Modification And Application Of Wheat Gluten

Protein and polysaccharide are the most important factors affecting the texture and quality of food.Protein and polysaccharide can form conjugate through Maillard's reaction under the control condition,and the conjugate has enhanced functional properties.Therefore,the study on the conjugate derived from protein and polysaccharide is very hot in recent years.WG which contains all kinds of amino acid is the source of the vegetable protein with abundant nutrition and excellent quality and reasonable price.It forms wet wheat-gluten with network structure after absorbing water,having heat solidification,emulsification and foaming properties.In addition,it has special functionalities such as visco-elasticity and extensibility, visco-elasticity and extensibility are the most important factors impacting the properties of wheat gluten protein.Because the WG produced in China has poor visco-elasticity and extensibility,it usually doesn't satisfy the need of food processing and has a limit in application,remaining import in a large quantity from other countries.The key of solving these problems lies in selecting appropriate modified methods,discussing the simple and practicable methods by quantitative analysis of all kinds of functionalities on WG and researching the effects of modified methods on WG functionality,which can provide theory and experiment basis of improving WG functionality,improving wheat quality and enlarging applying area of WG.The research content of the thesis included:(1)Study the condition of polysaccharide colloids modified WG,with the purpose of improving WG viscoelasticity and extensibility;(2)Study the condition of polysaccharide colloids modified WG,with the purpose of improving WG adhesive properties;(3)Study the influence of five polysaccharide colloids,Transglutaminase(MTG)and modified wheat gluten(M-G)on the quality of noodles;(4)Study the influence of laboratory-made composite organic acids on the acid resistance and anti-corrosion properties of noodles which had been added with different additives Main research conclusions of this thesis were following:1.Five polysaccharide colloids(gum Arabic,Konjac gum,Carrageenan, Xanthan Gum,and Pectin)were used to modify wheat gluten,the most suitable colloid is pectin which can maximize the extensibility of wheat gluten.The adding proportion of pectin,different acidic condition,the proportion of Ca²⁺were studied on the viscoelasticity and extensibility of wheat gluten.The optimum conditions were:25℃,pH 4.0,0.7%(w/w)Pectin,adding 70mg Ca²⁺to 1g pectin in the form of CaCl₂. From the graph of scanning electron microscope of modified wheat gluten(M-G), protein molecule of M-G become large after modification,the cross-linking of M-G catalyzed by modifying comparing with wheat gluten(WG)was obvious.2.Study the condition of polysaccharide colloids(gum Arabic,Konjac gum, Carrageenan,Xanthan Gum,and Pectin)modifing WG,with the purpose of improving WG adhesive properties,the most suitable colloid is Xanthan Gum which can improving WG adhesive properties remarkably.The adding proportion of Xanthan Gum,different acidic condition,the way of drying were studied on the adhesive properties of WG.The optimum conditions were:25℃,pH 3.2,0.7%(w/w) Xanthan Gum,spray drying.3.Study the influence of five polysaccharide colloids(Carrageenan,Xanthan Gum,gum Arabic,guar gum and Pectin),Transglutaminase(MTG)and modified wheat gluten(M-G)on the quality of noodles.The result of the study shows that: Xanthan Gum,Transglutaminase(MTG)and modified wheat gluten(M-G)can improve the quality of noodles remarkably.The optimal adding percent of Xanthan Gum is 0.2%,the optimal adding percent of MTG is 2.5 g/kg(TG 100 U/g),the optimal adding percent of M-G is 2%.4.Study the influence of laboratory-made composite organic acids on the acid resistance and anti-corrosion properties of noodles which had been added with different additives.The result of the study shows that:Xanthan Gum and wheat gluten do not have the function of acid resistance and anti-corrosion properties,but M-G and MTG do,the optimal additives of fresh noodles are M-G and MTG.The optimal pH of laboratory-made composite organic acids used in noodles is 5.7-5.9.