Study On The Removal Technology Of Tannin From Astringent Persimmon Juice

Diospyros kaki L.f or Persimmon is an economic plant widely planted in the world.It is also named vermeil fruit,rich in nutritious component and is also praised as "scared product".Except abundant astringent persimmon tannin,astringent persimmon also contains sugar,protein,amino acid,carotene,a few fat,some microelements such as autunite,phosphor,iron,zinc,kalium,natrium, magnesium,manganese,copper etc.and various vitamins,organic acid and fragrant material etc. Astringent persimmon is widely cultivated in China and it is a major approach in court virescence and increasing farmers' income.Astringent persimmon's astringency comes from tannin.It is the highest container of tannin, about 2%.Tannin undertakes complex biochemical changes with condition,which is difficult to control,especially in processing.Because of large amounts of tannin,processed goods of Astringent persimmon's quality deteriorates.(1) color sterility varies,difficult to control,(2) flesh cohesiveness, rough feeling(3) astringency reoccurrence These changes seriously affect Astringent persimmon's deep processing.This article starts from the astringent persimmon's juice processing,then uses physical and chemical methods,that is through the technology of adsorption and precipitation to remove large amount of persimmon tannin.This study mainly research the Process Parameters for removing tannin by physical adsorbent:Active Carbon,Kieselguhr,Polyvinylpyrrolidone,Bovine serum albumin.This research on one hand offers Process Parameters for processing no-astringent persimmon juice,on the other hand,it also offers theoretical Basis for Extracting high-quality low tannin juice from other fruits.Research results are shown as follows:1.Niuxin Astringent Persimmon Juice Preparation ExperimentThe results showed that under the condition of 45℃,keeping 30min in water,adding 0.1% pectinase and 0.1%cellulose,making astringent persimmon juice can effectively increase the extraction rate of juice.2.Active Carbon Treatment ExperimentThis experiment used activated carbon static adsorption to remove tannin in astringent persimmon juice.Single-factor experiment showed that the optimum condition of activated carbon to adsorb total phenol is:adsorption time:30min;adsorption temperature:45℃;the amount of activated carbon:0.6%;and the optimum condition of activated carbon to adsorb oligomeric proanthocyanidins:adsorption time 20min;adsorption temperature 45℃;the amount of activated carbon 0.8%;and the optimum condition of activated carbon to adsorb flavanolin is:adsorption time: 30rain;adsorption temperature:55℃;the amount of activated carbon:0.8%.The Optimal technology condition of gaining activated carbon to adsorb tannin material using orthogonal experiment and taking the tannin content as index is:adsorption time 30rain;adsorption temperature 45℃;the amount of activated carbon 0.8%.The rate of tannin's removal is 47.27%.3.Kieselguhr Treatment ExperimentThis experiment used kieselguhr static adsorption to remove tannin in astringent persimmon juice.Single-factor experiment showed that the optimum condition of kieselguhr to adsorb total phenol is:adsorption time 30min;adsorption temperature 45℃;the amount of activated carbon 0.8%;and the optimum condition of kieselguhr to adsorb oligomeric proanthocyanidins is: adsorption time 60min;adsorption temperature 45℃;the amount of activated carbon 0.8%;and the optimum condition of kieselguhr to adsorb flavanolin is:adsorption time 40rain;adsorption temperature 65℃;the amount of activated carbon 0.8%.The Optimal technology condition to remove total phenol using orthogonal experiment L₉(3⁴) and taking the tannin content of indicators is:adsorption time 30min;adsorption temperature 45℃;the amount of activated carbon 1.0%.The rate oftannin's removal is 48.44%.4.Polyvinylpyrrolidone(PVPP) Treatment ExperimentThis experiment used PVPP Chemical adsorption to remove tannin in Niuxin astringent persimmon juice.Single-factor experiment showed that the optimum condition of PVPP to adsorb total phenol is:adsorption time 60min;adsorption temperature 55℃;the amount of PVPP 7g/L;and the optimum condition of PVPP to adsorb oligomeric proanthocyanidins is:adsorption time 60min; adsorption temperature 35℃;the amount of PVPP 7g/L;and the optimum condition of PVPP to adsorb flavanolin is:adsorption time 60min;adsorption temperature 35℃;the amount of PVPP 7g/L. The Optimal technology condition to remove tannin material using orthogonal experiment L₉(3⁴)and taking the tannin content of indicators is:adsorption time 60min;adsorption temperature 55℃;the amount of activated carbon 9g/L.The rate of tannin's removal is 60.55%.5.Bovine serum albumin(BSA) Treatment ExperimentThis experiment used BSA Chemical.adsorption to remove tannin in Niuxin astringent persimmon juice.Single-factor trial showed that the optimum condition of BSA to adsorb total phenol is:adsorption time 40min;adsorption temperature 55℃;the amount of BSA 0.8mg/ml;and the optimum condition of BSA to adsorb oligomeric proanthocyanidins is:adsorption time 20min; adsorption temperature 45℃;the amount of BSA 1mg/ml;and the optimum condition of BSA to adsorb flavanolin is:adsorption time 30min;adsorption temperature 65℃;the amount of BSA 0.8mg/ml.The Optimal technology condition to remove tannin material using orthogonal experiment L₉(3⁴)and taking the tannin content of indicators is:adsorption time 40min;adsorption temperature 55℃;the amount of BSA 1.0mg/ml.The rate of tannin's removal is 86.33%.