Research of food systems based on pectin. Quantum-chemical modeling of galacturonic acid dimers

Abstract

The article is devoted to the study of the mechanisms of gelation in the pectin system. This article discusses the principles of chain high-esterified and low-esterified pectin in the system of hydrocolloid. This takes into account peculiarities of chemical structure of polymer molecules and reactivity of functional groups involved in the gel-formation with different rheological properties. By semiempirical quantum-chemical PM3 method simulation studied the geometry, electronic structure of the dimers molecule of α-1,4-galacturonic acid with different functional groups (carboxyl, ester and amide) in the software package Gaussian 09. Calculated thermal effects of reactions of formation of dimers, torsion angles (φ and ψ). From the resulting database was determined as the most stable state of the dimers, constructed their contour maps of potential energy. On the basis of quantum-chemical modeling was described by the points possible binding chains of pectin. The research objectives were defined an attempt to assess the degree of participation of dimers of α-1,4 -galacturonic acid containing various functional groups in the mechanism of gelation that occurs in food pectin systems with a view to the possible participation of other uronic acids types. The results will allow a more detailed description of the technological parameters in the production of dietary polysaccharides compositions in the form of films, gels, viscous fluids with the desired rheological characteristics.