题目：Analytical Determination of Tannin Quality in Wine
时间：2012年4月5日（星期四）下午2点
地点：农生环A-113
报告人简介：
Professor in enology, University of Applied Sciences Western Switzerland
Vice Director of Engineer School of Changins until 2010
Research fields:
Technical support for wine producers of winemaking issues, in botteling issues.
Technical expertise in wine field for court.
报告内容简介：
In enology it is common to measure the tannin concentration with the Follin Ciocalteu index or with a spectrophotometric measurement at 280 nm (total polyphenols). Tannin quality, however, is much more difficult to determine. Lucien Chapon (1965) developed an analytical method to measure the tannin concentration in beer which he termed “tannin power”. The group of Professor FABRE were the first to adapt this quantitative method to wine (1987).
The modified analytical method, using the same reaction products, yields analytical results that are in relationship with the tannin quality. The chemical principle is the simulation of the reaction of tannins with proteins using polyvinylpolypyrrolidon (PVP), a semi-synthetic polymer, the composition of which is stable and constant unlike that of proteins. The reaction product is insoluble, causing turbidity. The intensity of the turbidity is measured as a function of time and concentration of PVP by nephelometry. From the resulting curve it is then possible to distinguish between “soft” and “hard” tannins.
