Effects Of Phosphate-free Improved Water Retention Agent On The Frozen Quality Of Mytilus Edulis Linnaeus

Therefore,frozen preservation of mussels has gradually become an important part of mussel production and processing.In related research reports at home and abroad,it shows that phosphate-free water-retaining agents are gradually replacing phosphates to become safer,greener water-retaining agents.Therefore,in order to avoid excessive use of phosphate in frozen preservation of mussels and to improve the water retention and reduce mussel quality during frozen storage of mussels,Na Cl,trehalose,and sodium citrate were used as water retention agents to optimize the test.The optimum ratio of non-phosphorus-improved water-retaining agent was determined,and the processing conditions of mussels were optimized,and the effect of non-phosphorus-improved water-retaining agent on the quality of frozen mussels was explored in order to develop non-phosphorus improved water retention agent and harmless to the human body.The main content of this research:1.Optimization study of mussel-free non-phosphorus water retention agentPhosphorous-free improvement of water-retaining agent: Experiments were conducted to determine the optimal combination of non-phosphorus-improved water-retaining agent by single factor and orthogonal experiments with the weight gain rate,thawing loss rate,cooking loss rate,and sensory score of the mussels.The Na Cl mass fraction was 1.5%,the sodium citrate mass fraction was 2%,and the trehalose mass fraction was 0.5%.Optimization of mussel dipping time: As the dipping time increases,the soaking weight gain rate of mussels increases,and the thawing loss rate and cooking loss rate decrease.Considering the actual production and application,the choice of mussel dipping time is 2 h,and mussels can maintain good sensory quality during the dipping time.Optimization of thawing temperature of frozen mussels: Frozen mussels were respectively thawed at four temperatures of 5°C,10°C,25°C,and 37°C,and mussels low had lower thawing loss rate and cooking loss rate when thawed at 5°C and 10°C,and in the four thawing temperatures,the cooking loss rate and sensory score of the thawed mussels at 10°C are better than other thawing temperature groups,so the frozen mussels are the most The best thawing temperature was determined as 10°C.2.Effect of non-phosphorus-improved water retention agent on the quality of frozen musselsThe study was to evaluate the effects of phosphate-free improved water retention agent(composed by 1.5% Na Cl,0.5% trehalose and 2% sodium citrate)on the frozen quality of Mytilus edulis Linnaeus and using distilled water group as a blank control,compound phosphate group as a condition control.After 25 d of storage(-18 ?),the results indicated that treated by phosphate-free improved water retention agent,the water loss,thawing loss and cooking loss of mussels were significantly decreased and the rate of soaking and weight gain was significantly increased,there was no obvious difference in water loss reduction when compared with compound phosphate group(p>0.05),and compound phosphate had advantage in improving the soaking weight gain.The L* value of mussels kept decreasing and TVB-N value of mussel rised in frozen storage,L* values of mussels that treated with phosphate-free improved water retention agent maintain well,and significantly better than other groups(p<0.05),meanwhile,TVB-N value of mussels rised slowly,and significantly lower than other groups(p<0.05).While,phosphate-free improved water retention agent can reduce the loss of Ca2+-ATPase activity and the loss of myofibrillarr protein effectively,and significantly better than water group and compound phosphate group(p<0.05).Indicating,that phosphate-free improved water retention agent can effectively maintain the quality of mussel.3.Effect of non-phosphorus-improved water-retaining agent on amino acid and fatty acid of frozen musselThe content of water,crude protein and crude fat in the distilled water group,non-phosphorus improved water retaining agent group and complex phosphate group showed a decreasing trend during the frozen storage period.Among them,the water retaining agent group had a significant effect on suppressing the loss of basic components of mussels during the frozen storage period compared with the distilled water group,and the effect of the non-phosphorus improved water retaining agent group was particularly significant.At the beginning of frozen storage,mussels were found to contain 17 amino acids except for tryptophan.With the increase of frozen time,the amino acid content,essential amino acid content and taste amino acid content of mussels in the three treatment groups all decreased significantly(p<0.05).Among them,the decrease of amino acid content was the largest in cysteine(Cys),followed by arginine(Arg)and aspartic acid(Asp),and the decrease in glutamic acid(Glu)was smallest.The lowest decrease in essential amino acid content in the three groups was Val(Val),while the decrease in glycine(Gly)content in the taste-producing amino acids of the no-P improver water retention agent group was the smallest.A total of 29 fatty acids were detected,including ten saturated fatty acids(SFA),eight monounsaturated fatty acids(MUFA)and eleven polyunsaturated fatty acids(PUFA).With the increase of frozen storage time,the total fatty acid content,saturated fatty acid,monounsaturated fatty acid,and polyunsaturated fatty acid content in the three treatment groups were significantly decreased(p<0.05).With the increase of frozen storage time,the content of palmitoleic acid in distilled water group, non-phosphorus-improved water-retaining agent group and complex phosphate group in monounsaturated fatty acid also decreased.On the 50 th day of frozen storage,the phosphorus-free water-retaining agent group(EPA+DHA),n-3 series polyunsaturated fatty acids(n-3 PUFA)content,n-6 series polyunsaturated fatty acids(n-6 PUFA)content The decrease was significantly less than in the other two groups(p<0.05).