Dynamic rheological properties of wheat dough supplemented with extract of Cephalaria syriaca and characterization of functional components responsible for wheat dough strengthening

Mirwais Rahimi, Purdue University

Abstract

Wheat storage protein "Gluten" contributes to viscoelastic properties of dough while this property is highly dependent to the glaidin/glutenin ratio which balances between elastic and viscose properties and LMW-GS and HMW-GS which contribute to elasticity in dough system. Ability to form strong viscoelastic fibrils during dough making is highly desired in dough while wheat flour possessing low protein content is unable to form such viscoelastic fibrils. Therefore, they require some substance which is called dough improvers. Glutenin subunits have ability to polymerize via oxidation and sulfhydryl-disulfide interchange to make high molecular-weight protein with distinctive functional properties. Inorganic oxidants have been used for years to enhance wheat dough quality however, application is limited in some countries and most other banned due to carcinogenic effects. Cephalaria Syriaca is a perennial plant that commonly found in cereal fields is known as a competitive weed and potential seed contaminant. The major application this plant is as a dough strengthener in low-strength wheat cultivars. The overall goal of this project was to study dynamic rheological properties of dough made from wheat flour and C. syriaca seed flour mixture as well as determine the responsible compounds in C. syriaca that promote structure of the dough. Oscillation measurements indicates that addition of 3% defatted C. syriaca considerably increased storage modulus (G') and reduced loss tangent δ comparison to Bromated flour. Similar results were observed in glutenin macropolymer (GMP) gel extracted from wheat flour. GMP gel extracted from a mixture of 3% wheat flour and C. syriaca seed flour exhibited the highest elasticity and structural stiffness. To examine the effect of protein polymerization gel electrophoresis and chicken egg albumin were used as a model protein. Phenolic extracts of C. syriaca flour led to increased protein polymerization due to formation disulfide bonds and promoting sulfhydryl-disulfide interchange. These results suggest that the mechanism of the interaction of the C. syriaca and wheat dough is based on a redox reaction, and phenolic compounds are the main contributors of transferring electron among sulfhydryl groups. Redox reactions facilitate formation of disulfide bonds to increase protein polymerization and result in enhanced dough functional properties. HPLC-MS results showed that the C. syriaca phenolic extract contained wide range phenolics that characterization of those compounds requires further study.

Degree

M.S.

Advisors

Hamaker, Purdue University.

Subject Area

Plant biology|Food Science|Plant sciences

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