Using tara powder from Peru as raw material,rate of Ge precipitation from industrial mining liquor contaning zinc sulfate and germanium ion as index,the effects of extraction,refining and post-processing of tara extracts on the rate of Ge precipitation were studied.The results showed that using organic solvents(methanol,ethanol,ethyl acetate) extraction instead of water extraction,rate of Ge precipitation was more than 98%.Degumming of the extract with activated carbon and salting washing as well as through complexation by adding 1 % sodium chloride ammonium and 1% nitrilotriacetic acid effectively reduced non-tannin content in the product and enhanced the rate of Ge precipitation.When tara powder and gall flower of mixed in 8 ∶ 2 as raw material,followed by complexation of the extract,the rate of Ge precipitation reached 99.05%.The cost of the product was reduced,as well.

Gallic acid(3,4,5-trihydroxybenzoic acid) was widely used in the fields of biological,medical,chemical industries,etc.More and more researchers have concerned on the study of gallic acid.The progress on preparation and application of gallic acid in recent years were introducted and its future developments were also expected.

After discoloration, crude 2,3,4,4′-tetrahydroxybenzophenone, was adsorbed and separated by chromatographic column and micro-porous membrane, the impacts of membrane aperture and operating pressure on separation effect were studied. Furthermore, the adsorption-desorption regenerating test of the used column was done, the impacts of temperature and the amount of eluate on elution results were investigated. The results showed that the optimum separation conditions were: membrane aperture 0.2μm, pressure 0.06MPa, working the column in series with micro-porous membrane. Under these conditions the indices of the product were as follows: mass fraction ≥99.5%, impurities of Ca2+, Fe3+, Na+≤200μg/L. Using 300mL 50% ethanol as eluant for the regeneration of the used column, the desired results were obtained.

Pharmaceutical tannic acid was prepared from industrial tannic acid through methanol extraction and chromatography adsorption.The optimum conditions were determined as follows:ratio of industrial tannic acid to methanol 1∶5(g∶mL),temperature of actived carbon-adsorption column 60℃,and the flow rate 25mL/min.The content of tannic acid of product was over 93%.The other items had reached the requirements of pharmaceutical tannic acid.

In this paper,the recent research progresses in polyhydroxybenzophenones were reviewed.The different synthesis methods of polyhydroxybenzophenones,mainly the synthesis of 2,4-dihydroxybenzophenone by condensation reaction of benzoyl chloride,benzoic acid and trichlorotoluene with resorcinol,as well as other related synthesis methods of polyhydroxybenzophenones were introduced and compared in detail.It was suggested that exploitation of synthesis method with high efficiency,energy conservation,low-cost and environmental protection is the development trend at home and abroad in the future.

Tannin is an integral part of beer.Its existence affects the flavor and colloidal stability of beer.Addition of vegetable tannin has become one of the traditional crafts in beer brewing.Longyuan 99A Tannins are made from Chines gallnut.Purification,separation and other high-tech are used to create Longyuan 99A as a natural food additive.It has the characteristics of high content of tannin(≥99.5 %),low content of gallic acid(≤0.12 %),light color(Lovibond value≤1.0),low ignition residue(≤0.02 %)and good cold-solubility.In the application of beer production,it has achieved remarkable results.It is an ideal choice for beer brewing.

Polysulfone membrane was used to treat the solution of tara tannin.The influencs of several factors such as the mole-cular weight cutoff,trans-membrane pressure,flow velocity,and temperature on membrane property and product quality were studied.The experimental results showed that,under the conditions of molecular weight cutoff of 10000,trans-membrane pressure of 0.2MPa,flow velocity of 2.0m/s,and temperature of 40-45℃,the tara tannin with turbidity≤0.5NTU,and purity ≥85% was obtained.

Purification of tannin from Chinese gall nut was studied through treatment with granulated Fuller'earth and activated carbon. The results indicated that the sample with purity of tannin ≥98 %,color 0.6 (Lovibond total color),content of main metal ions ≤0.5 μg/g was obtained respectively by extracting Chinese gall nut solution by 95 % alcohol at 60 ℃,30 mL/min flow rate with combined columns of granulated Fuller'earth and activated carbon.

Tannin, which is a secondary metablite of plants and gets into beer from barley and hop in processing of beer,is an important ingredient in beer.Tannins in barley are condensed tannin consisting chiefly of dimeric and trimeric proanthocyanidins.In the process of saccharification and elution,the content of these oligomeric proanthocyanidins is reduced abruptly through oxidization into polymeric tannins.Tannins in hop consist of hydrolyzable tannins and condensed tannins,containing anthocyanin and odies tannins which inhibit muddy and improve colloidal stability of beer.Chinese gallotannin is hydrolyzable tannin.When Chinese gallotannin is put into wort and beer at 6?g/100?L,the macromolecular nitrogenous substance is reduced 5?mg/100?L in wort,the formation of diacetyl is also reduced,and the colloidal stability and flavour stability of the beer are improved.