Regresar

Relationship between gluten degradation by Aelia spp and Eurygaster spp and protein structure

Abstract:

Gluten from wheat damaged by heteropterous insects loses its functionality after a short period of resting. In this study the properties of the gluten from damaged wheat are compared with that from sound wheat in order to understand the changes produced during incubation at 37°C. The amounts of free thiol and amino groups were quantified, obtaining a marked increase of those groups during incubation of the damaged wheat. The thermal characterization of the damaged gluten showed a decrease in the denaturation temperature and a pronounced increase in the protein denaturation enthalpy after a short incubation, although the value of that enthalpy greatly dropped with a longer incubation period. The high-molecular-weight glutenin subunits (HMW-GS) were rapidly hydrolysed while the low-molecular-weight glutenin subunits (LMW-GS) showed a slower degradation. It seems that the HMW-GS backbone was first hydrolysed, leading to a protein structure with higher thermal stability but, as the hydrolysis proceeded, a deeper degradation of the structure yielded a protein structure with lower denaturation enthalpy. The loss of gluten functionality results from complex changes in the gluten structure at the first and second level of the protein organization structure. © 2005 Society of Chemical Industry.