Profiling of Dietary Fiber From Pumpkin ( Cucurbita moschata ) Seed Hulls Pertaining to Monosaccharide Composition, Structural, Thermal, and Functional Properties

ABSTRACT Insoluble (IDF) and soluble dietary fiber (SDF) were recovered from pumpkin seed hulls (PSHs) using hydrothermal treatment. Extraction variables (liquid/solid ratio: 20:1–60:1 mL·g −1 , extraction temperature: 80°C–98°C, and time: 80–120 min) were optimized to obtain maximum dietary fiber (DF). The IDF/SDF recovered under optimized conditions was comprehensively characterized. Glucose was the predominant monomer in both fiber samples, as observed by high‐performance liquid chromatography (HPLC). Functional group analysis (FTIR) showed some distinct peaks in insoluble (1450 and 1257 cm −1 ) and soluble fiber (1744, 1407, and 1096 cm −1 ) due to compositional differences, while X‐ray diffraction (XRD) revealed coexistence of crystalline and amorphous regions. Both DF fractions exhibited good thermal stability, as shown by differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. IDF possessed an open structure, while SDF appeared granular following scanning electron microscope (SEM) examination. IDF possessed higher oil holding capacity (OHC: 4.50 g·g −1 ) and cholesterol adsorption (CAC: 8.87–12.69 mg·g −1 ), while SDF showed greater water holding capacity (WHC: 5.18 g·g −1 ), swelling capacity (SC: 3.21 mL·g −1 ), and glucose adsorption capacity (GAC: 1.56–6.72 mmol·g −1 ). Overall, hydrothermal treatment proved to be a cost‐effective method to valorise PSH. PSH‐IDF and SDF showed remarkable structural and functional properties. The present approach paves the way to convert an agro‐industrial waste into a multi‐functional ingredient, thereby contributing to waste minimization.