Linear dextrin as curcumin delivery system: Effect of degree of polymerization on the functional stability of curcumin

Linear dextrin (LD)/curcumin complexes were fabricated through co-precipitation method. The effect of reaction time, weight ratio and degree of polymerization (DP) on curcumin payload, inclusion rate, as well as the yield of complexes was investigated. For LD with DP 77, the yield, curcumin payload and inclusion rate reached 73.98%, 28.76 μg/mg, and 23.81%, respectively. The inclusion complexes was verified by XRD, SAXS, DSC, and FT-IR, indicating that hydrogen bonding was the main driving force for complex formation. TGA revealed that the LD/curcumin complexes had higher thermal stability compared to pure curcumin. The photochemical stability and controlled release properties of curcumin were also improved by complexation. Overall, longer LD (DP 77) gained higher yields compared to the shorter LD (DP 32), and provided better protection for curcumin. These findings suggest that LD can be used as a food-grade carrier for curcumin, and that its molecular weight is important for enhanced functional stability of curcumin.