制麦和酿造过程中脱氧腐镰刀菌烯醇的初步研究

2008年江苏某农场的赤霉病感染相对严重的KA-4B大麦中,脱氧雪腐镰刀菌烯醇(DON)的含量为1.91mg/kg.以此大麦为原料,实验室规模下进行制麦和酿造实验,结果表明,浸麦可以洗去大麦本身含有的绝大部分DON;而大麦内部没有被洗掉的镰孢霉属真菌孢子在发芽阶段重新萌发、生长代谢,形成并积累大量的DON;焙燥阶段不能破坏DON,成品麦芽和麦根中DON的含量分别是原大麦中DON含量的51%和89%.麦芽中的DON可以经过糖化和发酵过程流入到啤酒中,啤酒中DON的总含量是麦芽粉中DON总量的86%.而同一年份相邻农场的基本未感染赤霉病的KA-4B大麦中,DON含量低于0.1 mg/kg,绿麦芽和麦根中均检测到低于0.1mg/kg的DON,而成品麦芽、麦汁和啤酒中均未检测到DON.制麦及酿造实验表明,与基本未感染赤霉病的KA-4B大麦相比,赤霉病感染程度严重的KA-4B大麦微生物污染严重,DON含量相对高,大麦品质较差,发芽率较低,麦芽浸出率低,所制得麦汁的过滤速度快,麦汁和啤酒的色度均较高.     

小麦麦芽部分替代大麦麦芽啤酒生产中酶制剂的应用试验

主要探讨在利用小麦麦芽替代部分大麦麦芽的啤酒酿造中，试验添加啤酒糖化复合酶NCB-501B．通过对麦汁过滤时间，定型麦汁质量，发酵波以及成品酒理化指标和感官评价的对比分析，表明NCB-50113能有效缩短麦汁过滤时间，增加α-氨基氮含量，提高啤酒品质和非生物稳定性，同时降低了生产成本。     

麦芽及啤酒酿造过程中的农残分析

为了解麦芽和啤酒中主要农药的残留状况,采用固相萃取一气质联用法对进厂麦芽中16种主要农药的残留量进行了检测,并跟踪总结了啤酒酿造过程中农残的变化特点。结果显示,A厂加拿大麦芽可检出农残4种,B厂加拿大麦芽可检出农残3种,B厂国产麦芽可检出农残2种;制麦过程中,三唑醇和溴氰菊酯含量可降至检出限以下,抗蚜威、乙草胺、三唑酮和p．p,-DDT的含量也均有不同程度的降低;啤酒酿造过程农残进一步降低。麦芽中检出抗蚜成、三唑酮、p．p-DDT3种农残,麦汁只检出三唑酮,成品啤酒未检出。检出的农践在0．0001～0．02mg／kg范围。     

啤酒及其酿造过程中的硅

据称啤酒是日常饮食硅的重要来源之一,但我们很少了解硅含量与啤酒类型和啤酒生产方式之间的关系。本研究的目的是检测各种啤酒中的硅含量,并确定影响啤酒中硅含量的原料配比和酿造参数。商业啤酒中的硅含量介于6．4～56．5mg／L之间。以大麦谷物酿造的啤酒往往比小麦谷物含有更多的硅,这可能是因为大麦皮壳中硅含量较高。与谷物相比,酒花中含有更多的硅,但对酿造啤酒而言,所用酒花的数量往往比麦芽要少,因此啤酒中的硅很少来自于酒花。在酿造过程中,大量的硅残存于麦糟中,但是,糖化麦汁制备时进行适当处理,就可以提高麦汁中的硅含量,使其大部分留存于啤酒中。由此可以推断,啤酒中富含硅元素。     

大麦替代部分麦芽用于酿酒大生产的试验

在外加酶制剂作用下,用部分大麦替代大麦芽进行了啤酒酿造的生产规模试验。比较了未添加大麦生产的麦汁与用部分大麦替代大麦芽和辅料所生产的麦汁在生产过程中pH及过滤参数的变化;考察了大麦和麦芽配比变化对冷麦汁、成熟发酵液和成品酒的一些重要理化指标的影响,并分析了成熟发酵液风味物质的不同。试验结果表明,用大麦部分替代麦芽可以得到和麦芽啤酒基本相同的风味及保质期,尽管在某些风味物质和稳定性指标上有所差异。     

啤酒生产过程中脱氧雪腐镰刀菌烯醇的控制研究

以感染镰孢霉属真菌的大麦为原料,确定了NaHSO3溶液浸泡的化学脱毒方法(浸泡浓度为10g/L和浸泡时间为50min)和在第一次浸麦阶段接种白地霉孢子106个/g大麦的微生物脱毒方法,并对比研究了两种脱毒方法的效果。对制麦和酿造过程中DON变化及相关理化指标的比较发现,添加白地霉G4的脱毒效果较NaHSO3溶液浸泡好,而采用NaHSO3溶液浸泡处理方法所制得的麦芽、麦汁和啤酒的理化指标相对较好。两种脱毒方式所制得的麦芽的理化指标均符合QB/T1686-2008中啤酒麦芽的要求,成品啤酒的常规理化指标均符合GB4927-2008中淡色啤酒的理化要求。     

啤酒生产过程中脱氧雪腐镰刀菌烯醇的控制研究

以感染镰孢霉属真菌的大麦为原料,确定了NaHSO3溶液浸泡的化学脱毒方法（浸泡浓度为10g/L和浸泡时间为50min）和在第一次浸麦阶段接种白地霉孢子106个/g大麦的微生物脱毒方法,并对比研究了两种脱毒方法的效果。对制麦和酿造过程中DON变化及相关理化指标的比较发现,添加白地霉G4的脱毒效果较NaHSO3溶液浸泡好,而采用NaHSO3溶液浸泡处理方法所制得的麦芽、麦汁和啤酒的理化指标相对较好。两种脱毒方式所制得的麦芽的理化指标均符合QB/T1686-2008中啤酒麦芽的要求,成品啤酒的常规理化指标均符合GB4927-2008中淡色啤酒的理化要求。      

加拿大新品系麦芽酿造特性的研究

本文在无锡轻工大学生物工程学院的1m~3小型啤酒设备上以相同的糖化、发酵工艺对三种加拿大新品系麦芽进行了酿造比较试验。实验结果表明加拿大三个新品系大麦与哈林顿相比,均是优秀的制麦大麦。麦特卡夫的酿造特性与哈林顿基本相近。其麦汁或啤酒的各项指标不比哈林顿差,尤其是β-葡聚糖含量较低,优于哈林顿,其麦芽库值一般较高。斯泰托斯属溶解较慢品种,其麦芽库值一般较低,麦汁色度也较浅,β-葡聚糖含量较低。其麦芽在糖化时要稍微延长蛋白质休止时间,以提高定型麦汁中的总氮和α-氮含量,酿造特性比较接近哈林顿。肯德尔麦芽蛋白质含量较适中。其麦汁极限发酵度在三个新品种中最高,麦汁色度较哈林顿浅,在糖化时要控制蛋白质休止时间,容易制成爽口的啤酒。整个试验中以哈林顿为对照。     

中性蛋白酶对啤酒酿造中麦汁质量的影响

随着啤酒工业的发展,酶制剂在啤酒酿造中的应用越来越广泛.文中主要对中性蛋白酶在糖化过程的应用及对麦汁的影响进行了研究.研究表明,中性蛋白酶添加量在250mg/(kg麦芽)以下,可以使麦汁中α-氨基酸态氮含量提高25%以上,高于250mg/(kg麦芽)反而不利于酶的作用.添加中性蛋白酶只能在一定程度上降低麦汁浊度和敏感蛋白含量,若要进一步提高麦汁稳定性,需要同时采取相应措施,控制麦汁中多酚物质的含量.     

利用废酵母和麦根实现啤酒高辅料酿造的可行性探讨

本文研究的目的是探讨将啤酒副产物提纯降解应用于啤酒酿造的可行性，以解决低麦芽酿造中的氮源不足问题。对于100L规模的14°P麦汁酿造，添加250g麦根和1．5L酵母水解液，可以将麦汁的α-氨基氮提高到要求范围，不会对酿造过程和啤酒质量造成明显影响。     

Transfer of Fusarium mycotoxins and 'masked' deoxynivalenol (deoxynivalenol-3-glucoside) from field barley through malt to beer

The fate of five Fusarium toxins--deoxynivalenol (DON), sum of 15- and 3-acetyl-deoxynivalenol (ADONs), HT-2 toxin (HT-2) representing the main trichothecenes and zearalenone (ZON) during the malting and brewing processes--was investigated. In addition to these 'free' mycotoxins, the occurrence of deoxynivalenol-3-glucoside (DON-3-Glc) was monitored for the first time in a beer production chain (currently, only DON and ZON are regulated). Two batches of barley, naturally infected and artificially inoculated with Fusarium spp. during the time of flowering, were used as a raw material for processing experiments. A highly sensitive procedure employing high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was validated for the analysis of 'free' Fusarium mycotoxins and DON-conjugate in all types of matrices. The method was also able to detect nivalenol (NIV), fusarenon-X (FUS-X) and T-2 toxin (T-2); nevertheless, none of these toxins was found in any of the samples. While steeping of barley grains (the first step in the malting process) apparently reduced Fusarium mycotoxin levels to below their quantification limits (5-10 microg kg(-1)), their successive accumulation occurred during germination. In malt, the content of monitored mycotoxins was higher compared with the original barley. The most significant increase was found for DON-3-Glc. During the brewing process, significant further increases in levels occurred. Concentrations of this 'masked' DON in final beers exceeded 'free' DON, while in malt grists this trichothecene was the most abundant, with the DON/DON-3-Glc ratio being approximately 5:1 in both sample series. When calculating mass balance, no significant changes were observed during brewing for ADONs. The content of DON and ZON slightly decreased by a maximum of 30%. Only traces of HT-2 were detected in some processing intermediates (wort after trub removal and green beer).     

The Effect of Barley Adjuncts on Free Amino Nitrogen Contents in Wort

Free amino nitrogen (FAN) and other low‐molecular‐weight nitrogen compounds (LNC) are highly important as nutrients for yeast. Many different types of low‐malt beer exist around the world, some of which are produced with barley as an adjunct. In these cases, inhibitors contained in barley are known to influence the amount of LNC in wort. Accordingly, it is important to investigate which proteinase class is key in producing these compounds. By investigating the relationship between the FAN contained in wort produced from malt and barley (barley adjunct wort) and malt proteinase activity, it was found that cysteine proteinase and 1,10‐orthophenanthroline (O‐Phen)‐inhibitable metallo proteinases had a significant correlation to the barley adjunct wort FAN levels. In addition, the relationship between malting conditions and these proteinase activities was investigated and the conditions defined for maximal production of proteinases as follows: steeping degree, 50%; germination temperature, 12°C; germination days, 6 days; water spray, 3 times and concentration of gibberellic acid, 10 mg/kg (barley).     

以未发芽大麦替代麦芽酿造啤酒及其麦香改善研究

本文研究了利用酶制剂Ondea Pro进行大麦啤酒的生产,对其麦汁糖谱、氨基酸谱、蛋白质区分、α-氨基氮和大麦啤酒理化成分及风味物质等指标进行了检测,特别是对麦香物质呋喃酮、2-乙酰吡咯、2-乙酰-1-吡咯啉、麦芽酚、2-甲基吡嗪、乙基吡嗪、乙酰呋喃和甲基糠醛等化合物进行了分析,并邀请专业品酒委员进行了感官品评。研究结果发现,利用Ondea Pro酶生产的麦汁,能够满足酵母发酵需求,然而大麦啤酒存在明显的麦香缺陷。通过额外添加不同比例的焦香麦芽,分析大麦啤酒中主要麦香物质的变化规律,结合感官品评,结果表明添加1%的焦香麦芽酿造而成的大麦啤酒,其主要麦香物质和品评口感与麦芽啤酒接近。添加少量焦香麦芽生产的大麦啤酒市场潜力具大,极具推广价值。      

Brewing with 100% Oat Malt

Oats are a cereal with beneficial nutritional properties and also unrealized brewing potential. Furthermore, oats can be tolerated by the majority of people who suffer from celiac disease. Malting of oats produced a malt, which was found suitable for brewing a 100% oat malt beer. The mashing regime, designed by using mathematical modelling, was successfully transferred to a pilot scale plant. The improved lautering performance of oat malt was due to its higher husk content, which also led to a lower extract content in oat wort when compared to barley wort. The protein profile of oat wort, as measured by using Lab‐on‐a‐Chip analysis, revealed that there was no significant difference in the protein profile between oat and barley wort. The fermentation of oat and barley worts followed the same trend; differences could only be seen in the higher pH and lower alcohol content of the oat beer. The flavour analysis of oat beer revealed some special characteristics such as a strong berry flavour and a lower amount of staling compounds when forced aged. This study revealed that it was possible to brew a 100% oat malt beer and that the produced beer was comparable to a barley malt beer.     

Effect of hot water treatments on the safety and quality of Fusarium-infected malting barley

Utilization of Fusarium-infected barley for malting may lead to mycotoxin contamination of malt and decreased malt quality. Hot water treatments may prevent or reduce safety and quality defects and allow use of otherwise good quality barley. We evaluated hot water treatments for preventing Fusarium growth and mycotoxin production while maintaining barley-malt characteristics. Four barley lots with varying deoxynivalenol (DON) concentrations were hot water-treated at 45 or 50 degrees C for 0, 1, 5, 12, and 20 min. Treated barley was malted in a pilot-scale malting unit. Barley and malt were analyzed for Fusarium infection (FI), germinative energy (GE), aerobic plate count (APC), mold and yeast count (MYC), and DON. Malt quality parameters included malt extract, soluble protein, wort color, wort viscosity, free amino nitrogen, alpha-amylase, and diastatic power. Significant decreases in FI occurred within 1 min at both 45 degrees C (41-66%) and 50 degrees C (51-69%) in all barley samples. Significant reductions in APC (1.0-1.8 log) and MYC (1.7-1.8 log) in barley were observed after 5 min at both temperatures. The largest reductions for DON were observed in malts prepared from barley treated with hot water at 45 degrees C (79-93%) and 50 degrees C (84-88%) for 20 min. GE and most of the malt quality parameters were only affected when barley was treated at 50 degrees C for 12 and 20 min. The results suggest that hot water treatments may offer the potential for treating mildly FHB infected malting barley.     

100%大麦啤酒酿造过程中老化Strecker醛的研究

分别采用上面发酵工艺与下面发酵工艺进行100%大麦啤酒及100%麦芽啤酒的酿制,并对其麦汁的氨基酸含量、老化Strecker醛、自由基以及新鲜啤酒中老化Strecker醛的含量等进行了对比分析。研究发现,就麦汁而言,100%大麦麦汁中老化Strecker醛的含量都明显低于100%麦芽麦汁;同样的麦汁,上面发酵方式还原Strecker醛的能力明显优于下面发酵方式。就啤酒而言,经酵母还原后,新鲜啤酒中的老化Strecker醛含量较麦汁含量低,且100%大麦啤酒中老化Strecker醛的含量低于100%麦芽啤酒中的含量。100%麦芽麦汁的自由基含量是100%大麦麦汁的近3倍。这都预示着100%大麦啤酒的风味稳定性（新鲜度）明显好于100%麦芽啤酒。     

Mold and mycotoxin problems encountered during malting and brewing

Fusarium infections in grains can have severe effects on malt and beer. While some degree of Fusarium mycotoxins, such as deoxynivalenol, present in infected barley may be lost during steeping, the Fusarium mold is still capable of growth and mycotoxin production during steeping, germination and kilning. Therefore, detoxification of grain before malting may not be practical unless further growth of the mold is also prevented. Methods to reduce the amount of mold growth during malting are needed. Physical, chemical and biological methods are reviewed. Irradiation looks very promising as a means to prevent Fusarium growth during malting, but the effect on the surviving mold to produce mycotoxins and the effect on malt quality needs further study. Chemical treatments such as ozonation, which would not leave residual chemical in the beer also appear to be promising. Although biological control methods may be desirable, due to the use of "natural" inhibition, the effects of these inhibitors on malt and beer quality requires further investigation. It may also be possible to incorporate detoxifying genes into fermentation yeasts, which would result in detoxification of the wort when mold growth is no longer a problem. Development of these types of technological interventions should help improve the safety of products, such as beer, made from Fusarium infected grain.     

Protein changes during malting and brewing with focus on haze and foam formation: a review

Beer is a complex mixture of over 450 constituents and, in addition, it contains macromolecules such as proteins, nucleic acids, polysaccharides, and lipids. In beer, several different protein groups, originating from barley, barley malt, and yeast, are known to influence beer quality. Some of them play a role in foam formation and mouthfeel, and others are known to form haze and have to be precipitated to guarantee haze stability, since turbidity gives a first visual impression of the quality of beer to the consumer. These proteins are derived from the malt used and are influenced, modified, and aggregated throughout the whole malting and brewing process. During malting, barley storage proteins are partially degraded by proteinases into amino acids and peptides that are critical for obtaining high-quality malt and therefore high-quality wort and beer. During mashing, proteins are solubilized and transferred into the produced wort. Throughout wort boiling proteins are glycated and coagulated being possible to separate those coagulated proteins from the wort as hot trub. In fermentation and maturation process, proteins aggregate as well, because of low pH, and can be separated. The understanding of beer protein also requires knowledge about the barley cultivar characteristics on barley/malt proteins, hordeins, protein Z, and LTP1. This review summarizes the protein composition and functions and the changes of malt proteins in beer during the malting and brewing process. Also methods for protein identification are described.     

Transfer of Fusarium mycotoxins and ‘masked’ deoxynivalenol (deoxynivalenol-3-glucoside) from field barley through malt to beer

The fate of five Fusarium toxins — deoxynivalenol (DON), sum of 15- and 3-acetyl-deoxynivalenol (ADONs), HT-2 toxin (HT-2) representing the main trichothecenes and zearalenone (ZON) during the malting and brewing processes — was investigated. In addition to these ‘free’ mycotoxins, the occurrence of deoxynivalenol-3-glucoside (DON-3-Glc) was monitored for the first time in a beer production chain (currently, only DON and ZON are regulated). Two batches of barley, naturally infected and artificially inoculated with Fusarium spp. during the time of flowering, were used as a raw material for processing experiments. A highly sensitive procedure employing high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was validated for the analysis of ‘free’ Fusarium mycotoxins and DON-conjugate in all types of matrices. The method was also able to detect nivalenol (NIV), fusarenon-X (FUS-X) and T-2 toxin (T-2); nevertheless, none of these toxins was found in any of the samples. While steeping of barley grains (the first step in the malting process) apparently reduced Fusarium mycotoxin levels to below their quantification limits (5–10 µg kg^?1), their successive accumulation occurred during germination. In malt, the content of monitored mycotoxins was higher compared with the original barley. The most significant increase was found for DON-3-Glc. During the brewing process, significant further increases in levels occurred. Concentrations of this ‘masked’ DON in final beers exceeded ‘free’ DON, while in malt grists this trichothecene was the most abundant, with the DON/DON-3-Glc ratio being approximately 5:1 in both sample series. When calculating mass balance, no significant changes were observed during brewing for ADONs. The content of DON and ZON slightly decreased by a maximum of 30%. Only traces of HT-2 were detected in some processing intermediates (wort after trub removal and green beer).     

Fungal Hydrophobins in the Barley‐to‐Beer Chain

Fungal hydrophobins have been shown to induce gushing of beer. In order to study the occurrence and fate of hydrophobins at different stages of the production chain of beer, barley samples artificially infected in the field with Fusarium culmorum, F. graminearum and F. poae were collected during the growing period as well as during various stages of the malting process. In addition, naturally infected malt was brewed in pilot scale and samples were collected throughout the process. The samples were assayed for hydrophobin content using an ELISA method. The results showed that fungi produced hydrophobins that accumulated during barley grain development in the field, but that production was more pronounced during malting. Prolonged storage of barley tended to reduce the ability of fungi to produce hydrophobins in malting. Studies on the fate of hydrophobins during the brewing process revealed that mashing released hydrophobins from the malt into the wort. Some loss of hydrophobins occurred throughout the brewing process with spent grains, cold break (wort boiling) and surplus yeast. In addition, the beer filtration step reduced hydrophobin levels. Despite the substantial loss of hydrophobins during brewing, the level was high enough to induce the gushing detected in the final beer.