Influence of Infrared Dry Heat Treatment on the Structure and Properties of Potato Starch

Abstract

The current study presents a novel approach to starch modification using infrared dry heat treatment (IR‐DHT). IR‐heating at 200 °C allows one to reduce the processing time to 15 min and does not lead to irreversible amorphization of starch structure. Upon IR‐DHT, an increase in density of starch granules from 1.4888 ± 0.0005 to 1.5038 ± 0.0005 g cm−3 is observed. The crystallinity degree of the starch exposed in water at 20 °C after IR‐DHT does not change compared to the crystallinity of native starch hydrated at the same temperature. However, the exposure in excess of water of native potato starch at 45 °C induces an increase of crystallinity up to 81% (along with a significant increase in the intensity of the d100 reflection), while heat‐treated starch exposed in water at the same temperature has reduced crystallinity (RC = 39%). In addition, the concentration of soluble carbohydrates released during the exposure process (45 °C, excess of water) increases by an order of magnitude for heat‐treated starch compared to the native sample. Hence, IR‐DHT may become a promising way to influence the processes of acid and enzymatic hydrolysis and control starch properties, such as pasting, solubility, and digestibility.