Study On The Aging Treatment Of Original Vinegar Respectively By Ultrasonic Wave And Immobilized Enzyme With The Improvement Of Its Quality

This paper aimed at improving the total ester content and amino acid nitrogen(AAN)content of vinegar by artificial aging technology,so as to the flavor of ester was enhanced and the quality of vinegar was improved.In this paper,the newly brewed Shanxi Zilin vinegar was studied by two methods of artificial aging.(1)Technology of accelerated the aging of original vinegar by ultrasonic.First of all,a single factor test was conducted on the original vinegar.According to the total ester content,the optimum ultrasonic treatment time,temperature,power and ethanol add amount were selected.Then,the process of ultrasonic aging vinegar was optimized by response surface methodology on the basis of single factor experiment,and the effect of ultrasonic on the physical and chemical indicators of vinegar was investigated.After,the volatile components of original vinegar and treated vinegar were determined and contrasted,used headspace-solid phase microextraction(HS-SPME)and gas chromatography-mass spectrometry(GC-MS).(2)Technology of accelerated the aging of original vinegar by immobilized acid protease and monascus esterase.First of all,the single factor test was carried out and the composite gel of food grade carrageenan(CG),sodium alginate(SA),xanthan gum(XG)and guar gum(GG)were as the immobilization carrier.The optimum immobilization carrier and conditions for immobilization of Monascus esterifying enzyme and acid protease were selected based on the relative enzyme activity.Immobilization of monascus esterase and acid protease were respectively made by embedding method and adsorption method.Then,the process of immobilized enzyme was optimized by response surface methodology on the basis of single factor experiment.After,the original vinegar was accelerated by immobilized enzyme.And the effect of immobilized enzyme on the physical and chemical indicators of vinegar was investigated,which was compared with original vinegar.Base on it,the volatile components of original vinegar and treated vinegar were determined and contrasted,used HS-SPME and GC-MS.The main findings are as follows:(1)The results showed that the optimal conditions by response surface method were that ultrasonic processing time was 137 min,ethanol add amount was 0.65%(V/V)and ultrasonic treatment temperature was 40 ?,which total ester content reach to 13.75 g/L(P<0.05),than the original vinegar total ester content increased 50%.And the effect of each factor on the response value(Y)was,in order: ultrasonic treatment time > ethanol addition > ultrasonic treatment temperature.The total ester content as old as vinegar,aged naturally for five months in laboratory.The ultrasonic treatment of vinegar became darker and clarified,soft taste,rich aroma.Using HS-SPME and GC-MS obtained 46 kinds of aroma components.The total relative content of esters increment was 0.84% than that of new vinegar,including ethyl acetate,ethyl methoxyacetate,diethyl succinate,ethyl phenylacetate and phenylethyl acetate.The relative content of 2,3,5,6-tetramethyl pyrazine was also increased,which had a significant contribution to the aroma of nuts in vinegar.(2)The results showed that the optimal conditions by response surface method were that immobilized monascus esterase was used sodium alginate and carrageenan(SA-CG)as immobilized carrier,ratio gel was5:2,gel concentration was 1.68g/100 m L,immobilization time was 153 min,curing solution concentration was 2.4%,enzyme solution addition was 7.23 m L,in this way the relative enzyme activity was reached 99.79%.And the effect of each factor on the response value(Y)was,in order: enzyme solution addition > gel concentration > immobilization time.The results showed that the optimal conditions by response surface method were that immobilized acid protease was used sodium alginate,carrageenan and xanthan gum(SA-CG-XG)as immobilized carrier,ratio gel was 4:1:1,gel concentration was 1.49g/100 m L,immobilization time was 190 min,curing solution concentration was 3%,Adsorption time of enzyme solution was 200 min,enzyme concentration was 42mg/g,in this way,the relative enzyme activity was reached 99.82%.And the effect of each factor on the response value(Y)was,in order: enzyme concentration > immobilization time > gel concentration.The results showed that the optimal conditions of immobilized enzyme aging new vinegar by response surface method were that the amount of immobilized monascus esterase was 13g/100 m L and acid protease was 8g/100 m L,the time of aging was for 40 h.In this way,the total ester content of the vinegar reach to 12.96g/L(P<0.05),and the AAN content could reach 2.89g/L(P<0.05).The effect of two immobilized enzymes on vinegar was better than that of single immobilized enzyme.Total ester content was than the original vinegar which increased 33.47%,and AAN content increased 11.15%.Using HS-SPME and GC-MS obtained 51 kinds of aroma components.The total relative content of esters increment was 2.07% than that of new vinegar,including methyl acetate,ethyl acetate,ethyl methoxy acetate,isobutyl acetate,and ethyl lactate.In this way,the total ester and AAN content were as old as vinegar,aged naturally for three months in laboratory were respectively 12.87g/L and 2.73g/L.