摘要:

Molecular breeding of a highly attenuating brewing yeast was performed using recombinant DNA techniques. A hybrid plasmid YCpGSTAI that carried theSaccharomyces diastaticusglucoamylase geneSTA1was constructed first. TheSTA1gene was found to be expressed in a strain of 5.carlsbergensisand two strains of brewing yeast. Glucoamylase was excreted into the culture medium by transformants harboring theSTA1gene. A trial microfermentation was carried out in flasks with wort, and the resulting young beer was analyzed. Real extract in the beer fermented by brewing yeast transformants harboring theSTA1gene was lower than in that fermented by the host.

ISSN:0361-0470    

DOI:10.1094/ASBCJ-47-0087

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

A Teflon high-pressure vessel and concentrated nitric acid were used to digest solid brewing samples in a conventional microwave oven. After digestion, the sample solutions were analyzed for trace elements by inductively coupled plasma spectrometry. The method validation showed that elements Ca, Cu, Fe, K, Mg, Mn, Na, and Zn could be run successfully by this method. Results on Si were unsatisfactory.

ISSN:0361-0470    

DOI:10.1094/ASBCJ-47-0091

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

A number of samples each of four beer brands produced at six different plants were taken at approximately weekly intervals. The beer aroma compounds were determined by Freon 112 extraction followed by capillary column gas chromatography. The results were examined using a number of multivariate analysis procedures. Some consistent patterns in the results were found that were partly or completely successful in characterizing either the beer brand or the plant of production. SIMCA, discriminant, and Bayesian analyses were particularly effective in deriving successful classification rules. Greater differences were observed between samples of different brands than between samples originating in different plants. It was of interest to note which compounds were important in making the distinctions observed and to consider whether they might result in significant flavor differences.

ISSN:0361-0470    

DOI:10.1094/ASBCJ-47-0093

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

The sources of wort nitrogen that are assimilable by yeast are mainly amino acids, ammonium ion, and to a lesser extent, di- and tripeptides. These substances are partly formed during malting and partly during mashing, due to the action of barley proteases on hordein. The level of wort amino acids varies depending on the barley variety, malting conditions, and mashing parameters, but the overall spectrum of amino acids is similar among worts. Brewing adjuncts dilute nitrogenous substances while increasing the wort fermentable extract. Consequently, high-adjunct worts are nitrogen deficient. Yeast food can be used to increase assimilable nitrogen levels; however, amounts added may be insufficient for full stimulation of fermentation. Wort amino acids are taken up by yeast in a characteristic sequence during fermentation, although environmental changes can alter this pattern. Absolute yeast nitrogen requirements in the literature differ, and such levels have never been ascertained for high gravity or very high gravity fermentations. Because of the preferred preparation methods for these worts, they can be expected to be nitrogen-limited. The role of free amino nitrogen (FAN) in the brewing fermentation is mainly incorporation into new yeast protein; however, nitrogen levels profoundly affect almost every aspect of fermentation performance. Of critical import are the levels of higher alcohols, vicinal diketones, and esters, all of which are intimately related to wort nitrogen profiles. This review covers the factors affecting the wort nitrogen content, the assimilable nitrogen levels and their profile in wort and beer, and the role of usable nitrogen in the fermentation. In addition, the effects of limiting and excess quantities of assimilable nitrogen are reviewed in light of current research findings.

ISSN:0361-0470    

DOI:10.1094/ASBCJ-47-0102

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

The electrophoretic banding patterns of chromosomal DNA from various yeasts were investigated using OFAGE (orthogonal-field-alternation gel electrophoresis). Yeasts belonging toSaccharomyces cerevisiae, including brewer's strains, showed more than 11 chromosomal DNA bands ranging from 250 to 1,000 kb or more. Most strains of the generaKluyveromyces, Schwanniomyces, Schizosaccharomyces, Zygosaccharomyces, andCandidarevealed several bands all larger than 1,000 kb. When cell fusants between a brewer's strain and a killer strain(Saccharomyces cerevisiae)were examined, their banding patterns clearly differed from those of the parents; the mixture of chromosomes derived from the parents was confirmed by Southern hybridization. OFAGE was found to be an effective tool to aid genetic research on a wide range of yeasts and yeast cell fusants.

ISSN:0361-0470    

DOI:10.1094/ASBCJ-47-0109

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0361-0470    

DOI:10.1094/ASBCJ-47-0114

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0361-0470    

DOI:10.1094/ASBCJ-47-0116

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0361-0470    

DOI:10.1094/ASBCJ-47-0117

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0361-0470    

DOI:10.1094/ASBCJ-47-0118

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0361-0470    

DOI:10.1094/ASBCJ-47-0119

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor