Study On Extraction And Clarification Effects Of Persimmon Tannin In Beer And Red Wine

Persimmon is rich in tannin. After brewing wine, tannin is transferred to persimmon pomace. The tannin extract conditions from persimmon pomace(persimmon tannin 2) are optimized. The clarification effects of tannin from persimmon pomace and from unripe persimmon which purified by our laboratory(persimmon tannin 1) on beer and wine were studied. As the comparison of other clarifiers commonly used, the optimum formulation of persimmon tannin-based clarifiers was developed. The research provides a scientific basis for the clarification application of persimmon tannin in alcoholic beverages. Following result were obtained:(1) After generated by brewing wine, persimmon pomace is used as raw materials for tannin extraction. A serious of single factor tests(the heat temperature, extraction time, p H value) and orthogonal test was introduced to optimized the extraction conditions. It concluded that the optimum extracting conditions for persinnon tannin were: heat temperature: 120℃, extraction time: 30 min, p H value: 1. The order of influence factors is: heating temperature>p H value>extraction time. The extraction rate reaches about 221.57 mg/g D.W under these optimal conditions.(2) Analysing nine extractions based on orthogonal test by HPLC, the main hydrolysis components of persimmon tannin including: gallic acid, epicatechin, gallocatechin. Under the condition of the heating temperature 120℃, the heating time of 30 min, and the extraction of the solution p H=1. The extraction rate of gallic acid is relatively higher than other compounds, it is reached 47.41mg/g D.W. The content of gallocatechin reaches about 26.92 mg/g D.W under these optimal conditions. Besides, under the condition of the heating temperature at 100℃, the heating time 40 min, and p H=1. The content in epicatechin reaches about 27.27mg/g D.W under these optimal conditions.(3) As the results of clarification, total phenols, total amino acids and TBA value of beer are investigated and the optimum addition are obtained. The study on persimmon tannin1 of clarification was shown that the clarification reaches 97.4%, the total phenols is 0.344mg/m L, the total amino acids is 11mg/L and the TBA value is 0.515. The study on persimmon tannin 2 is show that the clarification reaches 95.0%, the total phenols is 0.359mg/m L, the total amino acids is 0.010 and the TBA value is 0.407. Based on an overall consideration of various factors, the optimum additions of persimmon tannin 1 and persimmon tannin 2 are 0.7mg/L and 0.3mg/L, respectively.To take iron concentration, RSV value and sensory evaluation index into futher consideration, the clarification effects of persimmon tannins and diatomite are analyzed by contrast tests. The study showed that the clarification effects on beer can be improved by all clarifiers. The indexes of the beer clarified by diatomite were: the clarification 97.4%, iron concentration 0.16mg/L and RSV value 135.85. After clarified by persimmon tannin 2, the beer is influenced badly on sensory evaluation with high contents of total phenols and low clarification. The study on persimmon tannin 1 shows that the clarification reaches 97.4%, the total phenols is 0.027 mg/m L, the total amino acids is 335.55. Based on an overall consideration of various factors, among the three clarifiers, persimmon tannin 1 was most effective among three clarifers.(4)The influence of persimmon tannin, as a wine clarifying agent, was studied and the optimal formula was determined. The study are based on the theory that the condensation product of protein and tannin can absorb the insolubles in the wine. The influencing factors are: the type of protein( egg white or gelatin) and the ratio of persimmon tannin( persimmon tannin 1 or persimmon tannin 2) : protein. The results shows that the effect of egg-white is better than gelatin as a wine clarifying agent. The optimal additive amount of egg-white are 0.3%、0.5%、0.7%. The ratio of egg-white : tannin 1 are 1:1、1:2、1:4.Based on each factor level determined, dual factors experiment was adopted and the test shows that: the interaction of each variable is greatly effect on clarification and total phenolics, the colority is influenced by egg white. The best formula of persimmon tannin compound clarifiers is: the addition of egg whites about 0.7%, the ratio of egg white : persimmon tannin 1 about 1:2. The clarification of Red wine increased from 42.9% to 59.3% under this formula.According to physicochemical index, stability test and sensory evaluation, the clarification effects of egg white-persimmon tannin1 and bentonite are analyzed by contrast tests. The study shows that the clarification effects on red wine can be improved by both clarifiers. After clarified by bentonite, the red wine shows 48.3% on clarification. After clarified by egg white- persimmon tannin 1, the red wine shows 59.3% on clarification and the other indexes rather than else clarifers. Based on an overall consideration of various factors, among the three clarifiers, egg white- persimmon tannin 1 is most effective.