| As an acid liquid condiment,vinegar has rich nutrition and rich taste.It not only has the function of condiment,but also has certain nutritional value and physiological function.But vinegar will produce turbidity during brewing and storage,which will affect the quality of vinegar.Therefore,it is very important to solve the turbidity problem of vinegar for the development of vinegar industry.In order to improve the clarity and quality of vinegar,centrifugal method,composite clarificant method and ZTC1+1-? natural clarificant method were used to clarify vinegar.Response surface methodology was used to optimize the clarification conditions,and the clarification effects of different clarification methods were compared.1.After centrifuging the vinegar for 5,10,5,20,25 and 30 minutes at 3500,4000,4500,5000,5500 r/min,the results showed that the centrifugal speed was between 3500 and 4000 r/min.At the same speed,with the prolongation of the treatment time,the turbidity of vinegar gradually decreased and the clarification effect became better and better.When the centrifugal speed was between 4500 and 5500 r/min,and the turbidity decreased first and then increased with the prolongation of treatment time.After 15 minutes of treatment at 4500 r/min,the suspended matter and turbidity of vinegar decreased significantly(P<0.05),from 130.40 NTU to 80.95 NTU.Compared with the untreated vinegar,the physical and chemical indexes of vinegar(total acid,total ester,amino acid nitrogen,non-volatile acid,reducing sugar and soluble solids)did not change significantly(P>0.05).2.With turbidity as the detection index,the optimum additions of diatomite,bentonite and chitosan were determined.Three clarifying agents are grouped in pairs according to the determined optimal addition amount.The results showed that: Except for diatomite and bentonite combination,the turbidity of vinegar treated by other combination methods decreased significantly(P<0.05).The turbidity of vinegar treated with chitosan and diatomite was the lowest(23.37 NTU),which was 82.07% lower than that of vinegar.Therefore,diatomite and chitosan were used as composite clarificant for clarification test.3.Response surface methodology(RSM)was used to optimize the optimum conditions for clarifying vinegar with compound clarificant.The optimum parameters were determined as follows: The ratio of chitosan to diatomite is 1: 1,vinegar is treated at 31 ? for 20 min.The turbidity of clarified vinegar was 1.45 NTU,98.89% lower than that of original vinegar,which was basically consistent with the predicted value of 1.41 NTU.The treated vinegar was red-brown,clear and transparent,with soft acidity and harmonious taste,and there was no significant change in physical and chemical indexes(P<0.05).No precipitation was observed at room temperature for 6 months.4.Response surface methodology was used to optimize the process conditions for clarifying vinegar with ZTC1+1-? natural clarificant.The dosage of ZTC1+1-? natural clarificant(A:B)was 1:5,the treatment temperature was 15.6 ?,and the treatment time of A and B components was 2.1 h and 3 h.The turbidity of the clarified vinegar was 5.83 NTU,which was 96.7% lower than that of the original vinegar,almost in line with the predicted value of 5.74 NTU.The treated vinegar was red-brown,clear and transparent,with soft acidity and harmonious taste,and there was no significant change in physical and chemical indicators.No precipitation was observed at room temperature for 6 months.In conclusion,After The vinegar was clarified by centrifugal clarification,diatomite-chitosan(1:1)composite clarificant and ZTC1+1-? natural clarificant,the six physical and chemical indexes of vinegar did not change significantly,but the turbidity of vinegar was significantly lower than that of untreated vinegar,turbidity values decreased by 37.92%,98.89% and 96.70%,respectively.The clarification effect of the composite clarifier was better than that of ZTC1+1-? natural clarificant,and ZTC1+1-? natural clarificant is better than that of centrifugal clarification. |
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