Premium
Influence of ammonia and lysine supplementation on yeast growth and fermentation with respect to gluten‐free type brewing using unmalted sorghum grain
Author(s) -
Dlamini Bhekisisa C.,
Taylor John R. N.,
Buys Elna M.
Publication year - 2020
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.14373
Subject(s) - brewing , free amino nitrogen , yeast , maltose , fermentation , sorghum , food science , lysine , maltotriose , mashing , chemistry , biochemistry , biology , amino acid , agronomy , sucrose
Summary Because gluten‐free type brewing with unmalted sorghum does not provide adequate nitrogen for complete fermentation, wort supplementation with ammonia (as diammonium phosphate, DAP ) or lysine on yeast performance was investigated. By Phenotype Microarray, under aerobic conditions, greater yeast growth was indicated with DAP than lysine both as a single source and combined with sorghum wort amino acids. With sorghum fermentation, both DAP and lysine improved maltose and maltotriose uptake. However, DAP supplementation also maintained yeast numbers (24.0–21.3 × 10 6 cells mL −1 ), whereas there was a decline with lysine supplementation. Lysine supplementation also resulted in adverse effects on yeast cell morphology. Neither DAP nor lysine supplementation resulted in evident genetic change to the yeast, but the change in substrate from barley malt wort to unmalted sorghum wort slightly altered the yeast genetically. Therefore, ammonia as DAP has potential as a nitrogen supplement for improving yeast fermentation performance in sorghum gluten‐free brewing.