Dairy Ingredients for Food Processing

236 Chapter 10

of diacetyl imparts a buttery fl avor in cream
and cottage cheese. The salient features of
various cultures contained in starters are
shown in Tables 10.2 and 10.3.
Starter culture basically has two major
functions. One is to produce acidity during
cheese making, and the other is to aid in
ripening of cheese. Acid development leads
to milk coagulation in acid - coagulated
cheeses, a key step in cheese making. In
rennet - coagulated cheeses, acid development
accelerates coagulation. Acidity (low pH)
discourages the growth of pathogenic and
spoilage bacteria, thereby imparting a food
safety property to cheese. Acidity promotes
contraction and removal of water from curd

Table 10.2. Attributes of typical mesophilic cultures used in cheese making.

Attribute Lactococcus

lactis ssp.

lactis

Lactococcus

lactis ssp.

cremoris

Lactococcus

lactis ssp.

lactis biovar.

diacetylactis

Leuconostoc

lactis

Leuconostoc

mesentroides

ssp. cremoris

Cell shape and

confi guration

Cocci, Pairs,

short chains

Cocci, pairs,

short/long

chains

Cocci, pairs,

short chains

Cocci, pairs,

short/long

chains

Cocci, pairs,

chains

Catalase reaction – – – – –

Growth temperature ( ° C)

Optimum 28 – 31 22 28 20 – 25 20 – 25

Minimum 8 – 10 8 – 10 8 – 10 4 – 10 4 – 10

Maximum 40 37 – 39 40 37 37

Incubation

temperature ( ° C)

21 – 30 22 – 30 22 – 28 22 22

Heat tolerance,

60 ° C/30 minutes

± ± ± − −

Lactic acid isomers L( + ) L( + ) L( + ) D( − ) D( − )

% Lactic acid

produced in milk

0.8 – 1.0 0.8 – 1.0 0.4 – 0.8 0.1 – 0.3 0.1 – 0.3

% Acetic acid

produced in milk

• – – 0.2 – 0.4 0.2 – 0.4
  Gas (CO 2 ) production − − + ± ±
  Proteolytic activity + + + ± ±
  Lipolytic activity ± ± ± ± ±
  Citrate fermentation − − + + +
  Flavor/aroma
  compounds

+ + + + + + + + + + +

Mucopoly - saccharide

production

± ± ± − −

Hydrogen peroxide

production

+ + + ± ±

Alcohol production ± ± ± ± ±

Salt tolerance (%

maximum)

4 – 6.5 4.0 4 – 6.5 6.5 6.5

Adapted from Chandan and Shahani (1995)

matrix (syneresis); thus, it is a tool for cheese

moisture control. Furthermore, it is involved

in cheese fl avor and texture development. If

acidity is too low, off fl avors such bitterness,

fruitiness, and rancid fl avors develop in

cheese. On the other hand, high acidity leads

to a brittle texture and mottled cheese color.

During ripening, starter culture produces

factors for facilitating growth of non - starter

organisms which collectively are responsible

for desirable fl avor and texture. They also

furnish proteolytic and lipolytic enzymes

involved in cheese ripening.

Secondary cultures (Rattray, 2003 ) are

used for special functionality. Propionibac-

terium freudenreichii subsp. shermanii pro-