Food Biochemistry and Food Processing

324 Part III: Muscle Foods

which are very stable and have an optimal pH closer
to that in ham, would act during the full process
(Toldrá 1992). An example of the evolution of these
enzymes is shown in Figure 14.6.
Numerous peptides are generated during process-
ing: mainly in the range 2700–4500 Da during post-

salting and early ripening, and below 2700 Da dur-

ing ripening and drying (Aristoy and Toldrá 1995).

Some of the smaller tri- and dipeptides recently have

been sequenced. Dipeptidylpeptidase I and tripep-

tidylpeptidase I appear to be the major enzymes in-

volved in the release of di- and tripeptides, respec-

Table 14.2.Chemical Factors Affecting Proteolytic Activity during Meat and Meat Product

Processing

Factor Typical Trend Effect on Proteases

NaCl Low in aged meat No effect on enzyme activity

Medium concentration in cooked meat Partial inhibition of most proteases,

products except calpain and aminopeptidase B,

that are chloride-activated at low

NaCl concentration

High concentration in dry-cured hams Strong inhibition of almost all proteases

Nitrate and nitrite Concentration around 125 ppm in cured Slight inhibitory effect on the enzyme

meat products activity, except cathepsin B, that is

activated

Ascorbic acid Concentration around 500 ppm in cured Slight inhibition of m-calpain, cathepsin

meat products H, leucyl aminopeptidase, and

aminopeptidase B

Glucose Poor concentration in aged meat and No effect

dry-cured ham

High concentration (up to 2 g/L) in Slight activation of leucyl

fermented meats aminopeptidase and cathepsins B, H,

and D

Figure 14.6.Evolution of cathepsins during the processing of dry-cured ham. (Toldrá, unpublished data.)