Food Chemistry

2.7 Enzyme Utilization in the Food Industry 151

Table 2.22.Peptidases (proteinases) utilized in food processing

Name Source pH Optimal
optimum stability
pH range

A. Peptidases of
animal origin
Pancreatic
proteinasea Pancreas 9. 0 b 3–5
Pepsin Gastric lining of swine or bovine 2
Chymosin Stomach lining of calves
or genetically engineered
microorganismsB. Peptidases of 6–7 5 .5–6. 0
plant origin
Papain Tropical melon tree
(Carica papaya) 7–8 4 .5–6. 5
Bromelain Pineapple (fruit and stalk) 7–8
Ficin Figs (Ficus carica) 7–8
C. Bacterial peptidases
Alkaline
proteinases
e. g. subtilisin Bacillus subtilis 7–11 7 .5–9. 5
Neutral
proteinases
e. g. thermo-
lysin Bacillus thermoproteolyticus 6–9 6–8
Pronase Streptomyces griseus
D. Fungal peptidases
Acid proteinase Aspergillus oryzae 3 .0–4. 0 d 5
Neutral
proteinase Aspergillus oryzae 5 .5–7. 5 d 7. 0
Alkaline
proteinase Aspergillus oryzae 6 .0–9. 5 d 7–8
Proteinase Mucor pussillus 3 .5–4. 5 d 3–6
Proteinase Rhizopus chinensis 5. 03 .8–6. 5

aA mixture of trypsin, chymotrypsin, and various peptidases with amylase and lipase as accompanying enzymes.
bWith casein as a substrate.
cA mixture of various endo- and exopeptidases including amino- and carboxypeptidases.
dWith hemoglobin as as substrate.

by adding Ca^2 ⊕ions.α-Amylases added to the
wort in the beer production process accelerate
starch degradation. These enzymes are also used
in the baking industry (cf. 15.4.1.4.8).

2.7.2.2.3 Glucan-1,4-α-D-Glucosidase(Glucoamylase)................

Glucoamylase cleavesβ-D-glucose units from the
non-reducing end of an 1,4-α-D-glucan. Theα-
1,6-branching bond present in amylo-pectin is
cleaved at a rate about 30 times slower than theα-

1,4-linkages occurring in straight chains. The en-

zyme preparation is produced from bacterial and

fungal cultures. The removal of transglucosidase

enzymes which catalyze, for example, the trans-

fer of glucose to maltose, thus lowerung the yield

of glucose in the starch saccharification process,

is important in the production of glucoamy-lase.

The starch saccharification process is illustrated

in Fig. 2.50. In a purely enzymatic process

(left side of the figure), the swelling and gela-

tinization and liquefaction of starch can occur

in a single step using heat-stable bacterial

α-amylase (cf. 2.7.2.2.2). The action of amylases