Interaction of cellulose nanocrystals and amylase: Its influence on enzyme activity and resistant starch content

The aim of this work was to evaluate the effects of cellulose nanocrystals (CNCs) on amylolytic enzyme activity and starch digestibility. For the first time, we investigated the interaction between alpha-amylase or glucoamylase and CNCs using ultraviolet visible (UV-Vis) absorption spectroscopy, fluorescence quenching method, Fourier transform infrared (FTIR) spectroscopy, and circular dichroism (CD). The results of UV and fluorescence spectra suggested that CNCs interacted with a-amylase and glucoamylase. Increasing the concentration of CNCs caused a reduction of alpha-amylase and glucoamylase activities. The FTIR and CD results indicated that CNCs induced structural changes in the secondary structure of alpha-amylase and glucoamylase. By incorporating CNCs into maize, potato and pea starches, the contents of rapid digestible starch and slowly digestible starch of the cooked starches decreased while resistant starch content increased.