外加酶糖化法制啤酒的研究

原料大麦经精选后,使用干法或湿法粉碎,以达到麦粒压扁碎开,麦皮完整的要求,在麦芽用量降低到30％的前提下,采用国产食品级的α-淀粉酶、中性蛋白酶、β-葡聚糖酶、异淀粉酶、糖化酶等多种酶制剂进行糖化。该工艺与用70％麦芽的传统生产相比,麦汁产量有所增加,过滤时间相似,其麦汁成份符合要求,发酵正常,酿制的啤酒色浅、口味纯正,各项指标达到国标优质啤酒水平。经生产试验证明节粮可达6.76％,主要原料成本可降低6％,还可节省麦芽车间投资,有显著的经济效益和一定的社会效益。     

Aging fingerprint characterization of beer using electronic nose

In this work, attempts were made in order to characterize the change of aroma of alcoholic and non alcoholic beers during the aging process by use of a metal oxide semiconductor based electronic nose. The aged beer samples were statistically characterized in several classes. Linear techniques as principal component analysis (PCA) and Linear Discriminant Analaysis (LDA) were performed over the data that revealed non alcoholic beer classes are separated except a partial overlapping between zones corresponding to two specified classes of the aged beers. A clear discrimination was not found among the alcoholic beer classes showing the more stability of such type of beer compared with non alcoholic beer. In this research, to classify the classes, two types of artificial neural networks were used: Probabilistic Neural Networks (PNN) with Radial Basis Functions (RBF) and FeedForward Networks with Backpropagation (BP) learning method. The classification success was found to be 90% and 100% for alcoholic and non alcoholic beers, respectively. Application of PNN showed the classification accuracy of 83% and 100%, respectively for the aged alcoholic and non alcoholic beer classes as well. Finally, this study showed the capability of the electronic nose system for the evaluation of the aroma fingerprint changes in beer during the aging process.     

Development and Assessment of a Small‐Scale Wort Filtration Test for the Prediction of Beer Filtration Efficiency

A Small‐scale Wort rapid Filtration Test (SWIFT) that predicts beer filtration efficiency has been developed. The test is simple, cost effective and correlates with existing beer filtration tests such as beer V_max membrane (Esser test) and diatomaceous earth (Walton filter) tests. SWIFT has an advantage over existing beer filtration tests as it can be easily incorporated into barley quality laboratories utilising excess wort from extract analyses, thus negating the need for additional sample preparation or to ferment and age beer. Furthermore, the test does not rely on expensive equipment or specially trained laboratory technicians. SWIFT, which may also be used to evaluate degassed beer, is a syringe test that utilises a 13 mm diameter 0.45 μm membrane and is negatively influenced by wort viscosity (P<0.05). It is envisaged that SWIFT may be applied by barley breeding programs for the evaluation of progeny lines to provide a better prediction of beer filtration performance than total wort β‐glucan measurements. In addition, maltsters and brewers could use SWIFT to assess malt samples, and provide early warning of potential beer filtration problems during the brewing process.     

Rapid quality control of spirit drinks and beer using multivariate data analysis of Fourier transform infrared spectra

Fourier Transform Infrared (FTIR) spectroscopy in combination with multivariate data analysis is introduced for the quality control and authenticity assessment of spirit drinks and beer in official food control. The spectra were measured using a FTIR interferometer, which is purpose-built for the analysis of alcoholic beverages and includes an injection unit for liquids with automatic thermostating of the sample. Only 2 min are required for FTIR measurement. For spirit drinks, no sample preparation is required at all. Carbon dioxide containing samples, such as beer were prepared by degassing.     

尼泊金庚酯的研究进展以及在啤酒中的应用

本中介绍了近年来国内对尼泊金庚酯合成的研究进展，并介绍了国外专利关于尼泊金酯在啤酒中的应用研究。     

糖化酵母在干啤酒生产中应用的研究（Ⅰ）──具有糖化酶活性和去除POF1基因的糖化酵母的选育

比较了多株单、双倍体糖化酵母，选出糖化酶活性及发酵度较高的糖化酵母单倍体──Ｓｏｃ．ｄｉａｓｔａｔｉｃｕｓ２６０６７－４４。同时发现糖化酵母单倍体菌株的酶活性高于二倍体菌株。含有ＰＯＦ１基因的糖化酵母（ｐｏｆ＋表型）可脱羧肉桂酸形成苯乙烯，ｐｏｆ－菌株无此能力。通过气相色谱检测肉桂酸－酒花麦汁发酵液中的苯乙烯含量，可以鉴别出去除ＰＯＦｌ基因的菌株。本文利用酵母菌的群体杂交法，通过Ｓ．ｄｉａｓｔａｔｉｃｕｓ２６０６７－４４与酿酒酵母单倍体杂交，获得１株糖化酶活性及发酵度较高，并且去除了ＰＯＦ１基因的单倍体菌株Ｈ－３（２）－２（ａ，ＳＴＡ，ｐｏｆ－）·     

Aluminium content of beers

 The aluminium (Al) concentration in different brands of beers packaged in Al cans and glass bottles was measured at the end of the shelf-life of the beer, by the Zeeman graphite furnace atomic absorption spectrophotometry (ZGFAAS) method. The results show that in all cases a brand of beer packaged in an Al can has a higher Al content than the same brand bottled in glass. The measurements of the Al concentration in some Al-canned beers throughout 12 months of storage show that a relatively small increase of the Al concentration in beers occurs throughout storage. All these results indicate that some Al is taken up by the beer in Al cans, presumably through the slight and slow dissolution of Al from the can wall, due to some defects in the protective lacquer layer. The evaluated daily intake of Al (0.256 mg) possible through the consumption of beer was practically negligible in relation to both the total daily dietary Al intake and the tolerable daily Al intake. Thus, beers are an insignificant source of dietary Al intake and it appears that the Al intake from beers (due to the low content of Al in beers and its low bioavailability) should not be a cause for concern with regard to Al toxicity for the human body. Received: 22 April 1996     

A RAPID METHOD FOR THE EXTRACTION AND ANAYLSIS OF BEER FLAVOUR COMPONENTS

Dispersal of beer on a commercially available tube of kieselguhr and elution with dichloromethane was found to be a much faster and more efficient method of obtaining a beer flavour extract than liquid-liquid extraction. The constitution of each type of extract was qualitatively similar. The use of an internal standard allowed major flavour components to be quantitatively analysed.     

Confirmation of brand identity in foods by near infrared transflectance spectroscopy using classification and class-modelling chemometric techniques — The example of a Belgian beer

Food and beverage processors require tools to monitor conformance of finished goods to their defined specification; regulatory authorities need appropriate methods for detecting retail fraud. In this report, samples (n = 275) of Belgian and other European beers were collected and analysed using near infrared transflectance spectroscopy; three class-modelling techniques (soft independent modelling of class analogy, SIMCA; potential functions techniques, POTFUN; and unequal dispersed classes, UNEQ) were employed to characterise beer types (firstly Trappist and then Rochefort) while a classification method (partial least squares discriminant analysis, PLS-DA) was applied to discriminate between two final beer classes: Rochefort 8° and Rochefort 10°. The class-models and the classification rules developed were validated by means of an external prediction set. A discussion on the appropriate use of these chemometric approaches is included. Modelling of Trappist beers met with limited success while model efficiencies for Rochefort samples were highest for SIMCA and UNEQ applications i.e. 81.4% and 84.5% respectively. The classification of beers as Rochefort 8? or Rochefort 10? was possible with an average correct classification rate of 93.4%.     

啤酒过滤用化纤预涂介质——HU—D60型预涂介质的研制

目前我国的成品啤酒过滤操作中,板框式硅藻土过滤机得到了较普遍的应用。板框式硅藻土过滤机所采用的预涂介质纸板的使用寿命短,过滤酒损较大、成本较高。为改进此种现状,本研究研制出了HU-D60型预涂介质,并已获国家专利。 HU-D60型预涂介质所采用的是“隔层支撑”的特殊结构,即将带有粘合剂颗粒的多层绦纶材料经加热、加压一次成型所形成的结构。本研究用正文试验方法确定了HU-D60型预涂介质的适宜加工条件。在诸啤酒厂的大量试验表明,HU-D60型预涂介质具有良好的过滤性能。其使用寿命为国产纸板的5.9倍,为进口纸板的4.8倍,其单位面积的累积滤酒量为国产纸板的15.4倍,为进口纸板介质的6.4倍;其过滤酒损比国产纸板的减少0.6％,比进口纸板的减少0.45％;其吨酒耗土量比国产纸板的减少0.58kg,比进口纸板的减少0.43kg。显而易见,推广使用HU-D60型预涂介质的经济效益将是十分可观的。