Functional Ingredients from Dairy Fermentations 359ciated with the cell wall of bacteria, and loose
slime, which is secreted and non - cell associ-
ated, designated as EPS. In a later study, the
Utah State University group (Peterson et al.,
2000 ) compared the effect of Streptococcus
thermophilus (ST) strains producing Cps and
EPS, respectively, on low - fat mozzarella
cheese functionality and cheese whey viscos-
ity. They used four ST strains, each paired
with Lactobacillus helveticus LH 100 (a
commercial mozzarella cheese starter strain)
to make low - fat mozzarella cheese.
The starter pairings were as follows:Pairing A: LH 100 and ST strain MR - 1C
(capsular exopolysaccharide producer
Cps^ +^ )
Pairing B: LH 100 and ST strain DM 10 (a
non - capsular mutant of MR - 1C, Cps _ )
Pairing C: LH 100 and ST strain MTC 360
(a loose slime producer, EPS^ +^ )
Pairing D: LH 100 and ST strain TAO61 (a
commercial strain that did not produce
either type of exopolysaccharide)The cheeses were analyzed for chemical
composition, starter bacterial counts, and
cheese melt properties, and the cheese yields
were determined. The results revealed that
there were signifi cant differences in the mois-
ture and protein contents between the cheeses.
Hence, the cheese yields also varied. There
were no signifi cant differences in other chem-
ical indices measured, namely fat content
and calcium and sodium chloride levels. The
pH of the cheeses did not vary signifi cantly.
The moisture levels, from highest to
lowest, were as follows: Pairing C (57%),
Pairing A (53%), Pairing D (51%), and
Pairing B (49%). The protein contents were
inversely correlated with the moisture levels:
(Pairing B, 26%; Pairing D, 25%; Pairing A,
24%; and Pairing C, 22%). The cheese yields
were directly correlated with the moisture
contents; cheeses made with pairings C and
A had greater yields than those made with
pairings B and D.Because of these drawbacks, namely
the cost factor and the need to declare stabi-
lizers on the ingredient label, the industry
prefers to use yogurt starters that contain
EPS - producing strains. Exopolysaccharide -
generating strains are known among
Streptococcus thermophilus (coccus) and
Lactobacillus delbrueckii subspecies bulgar-
icus (rod). Starters containing either EPS -
generating coccus or rod or a combination of
both are available. The EPS generated during
fermentation by the starters provides the
functionality required for the body and tex-
tural attributes desired in the fi nished yogurt.
Furthermore, the smooth, viscous, and heavy
body produced by EPS - generating starters
also aids in the uniform suspension of fruit
in fruit - fl avored yogurts.
EPS - generating rod - coccus cultures also
are used to produce yogurt drinks, which
are now popular in the United States and
Europe. The important characteristic of
yogurt drinks is the thick, smooth, silky
body and texture that resembles a milkshake.
Yogurt starters containing EPS - producing
rod - coccus components yield a product with
a thick, heavy, viscous body, which, when
stirred gently through the use of slow speed
agitators, imparts a milkshake - like consis-
tency. For large - scale industrial production
of yogurt drinks, gentle handling, agitation,
and pumping is diffi cult to achieve. Therefore,
a suitable combination of an EPS - producing
culture and a stabilizer system is necessary.
The use of such EPS - producing cultures in
applications such as yogurt drinks has been
patented (Vedamuthu, 1982 ).
EPS - producing cultures also have been
used to improve cheese quality. Researchers
at Utah State University observed that a
capsule - producing (Cps^ +^ ) Streptococcus
thermophilus strain (MR - 1C) could increase
moisture content and functional properties of
low - fat mozzarella cheese (Perry et.al., 1997 ;
Low et.al., 1998 ). They classifi ed EPS pro-
duced by lactic acid bacteria (LAB) into two
groups: capsular (Cps), which is tightly asso-