Structural Properties Of Vegetable Oil And Myofibrillar Emulsified Composite Gel

Tuna is a kind of fish with high protein,low fat and riching in docosahexaenoic acid(DHA),eicosapentaenoic acid(EPA),methionine,taurine,minerals and vitamins.It is always known as the "sea gold".The quality of tuna fish products largely depends on myofibrillar proteins.One of the most important indicators of myofibrillar protein is gel properties.Previous studies have focused on the composite gels of myofibrillar proteins with various sugars,mixtures of proteins or others additive.High-value tuna is generally sold as food such as sushi and sashimi,while low-value tuna is mainly processed into canned products.In the processing of tuna,a large amount of waste,such as fish head,minced meat and dark meat,is produced,which accounts for 50%~70% of the total mass which has high utilization value.It is currently a central interest to develop recombinant myofibrillar protein products by mixing low-commercial fish or process waste with other substances.Because the addition of these substances may cause changes in the functional properties of fish myofibrillar proteins,thereby increasing their appetability or changing their sensory qualities.Therefore,this text studies the structural characteristics of vegetable oil and myofibrillar emulsified composite gel,and studies the content of emulsified oil,the emulsion homogenization rates and the different emulsifiers on the composite gel.It provides a theoretical basis for the type,proportion,size and mode of addition of oil in the production process of surimi and fish paste.Firstly,the effect of the different oils and their contents on the structural characteristics of vegetable oil and myofibrillar emulsified composite gel was studied.The rheological results showed that the composite gel of both oils’ G’(The storage modulus)increases with the increase of oil concentration;The texture results showed that both corn oil and olive oil had the best gel strength when the oil concentration reached 10%;Water holding results showed that corn oil and olive oil were the best when oil concentration reach 15%;Electron microscopy showed that there might be an interaction between emulsified oil and gel network.And the oil is not simply filled in the voids of the three-dimensional network of myofibrillar proteins.Secondly,the emulsion homogenization rates on the structural characteristics of vegetable oil and myofibrillar emulsified composite gel was studied.As the rotational speed increases,the particles of the emulsified oil are continuously decreasing.The rheological results showed that the composite gel of the two oils’ G’ increases with the decrease of oil concentration;The gel strength and water holding capacity of corn oil and olive oil are best at 22000 rpm.At 22000 rpm,the G’ of the olive oil composite gel is larger than corn oil,but the gel strength and water holding capacity are not as good as corn oil.Finally,the structural characteristics of the different emulsifiers of vegetable oil and myofibrillar emulsified composite gel were studied.The G’ is lager when emulsion choose MP instead of Tween 80;The gel strength is lager when emulsion choose MP rather than Tween 80;The water holding capacity of the MP emulsified composite gel is not significantly different from that of the Tween 80 emulsified composite gel,but both are greater than the composite gel without emulsified fat;Gel electrophores is results show that the MP as an emulsion does not participate in the three-dimensional network structure of the gel.