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65th ASBC Annual Meeting

Abstracts of Presentations

June 19-23, 1999
The Wigwam Resort , Phoenix, Arizona

Program | Poster Session |   Abstracts of Presentations

The number above an abstract corresponds to its designation in the program of the 1999 ASBC Annual Meeting in Phoenix, Arizona, June 19–23. An "O" preceding the number indicates an oral presentation. A "P" preceding the number indicates a poster presentation. Poster abstracts follow the oral abstracts.

O-1
HACCP - What It is and How It Can Benefit Your Brewery. Jack B. Friers, Miller Brewing Co., 863 E Meadow Rd., Eden, NC, 27288
HACCP (Hazard Analysis Critical Control Point) is a preventative approach to control food safety. It provides a mechanism to eliminate or minimize quality risks. HACCP was developed in the 1960’s to assure zero defects in the food supply for the U.S. astronauts. Its use was expanded to many food supply plants on a voluntary basis during the period of 1970 - 1997. In December 1997, FDA mandated HACCP for the seafood industry, and in January 1998, for meat and poultry plants with 500 or more employees. HACCP is a requirement for breweries selling beer within the European Union but is not currently a U.S. requirement. Benefits of an internal HACCP program from a risk control and quality improvement perspective are discussed. The seven principles of HACCP are reviewed. Identification of critical control 6 points using a multidisciplinary team to review the product and processing risks is the key to an effective HACCP plan. Miller Brewing Company’s HACCP plan was introduced at all brewery locations during the summer of 1998 and have been successfully implemented.

O-2
You Want to Put WHAT in The Bottle? How Science + Marketing = Product Success’. Nicole Derrick, Molson Breweries Center for Innovation, 33 Carlingview Drive, Etobicoke, Ontario, Canada M9W 5E4
In an increasingly competitive market place, breweries can no longer under utilize their scientific resources as data gathering units. The quality control technician, microbiologist and brewer can play a key role in the success of a new or existing product by understanding a product’s life cycle. The four stages are: Development, Growth, Maturity and Decline. The object of this paper is to outline areas where technical information and research can add significant value to each stage of the product life cycle. Data relevance, reporting styles and communication are key in supporting the long and strong life of a beer brand.

O-3
Automated Beer Delivery Systems. Chris Hughes, Larry Bock, Pertti Mutikainen and Dirk Bendiak, Molson Brewery, Centre for Innovation, 33 Carlingview Dr., Etobicoke, Ontario, Canada, M9W 5E4
Various brands of finished beer are stored in bright beer tanks ready for packaging. Brand change over from the bright tanks to the filler can be a very labor intensive operation and encourages opportunities for mistake and increased changeover time. One of the ways to overcome these errors is to fully automate the beer delivery system. In this particular paper we will talk about the interface between two bottling cellars into a single fill line through the use of fiber optics. A systems management approach will be discussed that will ensures brand integrity to meet production profiles. Quality Control is critical when doing brand changes and dilution water flushing. The use of conductivity probes are employed to sense the differences between brands and dilution water. The selection of brands are verified only when Quality control approves the bright beer. This is done through a Human Machine Interface (HMI) which is located in the beer cellars and at the filling station. The system provides the filler operator with the capability to pre-select source tanks for beer supply to the filler. When the system detects that the current source tank is closed to being empty, the operator will be notified. If no intervention is made, the system will automatically select the next pre-determine tank.

O-4
A Comparison of Visual Turbidity with Turbidity Measured by Commercially Available Instruments. Peter W. Gales, Brewing Technical Services, Anheuser-Busch, Inc., #1 Busch Place - Bldg. 36-5, St. Louis, MO 63118 USA.
Beer turbidity is an important consumer acceptance criteria. The brewer is concerned with both fresh turbidity as an indication of filtration quality and with physical stability as a measure of chillproofing effectiveness. Traditionally visual measurements have been used in conjunction with in-line turbidity meter readings to determine filtration quality while physical stability is more commonly measured on punished beer samples using a laboratory turbidity instrument. Laboratory instruments have traditionally utilized side scatter measurements, but recently forward scatter instruments have become more readily available. Visual turbidity standards based on latex spheres suspended in beer colored water were used as a standard of comparison for various laboratory instruments. Instruments were compared for reproducibility, linearity, effect of beer color on turbidity measurements and the effect of bottle type on the reading obtained. The instrument response to various types of turbidity was determined. In addition, ergonomic and practical factors were considered.

O-5
Visual and Instrumental Perceptions of Turbidity. Aurea Carrasco and Karl J. Siebert, Department of Food Science & Technology, Cornell University, Geneva, NY 14456.
There are many anecdotal reports of visual perceptions of haze, but few proper sensory experiments designed to determine the relationships between colloidal particle size and concentration and human and instrumental response have been carried out. Synthetic particle beads of three known narrow size distributions (0.769, 2.60, and 10.30 µm diameter) were obtained and added to clear and colored solutions at many different concentrations. These samples were presented to human panelists and a light scattering instrument. Threshold determinations were carried out with the Ascending Method of Limits and revealed that the turbidimeter response gave a better indication of haze intensity than either particle weight or number concentration. The thresholds ranged from 0.384 to 0.815 NTU. The intensity of suprathreshold turbidity was assessed with Magnitude Estimation and Descriptive Analysis. The instrumentally measured turbidity was successfully modeled as a function of particle size and concentration (R2 = 0.986).

O-6
The Effect of Protein/Polyphenol Ratio on the Size of Haze Particles. Karl J. Siebert and P.Y. Lynn, Department of Food Science & Technology, Cornell University, Geneva, NY 14456.
It was previously shown that the ratio of haze-active (HA) protein to HA polyphenol in a sample influences the intensity of the turbidity. Roughly equal proportions result in more haze than an excess of either protein or polyphenol. A conceptual model to account for this was proposed, in which the size of the particles formed was largest with a nearly equal proportion and particles were smaller with either a high or low ratio of protein to polyphenol. This hypothesis explained many observed behaviors, but it was not tested by particle size measurements. Laser diffraction particle size analysis has now been employed to measure particle size distribution patterns. This revealed a strong influence of protein/polyphenol ratio on the mean size of haze particles, with the largest particle size corresponding to the highest haze intensity. The effect of pH on particle size and haze was also examined. This, too, had a strong influence on particle size, but in this case the maximum haze intensity did not coincide with the largest particles.

O-7
Development of an Assay to Determine the Filterability of Young Beer Prior to the Filtration Process. Hiromichi Aoto, Kinya Kurihara , Kazuhiko Shimada, Fumihiko Yokoyama, Research Laboratory For Production Technology, KIRIN Brewery Co., Ltd., 17-1, Namamugi 1-chome, Tsurumi-ku, Yokohama 230-8628 Japan
Filterability, or the degree of ease with which filtration proceeds, is affected by a number of factors. If filterability is poor, the differential pressure within the filter increases, resulting in a reduction in the flow volume and a delay in the filtration process. In the worst cases, it is necessary to repeat the filtration process. In addition, inadequate filtration of the beer results in reduced stability of the products, which has a major effect on quality. If filterability could be determined prior to actual filtration, it would then be possible to take the appropriate measures to avoid problems during the filtration process. We have developed a simple and extremely rapid (less than 30s) method for determining filterability by analyzing the absorbance of a set wavelength of light by the beer prior to filtration. Here, we describe the development of a device incorporating this method that is also capable of determining whether the cause of reduced filterability is yeast-related or due to a beer component.

O-8
Effect of b -Glucan on the Rheological and Filtration Properties of Beer. Shane Patelakis, R. Alex Speers, Allan Poulson, and Robert J. Stewart* Department of Food Science and Technology, Dalhousie University, P.O. Box 1000, Halifax, NS, Canada B3J 2X4, *Technology Development, Labatt Brewing Company Ltd. P.O. Box 5050, London, ON N6A 4M3
The presence of b -glucan polymers in beer and their rheometric and filtration properties have been of interest to brewers due their effect on filtration rates and haze development in beer. This study reports on the results of rheometric and filtration experiments undertaken in various buffer systems, degassed beer, freeze-dried beer and a model beer system. A Plackett-Burman screening design was employed to examine the importance of 11 distinct factors (ethanol, pH, Ca++, Mg++, Na+, SO4--, Zn++, PO4++, maltose, yeast protein and freeze-dried beer). Only ethanol, pH and maltose significantly altered (p<0.05) the suspension viscosity of a buffer containing 0.5% (w/v) b -glucan. The results of subsequent filtration experiments indicated that the time/filtrate volume vs. time model of Sudarmana et al. (1996. Tech. Quart. 33:63) could be used to linearly transform the filtration data. This research also indicated that both laminar and turbulent shear have substantial effects on the viscosity and filtration of b -glucan dispersions.

O-9
Analysis of Foreign Materials in Packaged Beer. Masato Kawasaki, Shuso Sakuma and Motoo Ohkochi, Brewing Research Laboratories, Kirin Brewery Co., Ltd., 1-17-1 Namamugi, Tsurumi-ku, Yokohama, Kanagawa, 230-8628 Japan
The presence of foreign materials in packaged beer is a major source of consumer complaints. A rapid and reliable method of analysis is necessary to deal with consumer complaints. Some types of foreign materials are too small to identify morphologically. Therefore we have developed methods to identify these kind of foreign materials. Materials found in beer or in the packages were first observed, then a small sample was taken and investigated by staining or FTIR. These methods can be used to determine the major components of the foreign material. If the material contains proteins, lipids or carbohydrates, its composition was determined using SDS-PAGE, GC or LC and compared with that of known samples. These analytical methods can be used to identify foreign materials in the returned samples that consist of plastics, food proteins, plant oils, sea foods or soft drinks.

O-10
Important Roles of Fermentation Process on Beer Foam Stability. Kazuhisa Yasui, Chikako Shimizu, Junji Watari, and Ken Shinotsuka, Brewing Research Laboratories, Sapporo Breweries, Ltd., 10 Okatohme, Yaizu, Shizuoka, 425-0013 Japan
We reported a customer oriented foam stability evaluation system named FCT at ASBC annual meeting in 1997. The FCT value is defined as the time needed to collapse 32mm foam layer to be a single layer. Beer foam is generated in a consumer-use situation using PC controlled pouring apparatus. Beer bottles are kept in a cooling bath at 6° C, then attached to the pouring apparatus set in a room with 20° C constant temperature. We have refined on an automatic FCT measuring system with image analysis equipment designed into the package. We are now studying factors that affect visual foam stability based on the FCT value. Foam stability values of beers from the same wort fermented in different condition or different yeast are not always the same. These results are difficult to explain by the theoretical concept based on foam proteins in the beer or wort. We think one of the factors that causes the difference of foam stability is the difference in fermentation process. Our investigation results focused on the effect of yeast strain and fermentation ability suggest that control of fermentation process is important for the improvement of substantial beer foam stability.

O-11
Barley Biotechnology: State of Art and Intellectual Property Considerations. M.P. Davis, American Malting Barley Association, Inc., 740 N. Plankinton Ave., Milwaukee, WI, 53203; and W.J. Ladish, Ladish Malting Co., N5355 Junction Rd. Jefferson, WI, 53549
The North American Barley Genome Mapping Project (NABGMP) began in 1988, with initial funding from growers and the American Malting Barley Association, Inc. (AMBA). The goals of the NABGMP are construction of a saturated map and identification and location of genes of economic importance. The map also should provide the basis for varietal development by "design," generate new knowledge about barley genome evolution, and establish a molecular-breeding cooperative project that will serve as a model for other crops. Major efforts are underway to utilize gene mapping technology to develop resistance in barley to Fusarium head blight (scab) and stripe rust, and to characterize and improve feed and malting quality. Transformation, the direct insertion of new genes into plants, is new to barley and relatively new to crop plants in general. Genes from any organism, including those that can't be incorporated by traditional breeding, can be inserted into a barley chromosome, expressed by the plant, and passed on to the plant's progeny. Methods of transformation involve: preparing the gene to be inserted, inserting the gene into barley cells, selecting cells that contain the new gene, regenerating plants from the transgenic cells, and finally, testing the plants for the presence, expression, and transmission of the transgene. Patent law is the most important protection against the unauthorized use of biotechnology products or processes. In 1980, the U.S. Supreme Court ruled, in Diamond v. Chakrabarty, that patent protection can be extended to living organisms. This ruling opened the door to a new biotechnology industry and the need to consider intellectual property (IP) matters in barley research. The implications of the use of patent law to protect biotechnology processes that are used in barley research, as well as patented genes have moved to the forefront for AMBA and collaborating barley researchers. Another means of IP protection, Plant Variety Protection, must also be considered.

O-12
Aroma Profiling of Beer by Automated Multidimensional GC Olfactometry. Larry Nielsen, Don Wright and David Eaton, Microanalytics, 2713 Sam Bass Road, Round Rock, TX 78681.
Aroma profiles of beer can be obtained by analyzing their makeup in terms of individual flavor components. An effective way of doing this is to use an automated GC olfactometry system. An integrated GC system is described which has an embedded microprocessor and associated software that automatically runs heartcutting, cryotrapping, backflushing and other instrument functions. Such a system is used to define flavor profiles of beer samples and differences between beer samples. This type of information is used to evaluate product consistency, discovery product off-odors and determine unique flavor characteristics of products. Aroma results from the bench-style fermentation of unhopped wort will serve as an example.

O-13
Taste Sensing System and Its Application to Beer Evaluation. Katsushi Satoa, Rieko Toukuboa, Hidekazu Ikezakiab, Akira Taniguchiab, Kiyoshi Tokob, Shigeki Furushoc. aAnritsu Corporation, 1800 Onna, Atsugi, Kanagawa 243-8555, Japan; bKyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, Fukuoka 812-0053, Japan; cSapporo Breweries LTD., 10 Okatohme, Yaizu, Shizuoka 425-0013, Japan
We have developed a taste sensing system and applied it to the evaluation of beer taste. It consists of a multichannel taste sensor with lipid/polymer membranes. This sensor has the ability to determine the five basic taste qualities of sourness, saltiness, sweetness, bitterness and umami respectively. The present report describes quantification of the bitterness and the deterioration of beer. We found high correlation between outputs of the taste sensor and Bitterness Units (r=0.970) which was almost similar to human sensory tests by using multiple regression analysis. Moreover the taste sensor can distinguish the deterioration of beer by heat. Therefore, it is concluded that this method is useful for evaluation of Bitterness Units and deterioration degree of beer. The taste sensor will be applicable to substitute method for human sensory tests and physicochemical analysis of beer.

O-14
Chemometric Modeling of the Flavor Thresholds of Organic Acids in Beer. Karl J. Siebert, Department of Food Science & Technology, Cornell University, Geneva, NY 14456.
It was recently demonstrated that it is possible to model flavor thresholds of organic acids in beer as a function of their molecular properties. Principal Components Analysis was applied to acid property data. Four Principal Components (PC's), which mainly corresponded to molecular size, number of polar groups, number of double bonds and solubility in non-polar solvents, were obtained. Literature threshold data for acids in beer were modeled as a function of the four PC's, resulting in an R2 of 0.905. The validity of this model was tested by predicting the flavor thresholds of acids used to construct the PC's but not the threshold model. Predictions were also attempted for acids other than those used to construct the PC's.

O-15
Application of Near Infrared Spectroscopy to Analysis of Hops and Hop Products. Scott W. Garden, Tamara Pruneda, Shana Irby, Randy Bryant, Dale Hanks, David Hysert, John I. Haas, Inc., P. O. Box 1441, Yakima, WA 98907
The production of hop products (i.e. baled hops, hop pellets and hop extracts) from raw hops requires that numerous analytical tests be performed throughout the production process to ensure the quality of the finished material. A study was undertaken to determine whether near infrared (NIR) calibrations of suitable analytical performance for in-process analysis purposes could be developed for the measurement of a -acids content, b -acids content and hop storage index in hop products. Samples of hop products used for calibration development were collected over a three-year period. NIR spectra of hop products were collected over a wavelength range of 1100 – 2500 nm. Laboratory analysis of the hop products was performed using ASBC spectrophotometric methodology. The performance of NIR calibrations for in-process prediction a -acids, b -acids and hop storage index in hop products were evaluated by comparing the NIR analysis results with results obtained using traditional laboratory methods of analysis.

O-16
Anaerobic-Aerobic Treatment of Brewery Effluent. Kazuhiko Shimura, Research Laboratory for Production Technology, Kirin Brewery Co., Ltd., 17-1, Namamugi 1-chome, Tsurumi-ku, Yokohama, 230-8628 Japan.
A reduction in the level of aeration required and the ability to recover gas for use as fuel are two of the advantages associated with anaerobic treatment of brewery discharge by methane fermentation. On the other hand, despite the reduction in the overall concentration of organic compounds, the variation in the quality of the treated discharge creates difficulties in the removal of nitrogen and phosphorus in the downstream process. It is necessary to find a means of reducing the nitrogen and phosphorus concentration of the treated water so that the discharge does not cause environmental problems, this is particularly urgent in regions with strict regulations concerning water quality. Previously, we tested a pilot plant which combined methane fermentation with an aerobic microbial fixation system. However, we are at currently investigating measures to improve the standard activated sludge system. We have focused on diverting some of the waste water collected in the brewery discharge holding tank directly to the aerobic treatment tank, thus by-passing the anaerobic treatment tank. In this presentation, we describe the estimated capacity of our brewery water treatment systems to remove nitrogen and phosphorus. We also report the findings of this study.

O-17
Monoclonal Antibodies Specific for Beer Spoilage Ability of Lactic Acid Bacteria. Youichi Tsuchiya, Yasukazu Nakakita, Junji Watari, and Ken Shinotsuka, Brewing research laboratories, Sapporo breweries Ltd., 10 Okatohme, Yaizu, Shizuoka, 425-0013 Japan.
It is known that Lactobacillus brevis, L. lindneri, and Pediococcus damnosus are primary dangerous contaminants for packaged beer, however, all of the strains classified in these species are not able to grow in beer. We aimed to obtain monoclonal antibodies (MAbs) specific for the beer spoilage ability of lactic acid bacteria. Mice were immunized with whole cells of lactic acid bacteria cultured in beer, and then three MAbs named Lb2F37, BG3A5b4, and PQ3H8a9, were obtained. The MAb Lb2F37 showed high reactivity and specificity to almost of all the beer spoilage L. brevis and a few strains of beer spoilage P. damnosus tested here. The MAbs BG3A5b4 showed high reactivity and specificity to all of the beer spoilage L. lindneri and a few strains of beer spoilage L. brevis. The MAbs PQ3H8a9 showed high reactivity to all the beer spoilage P. damnosus and reacted partly with the beer spoilage L. brevis. When the lactic acid bacteria growing in beer were inoculated and cultured several times in the MRS medium, L. brevis became to lose the reactivity with the MAbs, whereas L. lindneri and P. damnosus did not lose the reactivity with the MAbs. Culturing in the modified MRS medium including isohomulone at pH 5.2, or treatment of cells with NaOH improved the reactivity of L. brevis with the MAbs, however, the reactivity did not recover to such a degree of the reactivity of L. brevis growing in beer. It suggested that the fall of reactivity resulted from decreasing of the expression of antigen reacted with the MAbs. Using these MAbs, we also developed a simple, rapid, and sensitive kit for prediction of the beer spoilage ability of lactic acid bacteria.

O-18
A Genetic Analysis of Maltotriose Transport in Brewer's Yeast. Kate L. Willcocks, Wilfrid J. Mitchell and Philip G. Meaden, International Centre For Brewing And Distilling, Heriot Watt University, Riccarton, Edinburgh, EH14 4AS, Scotland, U.K
The efficient uptake of maltotriose is a desirable property of brewing strains of yeast, but there is relatively little information at present on the genetic basis of this property. Only one gene in yeast (Saccharomyces cerevisiae), named AGT1, has been experimentally demonstrated to encode a maltotriose transporter or permease. A recent study showed that one strain of brewer's yeast, out of 30 that were examined, was completely devoid of AGT1 or closely related sequences. We have found that the AGT1-deficient yeast, a lager strain named KVL026, is nevertheless able to ferment maltotriose. This suggests that a maltotriose transporter gene other than AGT1 is being expressed in that yeast. In this work, we report on the expression of AGT1 in both ale and lager strains of brewer's yeast. As expected, AGT1 was abundantly expressed in ale strains. By contrast, expression of AGT1 was found to be very weak in the three lager strains of yeast that were studied, even though these strains are able to ferment maltotriose. This result provides further evidence for the expression of a maltotriose transporter gene other than AGT1, at least in lager strains of yeast. It is likely that the gene originates from the Saccharomyces bayanus parent of lager strains of yeast.

O-19
A Genetic Analysis of Sulfate Transport in Brewer's Yeast. Allan B. James, J. Colin Slaughter and Philip G. Meaden, International Centre for Brewing and Distilling (I.C.B.D.), Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK-Scotland.
Transport of sulfate across the plasma membrane is the first step in the assimilation of sulfate by yeast. The regulation of sulfate uptake has important consequences for beer quality, as both sulfur dioxide (SO2) and hydrogen sulfide (H2S) are by-products of the sulfate assimilation pathway. In the yeast Saccharomyces cerevisiae, two sulfate transporter genes (SUL1 and SUL2) have been identified, cloned and characterized. We have surveyed ale and lager brewing strains of yeast for the presence of these two genes, and investigated their expression under a variety of conditions. Our studies have confirmed the presence of alleles of both SUL1 and SUL2 in all of the brewing strains examined. We have also identified (and partially cloned) a third sulfate transporter gene, related to SUL1 and SUL2, which appears to be present in lager yeasts only. DNA hybridization studies have shown that this gene is likely to have originated from the Saccharomyces bayanus parent of lager yeasts. Expression of the SUL1 and SUL2 genes, in common with other structural genes of the sulfate assimilation pathway, is derepressed when the external concentration of methionine is low (0.25 mM), but repressed at 5 mM methionine. A dramatic increase in the expression of both SUL1 and SUL2 was observed in a medium containing 0.25 mM methionine and 1 mM sulfate. Given the low concentration of methionine found in brewery worts, our results suggest that repression of sulfate transport by methionine is not an important mechanism in the control of SO2 and H2S biosynthesis

O-20
Monoclonal Antibodies Reacting with Surface Antigens of Lactobacillus and Pediococcus Beer Spoilage Bacteria Recognize Three Spatially Distinct Sites on the Bacterial Lipoteichoic Acid. Barry Ziola, Marcie Ulmer, Janice Bueckert and Dawn Giesbrecht. Department of Microbiology and Immunology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK, Canada S7N 5E5
Antibodies able to react with both lactobacilli and pediococci which spoil beer would be useful in assembling rapidly performed immunoassays for detecting these bacteria. Starting with mice successively immunized with beer spoilage lactobacilli and pediococci, we obtained five hybridomas which secrete monoclonal antibodies (Mabs) recognizing surface antigens on a wide range of Gram-positive beer spoilage bacteria. Immunoblot analysis as well as protease treatment of the antigen each Mab recognizes indicated proteins are not involved. All five Mabs reacted strongly with isolated bacterial lipoteichoic acid. Ability of each Mab to inhibit the binding of enzyme-conjugated Mab was determined. This competition analysis revealed that the five Mabs recognize three distinct epitopes on the bacterial lipoteichoic acid.

O-21
Determination of Lightstruck Character in Beer by GC-MS. Susumu Masuda, Kaori Kikuchi, Koichi Harayama, Kazuhisa Sakai and Mitsuo Ikeda, Brewing Research & Development Laboratory, Asahi Breweries Ltd.,1-1-21, Midori, Moriya-machi, Kitasoma-gun, Ibaraki,302-0106,Japan
When beer is exposed to light, "skunky" aroma known as lightstruck character is formed. The character is due in the main to 3-methyl-2-butene-1-thiol (MBT). It reduces largely the commercial value and makes complaint against beer. It has such high flavor activity that it gives out an objectionable smell at very low concentration. Therefore, an analysis of MBT is very important. However, analysis of the lower concentration than the sensory threshold is very difficult because it is extremely low. There are some reports for analysis of MBT by FPD-GC and SCD-GC, but a more sensitive analytical method, which is able to detect less than the sensory threshold, has been desired. We developed a sensitive analytical method, using purge & trap and MSD-GC, which is able to detect 0.2ng/litre MBT in beer less than the sensory threshold. An increase of detective sensitivity has been achieved by the increase of the trap efficiency and the use of MSD-GC. With using this method, we compared the lightstruck character from bottled beer put at the different positions in the plastic case and with or without suncut sheet. The results showed that formation of lightstruck character was affected by the position in the plastic case and the suncut sheet could reduce largely the lightstruck character.

O-22
Identification of Off-Flavor Compounds in Beer. Shuso Sakuma, Hiromi Amano, Motoo Ohkochi. Brewing Research Laboratories, Kirin Brewery Co. Ltd., 1-17-1 Namamugi, Tsurumi-ku, Yokohama, 230-8628 Japan.
When off-flavor is detected in beer, it is important to identify the flavor compound responsible and remove it. When the concentration of the flavor compound is high, abnormal peaks can be detected on a gas chromatogram. When the flavor compound can be determined by tasting, the compound can be analyzed by GC-MS. However, when the concentration of the flavor compound is low and the flavor compound can not be determined by tasting, it is necessary to locate the peak of the flavor compound by GC olfactometry, and identify it by GC-MS. The flavor compounds which adhere to the surface of a can, bottle, or gasket were adsorbed onto a TENAX TA column and injected to a sniffing GC using a thermal desorption cold trap injector. Off-flavor from the inner surface of a can body was extracted with 5% ethanol solution, and then extracted with methylene chloride using a Solid Phase Extraction column and injected to a sniffing GC. Beer contains many volatile compounds, so it is difficult to detect the peak of flavor compounds on the sniffing gas chromatograms. Flavor compounds in beer were extracted with ethyl ether using a SPE column, and analyzed by a multidimensional sniffing GC, and identified by multidimensional GC-MSD. Using these techniques, cosmetics, solvent, and disinfectant flavors adhering to the can, bottle or gasket and musty, phenol, green grass, Welsh onion, and fruity flavor compounds in beer were identified.

O-23
Quantitative Analysis of Sulfur Compounds in Beer by Purge and Trap. Julie Kancler Tekmar-Dorhmann, 7143 East Kemper Road, Cincinnati, OH 45429
The study of volatile organic compounds and particularly sulfur compounds is becoming increasingly important to the beverage industry. Many of the off flavors and odors found in beer are caused by compounds that contain sulfur. The study of sulfur compounds in the beer industry is traditionally done by static headspace; it was thought that the sample foaming necessitated this. Research presented will show that purge and trap can be used for the analysis of volatiles in beer. The research goes onto show that the detection limits are equivalent and in many cases lower than those of static headspace. The accuracy, linearity and precision will also be discussed.

P-1
Yeast ADH1 Disruption : A Way to Promote Carbonyl Compounds Reduction in Alcohol-Free Beer Production. F. Evellin, P. Perpčte and S. Collin, Laboratoire de Brasserie et des Industries Alimentaires, Université Catholique de Louvain, Place Croix du Sud, 2 bte 7 B-1348 Louvain-la-Neuve, Belgium
Alcohol-free beers are usually characterized by worty off-flavors and the lack of the pleasant fruity or ester aroma found in regular beers. Enhancing yeast reduction of 3-methylthiopropionaldehyde, 3-methylbutanal and 2-methylbutanal through cold contact fermentation appears as a good choice to improve the organoleptic quality of alcohol-free beers. By screening various Saccharomyces cerevisiae yeasts for in vitro reductase activity, the haploid adh0 strain emerged as the most efficient yeast for the NADPH-dependent Strecker aldehyde reduction. Tetrad analysis of diploids (adh0 x 15D wild-type) demonstrated the predominant role of adh1 mutation to enhance aldehyde reductase. Consequently to such alcohol dehydrogenase gene disruption, acetaldehyde accumulates although partly oxidized into acetic acid by using the NADP cofactor. We propose that the regeneration of this cofactor in adh1 strains can be improved by promoting the NADPH-dependent aldehyde reductase activity.

P-2
A Novel Detection Method for Yeasts that Cause Premature Yeast Flocculation. Hidetaka Sone1, Osamu Kobayashi1, Takayuki Momma1 and Hiroshi Taguchi 2, 1Central Laboratories for Key Technology, 1-13-5, Fukuura, Kanazawa-ku, Yokohama-shi, Kanagawa 236-0004, and 2Research Laboratory for Brewing, Kirin Brewery Co. Ltd., 1-17-1, Namamugi, Tsurumi-ku, Yokohama-shi, Kanagawa 230-8628 Japan
It has previously been reported that PYF Factor (premature yeast flocculation-inducing factor), which originates in barley, is one cause of premature yeast flocculation during beer fermentation. However, we have found that certain yeasts in our brewing yeast collection have a characteristic that induces these yeasts to undergo premature flocculation. Genetic analysis of these premature flocculation-inducing yeasts was carried out. 1) Chromosome analysis using CHEF indicated that the premature flocculating yeasts are closely related to bottom fermenting yeast. 2) Southern analysis showed that the FLO1 homologue (Pf-FLO1) from the premature flocculation-inducing yeast clearly differs from the FLO1 homologue (Lg-FLO1) present in the bottom fermenting yeasts. 3) Nucleotide sequence analysis of the FLO1 homologue showed that the Pf-FLO1 has a high level of homology with Lg-FLO1. These sequence data enabled us to design primers for use in a PCR assay to detect yeasts with the premature flocculation-inducing characteristic prior to their use in beer brewing.

P-3
The Effect of Environmental Conditions on the Flocculation of Saccharomyces cerevisiae. Yu-lai Jin and R. Alex Speers. Department of Food Science and Technology, Dalhousie University, P. O. Box 1000, Halifax, NS, Canada B3J 2X4
The flocculation behavior of two S. cerevisiae strains expressing either Flo1 or NewFlo phenotype were examined. The behavior of the two strains was examined after varying ethanol (0-10%), pH (3.8-5.8), ionic strength (0.01-0.20M) and temperature (5-25oC). The flocculation behavior of Flo1 cells was insensitive to ethanol and pH change. Flocculation of NewFlo cells significantly increased with increases in ethanol concentration (P<0.05) and pH values (P<0.01). Increasing ionic strengths and decreasing temperatures significantly (P<0.01) retarded flocculation in both strains. The apparent activation energy of flocculation at pH 4 and 108 cells/ml was estimated to be 3.2 and 11.0 Kcal/mol for Flo1 and NewFlo respectively, indicating distinct sensitivities to temperature. Interestingly, flocculation inhibition by urea was overcome by washing with 100 mM acetate buffer (20 oC, pH 4, containing 1 mM Ca++) presumably due to the reversible unfolding of zymolectin molecules. A semi-empirical model was developed that indicated that the flocculation behavior is affected by the cell volume fraction for both Flo1 (R2 = 0.981) and NewFlo (R2 = 0.944) strains. This semi-empirical model allows adjustment of Helms values due to variation in cell volume fraction thus partially explaining reported variations of Helms values with respect to fermentation time.

P-4
The Tensiograph - A Novel Instrument for the Differentiation of Brewing Yeast Strains. A Kennedy (1), W Lancashire(2) and N McMillan(3), (1) Scottish Courage Brewing Ltd, Edinburgh, Scotland, UK, (2) W Lancashire - Brewing Research International, Nutfield, Surrey, UK, (3) N McMillan - Institute of Technology Carlow, Ireland
The tensiograph is a new instrument developed on the principles of the old established stalagmometric technology. The commercially available multianalyser is based on a specially engineered LED system working at the three wavelengths of 660, 770 and 950nm. Light is injected into a drop of liquid as it is formed by the instrument, and the multianalyser plots a trace of the variation of light intensity against time as the drop forms. From this tensiotrace, the physical attributes of the liquid (or material held in suspension) can be deduced. The instrument has previously been shown to offer a number of potential quality control applications in the brewing industry, including its use for the physical measurement of surface tension, density, refractive index, colour and viscosity of the product. In addition, the multianalyser has been used to produce tensiotrace fingerprints of liquids, which can be used to build a database library of products, and Indicator values are used to obtain a forensic test of the identity of two products. Other areas under investigation are in-process quality control checks of various physical parameters of the product, such as turbidity. In this poster, the authors describe the potential use of the tensiograph to differentiate different production strains of brewer's yeast, both ale and lager.

P-5
Comparison of the 16S-23S rDNA Spacer Region Sequences of Strictly Anaerobic, Gram-Negative, Rod-Shaped Bacteria Isolated from Breweries. Yasuo Motoyama and Tomoo Ogata, Brewing Research & Development Laboratory, Asahi Breweries, Ltd., 1-1-21, Midori, Moriya-machi, Kitasoma-gun, Ibaraki, 302-0106, Japan.
The 16S-23S rDNA spacer regions of two Pectinatus species, two Zymophilus species, and one Selenomonas species were cloned after PCR amplification. The results of PCR amplification revealed that these species have two types of spacer regions which differ in molecular size ("long", "short"). The "long" spacer regions in these bacteria contained one or two transfer RNA genes (alanine and/or isoleucine), on the other hand, the "short" spacer regions in these bacteria did not contain any transfer RNA genes. The spacer regions in these bacteria had relatively high level of homology. Homology was particularly high for bacteria belonging to the same genus. Interestingly, the order of the tRNA genes present in the "long" spacer regions of Pectinatus and Selenomonas was the reverse of that which had been reported for other bacteria. The results of homology analysis of the spacer regions and the order of tRNA genes suggests that the taxonomic classification of anaerobic bacteria isolated from the brewing process be re-examined.

P-6
Comparison of High Sensitivity Immunoassay Methods for Quantitative Analysis of Deoxynivalenol (DON) in Malt. Sherman H. Chan, Rahr Malting Co., 800 West First Avenue, Shakopee, MN 55379 USA
Commercially available immunoassays for DON have provided a rapid and cost effective means for screening DON levels in raw grain samples such as barley, wheat and corn. However, these assays have been shown to be unsuitable for screening DON levels in malt, apparently due to the presence of interfering compounds formed during the malting process. Accurate measurements of DON in malt have relied on time consuming and expensive methods such as GC-ECD, GC-MS, HPLC and TLC. Diagnostix, Inc. and R-Biopharm GmbH recently introduced high sensitivity immunoassays for the determination of DON. The suitability of the high sensitivity DON immunoassay for malt analysis comparing to GC-ECD was assessed in the present study. To conduct this study, extracts were prepared from ground malt samples and analyzed by three different methods; GC-ECD, Diagnostix EZ-Quant High Sensitivity DON Plate Kit and R-Biopharm Ridascreen Fast Don.

P-7
A Rapid, Accurate, Semi-quantitative or Quantitative Method for Analysis of the Mycotoxin, Deoxynivalenol (DON). Bruce Malone, Kraig Bond, Craig Humphrey, and Tom Romer, Romer Labs, Inc., Union, MO
A competitive enzyme-labeled immunoassay kit was developed, called the AccuTox™ DON, that is rapid and can be either semiquantitative or quantitative depending upon the user needs. DON is extracted from the ground sample by shaking with water. The aqueous extract is then filtered and the extract is tested in the immunoassay. The sample extract and the enzyme-labeled DON are added to antibody-coated tubes where the toxin from the extract and the labeled toxin compete for a limited number of antibody binding sites. Following incubation (the time differs for semiquantitative and quantitative analysis), the tube contents are removed and the tubes are washed to remove any unbound toxin or labeled toxin. A clear substrate is then added to the tubes and any bound enzyme-toxin conjugate causes the conversion to a blue color. After a 5 minute incubation, the reaction is stopped and the amount of color in each tube is read with an inexpensive fluorometer. DON concentration in the samples is calculated from a calibration curve derived from comparing the color of the calibrations to their concentration. The semiquantitative test takes 10 minutes and the quantitative test takes 20 minutes to complete. The AccuTox™ DON Test Kit has been approved by FGIS of GIPSA and applies to wheat, flour, middlings, barley, malted barley, oats and corn.

P-8
Mash Preparation and Fermentation of Uncooked Corn Grits and Whole Wheat Flour. W.J. Lee, J.R. Yoon and K.J. Park*, Department of Food Science, Kangnung National University, Korea 210-702 and *Liquor Business Group, DooSan Corporation, Yongin, Korea
Corn grits and whole wheat flour were liquefied with the heat stable a -amylase at 65, 80 and 95° C. The degree of liquefaction was quantitatively determined by the iodine affinity method. The highest degree of starch liquefaction was obtained at 80° C. After liquefaction at 80° C for 1 hr, mashes were saccharified with amyloglucosidase at 60° C for 1 hr. Mashes contained 20.0 to 21.5 g of dissolved solids per 100g and 20 mg/L of free amino nitrogen and mashes were fermented with active brewer’s yeast. The fermentation of corn and wheat mashes is accelerated by adding assimiable forms of nitrogen. The various yeast foods at the required level are too costly for routine use in the alcohol production industry. Also, yeast foods may contain substances, which produce undesirable taste in the finished products. Corn and wheat mashes were supplemented with dried brewer’s yeast at 200 mg free amino nitrogen/L and compared favourably with yeast food containing yeast extract and mineral ions in terms of fermentation time and ethanol yield. Corn and wheat mashes prepared by adding 1kg of grains to 3 liter of water produced over 10% v/v ethanol within 4 days of fermentation at 25° C. The use of inactive dried brewer’s yeast may be economically attractive for the industrial production of alcoholic beverages.

P-9
Identification of Molecular Markers Associated with Malt Modification in Barley. M.J. Wentz, R.D. Horsley, and P.B. Schwarz, Departments of Plant Sciences and Cereal Science, North Dakota State University, Fargo, ND 58105
The degree of malt modification (MM) can be estimated using many traits; however, little information is known on the genetics of any of these traits. The objectives of this project are 1) to identify loci possessing alleles influencing MM using molecular mapping techniques and 2) to determine if loci for the different MM traits map to similar chromosomal regions. We malted and evaluated the doubled-haploid population from the cross Steptoe/Morex. The population was grown in the field in 1996 and 1997. Data collected were friability, free amino nitrogen (FAN), fine-coarse extract (FC) difference, wort viscosity, Kolbach Index (KI), and beta-glucan conversion (BGC). Based on 1996 malt data, putative loci controlling MM traits were discovered on all chromosomes. Loci controlling friability were found on four chromosomes; three chromosomes for FAN, KI, and BGC; two chromosomes for viscosity; and one chromosome for FC difference. Loci were found on all chromosomes, except 7, that controlled multiple malt modification traits. For example, friability, FAN, and B-GC all mapped to a similar locus on chromosome 3. Except for one locus, loci controlling friability also controlled other MM traits. Research is continuing on the 1997 malt samples.

P-10
Purification and Partial Characterization of a Serine Protease from Green Malt. Debora Fontanini1 and Berne L. Jones1,2, Department of Agronomy, University of Wisconsin, Madison, WI and 2USDA, ARS, Cereal Crops Research Unit, 501 N. Walnut St., Madison WI 53705, USA.
Germinated barley contains many proteolytic activities. We are isolating and identifying some of these enzymes so that we can better understand the biochemical events that occur during brewing. Using a two-dimensional (2-D) native PAGE system containing incorporated gelatin substrate, we have identified a major serine protease in green malt. It has an optimum pH of 6 and maintains its activity throughout the kilning process. It may, herefore, hydrolyze proteins during brewing. We extracted this enzyme from green malt and subjected it to chromatographic separation, after which the enzyme yielded a single activity spot on 2-D PAGE analysis. It was further purified on an FPLC Mono-Q column. Characterization with class-specific protease inhibitors revealed that the enzyme was a serine class endoprotease. It is the first serine endoprotease that has been purified from germinated cereal seeds. It had an isoelectric point of about 4.7 and, when tested on PAGE with gelatin as substrate, it was active over a wide range of pH values (neutral to basic). The enzyme did not appear to have tryptic or chymotryptic activity, but it readily digested gelatin immobilized in PAGE gels and ß-purothionin in solution at pH 6. From its hydrolytic specificity, it seems unlikely that the enzyme hydrolyzes storage proteins during brewing.

P-11
Characteristics of Proteinases Produced by Fusarium Grown on Cereal Proteins. Anja Pekkarinen1, Marja-Leena Niku-Paavola1 and Berne L. Jones2, 1VTT Biotechnology and Food Research, P.O. Box 1501, FIN-02044 VTT, Finland and 2USDA, ARS, Cereal Crops Research Unit, 501 N. Walnut St., Madison, WI, 53705, USA
Recently, Fusarium fungal infections have seriously lowered the yields and quality of US cereal crops. Contaminating Fusarium species also produce mycotoxins that can render crops inedible for humans and/or animals. They can also decrease the malting quality of infected barley by reducing the seed germinability and seedling vigor. We are studying the proteinases of various Fusarium species to determine whether inactivating the proteinases will render the fungi unable to attack barley. To mimic the production of proteinases by F. graminearum growing on cereals, the fungus was cultured on media that contained either wheat gluten or barley grain. The proteinase activities that were excreted into the culture media by the fungus were measured at pH 2.2, 5.0 and 8.0 and were highest at pH 8.0. To more precisely characterize these proteinases, their pH optima were measured. The F. graminearum proteinases were most active at pH 9.0, but both neutral and alkaline enzymes were present. Studies using class-specific protease inhibitors indicated that both the neutral and alkaline enzymes were serine proteinases.

P-12
Key Steps During Barley Malting Which Influence the Concentration of Flavour Compounds. A. Mackie and J.C. Slaughter, The International Centre for Brewing & Distilling, Dept. of Biological Sciences, Heriot-Watt University, Edinburgh EH14 4AS.
Three important flavour compounds 5-methyl-4-hydroxy-3(2H)-furanone (MHF), 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) and 5(or2)-ethyl-2(or5)-methyl-4-hydroxy-3(2H)-furanone (EMHF) have been identified in various foods, for example bread crust, popcorn, beer, soy sauce, Japanese Miso, strawberry, pineapple, and honey. DMHF and EMHF, both have distinctive sweet/caramel-like flavours and aroma thresholds in water of 160µg/l and 20µg/l respectively, whereas MHF has a meaty/brothy flavour and a much higher threshold of 8.3mg/l. DMHF and MHF, but not EMHF, have been found in barley malts, and the concentrations of DMHF in hot water extracts often exceeded the flavour threshold. The aim of this work was to identify the key steps during malting which influenced the levels of the compounds. Initial laboratory results indicated that alterations in the length of time the grain was germinated and in the kilning parameters employed dramatically altered final levels of both DMHF and MHF. Further investigation into furanone yield during malting will give a clearer understanding of their production and allow control over their concentration in the final product.

P-13
Evaluation of Rapid Physical Stability Tests. Stephen L. McCarthy, Gerald D. Melm, and Alastair T. Pringle, Brewing Technical Services, Anheuser-Busch, Inc. #1 Busch Place - Bldg. 36-5, St. Louis, MO 63118 USA.
Several rapid methods for predicting the physical stability of beer were tested. These included: precipitation with ammonium sulfate, precipitation with PVP, precipitation with tannic acid, and the alcohol chill ("Chapon") test. An in-house version of ASBC method Beer 27-II was also tested. The success of these methods in predicting haze generated after long term storage will be discussed.

P-14
Effect of Beer Filtration on Colloidal Stability. Kenneth A. Berg, PQ Corporation, 280 Cedar Grove Rd., Conshohocken, PA 19428.
The affects of filtration parameters on beer clarity and colloidal stability were examined. The filtration rate, tightness of the precoat, the dose of body feed, and the type of DE in the body feed were varied. A laboratory simulation of a DE precoat using glass fiber depth filters was compared to a DE precoat. In general, beer initial clarity was best with tighter precoats, higher pressure, and lower flow rates. Under constant beer conditions, no affect on clarity was seen by the body feed dose alone. Filter "blinding" can be seen as upward-curved pressure/time curves, and can be prevented with more body feed. Glass fiber "precoats" may be too "loose" to simulate brewery filtrations accurately. Affects of these parameters on colloidal stability (as measured by ammonium sulfate precipitation and temperature forcing) are discussed.

P-15
The Measurement of 3-Methyl-2-Butene-1-Thiol in Beer by Isotopic Dilution GC/MS. David J. Maradyn and Michael J. McGarrity, Research Department, Labatt Brewing Company Limited, 150 Simcoe Street, London, Ontario, Canada, N6A 4M3.
The quantitative analysis of 3-methyl-2-butene-1-thiol in lightstruck beer has historically represented a challenge to the brewing chemist due to its low concentration and flavour threshold (4.4-35 ng/L), its tendency to adsorb onto surfaces, and its chemical reactivity. Methods reported in the literature to date involve purge and trap techniques followed by GC analysis. All suffer from one or more of the following short-comings; they require inordinate quantities of beer, employ hazardous reagents or place extreme demands on the deactivation of the apparatus. We wish to report a simple, rapid, accurate and precise method for measuring 3-methyl-2-butene-1-thiol at sub-threshold levels which overcomes these deficiencies. The method utilizes purge and trap analyte isolation coupled with isotopic dilution GC/MS detection. In analyses that are compromised by error derived from variable losses of analyte via adsorption or decomposition, isotopic dilution is advantageous since these sources of error are negligible as a consequence of the virtually identical chemical properties of the analyte in question and the isotopically labeled standard. Accordingly, a-d2 3-methyl-2-butene-1-thiol was prepared via a facile four step reaction. Indefinite stability of the isotope standard was achieved by storing as a frozen t-butanol solution. The method is as follows: a single bottle of the beer (341 mL), after addition of a-d2 3-methyl-2-butene-1-thiol and sodium dithionite, is purged for 90 minutes with dry helium with the effluent gas being vented through a Tenax trap whereupon the analytes are collected. The analytes are thermally desorbed from the trap under helium and are cryofocused prior to thermal desorption into the GC/MS. 3-Methyl-2-butenethiol and a-d2 3-methyl-2-butene-1-thiol are subsequently detected and quantified by selective ion monitoring.

P-16
Fermentation Conditions Affect the Ability of Acetolactate Decarboxylase to Reduce Fermentation Time. P. Heather Pilkington, Robert J. Stewart, Jadwiga Sobczak, Jeanette Cable, and Stéphane Dupire,* Patrick Haselaars* Technology Development, Labatt Brewing Company Ltd., P.O. Box 5050, London, ON Canada N6A 4M3, *Brewing Technology, Interbrew S.A., Vaartstraat 94, B-3000 Leuven, Belgium.
The enzyme acetolactate decarboxylase (ALDC) can be used to reduce fermentation and/or maturation time by its ability to convert acetolactate into acetoin. The ability of this enzyme to reduce fermentation time under different conditions was examined in this study. When fermentation temperature was 12.5° C for the first 8 days and lowered to 7° C for the remainder of fermentation, ALDC reduced the time for diacetyl to reach its target by 60 hours, with the peak diacetyl concentration dropping from 500 ppb to 200 ppb. Under isothermal conditions at 16° C, ALDC reduced the concentration of diacetyl early in fermentation with the peak value significantly lower than the control. However, the final levels of diacetyl (>120 hr) were not significantly changed and no time was saved. These results point to the key role that fermentation temperature plays when using ALDC for diacetyl reduction. When yeast from a batch fermentation with ALDC was repitched into fresh wort, the enzymatic activity of ALDC was not carried over with the yeast. Thus the enzyme must be reintroduced in successive batch fermentations. ALDC halved diacetyl levels during continuous fermentation, when fed into the fermenter with the wort. Finally, titration of ALDC in batch fermentations at 16° C revealed that diacetyl was maximally reduced at 24 hours with 1400 Units/L added, thus reducing the impact of the enzyme on cost.

P-17
Detection of Viable Lactobacilla in Beer Within 70 Minutes. Frank Nitzshe, König Brauerei GmbH & Co KG, Abt. BRAUQS, Friedrich Ebert Str. 255 - 263, 47139 Duisburg, Germany
The authors developed a method to detect viable lactic acid bacteria in beer within a complete analysis time of 70 minutes. The principle of the method depends on a fluorescent assay. After sampling the sample is added with three different substances. This three substances are added within one hour to the sample. During this time the sample is kept at a certain temperature. After the mentioned time the sample has to be filtered and the membrane has to be checked by using fluorescence microscopy. Viable lactic acid bacteria will give a blue light. The poster will show how to work with this method. The comparison to well known detection methods will be discussed.

P-18
Process Improvement Through the Utilization of a Standardized Process Management System. Louis F. Gentz, Anheuser Busch Quality Assurance, 2885 Belgium Road, Baldwinsville, New York 13027
With the increased use of Natural Work Teams for process improvement, a need has developed for a system to direct and monitor team progress. This standardized process management system includes: Identification of customer needs, linkage of customer needs to strategic objectives, development and utilization of Standard Operating Procedures (SOP’s), a communication process, and a statistically based evaluation system. This presentation will detail an Instrument Management System as applied by laboratory Natural Work Teams. However, this system also applies to any process or production related applications.

P-19
Identification of Molecular Markers Associated with Malt Modification in Barley. M.J. Wentz, R.D. Horsley, and P.B. Schwarz, Departments of Plant Sciences and Cereal Science, North Dakota State University, Fargo, ND 58105
The degree of malt modification (MM) can be estimated using many traits; however, little information is known on the genetics of any of these traits. The objectives of this project are 1) to identify loci possessing alleles influencing MM using molecular mapping techniques and 2) to determine if loci for the different MM traits map to similar chromosomal regions. We malted and evaluated the doubled-haploid population from the cross Steptoe/Morex. The population was grown in the field in 1996 and 1997. Data collected were friability, free amino nitrogen (FAN), fine-coarse extract (FC) difference, wort viscosity, Kolbach Index (KI), and beta-glucan conversion (BGC). Based on 1996 malt data, putative loci controlling MM traits were discovered on all chromosomes. Loci controlling friability were found on four chromosomes; three chromosomes for FAN, KI, and BGC; two chromosomes for viscosity; and one chromosome for FC difference. Loci were found on all chromosomes, except 7, that controlled multiple malt modification traits. For example, friability, FAN, and B-GC all mapped to a similar locus on chromosome 3. Except for one locus, loci controlling friability also controlled other MM traits. Research is continuing on the 1997 malt samples.

P-20
Practical Application of Bioluminescence for Assessing Cleaning. Laurence Franken, and Alastair T. Pringle, Brewing Technical Services, Anheuser-Busch, Inc. #1 Busch Place - Bldg. 156-2, St. Louis, MO 63118 USA.
Bioluminescence is an alternative method to microbiological plate counting for assessing cleanliness. Bioluminescence has an advantage over plate counting in that it provides results in minutes versus several days. We used bioluminescence to assess the effectiveness of cleaning in several brewing areas. The areas we will discuss include brewery tanks, kegs, draft beer lines, and packaging conveyers.

P-21
Developments in using off-line radio frequency impedance methods for measuring the viable cell concentration in the brewery. G. Austin 1 and J.P. Carvell 2, 1 Labatt Brewing Co, 150 Simcoe Street, London, Ontario N6A 4M3, Canada; 2 Aber Instruments Ltd, 5 Science Park, Aberystwyth SY23 3AH, Wales, U.K.
Radio-frequency impedance measurement off-line using the Aber Instruments Lab Yeast Analyser 800 is now widely used to determine the viable yeast cell concentration in the recovered slurry prior to pitching into the fermenter. The method relies on detecting the capacitance of the yeast cell membranes, and gives a very rapid response The impedance measurement technique does not require any dilution of the slurry or the addition of dyes. In this poster new data is presented on the accuracy and reproducibility of the measurement of the viable cell concentration of pitching slurries using Capacitance compared to the traditional centrifugation method with correction for viability with Methylene Blue. The data is compiled from a recent study by Brewing Research International (UK) and the analysis of a range of yeast strains collected from two of the Labatts breweries in Canada. The use of the instrument off-line to monitor cell growth during fermentation is also reported for the first time and data from the Lab Yeast Analyser is compared to haemocytometer and Coulter Counter readings. A good correlation was found between the capacitance and haemocytometer techniques for most fermentations but as the Lab Yeast Analyser measures the total viable biovolume of the yeast cells, any cell size change during fermentation can produce a quite distinct but different profile for the viable cell fraction.

P-22
The Application of Surface Plasmon Resonance Biosensor Technology for Measurement of Specific Proteins in Beer and Wort. Peter Rogers and Enrico L Filonzi, BrewTech - Carlton and United, 1 Bouverie St Carlton 3053; Biacore Australia, 32 Wadhurst Drive, Boronia, 3155, Australia
The use of sophisticated analytical technologies to monitor process and beer quality is well established in the brewing industry. These technologies nevertheless are seldom on line or even at line and often not measurements that can be applied in real time. Predictive indicators of performance in the plant are more likely to be high level measurements - pH, gravity, turbidity and oxygen, for example. The development of sophisticated on-line or at-line technlogies can provide the opportunity to develop more responsive and process - intelligent control of the brewing process, which may offer significant economies to large breweries producing a variety of products. We have investigated the use of an optical biosensor technology which employs surface plasmon resonance, developed by Biacore AB Uppsala Sweden, to measure a foam stabilising protein, as part of a broader study into the development of procedures for obtaining real time data for process management. A foam stabilising protein known as Z7 was purified from wort prepared from Sloop, an Australian malting barley. A polyclonal antibody was raised against the Z7 protein and immobilised to a carboxymethyldextran CM5 sensor chip and the binding of purified Z7 Barley protein monitored. It was found that (a) non specific binding of Z7 to the dextran surface was not significant; (b) binding of Z7 to the immobilised pAb produced a linear response from the instrument over the range from 5 ng/ml to beyond 50 ug / ml; (c) after Z7 bound to the pAb, the surface was regenerated very rapidly with phosphoric acid; (d) the binding response was almost totally repressed when Z7 was incubated with the pAb prior to injection to the sensor; (e) sensitivity may be increased by extending the injection time; (f) comparable data can be obtained using monoclonals in place of polyclonal antibodies. Studies were also conducted on beer and collapsed beer foam. In all cases nonspecific binding was minimal and the Z7 estimates were comparable to measurements using other techniques. The sensitivity of this method lends itself to on line analysis of beer and wort. Further application of the technology for the analysis of vitamins, beer proteins and polyphenols is being developed.

© Copyright 1999 by the American Society of  Brewing Chemists. All rights reserved.