Construction And Properties Of Wheat Gluten Based Food-Grade Colloidal Structure

Wheat gluten is a common plant protein resource,which is mainly divided into gliadin and glutenin.Wheat gluten is rich in intra-molecular disulfide bonds.It can form a strong protein network through the interaction of components and disulfide bonds cross-linking.Making use of components and cross-linking characteristics of wheat gluten is beneficial to build a colloidal structure of wheat gluten-based food.Therefore,in this thesis,wheat gluten was used as raw material to study the stability and digestion characteristics of emulsion by controlling the ratio of gliadin and glutenin,and explored the effect of disulfide bond cross-linking on the structure and rheological properties of wheat gluten emulsion gel.In addition,micro-paticulated wheat gluten was prepared based on disulfide bond cross-linking,which was used as food ingredient to produce high protein plant-based dairy products with smooth taste.The main conclusions are as follow:?1?Preparation of wheat protein-based food emulsion system with stable structure and delaying lipid digestion by controlling ratio of gliadin-to-glutenin was studied.The results showed that gliadin had good interfacial properties,which could form a stable interfacial layer.Although the interfacial activity of glutenin was poor,it could form strong network at the interface and protect the emulsion from external environment.Compared with the pure gluten-based emulsion,the composite protein controlled by wheat protein components had a lower interfacial tension value,and formed a dense fibrous protein interfacial layer and smaller emulsion droplets,which significantly improved the storage stability and thermal stability of emulsion samples.In addition,when the ratio of gliadin to glutenin was 1:2,the complex interfacial layer formed by interfacial synergy between wheat protein components was difficult to be replaced by bile salts and pancreatic lipase during gastrointestinal digestion,finally inhibits the digestion rate of lipid in the emulsion to a certain extent.?2?Preparation of wheat gluten emulsion gels by combination of disulfide bonds reductant?Na₂SO₃?and microfluidization technology.The effects of disulfide bonds cross-linking on the structure and rheological behavior of emulsion gels were studied by small amplitude oscillatory shear?SAOS?and large amplitude oscillatory shear?LAOS?.The results showed that with the increase of Na₂SO₃,the intra-molecular disulfide bonds in wheat gluten were reduced and more free sulfhydryl groups were released.Microfluidization induced the formation of inter-molecular disulfide bonds cross-linking.The bulk protein migrated to the interface,forming a dense cross-linking network and uniform oil droplets.SAOS showed that the storage modulus?G'?and cross-strain values increased with the addition of Na₂SO₃ in linear viscoelastic region,while LAOS showed that compared with high concentration of Na₂SO₃,low concentration of Na₂SO₃was more helpful for emulsion gels to resist structural damage under large deformation in non-linear viscoelastic region.The structure and rheological behavior of emulsion gels under large deformation need to be maintained by interfacial and bulk disulfide bonds cross-linking.?3?Preparation of micro-particulated wheat gltuen based on disulfide bonds crossl-inking and its application in high protein plant-based dairy products were studied.The results showed that disulfide bonds reductant Na₂SO₃ combined with microfluidization formed micro-particulated wheat gluten dispersion with good storage stability compared with no reductant or adding sulfhydryl blocking agent.After spray drying,uniform?1-2?m?micro-particulated wheat gluten?GRM?was prepared.Disulfide bonds cross-linking is the main driving force in the formation of GRM.Protein gels had good fluidity when GRM concentration was 15wt%as disulfide bonds cross-linking reduced interaction between protein molecules.The micro-particulated wheat gluten had a similar oral friction coefficient as commercial micro-particulated whey protein.As a food ingredient,micro-particulated wheat gluten can not only improve protein content,but also maintain smooth taste of plant protein-based dairy products,which provided a novel strategy for the development of high protein plant based dairy products with good sensation.