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Enzymes: Difference between revisions
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** '''Aminopeptidases''' (optimal 45°C, pH 7.0–7.2) degrade proteins & peptides into free amino acids.<ref name=esslinger/><ref name=kunzemashing/> Inactive during mashing. | ** '''Aminopeptidases''' (optimal 45°C, pH 7.0–7.2) degrade proteins & peptides into free amino acids.<ref name=esslinger/><ref name=kunzemashing/> Inactive during mashing. | ||
** '''Dipeptidase''' (optimal 45°C, pH 8.8) degrades dipeptides into free amino acids.<ref name=esslinger/><ref name=kunzemashing/> Inactive during mashing. | ** '''Dipeptidase''' (optimal 45°C, pH 8.8) degrades dipeptides into free amino acids.<ref name=esslinger/><ref name=kunzemashing/> Inactive during mashing. | ||
** '''Thiol oxidase''' (optimal pH 8.0) catalyzes oxidation of thiols. Very active during mashing.<ref name= | ** '''Thiol oxidase''' (optimal pH 8.0) catalyzes oxidation of thiols. Very active during mashing.<ref name=kanbam2>Kanauchi M, Bamforth CW. [https://www.themodernbrewhouse.com/wp-content/uploads/2019/02/BrewingScience_bamforth_82-84.pdf A Challenge in the study of flavour instability.] ''BrewingScience - Monatsschrift Brauwiss.'' 2018;71(Sept/Oct):82–84.</ref> | ||
* Beta-glucan liberation and degradation (see [[Beta-glucans and arabinoxylans]]) | * Beta-glucan liberation and degradation (see [[Beta-glucans and arabinoxylans]]) | ||
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** '''Catalase''' catalyses the conversion of peroxides to water and ground state (unreactive) oxygen, however it is rapidly destroyed during mashing at 149°F (65°C) and therefore it is largely irrelevant in the brewhouse.<ref name=etokakpan/> inactivated rapidly during mashing at 65°C.<ref name=poyri>Pöyri S, Mikola M, Sontag-Strohm T, Kaukovirta-Norja A, Home S. [https://onlinelibrary.wiley.com/doi/pdf/10.1002/j.2050-0416.2002.tb00550.x The formation and hydrolysis of barley malt gel-protein under different mashing conditions.] ''J Inst Brew.'' 2002;108(2):261–267.</ref> catalase - inactivated rapidly during mashing at 65°C.<ref name=poyri/> Catalase is denatured during mashing at 65C.<ref name=clalar/> 2H<sub>2</sub>O<sub>2</sub> --> 2 H<sub>2</sub>O + O<sub>2</sub> | ** '''Catalase''' catalyses the conversion of peroxides to water and ground state (unreactive) oxygen, however it is rapidly destroyed during mashing at 149°F (65°C) and therefore it is largely irrelevant in the brewhouse.<ref name=etokakpan/> inactivated rapidly during mashing at 65°C.<ref name=poyri>Pöyri S, Mikola M, Sontag-Strohm T, Kaukovirta-Norja A, Home S. [https://onlinelibrary.wiley.com/doi/pdf/10.1002/j.2050-0416.2002.tb00550.x The formation and hydrolysis of barley malt gel-protein under different mashing conditions.] ''J Inst Brew.'' 2002;108(2):261–267.</ref> catalase - inactivated rapidly during mashing at 65°C.<ref name=poyri/> Catalase is denatured during mashing at 65C.<ref name=clalar/> 2H<sub>2</sub>O<sub>2</sub> --> 2 H<sub>2</sub>O + O<sub>2</sub> | ||
** '''Superoxide dismutase''' catalyses the formation of peroxides from superoxides which in the absence of catalase leads to the formation of the hydroxyl radical.<ref name=etokakpan>EtokAkpan OU. [https://link.springer.com/article/10.1023/B:WIBI.0000043169.65135.b4 Preliminary study of fat oxidation in sorghum and maize brewing.] ''World J Microbiol Biotechnol.'' 2004;20:569–573.</ref> inactivated rapidly during mashing at 65°C.<ref name=poyri/> superoxide dismutase - inactivated rapidly during mashing at 65°C.<ref name=poyri/> SOD is destroyed within 15 minutes of mashing at 65C.<ref name=clalar/> 2O<sub>2</sub><sup>-</sup> + 2H<sup>+</sup> --> O<sub>2</sub> + H<sub>2</sub>O<sub>2</sub> | ** '''Superoxide dismutase''' catalyses the formation of peroxides from superoxides which in the absence of catalase leads to the formation of the hydroxyl radical.<ref name=etokakpan>EtokAkpan OU. [https://link.springer.com/article/10.1023/B:WIBI.0000043169.65135.b4 Preliminary study of fat oxidation in sorghum and maize brewing.] ''World J Microbiol Biotechnol.'' 2004;20:569–573.</ref> inactivated rapidly during mashing at 65°C.<ref name=poyri/> superoxide dismutase - inactivated rapidly during mashing at 65°C.<ref name=poyri/> SOD is destroyed within 15 minutes of mashing at 65C.<ref name=clalar/> 2O<sub>2</sub><sup>-</sup> + 2H<sup>+</sup> --> O<sub>2</sub> + H<sub>2</sub>O<sub>2</sub> | ||
** '''Oxalate oxidase''' Active during mashing<ref name= | ** '''Oxalate oxidase''' Active during mashing<ref name=kanbam2/> | ||
** '''Ascorbate oxidase''' | ** '''Ascorbate (per)oxidase''' - catalyzes the oxidation of [[ascorbic acid]] by hydrogen peroxide.<ref name=kanoxi>Kanauchi M. [https://www.intechopen.com/chapters/56077 Oxidative enzyme effects in malt for brewing.] In: Kanauchi M, ed. ''Brewing Technology.'' IntechOpen. 2017:29–47.</ref> Highly active during mashing.<ref name=kanbam2/> | ||
===Fermentation=== | ===Fermentation=== | ||