Computational Investigation of Bond Strength in α-D-Glucose under Strong Electric Fields: Implications for Plasma-Induced Starch Cross-Linking

Plasma technology offers a promising, environmentally friendly approach for starch modification, including cross-linking, which can significantly alter its functional properties. While macroscopic changes in plasma-treated starch are observable, the underlying molecular mechanisms, particularly the specific sites of cross-linking, remain challenging to elucidate experimentally. Starch is a complex polysaccharide composed primarily of glucose units. Understanding how individual glucose molecules respond to the plasma environment at the atomic level is crucial for revealing these mechanisms. This study employs Density Functional Theory (DFT) calculations to investigate the effect of strong static electric fields on the bond strength of α-D-glucose, a fundamental building block of starch. By systematically varying the applied electric field, we aim to simulate a key interaction experienced by starch molecules within a plasma environment. We will analyze changes in key molecular descriptors, such as bond lengths, bond orders, and vibrational frequencies, to quantify alterations in bond strength. We hypothesize that specific bonds within the glucose molecule will exhibit significant and consistent weakening under the influence of electric fields applied in certain orientations and strengths. Identifying these vulnerable locations computationally is expected to provide valuable theoretical insights into the preferred sites for bond cleavage or rearrangement—crucial initial steps in plasma-induced cross-linking—and offer molecular-level clues to complement experimental characterizations of cross-linking behavior in plasma-modified starch.