The Research On Optimized Total Wine Phenols Determination By Folin Ciocalteu Assay

The total polyphenol is to determine the quality of the wine, the detection is an important material for wine judge nutrition, the grapes and wine in the total phenolic content of essential.This paper mainly studies the selection and optimization of determination of the content of total phenols in wines and finds the best determination condition after selecting the best measurement methods, Folin-Ciocalteu (F-C) method with the help of Central Composite Design (CCD) experimental designs and getting an optimal design for two F-C methods from single factor to response surface method. Then the paper demonstrates a comparative study of traditional F-C method, simplified micro-F-C method and Microwave Accelerated F-C method, measures factors influencing determination results of F-C methods and studies the influence of these factors to determination of the content of total phenols in wines by Microwave Accelerated F-C method.First of all, the author optimizes the determination condition of the content of total phenols in wines (from F-C concentration, mass concentration of sodium carbonate, developing temperature and developing time) with simplified micro-F-C method and CCD design on the basis of single factor method. The experiment points out the optimal combination of determination condition of the content of total phenols in wines by simplified micro-F-C method, including 1.4mol/L of F-C concentration, 30g/L of mass concentration of sodium carbonate,45℃ of developing temperature and 112min of developing time for the purpose of simplicity and microscale.Then the author optimizes the determination condition of the content of total phenols in wines (from F-C concentration, mass concentration of sodium carbonate, developing temperature and developing time) with new inverter microwave oven by Microwave Accelerated F-C method and CCD design on the basis of single factor method. The experiment points out the optimal combination of determination condition of the content of total phenols in wines, including 1.2mol/L of F-C concentration,40.00g/L of mass concentration of sodium carbonate,60% of microwave frequency and 6min min of developing time for the purpose of speediness and microscale.the author makes reagents of concentration gradient and imitates wines samples with Microwave Accelerated F-C method according to factors influencing determination of the content of total phenols, which are educing agents and include experimental factors such as glucose, sucrose, fructose, sulfur dioxide (SO2), bovine serum albumin, Fe2+, proline, VB, and erythorbic acid. Through Microwave Accelerated F-C method, the result shows that these factors all have influences to the content of total phenols to some extent. The more concentration of the factors is, the more effects on the determination will be. The biggest factors are protein, Fe2+, vitamin B6 and erythorbic acid. If the method is used in the future for the determination of the content of total phenols in wines, factors should be considered and the test result should subtract the content of these factors.At last, the author makes the comparative experiment between traditional F-C method, simplified and optimized micro-F-C method and Microwave Accelerated F-C method from detectable amounts of total phenols, precision tests and added aconitine recovery in wines samples. She finds that the result has no significant difference in detectable amounts of total phenols from Microwave Accelerated F-C method and traditional F-C method, but the result by the simplified micro-F-C method show that the detectable amounts of total phenols are much fewer. The above three methods have good repeatability and stability, among which Microwave Accelerated F-C method has the best accuracy. The three methods all have good recovery effects. The study of comprehensive comparison shows that Microwave Accelerated F-C method is the best method in the determination of the content of total phenols in wines.