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%。     

挤压膨化大米做啤酒辅料的试验研究

该文通过实验室试验,研究了做啤酒辅料的大米挤压膨化系统诸参数(模孔孔径、套筒温度、物料含水率、螺杆转速),对醪液的主要考察指标(麦汁醪液的总还原糖、过滤速度)的影响规律,指出挤压膨化大米做啤酒辅料的可行性。     

膨化玉米作啤酒辅料的可行性试验研究

探讨了用不脱胚玉米挤压膨化物作啤酒辅料的可行性。指出：挤压膨化不脱胚玉米的绝干浸出率大于不膨化脱胚玉米的绝干浸出率，接近不膨化大米的绝干浸出率。可以用挤压膨化不脱胚玉米，代替目前传统工艺中不膨化的大米或脱胚玉米，作为酿制啤酒的辅料。同时使脱胚玉米辅料用量减少８％左右，麦芽用量减少１０％左右。     

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。     

脱胚玉米啤酒辅料的挤压蒸煮系统参数对其糖化过程的影响

该文通过实验室试验,研究了作啤酒辅料的脱胚玉米挤压蒸煮系统诸参数(模孔孔径、套筒温度、物料含水率、螺杆转速和模板内表面至螺杆末端端面的距离)，对醪液的主要考察指标（麦汁的过滤速度、碘值、浸出物收得率）的影响规律. 研究表明，挤压蒸煮脱胚玉米可以作啤酒辅料，其醪液的淀粉在糖化过程中被降解得彻底，淀粉的利用率较高。     

小米挤压膨化加工营养方便粥的工艺研究

通过氨基酸分析评价，了解本项目主料小米氨基酸品质，利用双螺杆挤压膨化机熟化，并采用调整膨化物料含水率、膨化喂料量，再结合乳化剂的使用和添加玉米等技术措施，改进小米的膨化效果。采用正交试验，设计产品配方。结果表明，选用小米为主料，其蛋白质基本符合模式标准，优于大米、小麦、玉米等多种谷物。控制上述4种膨化辅助条件，解决了小米膨化的难题，而且蛋白质、淀粉等大分子物质部分降解更有利于吸收。经正交试验选择出主料与多种辅料的最佳组合，使产品蛋白质含量和蛋白质质量大幅度提高，达到了全价蛋白质的营养水平，维生素、矿物质等多种营养元素含量也显著提高，营养很丰富。同时由于多种辅料的配合，产品的调溶性、复水性、口感等感官质量高，而且产品中富含了各种辅料所含的多种保健成分。     

挤压膨化大米应力-应变曲线的分形描述

挤压膨化物料的应力-应变曲线包含了物料的许多物性特征。该文利用分形几何的方法对挤压膨化大米的应力-应变曲线进行了定量分析。结果表明，该曲线具有分形特征，文中给出了挤压膨化大米应力-应变曲线分形维数的一种求取方法，并指出，挤压膨化大米的应力-应变曲线在低标度区和高标度区具有不同的分形维数，分形维数较膨化度能够更多地揭示挤压膨化物料的特征，为挤压膨化产品的准确描述提供了一种新的方法。     

麦芽质量缺陷对糖化麦汁品质的影响

麦芽质量对啤酒质量的影响非常大。研究有质量缺陷的麦芽在啤酒酿造过程中对糖化麦汁的影响,结果表明:麦芽感官缺陷会引起糖化麦汁口感异常;麦芽水分低于4.5%会让麦汁香气不足,水分高于5.5%则会使麦芽的利用率降低;麦芽中的β-葡聚糖含量超过20 mg/100g,不但会使糖化麦汁的过滤速度延长5～10 min,同时还会降低啤酒的非生物稳定性;麦芽粗细粉差直接影响糖化麦汁的粘度、α-氨基氮含量以及库值等的变化。     

膨化带胚玉米作啤酒辅料的试验研究

通过试验,研究了带胚玉米挤压膨化系统的诸参数（物料含水率,螺杆转速,套筒温度,模孔孔径）对各考查指标（糊化度、浸出率、脂肪、总还原糖、总酸）的影响规律,及其系统最优参数。结果表明,只要膨化系统诸参数选择合适,不加酶制剂,带胚玉米膨化物对应的麦汁醪液的糖化和过滤也可以顺利进行。     

姜汁保健啤酒研制

以普通原浆啤酒为对照,在啤酒酿造过程中加入生姜汁提取液,添加量为麦汁体积的3%,经过低温发酵工艺后得到一种姜汁保健啤酒。该姜汁啤酒既有原浆啤酒的麦芽香味和营养价值,又能结合麦芽和酒花香气,具有独特的纯正口味,并具有生姜暖胃的保健功能,具有可观的市场前景。     

Influence of the brewing process on furfuryl ethyl ether formation during beer aging

In beer, the development of a solvent-like stale flavor is associated with the formation of furfuryl ethyl ether. The synthesis rate of this important flavor compound is proportional to the concentration of furfuryl alcohol in beer. This study shows that furfuryl alcohol in beer is mainly formed by Maillard reactions initiated during wort boiling and malt production. A mechanism for its formation from alpha-(1,4)-oligoglucans and amino acids in wort and beer is proposed. During wort boiling, a quadratic relationship was found between the wort extract concentration, on the one hand, and the increase of furfuryl alcohol and furfural, on the other. The reduction of furfural by yeast during fermentation further increases the furfuryl alcohol content. In pale beers, the furfuryl alcohol concentration is essentially determined by the thermal load on wort during brewing operations. In dark beers, a considerable fraction of furfuryl alcohol may, however, come from the dark malts used. These results lead to important practical conclusions concerning the control over furfuryl ethyl ether in beer.     

Effective prevention of chill-haze in beer using an acid proline-specific endoprotease from Aspergillus niger

Chill-haze formation during beer production is known to involve polyphenols that interact with proline-rich proteins. We hypothesized that incubating beer wort with a proline-specific protease would extensively hydrolyze these proline-rich proteins, yielding a peptide fraction that is unable to form a haze. Predigestion of the proline-rich wheat gliadin with different proteases pointed toward a strong haze-suppressing effect by a proline-specific enzyme. This finding was confirmed in small-scale brewing experiments using a recently identified proline-specific protease with an acidic pH optimum. Subsequent pilot plant trials demonstrated that, upon its addition during the fermentation phase of beer brewing, even low levels of this acidic enzyme effectively prevented chill-haze formation in bottled beer. Results of beer foam stability measurements indicated that the enzyme treatment leaves the beer foam almost unaffected. In combination with the enzyme's cost-effectiveness and regulatory status, these preliminary test results seem to favor further industrial development of this enzymatic beer stabilization method.     

Addition of Sodium Stearoyl Lactylate to Corn and Sorghum Starch Extrudates Enhances the Performance of Pregelatinized Beer Adjuncts

Double mashing for wort production is a time‐consuming process that can be reduced if pregelatinized adjuncts are used. Optimal extruding conditions were determined to obtain brewing adjuncts from corn and sorghum starch. For corn starch extrusion, a Box–Behnken design was devised in which moisture, screw speed, temperature of the barrel, and concentrations of sodium stearoyl lactylate (SSL) were varied, and sorghum starch was extruded according to a 2³ model in which the modified variables were moisture, SSL concentration, and temperature. The aim was to maximize starch damage and minimize resistant starch and final viscosity as determined with a Rapid Visco Analyzer. The treatments that satisfied these requirements were mashed, and wort extract yield was determined. Glucose, maltose, and maltotriose concentrations in the resulting worts were determined by HPLC with a refractive index detector. Feedstock tempering and SSL content were the most important factors affecting the response; for corn starch, treatments with lower moisture (20%) and middle levels of SSL (0.5%) or with high levels of both moisture (40%) and SSL (1%) produced the most desirable samples for mashing, whereas for sorghum starch the best treatment was tempering to 20% moisture and containing middle levels of SSL (0.5%). No statistical differences were found between these experimental treatments and the control.     

Modification of the levels of polyphenols in wort and beer by addition of hexamethylenetetramine or sulfite during mashing.

The effects of addition of hexamethylenetetramine (HMT) or sulfite during mashing on the polyphenol content and oxidative stability of wort and beer have been evaluated in a series of laboratory mashings and pilot brews. HMT reduced the concentration of catechin, prodelphinidin B-3, and procyanidin B-3 in wort and beer, whereas the concentration of ferulic acid was unaffected. Sulfite had only a minor effect on the concentration of phenolics in wort and beer. Addition of HMT or sulfite during mashing increased the oxidative stability of the beer slightly as judged by the tendency of formation of radicals (ESR spin trapping technique), although sensory analysis gave identical flavor acceptance scores to beers produced from untreated and HMT-treated wort and lower scores to beer from sulfite-treated wort. No difference in the oxidative stability of the differently treated sweet worts could be detected as judged by the rate of formation of radicals. HMT addition during mashing has thus been demonstrated to be a valuable experimental tool to control the level of polyphenols in wort and for producing brews with various levels of polyphenols from a single malt.     

Impact of different wort boiling temperatures on the beer foam stabilizing properties of lipid transfer protein 1

Beer consumers demand satisfactory and consistent foam stability; thus, it is a high priority for brewers. Beer foam is stabilized by the interaction between certain beer proteins, including lipid transfer protein 1 (LTP1), and isomerized hop alpha-acids, but destabilized by lipids. In this study it was shown that the wort boiling temperature during the brewing process was critical in determining the final beer LTP1 content and conformation. LTP1 levels during brewing were measured by an LTP1 ELISA, using antinative barley LTP1 polyclonal antibodies. It was observed that the higher wort boiling temperatures ( approximately 102 degrees C), resulting from low altitude at sea level, reduced the final beer LTP1 level to 2-3 microg/mL, whereas the lower wort boiling temperatures ( approximately 96 degrees C), resulting from higher altitudes (1800 m), produced LTP1 levels between 17 and 35 microg/mL. Low levels of LTP1 in combination with elevated levels of free fatty acids (FFA) resulted in poor foam stability, whereas beer produced with low levels of LTP1 and FFA had satisfactory foam stability. Previous studies indicated the need for LTP1 denaturing to improve its foam stabilizing properties. However, the results presented here show that LTP1 denaturation reduces its ability to act as a binding protein for foam-damaging FFA. These investigations suggest that wort boiling temperature is an important factor in determining the level and conformation of LTP1, thereby favoring satisfactory beer foam stability.     

Fate of pesticides during beer brewing

The fates of more than 300 pesticide residues were investigated in the course of beer brewing. Ground malt artificially contaminated with pesticides was brewed via steps such as mashing, boiling, and fermentation. Analytical samples were taken from wort, spent grain, and beer produced at certain key points in the brewing process. The samples were extracted and purified with the QuEChERS (Quick Easy Cheap Effective Rugged and Safe) method and were then analyzed by LC-MS/MS using a multiresidue method. In the results, a majority of pesticides showed a reduction in the unhopped wort and were adsorbed onto the spent grain after mashing. In addition, some pesticides diminished during the boiling and fermentation. This suggests that the reduction was caused mainly by adsorption, pyrolysis, and hydrolysis. After the entire process of brewing, the risks of contaminating beer with pesticides were reduced remarkably, and only a few pesticides remained without being removed or resolved.