Dairy Ingredients in Dairy Food Processing 425minimum of 42% fat. Emulsifi ers, stabilizers,
anti - caking agents, antioxidants, and nutri-
tive sugars may be added.
As with whole milk powder, dried cream
can easily oxidize. It also can create issues
with processing because it does not fl ow the
same as fat - free powders and can stick to the
walls of spray dryers. Therefore, other ingre-
dients are added when manufacturing dried
cream. Cream is separated from milk, then
ingredients are added to help emulsify and
stabilize the fat. These ingredients include
caseinates, whey and milk protein concen-
trates, milk permeate and retentate, and skim
milk powder (Havea et al., 2009 ). Lecithin
is often added to help with dispersion of milk
fat in the dried product. The liquid blend is
then spray or drum dried, and fl ow - agents
can be added to the cooled powder. Oxygen
barrier plastic bag liners are used for packag-
ing, and nitrogen fl ushing is used to reduce
fat oxidation.
Buttermilk powder. Buttermilk powder
is produced as a waste stream of the butter -
making process. When cream is churned into
butter, the fat agglomerates and a phase
inversion occurs which releases water,
protein, lactose, and fat globule membrane
material as buttermilk. The U.S. Code of
Federal Regulations does not have a standard
of identity for buttermilk, other than the
labeling requirement that buttermilk can be
sweet cream buttermilk, concentrated sweet
cream buttermilk, reconstituted sweet cream
buttermilk, and dried sweet cream butter-
milk. The USDA grades dry buttermilk and
dry buttermilk product. Dry buttermilk has a
protein content of not less than 30%, whereas
dry buttermilk product has a protein content
of not greater than 30%. Other than that, the
grade requirements for extra and standard
grades are identical and both products contain
greater than 4.5% milk fat.
Buttermilk powder is unique from skim
and whole milk powders in that it contains
a higher percentage of phospholipids due to
the fat globule membrane material. Thesegrade or standard grade, or they are not
assigned a grade for failure to meet stan-
dards. Standards are based on fl avor, appear-
ance, bacterial counts, fat and moisture
content, solubility, scorched particles, and
titratable acidity. Extra grade has a lower
maximum milk fat (1.25%); less moisture
(4% vs. 5% for standard); and more stringent
solubility, titratable acidity, bacterial, and
scorched index requirements. There are dif-
ferent solubility and scorched index require-
ments for spray - dried and roller - dried milks
(USDA, 1984 ; USDA, 2001a,b,c ).
Whole milk powder. Whole milk powder
contains 26% to 40% fat (or up to 42% fat
outside the U.S.). Whole milk powder is
added to provide fat and functional milk pro-
teins to a product. It is not classifi ed on the
basis of heat treatment received, but it is
categorized by the USDA on the basis of
fl avor, appearance, bacterial counts, moisture
content, solubility, scorched particles, and
titratable acidity into “ extra ” and “ standard ”
grades, as with nonfat dry milk (USDA,
2001 ).
Nitrogen fl ushing of packages containing
milk powders has been shown to improve the
shelf life of stored higher fat powders; thus,
oxygen barrier plastic - lined bags are often
used for packaging and nitrogen fl ushing
(Lloyd et al., 2009 ). Due to issues with fat
oxidation, labeling of the maximum oxygen
content as a percentage is often optionally
provided on supplier specifi cations and pack-
aging. Dry whole milk has a shelf life of six
to nine months at ambient temperatures, but
it can be extended by storing it at refrigerated
temperatures.
Dried cream. Dried cream is added to
provide fat for functionality and fl avor. In the
United States it can contain between 40%
and 75% fat, according to the allowance in
the Code of Federal Regulations for blending
dried milk powders or lactose with dried
cream to obtain desired fat and protein levels.
International regulations such as the Codex
Alimentarius Standard 207 – 1999 require a