Physicochemical Insights into Interactions Between Whey Protein Isolate and Alcohol-Precipitated Crude Baobab Polysaccharides (Non–Triple-Helix): Structural and Functional Characterization

Baobab fruit crude polysaccharides (BBP) were extracted and purified with a yield of ۲۴.۰۱ ± ۱.۲۰%. BBP contained ۵۳.۲۰ ± ۱.۹۰% total sugars, with dominant monosaccharides including xylose (۵۵.۴۰%), glucose (۱۹.۴۴%), and galacturonic acid (۶.۲۱%). FTIR analysis revealed BBP–WPI interactions, with shifts in amide I and II bands indicating alterations in protein secondary structure, quantified as an increase in β-sheet content. Intrinsic fluorescence showed blue shifts in emission maxima from ۳۳۱ nm (WPI) to ۳۲۸–۳۲۱ nm in complexes, with the maximum intensity at ۳% BBP. UV absorption suggested molecular interactions, and SEM images showed morphological changes with increasing BBP. Congo red assay indicated no triple helix conformation in BBP. TGA revealed thermal degradation stages, with an initial mass loss (۳.۵%) at ۱۴۱.۹ °C due to moisture, followed by further decomposition at ۲۳۴.۱, ۳۵۲.۶, and ۷۳۳.۸ °C. The residual mass at ۹۰۰ °C was high, indicating considerable thermal resistance. BBP-WPI complexes demonstrated enhanced antioxidant activity (>۸۰% DPPH scavenging), reaching ۹۶.۸۷% at ۴% BBP. Surface hydrophobicity increased with BBP concentration, while emulsifying properties were concentration-dependent, with peak emulsifying activity observed at the lowest tested BBP concentration (۰.۵%). These findings support the potential of BBP-WPI complexes in functional food systems.

کلیدواژه ها:

Baobab fruits ، Polysaccharides ، Whey Protein Isolate ، antioxidants ، Emulsifying properties