Statistical comparison of a new rheological method for defining changes in mash consistency during mashing with the established Rapid Visco Analyser

The determination of mash consistency proved to be difficult but is of great importance particularly with regard to process and quality control. Therefore, the aim of this study was to develop a new rheological method for precisely determining changes in mash consistency occurring during the mashing process. For that purpose, five mashes with various levels of unmalted oats (0–40%) have been analyzed using a Physica MCR rheometer equipped with a paddle-shaped rotor enabling mash particles to be kept in suspension throughout the rheological measurement. For validating this new method, a statistical comparison with the established Rapid Visco Analyser (RVA) has been carried out. For this purpose, the mash consistency curves have been described by regression functions with the aim to determine characteristic curve points mathematically correct. As a result, the start and end point of starch gelatinization/liquefaction have been well-defined. By calculating the coefficients of determination, good to very good linear correlations between respective curve values and adjunct levels have been found for both methods (MCR and RVA). By calculating the repeatability, however, it has been revealed that the precision of the MCR method is significantly better than that of the RVA method.     

Experimental Study on Extruded Beer Adjunct Used for Brewing Beer

The properties of saccharified and boiled worts between extruded and traditional non-extruded beer adjuncts were studied at the laboratory and a small beer brewing equipment(100L) in this paper. Test results indicate that the main saccharification indices and filtration speeds of worts between extruded and traditional non-extruded beer adjuncts are similar basically. The collected rate of extracted material of worts of extruded beer adjuncts is 8% more than that of traditional non-extruded beer adjuncts. Fermentation time of worts of extruded beer adjuncts is 10% less than that of traditional non-extruded beer adjuncts. The energy consumption of extruded beer adjuncts in saccharification process is 13% less than that of traditional non-extruded beer adjuncts.     

Lactobacillus casei AST18抗真菌特性及其在酸奶保鲜中的应用

 【目的】考察来源于中国传统发酵制品中乳酸菌的抑真菌特性,研究其在酸奶贮藏中的抑制霉菌效果。【方法】高效液相色谱法（HPLC）检测7株具有抗真菌效果的乳杆菌发酵液中苯乳酸（PLA）含量,研究PLA与乳杆菌发酵液抗真菌活性的相关性。选取抑菌活性最强的菌株Lactobacillus casei AST18进行抑菌特性研究。Lactobacillus casei AST18分别以2%、4%、6%、8%接种量作为辅助发酵剂添加至酸奶发酵工艺中,成品酸奶贮藏期间,监测酸奶中霉菌生长状况,检测酸奶理化指标并进行感官评定。【结果】乳杆菌发酵液中苯乳酸含量与其抑真菌直径间相关关系不显著。Lactobacillus casei AST18发酵上清液经胃蛋白酶和胰蛋白酶处理后不影响其抑菌活性,而环境pH对其抑菌活性的影响显著,热处理可使其丧失抑菌活性。Lactobacillus casei AST18以 2%添加量作为辅助发酵剂应用在酸奶中可抑制霉菌菌丝生长和孢子生成,且对酸奶产品风味、感官品质无显著影响。【结论】Lactobacillus casei AST18具有较好的抑制霉菌生长能力,应用在酸奶中具有显著的防霉保鲜效果。     

挤压蒸煮大米啤酒辅料的糖化过程分析

为了合理地确定挤压蒸煮大米啤酒辅料的糖化工艺参数，通过挤压蒸煮大米不同糖化工艺的效果及传统蒸煮大米啤酒辅料糖化工艺的比较，分析了糖化过程。研究表明，两种大米啤酒辅料的糊化本质是相同的。不同的是，传统蒸煮大米啤酒辅料的双醪糖化工艺中的大米糊化过程中，包括了大米淀粉的糊化和液化过程；挤压蒸煮大米啤酒辅料仅完成了大米的糊化过程，其液化过程是在单醪糖化过程中完成。为此应调整挤压蒸煮大米的糖化工艺，充分发挥麦芽中的β-淀粉酶、α-淀粉酶及添加的耐高温α-淀粉酶的作用，使挤压蒸煮大米啤酒辅料的单醪糖化过程顺利进行，解决其糖化、过滤困难问题。     

膨化啤酒辅料酿造啤酒的试验研究

该文利用实验室试验和国产微型啤酒设备,对挤压膨化啤酒辅料与对照不膨化的传统蒸煮糊化啤酒辅料的对应醪液及其定型麦汁进行了试验研究。结果表明:膨化啤酒辅料与不膨化啤酒辅料相比,其麦汁醪液的主要糖化指标及其过滤速率基本相同,麦汁收得率,前者比后者约多8%,发酵时间,前者比后者减少10%;糖化过程的功耗,前者比后者少13%;糖化过程用水量,前者比后者约少用3%。     

挤压蒸煮大米啤酒辅料的外加酶糖化试验研究

用啤酒辅料挤压工艺可以代替其传统的蒸煮工艺,降低啤酒生产成本,增加啤酒产量.为此,考察了挤压蒸煮啤酒辅料的麦汁的过滤速度、浸出物收得率和还原糖等指标,应用正交旋转组合试验设计,研究其影响规律.实验室研究结果表明:挤压蒸煮大米辅料与传统的不挤压蒸煮大米辅料相比,麦汁浸出物收得率可提高6.52%左右,过滤速度加快6.29%左右,其它各项指标基本一致,符合啤酒生产工艺要求.     

挤压大米啤酒辅料糖化工艺参数对糖化过程的影响

为了合理确定挤压蒸煮大米啤酒辅料的糖化工艺参数,采用二次正交旋转组合试验,研究挤压蒸煮大米糖化工艺参数对麦汁主要考察指标的影响规律。研究结果表明,当65℃糖化时间为60min,71℃糖化时间为15min,α-淀粉酶添加量为2.1mL时,糖化麦汁的浸出物收得率可达76.25%,麦汁的碘值降至0.15,辅料中的淀粉残留率降至0.52%。另外,麦汁各项指标的检测结果表明,挤压膨化大米作啤酒辅料的糖化工艺是可行的。     

挤压系统参数对挤压蒸煮小麦啤酒辅料抗性淀粉的影响

对挤压蒸煮小麦辅料与传统蒸煮小麦辅料的抗性淀粉进行了实验室试验研究,得出挤压蒸煮系统对抗性淀粉含量的影响规律及产生抗性淀粉较少的最优参数。结果表明,挤压膨化小麦辅料与传统蒸煮小麦辅料糊化液的抗性淀粉含量相比,抗性淀粉含量减少1.2%,利于提高小麦淀粉的利用率,进而提高出酒率。     

挤压大米啤酒辅料麦汁浸出物收得率研究

文章对以挤压膨化大米为辅料经糖化后制得的麦汁浸出物收得率进行研究,并且以麦汁的碘值、还原糖及滤渣中的淀粉含量为指标,考察其淀粉的降解程度,从而初步分析了挤压膨化大米做啤酒辅料比传统蒸煮大米做啤酒辅料其麦汁收得率高的原因。     

挤压大米啤酒辅料的麦汁过滤性能试验研究

在挤压大米啤酒辅料的糖化试验基础上,对其麦汁的过滤性能进行了进一步试验研究。研究了挤压系统参数的套筒温度、大米含水率、螺杆转速对麦汁的过滤速度和滤层粒度的影响规律。研究结果表明：套筒温度为60．7～74．1℃,物料含水率为17．9％～21％,螺杆转速为195～230r／min时,麦汁的过滤速度大于0．2mL／s,浸出物收得率高于74％,滤层的粒度大于550um。