The Experimental Study On Rice Added With Enzymes Extruded At Low Temperature Used As Beer Adjunct

At present around the world, except Germany, most of the beer enterprises used rice, corn starch and syrup as adjunct. The rice and corn need to be cooked and make them gelatinization. But the process of the traditional method is long and consumes a large amount of steam.Extrusion cooking technology could make starch gelatinize in the extruder, which has an significant advantages compared to the traditional process. But high temperature extruded adjunct also has the the difficulty in saccharification of the mash and the poor performance of filtration.The low temperature extruded beer adjunct (lower than 70℃) solved this problem and obtained national patent. The paper was carry out at the base of three patents < Processing method, equipment and saccharifaction method of extruded expansion beer adjunct, Patent No. 00122033.0;Processing method, equipment and saccharifaction method of extruded beer adjunct, Patent No. 200510045328.6; Processing method, equipment and saccharifaction method of extruded beer adjunct with or without enzymes, Patent No. 200810014639.X)> and the funds of the ministry of science and technology agricultural transformation. The study obtained the optimization parameters of extrusion-liquefaction after the experiments of extruding rice adding thermostableα-amylases and mesophilicα-amylases separately as beer adjunct. The change of the chemical composition of rice in extruder was studied and constructed a method to determined the sugar composition by HPLC.(1) It was studied the influence of liquefaction-extrusion system pararmeters (extrusion temperature, screw rotate speed, the content ofα-amylase during extrusion, the content ofα-amylase during liquefaction, ration of water to material) on the index of wort made from extruded rice added thermostableα-amylases as adjunct.The optimized pararmeters of liquefaction-extrusion system were got through analysising and optimizing the index by the regression method of SAS. The results show that extruded rice added thermostableα-amylases used as beer adjunct was feasible, and the index of validated results were advantage than those of contrast experiment through the validated tests.The optimized system pararmeters of liquefaction-extrusion by orthogonal tests and validated experiments were below: the extrusion temperature was 52.82~59.75℃, the screw rotate speed 169.88~187.00r/min, the content ofα-amylase during extrusion 0.97~1.12L/t, the content ofα-amylase during liquefaction 0.53~0.62L/t, the ration of water to material was 4.23~4.79.(2) It was studied the influence of extrusion- liquefaction system pararmeters (the content of amylase during extrusion, the content of amylase during liquefaction, screw rotate speed, liquefaction temperature, extrusion temperature) on the index of wort made from extruded rice added mesophilicα-amylase.The optimized pararmeters of extrusion- liquefaction system were got through analysising and optimizing the index by the regression method of SAS. The validated results showed that the process of producing wort used extruded riceadded mesophilicα-amylases as beer adjunct was feasible, and the index of validated results were advantage than those of contrast experiment.The optimized pararmeters of extrusion-liquefaction system by orthogonal tests and validated experiments were below: the content of amylase added to rice during extrusion was 4.27~5.74L/t, the content of amylase during liquefaction 2.82~2.94L/t, the screw rotate speed 198.51~226.72r/min, the liquefaction temperature was 75.70~80.39℃, the extrusion temperature 63.62~69.00℃.The rice was extruded under the optimizing parameters and took saccharfication- fermentation pilot scale production in beer enterprise. The results was shown that the the yield of beer increased 2~3% of extruded rice added enzymes as beer adjunct than that of extruded native rice. All the indexes of beer meeted the national standard(GB-4927-2001).(3) The change of main chemical compositions of rice and enzymes during was determined. The samples were took at the specified 6 points along the screw direction. The results showed that the enzyme activity was decreased, the gelatinization degree was increase, the content of starch and lipid was decreased. The difference of reducing sugar of extruded native rice added enzymes was increased obviously than that of the extruded native rice. The reducing sugar of extruded native rice was decreased. The resistant starch of extruded rice added enzymes was decreased, but that of the extruded native rice was increased.(4) The determined method of sugar components among extruded rice by HPLC was obtained. The chromatogram conditions was shown below: the chromatographic column (Carbohydrate High Performance 4μm,size:4.6mm×250mm Cartridge;American Waters Co., LTD) ;Waters Carbohydrate High Performance 4μm chromatographic column with refractive index detector; the mobile phase: elution influent acetonitrile: ultrapure water (V,V)81:19,flow rate 1.1ml/min;Detector pool temperature: 35℃; the column temperature: 45℃;the injection volume15μl. The measurement method was quick and accurate.The sugar components of extruded native rice was shown below: the content of fructose was 0.002(g/ml), the content of glucose was 0.078(g/ml), the sucrose was 036(g/ml),the maltose was 0.383(g/ml),the maltotriose was0.004(g/ml).The sugar components of extruded rice added thermostableα-amylases was shown below: the content of fructose was 0.121(g/ml), the content of glucose was 1.261(g/ml), the sucrose was 0.093(g/ml),the maltose was 3.955(g/ml),the maltotriose was3.207(g/ml).The sugar components of extruded rice added mesophilicα-amylases was shown below: the content of fructose was 0.129(g/ml), the content of glucose was 1.953(g/ml), the sucrose was 0.366(g/ml),the maltose was 2.942(g/ml),the maltotriose was2.311(g/ml).The experimental study on rice added with enzymes extruded at low temperature used as beer adjunct provide a scientific basis in beer production.