超声波处理对荞麦种子营养物质累积以及抗氧化活性的影响

采用超声波对荞麦种子进行预处理,测定其萌发率,比较了萌发过程中水分含量、可溶性糖、粗蛋白、总酚和总黄酮的含量,以及体外抗氧化活性的变化。结果表明:10~20min的超声波处理可以提高荞麦的发芽率,而且萌发后荞麦芽的品质有所提高,其抗氧化物质有一定程度的累积,体外抗氧化活性增强。其中以超声波处理20min效果最理想,发芽率提高至94%,总酚含量达到180.8μg GAE/m L,总黄酮含量为156.701mg芦丁/g样品,DPPH自由基清除活力达到最大值(0.197mg Trolox eq/g冻干样)。荞麦萌发之前采用适宜的短时间的超声波处理,不仅能促进萌发,还能促进其抗氧化能力的提高。     

麦芽品质与啤酒质量研究进展

大麦是啤酒工业的主要原料，大麦的籽粒品质决定了麦芽的品质性状，麦芽品质是决定啤酒质量的主要因素。综述了麦芽主要成分对啤酒质量的影响，有助于啤酒生产者及麦制造者更充分的了解麦芽的特性，从而指导啤酒生产。     

大麦萌发过程的温度效应与相关因素分析

制麦过程是人工控制的大麦种子发芽生理反应的一个阶段。在这一阶段中,大麦种子需要有足够的水分、适当的温度和充足的氧气条件才能正常萌发溶解。这三大要素既是大麦种子生化反应的促进因素,又可形成种子生化过程中的制约条件。正确认识三大要素对大麦种子萌发的影响,是制定制麦工艺的关键。本文将对麦芽萌发过程的温度效应及温度与其它两大因素的关系作一论述,与同行们共商榷。三大麦萌发过程的环境因素分析制麦的实质是大麦种子在一定的环境条件下生长并适时终止生长过程。在大麦萌发过程中,大麦胚乳的贮藏物质在酶的作用下溶解供胚…     

脉冲电场对啤酒大麦萌发性质的影响

在啤酒麦芽制备过程中引入脉冲电场(PEF)技术,对浸渍后的大麦种子进行不同电场强度的处理,以了解PEF对大麦萌发性质的影响。结果表明,PEF处理有利于提高大麦萌发活力和相关理化性质。大麦籽粒经电场强度1.5、3.0、4.5、6.0、7.5 kV/cm处理后,萌发大麦的芽长、根长、根数、鲜重、干重、发芽势、发芽率、简化活力指数、还原糖含量、β-葡聚糖酶活力、α-淀粉酶活力、β-淀粉酶活力、可溶性蛋白质和氨基态氮含量等指标与对照组比较均有明显提高,发芽势、根长、β-葡聚糖酶活力、α-淀粉酶活力和β-淀粉酶活力提高的幅度分别为38.96%、43.33%、21.46%、26.48%和23.57%。对14项指标进行主成分分析的结果表明,当电场强度为6.0 kV/cm时,脉冲电场对大麦萌发的促进效果最好。     

超声波处理对苦荞麦萌发、芽苗还原糖和总黄酮含量及抗氧化活性的影响

采用超声波预处理苦荞麦种子,研究超声波的功率、时间和温度对苦荞麦种子萌发率及麦苗还原糖、总黄酮含量和对DPPH自由基清除能力的影响。结果表明:超声波的功率、时间和温度对种子的初始萌发率影响显著。在超声波功率280 W、温度20℃、时间35min处理条件下,苦荞麦种子的初始萌发率和最终萌发率分别达88.00%和100%。在超声波功率240 W、温度15℃、时间35min处理条件下,苦荞麦芽苗(4d)中还原糖含量最高达11.24g/100g,分别比种子和对照增加303.99%和40.03%。而在超声波功率280 W、温度30℃、时间30min处理条件下,苦荞麦芽苗(6d)中总黄酮的含量达9.46 g/100 g,分别比种子和对照增加228.07%和69.71%,该条件下芽苗对DPPH自由基的清除率达86.47%。     

澳大利亚麦芽大麦和加拿大麦芽大麦品质比较研究

对１９９６～１９９８年度上海口岸进口的澳大利亚麦芽大麦和加拿大麦芽大麦的品质项目逐一进行了比较分析。研究表明,澳大利亚麦芽大麦的发芽率,容重,千粒重,饱满粒含量较高,加拿大麦芽大麦的蛋白质,水分,瘦小粒,杂质含量较高。     

啤酒原料大麦的劣变与贮藏原理

啤酒原料大麦的劣变与贮藏原理金玉来（江苏农学院扬州；２２５００１）众所周知，麦芽制造是啤酒酿造的首要工序，原料大麦的品质对啤酒质量的影响不言而喻。虽然习惯上把胚根突破种皮作为萌发的标志，但实际上自从卵细胞受精的那一刻起就已经开始了新生命的活动，从生物...     

赤霉酸的添加对成品麦芽中残留量的影响

作为植物生长调节剂,赤霉酸添加到制麦过程中,可以加速大麦发芽,提高麦芽质量。但是若使用不当,会引起麦汁煮沸色度增加、赤霉酸残留量增加等问题。本文选取澳麦、法麦和国产苏北大麦为主要研究对象,考察了制麦过程添加赤霉酸对成品麦芽品质的影响。研究结果显示:赤霉酸对三个不同地区的大麦麦芽质量指标及其赤霉酸残留量的影响趋势基本一致,即添加量在0～0.3mg/kg范围内,对麦芽质量有明显提高,超过0.3mg/kg后趋于平缓。添加赤霉酸对麦汁色度的影响与大麦产地相关,法麦煮沸色度受影响最大,澳大利亚大麦受影响程度最小。成品麦芽中赤霉酸的残留量与制麦时的添加量具有非常明显的正相关性(R~2>0.99))。所以合理使用赤霉酸对麦芽品质的改善和控制具有重要意义。     

SNP标记分型与品质分析联合的麦芽纯度及品种真实性鉴定

大麦麦芽是啤酒酿造的主要原料,大麦品种的品质特性是制定相应的生产加工工艺的依据之一,而麦芽纯度则直接影响麦芽原料的均一性以及最终啤酒品质因此,本研究针对目前国内麦芽生产中存在的麦芽原料纯度和品种真实性无法及时准确判定的现状,对某啤酒厂送检的两份标注为麦特卡夫的麦芽样本,同时开展了基因型和品质分析。结果表明,通过基因型和品质的联合检测,不仅可以快速确定麦芽纯度,同时还能够对品种的真实性做出判断,为企业进行麦芽原料采购和品质监测提供依据。     

大麦和麦芽水溶性蛋白提取方案的优化及双向电泳图谱的建立

为了建立一套适用于大麦和麦芽的双向电泳分析方法,得到更加清晰、全面的双向电泳图谱。以高产优质大麦品种Gairdner为材料,对提取方法以及提取过程中所用的试剂的种类、用量和处理时间等进行比较分析和优化,运用蛋白定量法测定提取样品的蛋白质含量,摸索出一套完整的用于双向电泳分析的大麦蛋白提取和样品制备方法。大麦或麦芽经研磨,缓冲液-苯酚提取,醇洗,冻干后得到的蛋白质样品,双向电泳分离,硝酸银染色,PDQuest分析,图谱结果显示大麦检测到700个蛋白质点,麦芽检测到500个蛋白质点。这一方法的构建可作为大麦蛋白质组研究的重要工具,为今后大麦蛋白质组学以及对大麦品质改良的研究奠定了一定的基础。     

The Influence of Barley Storage on Respiration and Glucose‐6‐Phosphate Dehydrogenase During Malting

Malt is produced by the controlled, but limited germination of barley. To produce good quality malt, the barley employed must be able to germinate rapidly and synchronously. Dormancy is a seed characteristic that can interfere with the rapid and uniform germination of barley, thereby reducing the resultant malt quality. Various studies have shown that post harvest storage can be used to remove dormancy and enhance barley germination characteristics and malt quality. Because of its complexity, the fundamental basis of dormancy induction, maintenance and termination remain unknown. Glucose‐6‐phosphate dehydrogenase (G6PDH) is the rate limiting enzyme of the pentose phosphate pathway and has been associated with dormancy decay and increased seed vigor of a variety of different seeds. The aim of this study was to determine if changes in barley germination vigour were associated with respiration and/or G6PDH changes during malting. Commercially grown barley (cv. Gairdner) was obtained from various states of Australia and stored at room temperature for up to 7 months. At 1, 3 and 7 months, samples were taken and stored at ?18°C. The germinative energy (GE) and germinative index (GI) of these samples were measured. Samples were micro‐malted and the α‐amylase activity, respiration rate, and G6PDH activity of the germinating grains were measured at various stages of malting. It was found that storage of barley for up to seven months significantly improved the germination characteristics and increased the α‐amylase activity during malting. However, these improvements were not associated with concomitant changes in respiration rate or G6PDH activity during malting.     

Application of Ultrasonic Waves as a Priming Technique for Accelerating and Enhancing the Germination of Barley Seed: Optimization of Method by the Taguchi Approach

In this study the effects of different intensities and exposure time of ultrasound on barley seed have been investigated to determine the optimal conditions for accelerating germination. For optimization, the Taguchi approach was used. The germination rates and/or yield of the treated sample seed were compared with those of the untreated seed germinated under normal conditions. The seeds were treated with ultrasonic energy (input power 20–90% of 460W) and were exposed to three time periods ranging from 5 to 15 min. It was found that germination of the treated barley seed was increased about 1.042‐1.065 times compared with that of the untreated seed. The ultrasonic treatment proved to be efficient in reducing the germination period by 30–45%. It was concluded that priming of seeds with ultrasound was effective in improving water uptake and germination. The data presented in this paper suggest that the increase in final germination percentage, together with the reduced germination period in treated seeds, may be due to the action of ultrasound and that it led to an improved hydration process with concurrent shell fragmentation.     

制麦和酿造过程中脱氧雪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,脱氧雪腐镰刀茵烯醇（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0．1mg/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。     

A New Germinative Classification Model of Barley for Prediction of Malt Quality Amplified by a Near Infrared Transmission Spectroscopy Calibration for Vigour “On Line” Both Implemented by Multivariate Data Analysis

A new germinative two‐dimensional classification plot fully compatible to the current EBC analyses (EBC methods 3.5–3.7) is proposed for malting barley based on separate estimates for “vigour” (24 h germination) as abscissa with limits at 70% and 30% and for “viability” (72 h germination) as ordinate with limits at 98% and 92%. Early detection of germination by image analysis was improved by utilising the auto fluorescence of the root cap. The seven hierarchical germinative classes visualise the quality differences in a consistent way, ordering classes according to falling extract % and increasing wort β‐glucan (mg/L). It was surprising to discover that significant barley Near Infrared Transmission (NIT) spectroscopy based Partial Least Squares Regression prediction models for “vigour” and “viability” were obtained after removing the PLSR outliers. The majority of these were found to be low in vigour. It was concluded after experimental validation that the physical‐chemical structure of the seed, reflected by the correlation of the barley NIT spectral fingerprints to germination speed, is connected to the availability of substrate for germ growth. This is another aspect of the speed of malt modification. An automated combination instrument for measuring physical‐chemical and seed germination parameters is suggested for quality control and to establish an on‐line NIT calibration network for integrated germinative and malting quality classification.     

CONTROLLING MALTING LOSSES WITH ANOXIA,CARBON DIOXIDE,AND SULPHUR DIOXIDE

Micromalting trials were used to evaluate the effectiveness of various treatments with anaeroblosis, carbon dioxide or sulphur dioxide in controlling malting losses with grain treated with gibberellic acid. Periods of increasing anoxia, with carbon dioxide accumulation as in Kropff malting, produced malt with a reduced malting loss and a lower hot water extract than control malting. Covering germinating barley with atmospheres containing various partial pressures of carbon dioxide reduced malting losses, but the resulting malts were usually inferior in quality to the controls. Sulphur dioxide gas, applied to moist germinating barley three days after casting, reduced malting losses by almost 3%, and increased the hot water extract by about 3 lb./Qr. relative to control malts. The treated malt occupied less space than the control, and the heat output was reduced. Sulphur dioxide treatment and only 4 days' germination produced a malt in high yield, with an extract identical to that of a control malt germinated for five days. The sulphur dioxide malts yielded worts with lower pH and higher soluble nitrogen values than the control and the fermentability of the worts was normal.     

Changes in Germination and Malting Quality During Storage of Barley

To increase brewing yield and efficiency, malts with high extract values, high enzymic activities and good modification are essential. To produce malt that meets these requirements, the barley employed must have minimal post‐harvest dormancy and be able to germinate vigorously. The aims of this study were to determine the extent to which some Australian barley varieties changed during post‐harvest storage, how these changes influenced germination characteristics, enzyme production and malt quality, and, of the germination tests examined, which gave the best indication of a barley's malting potential. Four commercially grown barley samples were obtained, one from Tasmania and three from Victoria. Each sample was stored at room temperature for one year. At monthly intervals, samples were taken and placed at ?18°C. The germinative energy (GE) and germinative index (GI) of these samples were measured. Samples were also micro‐malted and the quality of the malt was assessed using standard EBC methodology. Storage at room temperature positively influenced the germination characteristics of all samples, with concomitant improvements in hydrolytic enzyme production during malting and in a number of malt quality parameters. It was found that, of the germination tests examined, the GI consistently correlated with enzyme activities during malting and with various malt quality parameters thus indicating that the GI is a good indicator of malting potential.     

Performance of Husked,Acid Dehusked and Hull‐less Barley and Malt in Relation to Alcohol Production

Studies carried out on normal husked barley, normal hull‐less (naked) barley, acid dehusked barley and acid dehusked hull‐less barley, as well as the malts derived from them, showed that when acid dehusked barley samples (obtained from either husked or hull‐less barley), were processed using commercial enzyme preparations, they produced more alcohol when compared with the alcohol yield obtained from the barley samples from which the acid dehusked samples were derived. When the husked (Optic) control, acid dehusked and hull‐less barley samples were malted, Optic control barley produced malt that gave higher dextrinising units (DU) and diastatic power (DP), whilst acid dehusked Optic and hull‐less barley produced malts that gave similar DU results on day 5 of the germination time. When mashed, acid dehusked (Optic) barley malt produced wort that filtered faster than the wort obtained from the malt made from hull‐less barley. This observation is very important because it shows that the husk of the barley is not the only factor that determines the filtration performance of the malted barley, since both the malt samples made from husked and acid dehusked barley had similar filtration rates on day 5 of the germination time. The slow filtration rate observed for the wort made from hull‐less barley suggests that other factors play some role during the filtration of the mash made from hull‐less barley malt. Although hull‐less malt appeared to develop lower DU and DP enzyme activities, when compared with the values obtained for the Optic control, hull‐less barley malted faster and produced optimum predicted spirit yield (PSY) at day 4 of the germination time. In contrast, the control husked Optic barley malt that had higher DU and DP produced equivalent (optimum) predicted spirit yield one day later at 5 days germination time. This is an advantage for hull‐less barley, both in terms of time and energy saving during the malting of barley. Although the acid dehusked Optic barley produced more alcohol than the husked control when commercial enzyme preparation was used to process barley, it was surprising that when the derived malt was assessed, it gave a lower predicted spirit yield than the husked control, even though it produced a higher amount of hot water extract (HWE). The higher extract yield and lower predicted spirit yield obtained from the malt made from acid dehusked malt confirmed that high extract yield is not necessarily associated with high fermentable extract.     

Malting Performance of Normal Huskless and Acid‐Dehusked Barley Samples

Sulphuric acid dehusked barley had a higher germinative energy and lower microbial infection than normal huskless (naked) barley, suggesting that the pericarp layer harboured microbial infection which may have limited the germination rate. Dehusking the normal huskless barley using sulphuric acid resulted in lower microbial infection, and increased germinative energy. The normal huskless barley sample had a higher β‐glucan content than the acid‐dehusked barley and had slower β‐glucan breakdown during malting. This resulted in the release of seven times more β‐glucan during mashing, and the production of wort of higher viscosity. The normal huskless barley sample had a higher total nitrogen content than the acid‐dehusked barley but both samples produced similar levels of amylolytic (α‐ and β‐amylase) activity over the same malting period. No direct correlation was found between barley total nitrogen level and the amylolytic activity of the malt. When barley loses its husk at harvest, the embryo is exposed and may be damaged. This may result in uneven germination which can reduce malting performance and hence malt quality.     

Effect of batch‐to‐batch variation on the quality of laboratory and commercially malted Oxbridge barley

The malting performance of two different batches of Oxbridge barley was studied. The study showed that a single 24 h continuous laboratory steep was suitable for steeping the two batches of Oxbridge to provide good quality malt. Although each batch represented the same variety, and was of similar malting quality, they behaved differently in terms of friability scores, filtration rate and predicted spirit yield (PSY) by day 4 of the germination period. Worts prepared from the two malts gave different patterns of filtration rates, showing that each batch of Oxbridge modified at a different rate and in a different way, although they achieved similar final PSY results at the end of the malting period. The two batches of Oxbridge both malted rapidly, but behaved differently in terms of modification pattern, as revealed by the Rapid Visco‐Analysis peak viscosities, as well visual germination results. The results of this study confirmed that, given the same malting conditions, batch 1 germinated more rapidly than batch 2, and supports the view that Oxbridge shows some inconsistency as a malting barley variety. The study further showed that the PSY result per se is not necessarily a good indicator of optimum modification of finished malted barley. This study showed that, while a particular barley variety, such as Oxbridge, may be associated with certain qualities and can produce good quality malt when a short steeping cycle is used, other factors are likely to cause batch‐to‐batch variations from the same barley variety. While the short steeping cycle was very successful in producing high‐quality laboratory malt from Oxbridge, and results in a significant reduction of the quantity of water required for steeping, reduces malting time and also saves costs, there is evidence that there may be some additional variability associated with Oxbridge malting barley. Copyright © 2012 The Institute of Brewing & Distilling