Handbook of Meat Processing

Starter Cultures for Meat Fermentation 207

heme catalase and the second group nonheme

Mn - containing catalase. The presence of a

heme - dependent catalase has been demon-

strated in L. plantarum (Igarashi et al. 1996 )

and L. sakei (Noonpakdeea et al. 1996 ); it can

be active in meat products because these

substrates contain abundant heme sources

(Hertel et al. 1998 ). Moreover, analysis of the

genome of L. sakei revealed that this meat

organism harbors systems for protection

against reactive oxygen species, such as Mn -

dependent SOD and heme - dependent cata-

lase (Chaillou et al. 2005 ). The L. sakei

genome contains genes encoding a heme -

dependent catalase, a superoxide dismutase,

and a NADH oxidase to cope with reactive

oxygen species, and there are several systems

to cope with changes in the redox potential.

this gene is activated and induced by oxygen
and hydrogen peroxide upon entry into the
stationary phase. Moreover, a second gene
coding for heme - dependent catalase has been
detected in S. xylosus. The well - described
antioxidant property of S. carnous TM300,
involved in the protection of meat products
from hydrogen peroxide damage, depends on
a set of genes, one superoxide dismutase, two
catalases, and various peroxidases, involved
in the protection against oxygen reactive
species (Rosenstein et al. 2009 ).
Although lactic acid bacteria have long
been considered as catalase - negative micro-
organisms, two groups of catalase activity
have been reported in the last decade in
genera Lactobacillus , Pediococcus , and
Leuconostoc. The fi rst group is defi ned as

LIPIDS PROTEINS GLYCOGEN GLUCOSE

LACTATE

ATP

LACTATE

ACETATE

NH 3

Orn

NH 3

B.A.

fatty-acids

peptides

a.a.

H 2 O 2

NITRATE O 2

Methylketones NITRITE

ALDEHYDES

ACIDS

ESTERS

ALCHOOLS

glucose glycolysis

nitrate reductase

catalasecatalase

NAD oxidase

phosphoketolase

LACTATE

glycolysis

transaminasedecarboxilase

Arg

a.a. metabolism

deiminase

b-oxidation

lipase

Figure 10.1. Meat starter culture bacteria: major metabolic pathways in meat fermentation. Main
enzymatic activities of coagulase negative staphylococci and lactobacilli are indicated by light grey arrows and
dark grey arrows, respectively. The metabolic activities ascribed to both bacterial groups are indicated by white
arrows. Dotted - line arrows indicate action of endogenous meat enzymes. Abbrevations: a.a., amino acids; Arg,
arginine; B.A., Biogenic Amines; Orn, ornithine. Sugars added to the batter are rapidly metabolized to lactate
by starter cultures of lactic acid bacteria. Glycogen, proteins, and lipids catabolism are also used for microbial
growth during fermentation. Ribose is released by ATP hydrolysis, and the subsequent metabolism of ribose -
derived molecules is used for energy production by L. sakei. When sugar concentration declines, free amino
acids (a.a) are utilized for microbial growth. Via the arginine deiminase (ADI) pathway, arginine is converted to
ornithine and supports the growth of lactobacilli in the latter stage of meat fermentation. Staphylococci modu-
late the aroma through the conversion of amino acids (particularly the branched - chain amino acids leucine,
isoleucine, and valine) into methyl - branched aldehyde, methyl - branched acids and sulphites, diacetyl, and ethyl
ester. The methyl ketones (2 - pentanone and 2 - heptanone) derive from intermediates of an incomplete ß -
oxidation pathway in staphylococci.