Utilization of electron beam irradiation pretreatment for the extraction of pectic polysaccharides from Diaphragma juglandis fructus: Structural, physicochemical, and functional properties

Abstract

The effects of electron beam irradiation (EBI) pretreatment on the alkaline extraction of pectic polysaccharides from Diaphragma juglandis fructus (DJF) are highly dependent on the irradiation dosage. Comprehensive characterizations encompassing physicochemical, structural, and functional properties were conducted on crude pectic polysaccharide extract from DJF subjected to various EBI doses. EBI pretreatment significantly increased the yields of crude pectic polysaccharides extract (increasing by 41.89 %), also facilitating the extraction of uronic acid, RG-I structure, and protein content, despite causing a decrease in total sugar content. EBI pretreatment induced the degradation of pectin, resulting in decreased molecular weight, particle size, crystallinity, viscosity, thermal stability, and water holding capacity, while enhancing solubility and oil holding capacity. Variations in physicochemical and structural properties induced by different EBI doses influenced the functional activities of DJF pectic polysaccharides. Low-dose EBI (at 5 kGy) pretreatment markedly improved the emulsifying activity/stability (increasing by 20.82/74.10 %) and ABTS/DPPH radical scavenging activity (increasing by 27.91/12.40 %), whereas high-dose EBI pretreatment (50 kGy) greatly enhanced foaming capacity/stability (increasing by 259.99/175.56 %). These findings provide a novel regulatory strategy for the functional activity of pectic polysaccharides.