Insights into the physicochemical and structural properties of pumpkin flour via synergistic treatments with debranching enzymes and freeze-thaw cycle
Ping‐Hsiu Huang, T.T.Y. Wang, Wen‐Chang Chang
Abstract
This study investigated the feasibility of increasing the resistant starch (RS) content and decreasing the glycemic index (GI) of modified pumpkin flour (MPF) by using the enzyme debranching treatment of pullulanase (P) combined with synergistic treatments with different freeze-thaw (FT) cycle treatments (0–7 times) to optimize the functionality of the MPF. This study showed that the best enzyme reaction parameter for debranching treatment was 200NPUN and reacted for 12 h. Subsequent synergistic treatments revealed that MPF obtained from pullulanase combined with freeze-thaw cycle 7 times (P-7FT) possessed the maximum RS content, whereas pullulanase combined with freeze-thaw cycle 3 times (P-3FT) and P-7FT were found to have top amylose content. Regarding the physicochemical properties, the synergistic treatments assisted in converting the MPF into a lower GI, and the enthalpy of pasting, oil holding capacity, and solubility were also enhanced. However, structural analysis showed that synergistic treatments could not change the crystalline patterns of the MPF, which remained as B-type ones. The degree of polymerization and molecular weight decreased significantly. This study emphasized the potential of MPF utilizing synergistic treatments combining debranching enzymes with FT and creating a multifunctional carrier for a broader range of processing applications.