366 Chapter 14
measured amounts of sweet cream buttermilk
(drained from the churn) cultured with
Leuconostoc strains are worked into the
butter at the time of moisture adjustment, to
adjust the moisture content to the legal limit
(Vedamuthu, 1994 ). A suitable procedure for
these operations was described by Seas et al.
(1960).
Lundstedt (1962) patented a procedure in
which citrated whey (preferably cottage
cheese whey) is suitably “ sterilized ” and then
inoculated with a strain of Streptococcus
diacetilactis (cit^ +^ Lactococcus lactis ssp.
lactis ) and cultured at 21 ° C (69.8 ° F) for 18
hours and then added to butter “ at any stage
before working or texturizing, provided it is
not subjected to temperatures in excess of
about 50 ° C (122 ° F). ” During the holding of
the butter in cold storage, diacetyl levels
gradually increase to yield a fi ne fl avored
butter. For additional details, refer to the
patent (Lundstedt, 1962 ).
Hugenholtz (1993) described a high -
diacetyl - producing starter, designated NIZO
4/25, from which a Lactococcus lacis strain
that accumulated very high concentrations of
α - acetolactate from citrate was isolated. This
strain had multiple designations, including
Ru4, SD806, and 425A. Biochemical charac-
terization of the strain revealed that it lacked
α - acetolactate decarboxlase, which resulted
in the accumulation of α - acetolactate. α -
acetolactate is the precursor of diacetyl and
is an unstable compound that can be chemi-
cally converted to diacetyl. Because of the
accumulation of α - acetolactate, this strain
produces high amounts of diacetyl when used
in fermented dairy products.
Exploiting the metabolic quirk in strain
NIZO 4/25, Veringa et al. (1974) developed
a procedure for manufacturing high - fl avored
butter. The procedure consists of the follow-
ing steps. Two cultures are used in this
process: an L culture (culture containing
Leuconostoc ) designated Fr 19, and the D
culture (culture containing diacetylactis
strain, currently called Cit^ +^ Lactococcusfl avored milks and may be used as a stabilizer
in ice cream. When grown in a sucrose - salt
medium, the organism produces a slushy,
applesauce - like particulate, a gel - like struc-
tured dextran product that exhibits anti -
microbial properties and is stable at room
temperature for 12 months. The dextran from
this strain was examined for polymer compo-
sition and degree of branching by C - NMR
analysis. It was found to contain
a mixture of polymers containing 1, 6 -
glucopyranose with branching approximately
every 11 residues as well as 2% fructofura-
nose. This process for producing dextran has
been commercialized.
The trade literature for these products
claims that they fulfi ll the requirements for
all natural ingredient declaration and comply
with 21 CFR 131.146 for dried cultured skim
milk. Furthermore, these products provide
good textural properties and an improved
creamy, buttery mouth feel in ice cream and
other dairy products. Among the additional
advantages, these products could reduce or
replace non - fat milk and sweetener within
the fat content limits in dairy formulations,
provide heat shock protection in ice cream,
and allow higher aeration compared to prod-
ucts without emulsifi ers or gums (Kerry,
2004b ).
Bio - fl avorings
One of the earliest applications of bioingre-
dients in dairy products was the development
of fl avor enhancers for creamery butter.
Culturing cream for butter making has not
been widely practiced because of the greater
propensity of salted, cultured butter to
undergo fat oxidation and other chemical
deterioration during holding than sweet
cream butter. Sweet cream butter, however,
lacks good “ buttery ” fl avor, and is often criti-
cized as fl at and lacking in fl avor. To remedy
the lack of fl avor, procedures have been
developed to add cultured fl avor directly to
butter. After churning and working of butter,