and CH₃). On the other hand, the extracted (water-soluble) polysaccharides exhibited high thermal stability (up to 220 °C) that makes them applicable in high-temperature food processing. PoP and PeP showed good water holding capacities (4 g water/g sample each) and PeP showed higher emulsifying capacity and stability (41.88%, 37.23%). Furthermore, PoP, PeP and TP polysaccharides exhibited noticeable antioxidant potentials as indicated by IC₅₀ values (1.91, 3.96 and 8.41 mg/mL). Overall, the findings in the present study indicated that PoP, PeP and TP from waste products might be considered as promising sources for natural functional additives for different types of foods.