Dairy Ingredients for Food Processing

336 Chapter 13

improve the texture of fermented milk

products.

Fermented Dairy Products

Yogurt

Although it is not known when fermented

milk (yogurt) was fi rst consumed, it is

believed that fermented milk foods predated

cheese and originated about 8,000 to 10,000

BC when dairy animals were fi rst domesti-

cated (Fox 1987 ). Various writings reported

the consumption of fermented milk foods.

Dahi, a fermented milk from India, for

instance, has been consumed for thousands

of years by people on the subcontinent, while

a fermented milk product from the Middle

The fl avor - producing bacteria convert
citrate in milk into acetate, diacetyl, acetoin,
2,3 - butanediol, and carbon dioxide, which
are responsible for the fl avor of fermented
milk products. Diacetyl is an important fl avor
component of various fermented milk prod-
ucts such as cultured buttermilk, sour cream,
fromage frais, and quark. The metabolism of
citrate is an important property of some
mesophilic, but not thermophilic, bacteria
such as Lc. lactis subsp. lactis and Leuconostoc
sp. Acetate also plays a role in the fl avor of
cheese, while acetoin and 2,3 - butanediol are
tasteless and not involved in fl avor develop-
ment (Monnet et al. 1995 ). Some bacterial
cultures also have been reported to produce
exocellular polysaccharides (EPS) (Cerning
et al. 1992 , Bouzar et al. 1996 ) that can

Table 13.1. Microfl ora commonly used for selected milk fermentation. a

Product category Product

names

Raw

material

Starter culture Citrate

metabolism b,e

Isomer of

lactate b,f

Mesophilic

fermentation

(Soft unripened

cheese)

Cottage

cheese

Skim milk Lc. lactis subsp. cremoris

Lc. lactis subsp. lactis

Leuc. mesenteroides

subsp. cremoris

−

±

+

L

L

D

Quark Skim milk Lc. lactis subsp. cremoris

Lc. lactis subsp. lactis

S. diacetylactis c

−

±

+

L

L

D

Cream

cheese

Cream Lc. lactis subsp. cremoris

Lc. lactis subsp. lactis

Leuc. mesenteroides

subsp. cremoris

−

±

+

L

L

D

Cultured

buttermilk

Skim milk Lc. lactis subsp. cremoris

Lc. lactis subsp. lactis

Lc. lactis subsp. lactis

biovar. Diacetylactis c

−

±

+

L

L

D

Sour cream Cream Lc. lactis subsp. cremoris

Lc. lactis subsp. lactis

Leuc. mesenteroides

subsp. cremoris

Lc. lactis subsp. lactis

biovar. Diacetylactis d

−

±

+

+

L

L

D

D

Thermophilic

fermentation

Yogurt Milk S. thermophilus

Lb. delbrueckii subsp.

bulgaricus

−

−

L

D

a Farkye (2007) unless stated otherwise
b Cogan (1995)
c Walstra et al. (2006)
d Kosikowski and Mistry (1997)
e Symbols + , − , and ± indicate the ability, inability, or both of the microfl ora to produce citric acid
f Indicates the ability of the microfl ora to produce different isomers of lactate