Enhanced physicochemical, structural and functional characteristics of Ponkan dietary fiber through...

Ponkan peel was subjected to either alkali treatment or an integrated alkali and homogenization-enzymolysis (HE) process, yielding four distinct dietary fiber (DF) fractions: alkali-treated soluble dietary fiber (SDF), alkali-treated insoluble dietary fiber (IDF), alkali-HE-treated SDF, and alkali-HE-treated IDF. Comprehensive analyses demonstrated that both alkali and HE treatments significantly enhanced the SDF content while reducing cellulose, hemicellulose, and lignin levels. The primary monosaccharides identified were galacturonic acid, glucose, and rhamnose, with HE treatment notably decreasing glucose content and increasing galacturonic acid levels. Structural characterizations revealed that HE treatment induced a honeycomb-like structure with increased porosity and reduced crystallinity, resulting in lower thermal stability compared to alkali treatment alone. Seven key physicochemical properties, including water-holding capacity, oil-holding capacity, and glucose absorption capacity, were markedly improved following HE treatment. In vivo experiments using STZ (streptozotocin)-induced diabetic mice demonstrated that alkali-HE-treated DF interventions exhibited significant hypoglycemic effects, alongside beneficial modifications in gut microbiota composition. These findings not only introduce a novel method for processing Ponkan peel but also lay a robust foundation for expanding its applications in functional foods and nutraceuticals. This study supports the potential role of these enhanced DFs in managing glycemic control and lipid profiles, thereby contributing to diabetes management and overall metabolic health.