The Preparation And Characterization Of Low Strength Surimi Products

Surimi products have been deeply loved by consumers,because it has high nutrition and can be digested easily.The consumption and demand of surimi products both have been increasing year by year.With the increasing trend of the Chinese elderly population and the single characteristic of elderly food,surimi products which have the characteristic of high protein,low fat and convenient for eating can be used to develop a kind of low strength surimi products suitable for the elder people.Therefore,using the gel strength of elderly foods' demand in the Ministry of Health,Labor and Welfare of Japan as the low strength surimi products' standard,the low strength surimi products were produced by adding compound hydrocolloids in this research.Then,the effects of different fish species on low strength surimi products were investigated and the gracilaria powder was used to fortify the dietary fiber nutritional function of the surimi products.Firstly,the effects of compound hydrocolloids on the gel properties of the silver carp surimi products were studied.Low strength surimi products were prepared by adding compound hydrocolloids including guar gum,soy protein,egg white proteins and the orthogonal tests were used to optimize hydrocolloids adding conditions.Then,the heating method was also optimized.As a result,the optimum ratios were 0.3% guar gum,0.5% soy protein,1.0% egg white proteins.Under the optimum conditions with comparing to control group,the gel strength,hardness and chewiness of surimi gels were decreased from 155.17 g·cm to 125.19 g·cm,14.20 N to 9.61 N,82.79 mJ to 60.86 mJ,respectively.However,cooking absorption of surimi gels was increased from 3.85% to 15.40%.Based on the results of SDS-PAGE and gel microstructure,it was revealed that the interaction between myosin heavy chain and actin was hindered by adding hydrocolloids,resulting in the formed low strength surimi products with porous matrix.In addition,the direct heating highly was more suitable for preparing low gel strength surimi products than two-step heating.Then,the gel properties of surimi products from silver carp,hairtail,Nemipterus virgatus were studied with and without compound hydrocolloid.Fish species were important factors to influence gel properties of surimi products.Under the conditions of compound hydrocolloid added,the gel strength of hairtail surimi products was improved from 58.38 g·cm to 107.27 g·cm,Nemipterus virgatus surimi products was lowed from 328.68 g·cm to 137.55 g·cm,but silver carp surimi products had no significantly change.On the other hand,the addition of hydrocolloids can significantly reduce the hardness,cohesiveness,chewiness of silver carp,hairtail,Nemipterus virgatus surimi products,but significantly increase the moisture content,water holding capacity,cooking absorption of all three fish surimi products.In addition,from the results of SDS-PAGE and gel microstructure of SEM,it was found that the addition of hydrocolloids can inhibit the degradation of hairtail surimi somewhat;but the addition of hydrocolloids can hinder the cross-linking of silver carp,Nemipterus virgatus surimi proteins as fillers.Based on above results,it was found that hairtail were more suitable to be the raw fish material for the preparation of the elderly surimi products.Finally,the effects of gracilaria powder addition on the gel properties of the hairtail surimi products with compound hydrocolloids were investigated.The addition of gracilaria powder had no significant effect on the gel strength,TPA,moisture content,water holding capacity,protein components of the hairtail surimi products.While the color of the hairtail surimi products added with gracilaria powder obviously changed from offwhitess to organic greeness,and the cooking absorption were improved to a certain extent.The results of the sensory evaluation indicated that the sensory score added with gracilaria powder at 1% was the highest.In a conclusion,low strength surimi products can be prepared by the addition of compound hydrocolloid.In addition,hairtail surimi is more suitable as the raw fish material for the preparation of elderly surimi products,and the addition of gracilaria powder can improve the sensory score of surimi products.The results of this research not only can increase the kinds of the surimi products,but also provide some reference to the development of the surimi products suitable for the elderly consumption.