Conversion of methionine to methional by Lactococcus lactis

Amárita, Félix

doi:10.1016/s0378-1097(01)00402-5

Cited by 33 publications

(31 citation statements)

References 16 publications

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“…In the present study, 3-(methylthio) propanal (methional), the Strecker aldehyde of methionine, has been detected in most of the miso samples. The production of methional was reported as a process mediated by amino transferase and aketo acid decarboxylase activities (Amarita, Fernandez-Espla, Requena, & Pelaez, 2001). Methional with lower threshold perception (0.45 lg/L in water) imparts meaty and cooked potato aroma to the finished products and could be considered one of the odour active constituent of the different miso samples.…”

Section: Resultsmentioning

confidence: 99%

Identification and characterisation of headspace volatiles of fish miso, a Japanese fish meat based fermented paste, with special emphasis on effect of fish species and meat washing

2010

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Section: Resultsmentioning

confidence: 99%

Identification and characterisation of headspace volatiles of fish miso, a Japanese fish meat based fermented paste, with special emphasis on effect of fish species and meat washing

2010

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“…In the present study, 3-(methylthio) propanal (methional), a Strecker aldehyde of methionine, was detected in most of the miso and sauce samples. The production of methional was reported as a process mediated by amino transferase and a-ketoacid decarboxylase activities (Amarita, Fernandez-Espla, Requena, & Pelaez, 2001). 3-(Methylthio) propanol (methionol), existed in several miso samples, has been reported to be produced by the 4-metylthio-2-oxobutyric acid, a transamination product of methionine, which yields methional, followed by a reduction step.…”

Section: Resultsmentioning

confidence: 99%

Olfactometric characterization of aroma active compounds in fermented fish paste in comparison with fish sauce, fermented soy paste and sauce products

Giri

Osako

Okamoto

et al. 2010

Food Research International

204

142

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“…A number of thiamine pyrophosphate (TPP)-dependent ␣-keto acid decarboxylases have been identified in various organisms, and these enzymes include pyruvate decarboxylase (EC 4.1.1.1) (34), phenylpyruvate decarboxylase (EC 4.1.1.43) (4,40), branched-chain 2-oxoacid decarboxylase (EC 4.1.1.72) (27), 2-oxoglutarate decarboxylase (EC 4.1.1.71) (28,33), and indole-3-pyruvate decarboxylase (IPD) (EC 4.1.1.74) (18). In L. lactis, however, there has been only one report of partial purification of an ␣-keto acid decarboxylase (3), and in the genome of L. lactis IL1403 (8) a putative (partial) indole-3-pyruvate decarboxylase gene and a 2-oxoglutarate decarboxylase gene have been identified but pyruvate decarboxylase and branched-chain keto acid decarboxylase genes are absent. In the present paper we describe the identification and cloning of the gene encoding the branched-chain ␣-keto acid decarboxylase (kdcA) responsible for KICA conversion in L. lactis B1157.…”

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Identification, Cloning, and Characterization of a Lactococcus lactis Branched-Chain α-Keto Acid Decarboxylase Involved in Flavor Formation

Smit

Vlieg

Engels

et al. 2005

Appl Environ Microbiol

122

139

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The biochemical pathway for formation of branched-chain aldehydes, which are important flavor compounds derived from proteins in fermented dairy products, consists of a protease, peptidases, a transaminase, and a branched-chain ␣-keto acid decarboxylase (KdcA). The activity of the latter enzyme has been found only in a limited number of Lactococcus lactis strains. By using a random mutagenesis approach, the gene encoding KdcA in L. lactis B1157 was identified. The gene for this enzyme is highly homologous to the gene annotated ipd, which encodes a putative indole pyruvate decarboxylase, in L. lactis IL1403. Strain IL1403 does not produce KdcA, which could be explained by a 270-nucleotide deletion at the 3 terminus of the ipd gene encoding a truncated nonfunctional decarboxylase. The kdcA gene was overexpressed in L. lactis for further characterization of the decarboxylase enzyme. Of all of the potential substrates tested, the highest activity was observed with branchedchain ␣-keto acids. Moreover, the enzyme activity was hardly affected by high salinity, and optimal activity was found at pH 6.3, indicating that the enzyme might be active under cheese ripening conditions.Flavor formation in cheeses is mainly the result of catabolism of milk proteins, sugar, and lipids. Degradation of proteins into amino acids followed by conversion of these amino acids by Lactococcus spp. is very important for flavor formation in semihard types of cheese, like Gouda (for reviews see references 12, 25, 38, and 43). One of the predominant amino acid conversion routes is initiated by transaminases. Transamination of amino acids yields the corresponding ␣-keto acids, which do not have strong flavor properties (12, 13) but are the precursors of various aldehydes, alcohols, acids, and (thio-)esters. The latter compounds generally have much lower odor thresholds and strongly contribute to cheese flavor. This is exemplified by the production of flavor compounds from leucine. Transamination of leucine results in the production of ␣-isocaproic acid (KICA). Interestingly, only a limited number of Lactococcus lactis strains are capable of decarboxylating this ␣-keto acid to 3-methylbutanal (36, 37). The decarboxylating activity is observed mainly in L. lactis strains with nondairy origins, whereas the industrial strains tested hardly showed this activity (36). Subsequently, (de)hydrogenation of 3-methylbutanal results in 3-methylbutanol or 3-methylbutyric acid, which also contributes to the flavor of cheese, but the odor thresholds for these compounds are higher than the odor threshold for 3-methylbutanal (24, 29). The rate-determining step in this route is the decarboxylation of KICA, and therefore, control of this enzyme offers good prospects for the design of starter cultures with tailored flavor production (37, 43).The enzyme performing this reaction has not been identified. A number of thiamine pyrophosphate (TPP)-dependent

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Conversion of methionine to methional by Lactococcus lactis

Cited by 33 publications

References 16 publications

Identification and characterisation of headspace volatiles of fish miso, a Japanese fish meat based fermented paste, with special emphasis on effect of fish species and meat washing

Identification and characterisation of headspace volatiles of fish miso, a Japanese fish meat based fermented paste, with special emphasis on effect of fish species and meat washing

Olfactometric characterization of aroma active compounds in fermented fish paste in comparison with fish sauce, fermented soy paste and sauce products

Identification, Cloning, and Characterization of a Lactococcus lactis Branched-Chain α-Keto Acid Decarboxylase Involved in Flavor Formation

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