The Experimental Study On Beer Brewing Using Extruded Sorghum Added Medium Temperature Alpha-amylase As Beer Adjunct

Using sorghum as beer adjunct could reduce production cost because of the high starch content and low price, but it also has some problems include high gelatinization temperature, long saccharifying time, incomplete amylolysis and poor wort filtration, the traditional cooking method is difficult to degrade sorghum starch completely because of the close structure and high amylopectin content. Extrusion technology with enzyme supplementation solves the problems effectively. Based on the previous studies, using extruded sorghum added medium temperature alpha-amylase as beer adjunct discusses the following questions and lays a theoretical foundation for sorghum adjunct beer.The optimal extrusion parameters using extruded sorghum added medium temperature alpha-amylaseas beer adjunct were determined. The quadratic orthogonal rotating combination test design involving 5 factors and 5 levels. the SAS 9.3 software and response surface methodology was used to study the effects of the extrusion system pararmeters on each check indexes of wort(the ratio of wort, content of reducing sugar, content of α-amino nitrogen, filtration rate of 50 m L wort). Finally the optimal parameters of the extrusion by ridge regression method were shown as follow: the barrel temperature is 70℃,the screw speed is 200r/min, the moisture content is 30%, the die hole diameter is 8mm, the amount of enzyme is 9L/t. The ratio of wort reached 72.0% under these conditions, it is meet the requirement of producing light beer.The optimal saccharification parameters using extruded sorghum added medium temperature alpha-amylaseas beer adjunct were determined. The quadratic orthogonal rotating combination test design involving 5 factors and 5 levels. The SAS 9.3 software and response surface methodology was used to study the effects of the saccharification system pararmeters on each check indexes of wort( the ratio of wort, content of reducing sugar, content of α-amino nitrogen,filtration rate of 50 m L wort). Finally the optimal parameters of the saccharificationby ridge regression method were shown as follow: extruded sorghum proportion was31%, the ratio of water to 4.20(v/w), 50 ℃ protein resting time 52 min, 63 ℃saccharification time was 57 min, 70℃ saccharification time was 32 min. The ratio of wort reached 72.0% and the other indexes of validated results were advantage than the control group under these conditions.High performance liquid chromatography method was used to analyze the fermentable sugar component in wort, including qualitative analysis and quantitative analysis. Producing wort under the optimal liquefaction-extrusion system pararmeters. The content of fructose, glucose, sucrose, maltose and maltotriose was 0.151mg/L, 1.639mg/L, 5.244mg/L, 0.152mg/L, 1.678mg/L, the wort sugar component is conform to fermentation requirement of producing light beer.Using extruded sorghum added medium temperature alpha-amylase as beer adjunct and traditional cooking sorghum as control group, the ratio of wort improves 2%, filtration rate of 50 m L wort improves 0.12 m L/s, the index of validated results were advantage than those of control group, the wort is conform to beer brewing requirements.