Effects of vitamin C on the structural and functional characteristics of wheat gluten

Vitamin C(VC)can greatly enhance the quality properties of dough and steamed bread in the food field.However,there are few studies on the interaction between VC and gluten,and the mechanism of VC influencing the foaming capacity,emulsifiablity,and dynamic viscosity of gluten is not clear.In this study,different content of VC(0,1%,2%,3%,4%and 5%)was added to gluten to obtain VC-gluten dough samples(CK,GV1,GV2,GV3,GV4 and GV5),and the properties of the VC-gluten dough were determined.Results showed that the increasing VC content lead to increase in the content of high-,medium-and low-molecular weight gluten,suggesting that VC improved the protein solubility of gluten.The G'and G"values of dough containing VC were higher than those of the control with the increase of scanning frequency.The foaming ability of gluten increased with the increase of VC content.Emulsibility of the dough of GV1 to GV 5 were significantly lower than that of the CK.Furthermore,VC could reduce the number of bubbles in gluten protein,when the VC content was less than 3%.In conclusion,VC might reduce the emulsifying characteristic and emulsifying stability of gluten,increase the solubility of gluten,and improve the dynamic viscosity of gluten dough by changing the content of disulfide bond in gluten.This study hopes to not only improve the functional characteristics of gluten protein,but also provide the basis for future development and improvement of VC-enriched health foods.

Functional properties of sesame (Sesamum indicum Linn) seed protein fractions

This work evaluated the functional properties of sesame protein fractions in order to determine their potential in food applications.Sesame seed protein fractions were prepared according to their solubility:water-soluble(albumin),salt-soluble(globulin),alkaline-soluble(glutelin)and ethanol-soluble(prolamin).Globulin was the most abundant fraction,consisting of 91%protein,followed by glutelin,albumin and prolamin in decreasing order.Non-reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)showed polypeptides of sizes≥20 kDa for albumin while glutelin and globulin had similar polypeptide sizes at 19,85 and 100 kDa.Prolamin had polypeptide sizes 20,40 and 100 kDa.The albumin and globulin fractions had higher intrinsic fluorescence intensity(FI)values than the glutelin.Albumin had a higher solubility(ranging from 80 to 100%)over a wide pH range when compared with the other fractions.Water holding capacity(g/g)reduced from 2.76(glutelin)to 1.35(prolamin)followed by 0.42(globulin)and 0.08(albumin).Oil holding capacity(g/g)reduced from:4.13(glutelin)to 2.57(globulin)and 1.56,1.50 for albumin and prolamin respectively.Gelling ability was stronger for prolamin and glutelin than albumin and globulin,while higher emulsion(p<0.05)quality was obtained for prolamin and albumin than for glutelin and globulin.