Study On Beer Brewing With Low Temperature Extruded Wheat Kernels As Adjunct

The response surface model was designed to confirm the optimal parameters ofsaccharificaion of the beer brewing with low temperature extruded wheat kernels asadjunct. The ratio of water to material, proportion of extruded kernels as adjunct, holdingtime at50℃, holding time at63℃, and holding time at70℃were used as the fiveparameters of saccharification process. And the ratio of wort, content of reducing sugar,content of α-amino nitrogen, filtration rate of50mL wort, value of pH and value of totalacid were used as the main indicators. In this paper, the influence of five parameters tomain indicators was studied. The response surface model was used in the trial to analyzethe data by SAS9.1software. Then the best parameters were shown: the ratio of water tomaterial was4.2(v/w), the extruded wheat kernels content was28%, and saccharifactiontimes were50min,50min and35min at50℃,63℃and70℃respectively. And the gettingratio of wort was71.81%. And100litres of beer experiment in our laboratory was carriedout under the optimal parameters of saccharificaion.The fermentable sugar compositions in wort was analyzed which included thequantitative analysis and the qualitative analysis by HPLC. Results showed that five kindsof fermentable sugar components were detected in the wort, and the content of five kindsof fermentable sugar was6.037g/100mL、1.373g/100mL、1.140g/100mL、0.211g/100mLand0.174g/100mL.The glucosan gel filtration chromatography was employed to separate the solubleprotein constituents in wort and beer brewing with low temperature extruded wheat kernelsas adjunct. And the results showed that the protein constituents and molecular weight werevery similar with two obvious peaks in both wort and beer. The position of the two obviouspeaks were similar, but the height and area were different slightly. The protein componentsin both wort and beer were detected by Folin-phenol method, and results expounded thatthe total soluble protein content of wort was6842μg/mL and the total soluble proteincontent of beer was4072μg/mL. The molecular weight distribution of the protein in wortwas detected by SDS-PAGE technology, and results showed that the components of proteinand peptides in the wort were main between8kDa and18.4kDa,31kDa and36kDa,37kDa and45kDa.The volatile aroma components in the beer were analyzed which included qualitativeanalysis and quantitative analysis by auto static sampler combination capillary column GC using N-butyl alcohol as internal standard. The result showed that eight kinds of volatilearoma compounds were separated from the beer brewing with low temperature extrudedwheat kernels as adjunct. The components were isoamyl alcohol(70.59mg/L), acetaldehyde(14.95mg/L), ethyl acetate (13.26mg/L), N-propanol(10.33mg/L), isobutyl alcohol(10.27mg/L), isoamyl acetate(2.25mg/L), ethyl hexanoate(0.19mg/L), ethyl octanoate(0.13mg/L), which were sorted of the content from high to low. They all required the normalcontent of beer.