Characterization of Unmalted Barley Treated with Aspergillus oryzae

Abstract Koji is a complex of substrate and the filamentous fungus Aspergillus oryzae. It is used for saccharification in fermented foods and beverages. Its role in co-fermentations is known, but its application in beer brewing contexts is unclear. The goal of this study was to determine what effect A. oryzae has on the characteristics of unmalted barley in brewing contexts, if it might bypass traditional malting, and what sensory attributes a koji beer might exhibit. Koji barley was prepared with pearled barley and a red rice koji strain and compared to untreated pearled barley and malted barley control groups. The total production time of koji barley was nine days and the process consumed 4 ± 2 L water per kg of grain. Coarse grind extract in koji barley was three times greater than pearled barley while approximately ten percent less than malted barley. Diastatic power was over three times greater in malted barley versus koji barley, while no significant difference (p < 0.05) was found between koji barley and untreated pearled barley. Koji barley congress wort exhibited three times more glucose but less than half the maltose content of malted barley wort. Analysis of wort organic acids showed increased concentrations of citric, succinic, and kojic acid in koji barley versus pearled barley. Qualitative sensory analysis of fermented koji barley wort identified moderate tropical, citrus, and sour flavors as well as green apple and tropical fruit aromas. The results demonstrated that koji barley shows characteristics similar to specialty malts and may favor hazy, fruited, and sour beer styles.

[1]  M. Goto,et al.  Citrate exporter enhances both extracellular and intracellular citric acid accumulation in the koji fungi Aspergillus luchuensis mut. kawachii and Aspergillus oryzae. , 2020, Journal of bioscience and bioengineering.

[2]  Simon J. McQueen-Mason,et al.  In silico evolution of Aspergillus niger organic acid production suggests strategies for switching acid output , 2020, Biotechnology for Biofuels.

[3]  P. Punt,et al.  Disruption of a putative mitochondrial oxaloacetate shuttle protein in Aspergillus carbonarius results in secretion of malic acid at the expense of citric acid production , 2019, BMC Biotechnology.

[4]  S. Saran,et al.  Consistent production of kojic acid from Aspergillus sojae SSC-3 isolated from rice husk , 2019, Molecular Biology Reports.

[5]  G. Stewart,et al.  Free Amino Nitrogen in Brewing , 2019, Fermentation.

[6]  M. Islam.  EVALUATION OF ORGANIC ACID PRODUCTION POTENTIAL OF PHOSPHATE SOLUBILIZING FUNGI ISOLATED FROM SOILS IN OKINAWA, JAPAN , 2019, Applied Ecology and Environmental Research.

[7]  Gregory H. Miller.  Malting , 2019, Whisky Science.

[8]  F. D. Montanuci,et al.  Effect of steeping time and temperature on malting process , 2017 .

[9]  Yoshifumi Oguro,et al.  Metabolite profile of koji amazake and its lactic acid fermentation product by Lactobacillus sakei UONUMA. , 2017, Journal of bioscience and bioengineering.

[10]  S. Serna-Saldívar,et al.  Malting Sorghum with Aspergillus Oryzae Enhances Gluten-Free Wort Yield and Extract , 2017 .

[11]  R. Guiné,et al.  Engineering Aspects of Cereal and Cereal-Based Products , 2016 .

[12]  F. Methner,et al.  An accelerated malting procedure – influences on malt quality and cost savings by reduced energy consumption and malting losses , 2015 .

[13]  K. Kitamoto.  Cell biology of the Koji mold Aspergillus oryzae , 2015, Bioscience, biotechnology, and biochemistry.

[14]  R. D. Phillips,et al.  Changes in selected physical property and enzyme activity of rice and barley koji during fermentation and storage. , 2012, Journal of food science.

[15]  G. Bennett,et al.  Succinate production in Escherichia coli , 2012, Biotechnology journal.

[16]  Toshikazu Sugimoto,et al.  Indigestible dextrin is an excellent inducer for α-amylase, α-glucosidase and glucoamylase production in a submerged culture of Aspergillus oryzae , 2011, Biotechnology Letters.

[17]  Toshikazu Sugimoto,et al.  Analysis of Enzyme Production by Submerged Culture of Aspergillus oryzae Using Whole Barley , 2009, Bioscience, biotechnology, and biochemistry.

[18]  Masayuki Machida,et al.  Genomics of Aspergillus oryzae: Learning from the History of Koji Mold and Exploration of Its Future , 2008, DNA research : an international journal for rapid publication of reports on genes and genomes.

[19]  M. Fick,et al.  Quantification of the inhibitory effect of steep effluents on barley germination , 2008 .

[20]  G. Steinberg,et al.  Hyphal Growth: a Tale of Motors, Lipids, and the Spitzenkörper , 2007, Eukaryotic Cell.

[21]  Jian Lu,et al.  Effects of arabinoxylan solubilization on wort viscosity and filtration when mashing with grist containing wheat and wheat malt , 2006 .

[22]  Aleksandra Virag,et al.  The Spitzenkörper: a molecular perspective. , 2006, Mycological research.

[23]  A. Iwami,et al.  Effect of the Variety of Barley and Pearling Rate on the Quality of Shochu Koji , 2005 .

[24]  Chris Boulton,et al.  Brewing: Science and Practice , 2004 .

[25]  R. Speers,et al.  Effects of β‐Glucan, Shearing and Environmental Factors on the Turbidity of Wort and Beer , 2003 .

[26]  P. Schwarz,et al.  Effect of Arabinoxylans, β-Glucans, and Dextrins on the Viscosity and Membrane Filterability of a Beer Model Solution , 2002 .

[27]  S. Mikami,et al.  Properties of cellulose-degrading enzymes from Aspergillus oryzae and their contribution to material utilization and alcohol yield in sake mash fermentation. , 2002, Journal of bioscience and bioengineering.

[28]  L. A. Underkofler,et al.  Saccharification of Starchy Grain Mashes for the Alcoholic Fermentation Industrv , 2002 .

[29]  Kiyoshi Matsumoto,et al.  Flow-injection fluorometric quantification of succinate in foodstuffs based on the use of an immobilized enzyme reactor , 2000 .

[30]  K. Sakka,et al.  Molecular Cloning, Overexpression, and Purification of a Major Xylanase from Aspergillus oryzae , 2000, Bioscience, biotechnology, and biochemistry.

[31]  K. Siebert.  Modeling the flavor thresholds of organic acids in beer as a function of their molecular properties , 1999 .

[32]  J. Visser,et al.  Carbon repression in Aspergilli. , 1997, FEMS microbiology letters.

[33]  T. Kimura,et al.  Molecular cloning, purification and characterization of two endo-1,4-β-glucanases from Aspergillus oryzae KBN616 , 1996, Applied Microbiology and Biotechnology.

[34]  R. Henry,et al.  Genetic and environmental variation in the diastatic power of australian barley , 1995 .

[35]  M. Marshall,et al.  Inhibition mechanism of kojic acid on polyphenol oxidase , 1991 .

[36]  R. M. Camañas,et al.  Determination of the protein and free amino acid content in a sample using o-phthalaldehyde and N-acetyl-L-cysteine , 1990 .

[37]  A. Qureshi,et al.  Quantitation of potential flavoring compounds in worts and beers by HPLC , 1979 .

[38]  G. Sommer.  Reduced Effluent Steeping in the Malting Process1 , 1977 .

[39]  B. Kirsop,et al.  A HAZE CONSISTING LARGELY OF PENTOSAN , 1976 .

[40]  S. Engan.  ORGANOLEPTIC THRESHOLD VALUES OF SOME ORGANIC ACIDS IN BEER , 1974 .

[41]  S. Das,et al.  Production of Amylase in Liquid Culture by a Strain of Aspergillus oryzae , 1970 .

[42]  S. Das,et al.  Production of amylase in liquid culture by a strain of Aspergillus oryzae. , 1970, Applied microbiology.

[43]  A. H. Cook,et al.  CHEMICAL ASPECTS OF MALTING: II. METHOD FOR ASSAYING THE GERMINATION‐INHIBITORY ACTIVITY OF BARLEY STEEPING LIQUORS , 1952 .

[44]  Stephen Laufer,et al.  American Society of Brewing Chemists , 1944 .

[45]  Amber 'i.E,et al.  Brewing , 1940, Nature.

[46]  Ellis I. Fulmer,et al.  Saccharification of Starchy Grain Mashes for the Alcoholic Fermentation ?Industry , 1939 .

[47]  Jokichi Takamine,et al.  Enzymes of Aspergillus Oryzae and the Application of Its Amyloclastic Enzyme to the Fermentation Industry. , 1914 .