Effect of Pullulanase debranching freeze-thaw treatments and fatty acid on functional properties of yam starches

This study was performed using yam starches (Tainung No. (TNG)1 and 2), which were modification through Pullulanase debranching (PD) or addition of four fatty acids lauric acid (LA), myristic acid (MA), palmitic acid (PA), and stearic acid (SA), followed by one cycle of freeze-thaw synergy treatment. This study showed that increasing enzyme levels and extending treatment time during the PD synergized FT process significantly increased the amylose contents of yam starches from 33-36 to 48-65% (p < 0.05). Notably, the crystalline structure of yam starches changed from B to C-type, while those treated with fatty acids changed to C + V-type. This study showed that the glycemic index (eGI) of adding fatty acids to TNG2 starch treated with PD synergistic FT was consistent with the definition of low GI foods. Therefore, this study reveals techniques that can enhance yam starch's functional properties, which may interest food industry stakeholders.