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Chapter 13

Fermented Dairy Ingredients

Junus Salampessy and Kasipathy Kailasapathy

Introduction

“ When people have learnt how to cul-

tivate a suitable fl ora in the intestine of

children as soon as they are weaned

from the breast, the normal life may

extend to twice my 70 years. ”

That rather prophetic statement by É lie
Metchnikoff (1921) has arguably never been
achieved because there is no report to date
that humans can normally live up to 140
years. However, the statement emphasizes
maintaining balanced intestinal fl ora to have
a healthy life. Over the last few decades the
market for fermented food products, espe-
cially fermented dairy products such as
yogurt, has increased signifi cantly along with
the steadily increasing knowledge of the
health benefi ts of fermented dairy products.
The health benefi ts of fermented dairy prod-
ucts, however, are not new. Various studies
have been carried out for many years to
investigate health - related activities of fer-
mented milk products. Fermented dairy prod-
ucts have been human staples for centuries;
they come from different parts of the world
and in different forms, fl avors, and textures.
This chapter discusses various fermented
milk products, especially mesophilic - acid -
coagulated and thermophilic products, and
their use as dairy ingredients.

Microfl ora of Milk Fermentation

The type and characteristics of microorgan-

isms used as starter cultures for milk fermen-

tation are two of the most important factors

that determine the overall quality of the fer-

mented products (Bouzar et al. 1997 ). A

proper selection and composition of starter

culture can improve the product fl avor,

aroma, stability, and texture. Therefore, it is

of great importance to understand the char-

acteristics of the starter bacteria to obtain

desirable, quality products. The microorgan-

isms commonly used in various milk fermen-

tations are listed in Table 13.1.

The microorganisms used in milk fermen-

tation can be categorized into three groups:

mesophilic, thermophilic, and artisanal. The

optimum temperatures for the fi rst two groups

are approximately 26 ° C (79 ° F) and 42 ° C

(108 ° F), respectively, and they consist of dif-

ferent species of bacteria. The artisanal is an

undefi ned bacterial culture that is produced

daily in cheese plants and contains various

numbers and types of lactic acid bacteria

(LAB) (Cogan 1995 ). Furthermore, the

starter bacterial culture can be classifi ed into

acid - and fl avor - producing bacteria. The

acid - producing bacteria mainly convert milk

sugar, or lactose, into lactic acid and, to a

lesser extent, acetic acid, through a homo-

fermentative pathway. This group includes

Str. Thermophilus ; Lb. delbrueckii subsp.

Bulgaricus ; Lb. helveticus ; and some Lacto-

coccus , Leuconostoc , and Bifi dobacterium

species (Monnet et al. 1995 ).

Dairy Ingredients for Food Processing edited by
Ramesh C. Chandan and Arun Kilara
© 2011 Blackwell Publishing Ltd.