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Addition of oxidizing or reducing agents to the reaction medium influences amino acid conversion to aroma compounds by Lactococcus lactis
Author(s) -
Kieronczyk A.,
Cachon R.,
Feron G.,
Yvon M.
Publication year - 2006
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2006.02999.x
Subject(s) - aroma , lactococcus lactis , chemistry , food science , transamination , oxidizing agent , amino acid , ripening , biochemistry , organic chemistry , bacteria , lactic acid , biology , genetics
Aims: The aim of this research was to investigate the impact of extracellular redox potential ( E h ) on amino acid conversion to aroma compounds by Lactococcus lactis that is commonly used as a starter in the cheese industry. Methods and Results: The study was realized in vitro by incubating resting cells of L. lactis in reaction media in which E h was modified by the addition of oxidizing or reducing agents. Oxidative condition (+300 mV) favoured the production of aldehydes and volatile sulfur compounds responsible for malty, floral, fruity, almond and cabbage aroma. This production was mainly the result of a chemical oxidation of the α ‐keto acids produced by amino acid transamination. In contrast, reducing condition (−200 mV) stimulated the production of carboxylic acids such as phenylacetic, methylthiopropionic and isovaleric acids, which contribute to the very‐ripened‐cheese aroma as well as the production of hydroxy acids. Conclusions: Eh of the medium highly influences the nature of aroma compounds produced from amino acid catabolism by the resting cells of L. lactis . Significance and Impact of the Study: Eh is a parameter that is not controlled during cheese production. Its control throughout cheese making and ripening could permit control of aroma formation in cheese.