Thermal, Structural, and Functional Interactions of Date Seed Powder-Sucrose Composites Produced by Thermal Treatment

Abstract

The incorporation of dietary fibers into sucrose-rich food systems represents a promising strategy for developing healthier reduced-sugar formulations; however, the structural interactions governing their functionality during thermal processing remain poorly understood. This study investigated the physicochemical, thermal, and microstructural interactions between sucrose (SU) and date seed powder (DC) in composite systems prepared at 40 °C (M1-M5) and 70 °C (N1-N5). Progressive DC incorporation significantly reduced hygroscopicity from 25.89 to 18.50 g/100 g (40 °C) and 19.54 g/100 g (70 °C), while solubility decreased from 71.80 to 30.84 and 31.97 g/L, respectively. Conversely, water absorption capacity increased from 25.90 to 66.20% and 64.91%, reflecting enhanced hydration through the lignocellulosic network. Differential scanning calorimetry (DSC) demonstrated modified melting behaviour and reduced melting enthalpy, indicating disruption of sucrose crystal organization following interaction with DC. Fourier Transform Infrared (FTIR) spectra revealed shifts in hydroxyl and carbonyl vibrations consistent with hydrogen-bond rearrangement, whereas Field Emission Scanning Electron Microscopy (FE-SEM) showed progressive embedding of sucrose crystals within a compact fibrous matrix, particularly after heating at 70 °C, indicating stronger interfacial integration than at 40 °C. Collectively, these findings demonstrate that mild heating promotes structural reorganization between sucrose and date seed powder, producing composites with improved moisture management and physicochemical stability. The resulting ingredients show promise for confectioneries, cereal bars, fillings, and other sugar-containing food systems where partial sugar replacement and enhanced product stability are desired.