The Experimental Study On Beer Brewing Using Sorghum Extruded At Low Temperature As Adjunct

Processing brewing adjuncts with low temperature extrusion technology is a newdevelopment tendency of beer brewing techniques, which has advantages such assimplifying production process, high utilization rate of raw materials, shorteningfermentation period, high production efficiency, green energy-saving, etc. On the basis ofthe study of beer brewing with sorghum used as adjunct and extruded brewing adjunctsby domestic and overseas scholars, we carried on the research into beer brewing withsorghum as adjunct in combination with low temperature extrusion technology, mainlyincludes the following aspects:(1) The optimum extrusion parameters of beer brewing using sorghum extruded atlow temperature asadjunct was determined. In this paper, the quadratic orthogonalrotation combination test design was applied and the SAS9.1.3software and responsesurface methodology was used to study the effects of the temperature of the sleeve, screwrevolving speed, the moisture content of material and the diameter of die orifice on eachcheck indexes of wort. Through the ridge regression optimization and validatedexperiments, the optimum parameter of extrusion was obtained based on the extractionobtaining ratio of wort and filtration speed as follows: the temperature of the sleeve was80℃, screw revolving speed was210r/min, the moisture content of material was21%and the diameter of die orifice was10mm.(2) The optimum mashing procedures parameters of beer brewing using sorghumextruded at low temperature as adjunct was determined. In this paper, the quadraticorthogonal rotation combination test design was applied and the SAS9.1.3software andresponse surface methodology was used to study the effects of extruded sorghum content,water/grain ratio, protein interregna at50℃, saccharification time at63℃andsaccharification time at70℃on each check indexes of wort. By the ridge regressionoptimization and validated experiments, the optimum parameter of mashing procedureswas obtained based on the extraction obtaining ratio of wort and filtration speed asfollows: the extruded sorghum content was30%, the water/grain ratio was4.2, theprotein interregna at50℃was50min, the saccharification time at63℃was59min andthe saccharification time at70℃was31min.(3) The fermentable sugar components in wort produced from extruded sorghum adjunct at low temperature were analysized. High performance liquid chromatographymethod was employed to analyze the fermentable sugar components in wort, includingqualitative analysis and quantitative analysis. Through analyzing, fermentable sugarcomponents and their content were as follows: fructose0.17g/100mL, glucose1.29g/100mL, sucrose0.18g/100mL, maltose6.48g/100mL and maltotriose1.23g/100mL.The fermentability sugar accounted for about80%of the total sugar in wort, which canmeet the requirements of general fermentation.(4) The volatile flavor components in beer produced from extruded sorghum adjunctat low temperature were analysized. The auto static headspace injection gaschromatography combined with capillary column method was employed to analyzevolatile flavor components in beer, including qualitative analysis and quantitativeanalysis. The results shown that, the volatile flavor components and their content in beerwere acetaldehyde9.87mg/L, ethyl acetate23.12mg/L, isoamyl acetate4.02mg/L, ethylhexanoate0.22mg/L, ethyl octanoate0.18mg/L, n-propanol7.39mg/L, isobutyl alcohol13.36mg/L and isoamyl alcohol57.70mg/L. All the content of volatile flavorcompounds were within the scope of the normal content of lager beer.(5) The protein components in wort and beer produced from extruded sorghumadjunct at low temperature were analysized. In this part of research, the sephadex G-75glucan gel chromatographic column, Folin-phenol method and SDS-PAGE technologywere used for the analysis and determination of protein components in wort and beer.The results shown that, the components of protein in wort and beer were very similarwith two main components.And the total soluble protein content of wort and beer were5611.5μg/mL and4041.47μg/mL, respectively. And the molecular weight of proteincomponents in wort turned out to between9.6~25.0kDa and31.5~40.5kDa. And themolecular weight of protein components in beer turned out to between8.6~25.0kDa and29.6~39.1kDa.This experimental Study provided an experimental basis for beer brewing usingsorghum extruded at low temperature as adjunct.