358 Chapter 14
imparted by EPS - generating lactococci
also suppress foaming during cultured but-
termilk packaging operations, which for-
merly caused problems in completely fi lling
the bottles.
Exopolysaccharide - producing lactococci
are also susceptible to lysis by virulent phages.
To overcome phage - related failures in butter-
milk and sour cream manufacture, rotation of
starter cultures containing EPS - producing
strains of variable phage susceptibility is nec-
essary. Unfortunately, the availability of a
large number of EPS - producing lactococci is
limited. Procedures for converting non - EPS
lactococcal strains to EPS - generating vari-
ants by conjugative transfer of plasmid coding
for EPS production have been developed
and patented (Vedamuthu, 1989 ). This tech-
nique has provided a means for developing
suffi cient numbers of heavy body cultures
with EPS - generating lactococci of variable
phage - sensitivities.
Nielson (1975) listed the following attri-
butes for a high - quality yogurt with respect
to the body characteristics. The body of
yogurt should have a relatively high viscosity
and should be fi rm and cohesive enough to
be removed from the container and eaten
with a spoon. It should have enough resil-
ience to withstand normal handling during
post - incubation operations and by consumers
in the home without undue wheying off or
shattering. The solids content of the yogurt
mix should be high to obtain the smooth,
viscous body resistant to easy shattering or
wheying - off.
Stabilizers are used to further enhance the
water - holding capacity of yogurt and increase
its viscosity and smoothness. Common
yogurt stabilizers include gelatin, alginates,
carrageenan, carob gum, guar gum, starch,
and carboxymethyl cellulose. Sometimes
multiple stabilizers are used in combination.
Stabilizers should always be declared in the
label. Kosher requirements do not allow the
use of gelatin, and Kosher - grade gelatin is
very expensive.preserving foods against spoilage and helping
to prevent food - borne transmission of patho-
gens and their toxins. Functional bioingredi-
ents fulfi ll other functionalities of chemicals
used for various purposes listed earlier. This
chapter considers bio - ingredients developed
in situ during the manufacture of dairy prod-
ucts as well as those derived in separate fer-
mentations and the resultant ingredient(s)
added to the dairy product to obtain the desired
functionality.
Functional Bio - ingredients:
Live Cultures
Use of Live Functional Cultures
Functional cultures are used to develop
in situ the desired body, texture, and fl avor
attributes in dairy and other foods. A very
good example of functional cultures used
in dairy fermentations is the inclusion of
exopolysaccharide - producing (EPS) starter
cultures.
One of the traditional uses of EPS cultures
is found in viili production. The desired
heavy, somewhat slimy body, and the ropy,
stringy texture of viili are imparted by the
EPS generated by the starter lactococci in
viili starters. Vedamuthu (2006) and Robinson
et al. (2002) have described the attributes and
production of viili.
During the past decade, selected EPS -
producing lactococci have been used because
of the escalating cost of nonfat milk solids
used in fortifying fl uid skim milk for cultured
buttermilk, and for increasing the solids
level in cultured sour cream. Such cultures
are called heavy body cultures. The EPS is
generated in situ during the respective fer-
mentation to impart a heavy body without
sliminess or ropiness under normal prod-
uction conditions of these products. The
use of such heavy body cultures saves money
by helping to decrease or even completely
replace the costly nonfat dry milk solids
needed. The smooth texture and heavy body