Development Of Amur Sturgeon(acipenser Schrenckii)surimi:Study On The Gel Properties,setting Response,and Enhanced Reduced-salt Gel By Using Different Additives

To make a product from A.schrenckii meat which is widely acceptable,further processing to remove the thick skin,bones,mucus,and odorous aroma of Amur sturgeon meat is required.In general,the sarcoplasmic proteins and undesirable substances are removed during surimi processing to obtain the white muscle as the primary ingredient for further processing steps.Setting temperature has been reported to improve the gel properties of surimi.It is responsible for the formation of final gel with greater textural strength and elasticity.Setting responses are different for each fish species tested.To the best of our knowledge,there is no study that focusing on the gel properties and setting responses of surimi made from A.schrenckii before.Recently,reducing salt content on surimi has become an important research topic due to the growing concern among consumers over excess sodium consumption.Excessive sodium intake?>2 grams/day,equivalent to 5 g salt/day?has been linked to hypertension and high blood pressure,which may increase the risk of stroke and premature death from cardiovascular diseases?CVD?.Considering the above facts,this study was aimed:?1?to study the gel properties of surimi gel made from A.schrenckii under high-temperature setting,and to assess the general characteristics and quality of the surimi gel made from A.schrenckii to seeing whether A.schrenckii can be used as a surimi material or not.?2?This work was also aimed to make a healthier surimi product by reducing salt concent from normal concentration(30 g kg^-1)to reduced concentration(3 g kg^-1),and to enhance the gel properties of reduced-salt gels by using some potential,health beneficial and commercially available additives?Lecithin,Arginine,Histidine?.Overall,main contributions of this work are as follows:1.The results suggested that setting duration from 0.5 to 1.5 h can be implemented to optimize the gel properties of A.schrenckii.Whereas,extended duration?>2 h? must be avoided as it decreased gel properties.The decrease of the gel properties was related to the protein degradation detected by TCA analysis.The sensory evaluation indicated that A.schrenckii surimi was generally accepted by the panelists in terms of color,texture,and aroma.Overall,the first investigation in chapter II provided some necessary information about setting response,gel properties,sensory evaluation,and surimi yield in A.schrenckii,which will be useful for further development of this product.2.In the chapter III,the results demonstrated that lecithin at different levels(10&30 g kg^-1)could be used to fortify reduced-salt surimi gels.Progressive increases in hydrogen bonds and?-sheet formations were found when lecithin added at the level 10 and 30 g kg^-1.Rheological patterns showed higher elasticity and physical properties such as gel strength,WHC,TPA,and microstructures also enhanced. However,additives with stronger effects are needed to obtain reduced-salt gels with similar gel properties as regular-salt surimi gels.3.More strikingly,the addition of L-Arginine(20&30 g kg^-1)and L-Histidine(30 g kg^-1)could produce reduced-salt gels with the same physical properties as regular- salt surimi gels.Moreover,L-Arg and L-His at the above levels also enhanced the thermal gelation which indicated by increased G?of the final gels._L-Arg and _L-His also significantly increased product yield and sensory qualities as well.