Influence of glucose addition on the physical, ph, and thermo-responsive properties of alginate beads

Alginate is a promising material for probiotic encapsulation due to its gel-forming that is able protecting any bioactive compounds used both in food and pharmaceutical industries. Glucose is known for its key role in the food industries being used as flavour, colouring agent and controlling the water activity. Encapsulation and delivery efficacy of the alginate beads highly depends on stability of the material withstanding extreme digestions mechanical and chemical processes This study examined the effects of glucose addition on the pH and thermal response of alginate beads meant to use for probiotic encapsulation. Beads were prepared with 1.5% and 2.0% (w/v) alginate in PBS (pH 4) and incorporated with 4%, 6%, 8%, or 10% (w/v) glucose. All groups formed spherical beads, with glucose increasing bead diameter via osmotic effects. Bead stability was tested in PBS at pH 2, 7, and 10 for 30 minutes. No significant diameter differences were observed between pH 7 and 10, but both differed from pH 2 (p<0.05), showing swelling at neutral/alkaline pH and shrinkage at acidic pH. Thermogravimetric analysis revealed lower weight loss in all glucose groups compared to control, indicating improved thermal stability. Notably, beads with 8% glucose showed the greatest stability, with minimal weight loss (-5.624 ± 2.307 at 1.5% and -6.367 ± 2.678 at 2.0% alginate).