Study On Low Temperature Extruded Degermed Corn As Adjunct To Brew Beer

The method of orthogonal rotation combination test design of five factors and five levels was developed in this experiment, and SAS9.1software was employed for the response surface analysis of theresults data. It was investigated for the principle that the getting ratio of wort, reducing sugar, a-amino nitrogen and filtration time affected by water quantity, the content of the extruded degermed corn, heat preservation time at50℃,62℃,70℃directly pertinent to saccharificaion process. And the optimal parameters were obtained:extruded degermed corn added ratio was33.0%, the ratio water to feed was4.2:1, and the heat preservation time were at50℃for40min, at62℃for27min, at70℃for39min. A100L beer pilot experiment carried out according to above results. Furthermore we study the process of saccharification and fermentation for the beer using low-temperature extruded degermed corn as adjuct.High performance liquid chromatography (HPLC) was used to analyze the fermentable sugar components in the mashing wort. The results shown that the wort of degermed corn as adjunct contain five fermentable sugars, i.e. fructose, glucose, sucrose, maltose and maltotriose, which content were0.38g/100mL,0.74g/100mL,0.42g/100mL,5.38g/100mL and1.06g/100mL, respectively.Headspace sampling-gas chromatography (HS-GC) coupled with an internal standard method (ISM) was used to analyze the volatile flavor compounds in the beer made of low temperature extruded degermed corn as adjunct. The results showed that eight compounds, i.e. acetaldehyde, N-propanol, ethyl acetate, isobutyl alcohol, isoamyl alcohol, isoamyl acetate, ethyl hexanoate and ethyl octanoate were separated and quantified, and the content were7.59mg/L,6.39mg/L,19.35mg/L,6.52mg/L,55.02mg/L,8.2mg/L,0.17mg/L and0.22mg/L, respectively. According to flavor intensity value (FU), isoamyl acetate (FU=5.467>2) was the the most important material which affecting the flavor of beer, acetaldehyde (FU=0.759), ethyl acetate (FU=0.645), isoamyl alcohol (FU=0.786), ethyl caproate (FU=0.850) were the secondary flavour compounds affecting the flavor of beer, the third type of flavor compounds were octylic acid ethyl ester (FU=0.220), propanol (FU=0.008) and isobutyl alcohol (FU=0.033), which had a little effect to beer flavor because of the small amounts in beer.