Abstract

The study was aimed to evaluate the effect of thermo-molding on gluten and gluten fractions composition and its extractability with 1.0 ml 0.05 M sodium phosphate buffer (pH 6.8) with 2.0% sodium dodecyl sulfate (SDS) at 130 and 150°C for 5 and 25 min. The gluten, gliadin and glutenin composition as affected by thermo-molding was analysed with reverse phase high performance liquid chromatography (RP-HPLC) and amino acid was analysed with acid hydrolysis using high-performance anion-exchange chromatography with integrated pulsed amperometric detection (HPAEC-IPAD). The extractability and composition were significantly affected. Gluten extracts were found in equivalent proportions; gliadin (51%) and glutenins (49%). Gluten, gliadin and glutenin subunits (GS) extracts were significantly affected and a reduction with increased molding condition explains the occurrence of polymerization reactions due to SH-disulfide interchange reactions. The glutenin fraction contains 15% gliadin while the gliadin fraction contains 2.5% glutenin after extraction with 60% ethanol. The extractability of the gliadin types and GS decreased with increasing molding time and temperature.

Key words: Gluten, gliadin, glutenin, extractability, composition, thermo-molding, amino acids.