Fermentation: Microbiology and Biochemistry 191Table 9.2. Metabolic end products formed during fermentation and ripening of dry fermented
sausages
End product Natural fl ora Starter culture Kocuria added Yeast - molds added
Lactic acid x x x
Acetic acid x x x
Butyric acid x x
Oxalic acid x
Citric acid x
Pyruvic acid x
Malic acid x
Formic acid x
Fumaric acid x
Propionic acid x x
Diacetyl x x x
Acetoin x x x
2,3 - butyleneglycol x
Ethanol x x x
Free fatty acids x x x
Peptides x x x
Free amino acids x x x x
Amines x x x
Ammonia x x x x
Aldehydes, ketones x xcases, it seems that the mode of proteolysis
is a strain - dependent property. Drosinos et al.
(2007) reported that six Lb. sakei strains were
found proteolytic only against the myofi bril-
lar protein fraction and by a mode quite dif-
ferent from the one already described by
Fadda et al. (1999a) referring to Lb. planta-
rum strain CRL 681. In the former case, a
complete decomposition of myosin, actin,
and all myofi brillar proteins ranging in
molecular weight from 200 to 12 kDa was
observed, compared with the partial hydroly-
sis of only actin and myosin that was
observed by Lb. plantarum strain CRL 681
(Fadda et al. 1999a ). Comparable differences
were observed in the proteolysis of sarco-
plasmic and myofi brillar protein fractions by
staphylococci (Drosinos et al. 2007 ). The
results obtained in that study were not in
accordance with the ones obtained by
Mauriello et al. (2002) referring to the
decomposition of sarcoplasmic proteins. In
the latter study, the decrease in intensity of
protein bands at approximately 48.4, 41.6,
22.4, and 20.3 kDa ( St. xylosus strains BS5
and ES1) or their complete hydrolysis ( St.
xylosus strain AS27) has been reported,
whereas in the study by Drosinos et al.
(2007) , seven Staphylococcus sp. strains
hydrolyzed the sarcoplasmic protein fraction
by the same mode and only one St. xylosus
strain LQC 5401 by a different mode. As far
as the myofi brillar protein fraction was con-
cerned, Mauriello et al. (2002) reported that
strains ES2 and BS5 resulted in a complete
decomposition of myosin and actin, and the
appearance of bands at about 100 and 25 kDa.
On the other hand, Drosinos et al. (2007)
reported that all 53 Staphylococcus sp. strains
found to be proteolytic were able to com-
pletely hydrolyze the myofi brillar fraction to
polypeptides with molecular weight less than
12 kDa.
Lipolysis in fermented sausages has been
attributed partly to the microbiota and partly
to tissue lipases. It has been estimated that
muscle lipases contribute at 60% – 80%, with
the rest being due to microbial ones (Molly
et al. 1996, 1997 ). Several authors have
studied the lipolytic activities of both lactic
acid bacteria and staphylococci in pork fat.
In general, lactic acid bacteria hydrolyze