The manufacture of high-solids evaporated milk


Keeney, M.; Josephson, D.V.

Journal of Dairy Science 30(8): 539-540

1947


Attempts were made to manufacture evaporated milks containing up to 40 per cent. of total solids. Heat coagulation was prevented either by adding 8 to 10 per cent., on a solids basis, of dried milk which had had 60 per cent. of its calcium removed by treatment of the original milk with Ambezlite IR-100, or by adding 70 to 85 oz. of disodium phosphate per 1, 000 Ib. of evaporated milk containing 40 per cent. of solids. However, noticeable mineral deposits were found a few days after sterilization in all products containing 32 per cent. or more of solids. The pH decreased with increases in the total solids whereas the percentage destruction of optically active lactose appeared to be unrelated to the solids content.

FORTY-SECOND
ANNUAL
MEETING
539
M32
The
Utilization
of
the
Mineral-Ion
Exchange
Principle
in
Stabi-
lizing
Evaporated
Milk.
D.
V.
JOSEPHSON
AND
C.
B.
REEVES,
Department
of
Dairy
Technology,
Ohio
State
University.
The
proteins
in
evaporated
milk
usually
are
somewhat
unstable
to
the
heat
of
sterilization.
This
condition
has
been
attributed
primarily
to
an
excess
of
calcium
ions
and,
possibly,
of
magnesium
ions
and
is
corrected
in
commercial
manufacture
by
the
use
of
certain
salts,
usually
disodium
phosphate.
The
present
study
was
undertaken
to
investigate
the
possibility
of
using
some
ion
exchange
method
to
remove
the
excess
calcium
and
magnesium
ions
from
milk
and
render
the
concentrated
product
stable
to
240
°
F.
for
15
minutes.
A
cation
exchanger
(Amberlite
IR-100)
which
exhibits
a
high
degree
of
specificity
for
polyvalent
cations
was
used
for
treating
whole
milks
and
skim
milks.
When
this
resinous
type
material
was
used
in
the
sodium
cycle,
it
effected
an
efficient
removal
of
calcium
(60
per
cent)
and
magnesium
from
milk.
The
mineral-ion
exchange
treated
milks
were
added
as
fluids,
concen-
trates,
and
powders
to
the
bulk
lots
of
regular
fluid
milk
before
forewarming
or
to
the
untreated
concentrates
before
sterilization.
Under
average
condi-
tions
where
evaporated
milk
required
2
to
6
ounces
of
disodium
phosphate
per
1,000
lb.
of
concentrate
to
produce
stability,
the
same
correction
was
effected
by
treating
from
0.5
to
2.0
per
cent
of
the
original
milk
(or
equiva-
lent)
by
the
mineral-ion
exchange
process.
The
addition
of
the
mineral-ion
exchange
treated
milk
at
the
hot
well
before
forewarming
produced
greater
efficiency
of
stabilization
than
addition
later.
The
mineral-ion
exchange
treated
milk
can
be
used
as
a
fluid,
concen-
trate,
or
powder
with
equal
effectiveness.
Both
whole
and
skimmed
milks
can
be
treated
by
the
process,
but
skim
milk
is
more
practical
from
the
commercial
point
of
view.
Changes
in
the
calcium,
phosphorus,
and
ash
content
of
evaporated
milk
as
a
result
of
mineral-ion
exchange
treatment
are
so
insignificant
as
to
be
within
the
limits
of
error
for
the
analytical
tech-
niques
used.
The
mineral-ion
exchange
process
as
employed
in
these
experi-
ments
with
evaporated
milk
appears
to
be
a
practical
procedure
for
the
control
of
heat
coagulation
of
evaporated
milk.
M33
The
Manufacture
of
High-Solids
Evaporated
Milk.
MARK
KEENEY
AND
DONALD
V.
JOSEPHSON,
Department
of
Dairy
Technology,
Ohio
State
University.
This
study
was
undertaken
to
investigate
the
possibility
of
manufactur-
ing
a
commercially-acceptable
evaporated
milk
containing
an
appreciably
greater
total
solids
content
than
the
present
standard
product
of
26
per
cent
total
solids.
Attention
was
focused
on
the
manufacture
of
evaporated
milk
at
levels
of
32, 34, 36,
38,
39,
and
40
per
cent
total
solids.
540
PAPERS
PRESENTED
AT
THE
The
intensification
of
the
physical
and
chemical
changes
in
milk
caused
by
the
heat
of
sterilization
at
high
solids
concentration
has
handicapped
the
development
of
such
a
product.
Prohibitive
amounts
of
disodium
phosphate
are
necessary
during
most
seasons
of
the
year
to
stabilize
evaporated
milk
containing
34
to
40
per
cent
solids.
In
this
study
the
mineral-ion
exchange
principle
was
used
and
compared
with
the
procedure
of
stabilization
by
disodium
phosphate.
During
January,
February,
and
March
the
40
per
cent
solids
evaporated
milk
could
be
stabilized
against
heat
coagulation
by
the
addition
of
8
to
11
per
cent
(on
a
solids
basis)
of
mineral-ion
exchange
powder
(from
which
60
per
cent
of
the
calcium
had
been
removed)
at
the
hot
well.
The
same
milks,
untreated,
required
from
70
to
85
ounces
of
disodium
phosphate
per
1,000
lb.
of
40
per
cent
solids
milk
to
prevent
coagulation.
As
the
solids
content
was
increased,
the
degree
of
browning
was
intensi-
fied.
The
products
reconstituted
to
give
13
per
cent
solids
exhibited
lower
pH
as
the
solids
concentration
of
the
sterilized
product
increased.
A
nor-
mal
milk
which
exhibited
a
pH
of
6.55
before
sterilization
usually
had
a
pH
of
about
6.35
after
sterilization
at
a
normal
concentration.
The
pH
of
steril-
ized
high
solids
concentrates
decreased
as
solids
increased,
so
that
a
value
of
6.20
or
lower
was
common
with
a
40
per
cent
solids
product
(reconstituted).
Sterilization
causes
a
considerable
change
in
the
optically
active
lactose
content
of
evaporated
milk.
The
per
cent
destruction
of
optically
active
lactose
ranged
from
9
to
15
per
cent.
The
per
cent
solids
at
sterilization
seemed
to
have
little
or
no
effect
upon
the
per
cent
destruction.
All
of
the
batches
containing
32
per
cent
or
more
solids
left
a
noticeable
mineral
deposit
in
the
cans
within
a
few
days
after
sterilization.
This
was
true
in
both
the
mineral-ion
exchange
treated
batches
and
the
products
stabilized
with
disodium
phosphate.
M34
Condensing
Whole
Milk
for
Ice
Cream
Mix
with
the
Vacreator.
G.
H.
Wits'rrat
AND
K.
C.
Lu,
Oregon
State
College.
The
process
of
condensing
whole
milk
with
a
"baby"
size
Vacreator
was
studied.
The
whole
milk
first
was
placed
in
a
storage
vat
and
then
pumped
either
through
a
flash
preheater
or
a
tubular
preheater,
heated
to
200
±
F.,
and
evaporated
under
24
and
28
inches
of
partial
vacuum,
consecutively,
in
the
Vacreator.
The
partially
condensed
whole
milk
was
returned
to
the
storage
vat
as
it
emerged
from
the
machine.
By
continuous
circulation
through
the
Vacreator,
the
milk
was
condensed
to
the
desired
ratio
of
con-
centration
of
about
2.1:
1
for
use
in
ice
cream
mix.
Increasing
the
rate
of
inflow
of
milk
to
the
Vacreator
up
to
its
maximum
intake
capacity
resulted
in
a
higher
water-evaporating
efficiency.
An
in-
crease
in
the
rate
of
inflow
of
the
milk
from
85
to
105
lb.
per
minute
increased