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The acetic acid is one of the most important organic acids in beer and the high content of acetic acid is the main reason why beer is sour.The physicochemical properties of acetic acid,the comparison of HPLC and IC method for analysis of acetic acid,and the changing rule of acetic acid during the brewing were reported.The effect of start temperature of saccharification and adjunct ratio of rice on the acetic acid in wort was systematically studied.The optimum process parameters were found employing the response surface methodology and they are as follows:fermentation temperature 13.2℃,pH of wort 5.7,and the pitch rate 2.1× 107cells/mL.The model that predicts the acetic acid concentration in final beer was established based on the artificial neural network.The structure of the model is 3 ×6× 1,and the training function of the BP(back propagation) network is trained and the training parameters were as follows:the maximum steps 10000,aim error 0.0001 and the study rate 0.01.The simulation results had good correlation to the untrained actual samples and the correlation coefficient was 0.996.