Fermentation profile of Saccharomyces cerevisiae and Candida tropicalis as starter cultures on barley malt medium
Wazé Aimée Mireille Alloue-Boraud, Kouadio Florent N’Guessan, N’Dédé Théodore Djeni, Serge Hiligsmann, Koffi Marcellin Djè, Franck Delvigne
J Food Sci Technol. 2015 Aug; 52(8): 5236–5242. Published online 2014 Aug 31. doi: 10.1007/s13197-014-1526-0
Investigation of Barley, Malt and Beer for Vitamins B and C
Arthur Harden, Sylvester Solomon Zilva
Biochem J. 1924; 18(5): 1129–1132. doi: 10.1042/bj0181129

The Microbiology of Malting and Brewing
Nicholas A. Bokulich, Charles W. Bamforth
Microbiol Mol Biol Rev. 2013 Jun; 77(2): 157–172. doi: 10.1128/MMBR.00060-12

Analysis of β-glucan molar mass from barley malt and brewer's spent grain with asymmetric flow field-flow fractionation (AF4) and their association to proteins.
Zielke C, Teixeira C, Ding H, Cui S, Nyman M, Nilsson L.
Carbohydr Polym. 2017 Feb 10;157:541-549. doi: 10.1016/j.carbpol.2016.10.045.

Barley malt increases hindgut and portal butyric acid, modulates gene expression of gut tight junction proteins and Toll-like receptors in rats fed high-fat diets, but high advanced glycation end-products partially attenuate the effects.
Zhong Y, Teixeira C, Marungruang N, Sae-Lim W, Tareke E, Andersson R, Fåk F, Nyman M.
Food Funct. 2015 Sep;6(9):3165-76. doi: 10.1039/c5fo00150a.

Genetic Diversity of Individual Phenolic Acids in Barley and Their Correlation with Barley Malt Quality.
Cai S, Han Z, Huang Y, Chen ZH, Zhang G, Dai F.
J Agric Food Chem. 2015 Aug 12;63(31):7051-7. doi: 10.1021/acs.jafc.5b02960.

Further insights into the role of melanoidins on the antioxidant potential of barley malt.
Carvalho DO, Correia E, Lopes L, Guido LF.
Food Chem. 2014 Oct 1;160:127-33. doi: 10.1016/j.foodchem.2014.03.074.

Comparison of beer quality attributes between beers brewed with 100% barley malt and 100% barley raw material.
Steiner E, Auer A, Becker T, Gastl M.
J Sci Food Agric. 2012 Mar 15;92(4):803-13. doi: 10.1002/jsfa.4651.

Barley malt is traditionally used in the brewing industry and it is the product of the germination of barley. During germination, the non-starch polysaccharides (NSPs) in the cell wall of barley, constituting mainly arabinoxylans and β-glucans, are solubilised and partly degraded into smaller molecules (1).

Health

 Barley and germinated barley contain large quantities of glutamine (2) an important substrate for colonic mucosa. Glutamine is easily degraded by the low pH in the stomach, but some of the glutamine is protected by the dietary fibre during digestion in the stomach (3) and therefore reaches the colon. In this study, starting from the premise that Butyric acid, one of the key products formed when β-glucans are degraded by the microbiota in the colon, has been proposed to be important for colonic health. Glutamine bound to the fibre may have similar effects once it has been liberated from the fibre in the colon. Both β-glucans and glutamine are found in high amounts in malted barley. Lactobacillus rhamnosus together with malt has been shown to increase the formation of butyric acid further in rats (4).

Sugars

 The malted grain contains a significantly higher amount of reducing sugars in comparison with the unmalted grain (p < 0.05). The percentage of reducing sugars in total sugars in barley grain of the Karakan variety and in barley malt were 10% and 25%, respectively (5).

Chemical composition

Phenolic acids have been extensively studied in food science research for their antioxidant effect. In this study (6), the genotype difference and the genetic control of phenolic acids and their correlation with malt quality have been studied. Ferulic acid (FA) and p-cumaric acid (p-CA) have been identified as two major phenolic acids, showing wide variations between the 68 barley genotypes. The mean content of FA and p-CA was 2.15 μg g (-1) and 1.10 μg g (-1) in the granules and 4.07 μg g (-1) and 1.44 μg g -1) respectively in barley malt (6).

Mashes

The barley malt is started towards an industrial fermentation process called "mashes". Temperatures range from 50° to 70°.

Barley malt studies

 References_________________________________________________________

(1) Jamar C, Jardin Pd, Fauconnier M. Cell wall polysaccharides hydrolysis of malting barley (Hordeum vulgare L.): a review. Biotechnol Agron Soc Environ. 2011;15:301–13

(2)  Robertson JA, I'Anson KJA, Treimo J, Faulds CB, Brocklehurst TF, Eijsink VGH, et al. Profiling brewers’ spent grain for composition and microbial ecology at the site of production. LWT Food Sci Technol. 2010;43:890–6

(3) Protein, and dietary fiber-rich new foodstuff from brewer's spent grain increased excretion of feces and jejunum mucosal protein content in rats.  Kanauchi O, Agata K  Biosci Biotechnol Biochem. 1997 Jan; 61(1):29-33.

(4) Prebiotic and synbiotic effects on rats fed malted barley with selected bacteria strains.  Zhong Y, Nyman M.  Food Nutr Res. 2014 Oct 6;58. doi: 10.3402/fnr.v58.24848.

(5) The Effect of Different Starch Liberation and Saccharification Methods on the Microbial Contaminations of Distillery Mashes, Fermentation Efficiency, and Spirits Quality.  Pielech-Przybylska K, Balcerek M, Nowak A, Wojtczak M, Czyżowska A, Dziekońska-Kubczak U, Patelski P.  Molecules. 2017 Sep 30;22(10). pii: E1647. doi: 10.3390/molecules22101647.

(6) Genetic Diversity of Individual Phenolic Acids in Barley and Their Correlation with Barley Malt Quality.  Cai S, Han Z, Huang Y, Chen ZH, Zhang G, Dai F.  J Agric Food Chem. 2015 Aug 12;63(31):7051-7. doi: 10.1021/acs.jafc.5b02960.