| Tilapia is an important economic fish in China.It is very popular among consumers because of its delicious taste,tender meat and favorable price.It is mainly exported and sold in the form of fresh frozen slices,and is exported to the United States,Mexico,Africa and other places.Tilapia has high protein content,is prone to spoilage and is difficult to meet the needs of long-distance transportation,which restricts the development of the tilapia industry.As a traditional microbicide,sodium hypochlorite is often used in the processing of tilapia,but its use can cause chlorine residues,and chlorine residues are very harmful to humans.Under this circumstance,electrolyzed water enter the field of vision as a new type of fungicide.Due to its broad spectrum,high efficiency and no residue,it has attracted widespread attention in society.This paper takes tilapia as the research object,studies the stability of the acidic oxidation potential water generator,and the stability of physical and chemical properties of electrolyzed water under different storage conditions such as avoid light/see light,open/sealed,indoor/outdoor.Sterilization of live tilapia surface with alkaline electrolyzed water,study the effect of p H(hydrogen ion concentration),salinity and treatment time on bactericidal effect,and optimize the sterilization process by response surface method.Uses acidic electrolyzed water to sterilize the tilapia fillet,studies the bactericidal effects of sterilization methods,ORP(oxidation-reduction potential)value,sterilization time,ratio of material to liquid,Compare the bactericidal effect of acidic electrolyzed water and other microbicides.Using the orthogonal analysis method to optimize the sterilization process.Study the effect of electrolyzed water on the quality of tilapia.The purpose is to provide basic research for electrolyzed water in tilapia preservation and processing applications,accumulate basic data of electrolyzed water applied in tilapia preservation and processing,provide technical support for the development of the tilapia industry and the transformation and upgrading of the industry,and provide theoretical support for the improvement of the aquatic product quality and safety system.The main findings are as follows:(1)After operating 2 minutes,the acidic oxidation potential water generator can produce electrolyzed water with stable physical and chemical properties.Different storage environments have different effects on ORP,p H,and ACC(available chlorine concentration),light conditions,sealing conditions,storage temperature,storage time have great impact on the stability of electrolyzed water.ORP is stable under the condition of indoor sealing and protection from light,only 1.0% lower after 30 days of storage.Under other storage conditions,ORP gradually decreased.ACC has the worst stability and the fastest change.Under various storage conditions,ACC decreased significantly and gradually decreased to zero as the storage time progressed.Different storage conditions vary in p H over time.The p H of the electrolyzed water stored under the condition of sealing and protection from light is not obvious.Under open conditions,it first rises and then falls.It sees a downward trend under the condition of sealing and see light.The optimal storage conditions for electrolyzed water are indoor sealing and protection from light,ts physical and chemical properties can be maintained for 6 days without significant changes..(2)Alkaline electrolyzed water has a significant bactericidal effect on the surface of tilapia living body.The best single factor for sterilization is: p H 11.00,salinity 8 ‰,treatment time 60 min.The optimal process parameters were obtained by response surface optimization: p H 10.00,salinity 8 ‰,treatment time 60 min.After the alkaline electrolyzed water treatment under these conditions,the theoretical bactericidal rate of tilapia surface was 94.7%.The verification experiment was carried out on the optimum process parameters,and the result was(94.1±1.5)%.The order of influence of each single factor is: p H> treatment time>salinity.(3)Acidic electrolyzed water sterilizes tilapia fillets significantly,the best single factor for sterilization is: soaking method,ORP 1163 m V,sterilization time 6 min,material to liquid ratio 3:70.Different sterilization methods belong to different sterilization processes,the sterilization time has no significant effect on the sterilization effect(p>0.05),so we chose ORP and the ratio of material to liquid to optimize the sterilization process.The optimal process parameters were obtained by orthogonal optimization: ORP 1163 m V,material-to-liquid ratio 3:80,and the sterilization rate reached(98.0±0.4)%.The verification experiment was carried out on the optimum process parameters,and the result was(98.1±0.1)%.The amplification experiment was carried out using the optimum process parameters,the magnification was 10 times,and the result was(98.2 ± 0.5)%.The order of influence of each single factor is: ORP value > material to liquid ratio > sterilization time.The bactericidal effect of acidic electrolyzed water on tilapia fillets is better than that of sodium hypochlorite and hydrogen peroxide.(4)After sterilizing by alkaline electrolyzed water under the optimal conditions,the color difference and texture of tilapia fillets were not significantly different from fresh tilapia(p>0.05).After sterilizing by acidic electrolyzed water under the optimal condition,the color difference of tilapia fillets were not significantly different from fresh tilapia.The acidic electrolyzed water had a slight influence on the chewiness of tilapia fillets,but the hardness,cohesiveness,elasticity and adhesion have little effect. |
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