Processed cheese foods with added whey protein concentrates

Lait (1992) 72, 201-212
201
© ElsevierllNRA
Original article
Processed cheese foods
with added whey protein concentrates
VK Gupta*, H Reuter
Institut für Verfahrenstechnik
der Bundesanstalt
für Milchforschung,
Kiel, Germany
(Received 10 June 1991; accepted 15 November 1991)
5ummary -
The technique for the manufacture of processed cheese foods has been standardized
with 20% of their cheese solids replaced by whey protein concentrates (WPC). Among the different
emulsifiers tested (a combination of trisodium citrate and disodium phosphate and trisodium citrate
alone) only trisodium citrate was able to produce a smooth texture. Trisodium citrate at 2.5% and
with a moisture content of 45.2% resulted in processed cheese foods with the best sensory
characteristics (out of a total of 7, the scores were as follows: f1avour, 5.5; consistency, 6;
appearance, 5.8; overall acceptability, 5.6). WPC with a high UF concentration (26.1% TS) and low
calcium content (0.7% on dry basis) were found to be the most suitable for incorporation in
processed cheese foods. Diafiltration of WPC had a negative effect as regards suitability for the
product. The standardized technique for processed cheese manufacture is: take a mixture of 25%
6.5-7.5-month-old and 55% 2-3-month-old grated cheddar cheese), WPC equivalent to 20% of
cheese solids, dry salt and water; heat the contents with thorough stirring by indirect steam heating.
At a temperature of about 49 oC, sprinkle 2.5% dry trisodium citrate and continue heating until the
temperature reaches 82 "C, and maintain this temperature for 3-4 min.
processed cheese foods 1 whey protein concentrate addition 1 emulsifying salis
Résumé -
Fabrication de fromage fondu avec ajout de concentrés de protéines de lactosé-
rum. Un procédé de fabrication
de fromage
fondu basé sur le remplacement
de 20% de la matière
sèche fromagère par un concentré
de protéines
de lactosérum
(CPL) a été développé.
Parmi les dit-
férents émulsifiants
testés (citrate trisodique
seul ou citrate trisodique
+ phosphate
disodique),
seul
le citrate trisodique
était à même de donner une texture lisse au produit.
Les meilleures
caractéristi-
ques sensorielles
(sur 7, les scores étant pour la flaveur:
5,5, la consistance:
6, l'apparence:
5,8,
l'acceptabilité
générale:
5,6) étaient obtenues avec 2,5% de citrate trisodique et une teneur en eau
de 45,2%. Une forte concentration
des CPL (26,1% de la matière sèche) et une faible teneur en cal-
cium (0,7% de la matière sèche) facilitaient
leur incorporation
dans le mélange
de fonte. Par contre,
la diafi/tration
conduisait
à un effet inverse. Le procédé de fabrication développé
était le suivant:
ad-
dition dans le pétrin de fromage cheddar rapé (mélange de 25% de fromage âgé de 6,5-7,5 mois, et
55% de fromage
âgé de 2-3 mois), d'une quantité de CPL équivalente
à 20% de la matière sèche
du fromage, de sel sec et d'eau; chauffage
du contenu par la paroi avec agitation régulière.
Lorsque
la température
atteignait
49 "C, saupoudrage
de citrate trisodique
sec à 2,5%; poursuite
du chauf-
fage jusqu'à
82 oC et maintien de cette température pendant 3 à 4 min.
fromage
fondu
/ concentré
de protéine
de lactosérum
/ sels émulsifiants
• Present address: Dairy Technology Division, National Dairy Research Institute, Karnal-132 001,
India.

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202
VK Gupta, H Reuter
INTRODUCTION
MATERIALS
AND METHODS
A fairly large amount of processed
cheese
Manufacture
of WPC
foods
is
prepared
in the
USA,
Russia
and many
East
European
countries,
but
much work still has to be done on stan-
Different types of WPC (table 1)were prepared
dardizing
this product.
There is very little
by ultrafiltration (UF) of Tilsit cheese whey
on an UF module with a hollow fiber membrane
information
available on processed cheese
(Romicon, polysulfone membrane type pM 50, fi-
foods
with added
whey
protein
concen-
ber inside diameter 1.1 mm, effective membrane
trates (Georgakis,
1975; Kairyukshtene
et
area 2.5 m2, molecular weight cutolt, 50 000) by
al, 1978).
varying; a) preheating treatment of whey (hold-
ing period, 30 min); b), UF temperature; cl, level
Whey has long been known to contain
of UF concentration; and dl, diafiltration treat-
proteins of high nutritional
value, but their
ment as described earlier (Gupta and Reuter,
use in human
nutrition
has been compli-
1987). These WPC were put in polythene bags
cated by the high lactose and low protein
and kept at -20 oC till used.
content (Forsum, 1975). Ultrafiltration
(UF)
technology
developed
over the last 2 dec-
ades has now made possible the produc-
Manufacture
of processed
chee se/
tion
at a relatively
economical
priee
of
processed
cheese foods
whey
protein
concentrates
(WPC)
which
are low in lactose. With this new technolo-
A blend of 25% old Cheddar cheese (6.5-7.5
gy,1I has also become possible to produce
months old) and 75% young Cheddar cheese
WPC
with different
physicochemical
and
(2-3
months old) was used for processed
functional
properties for applications
in dif-
cheese manufacture. For processed cheese
ferent food systems.
foods, part of the young cheddar cheese solids
were replaced by WPC solids. The amount of
Processed cheese is a complex system
WPC for replacement of Cheddar cheese was
composed
of protein, fat, minerai salts and
calculated as follows:
other ingredients.
Its properties
are affect-
ed by many variables such as composition
axb
amount of WPC (g) :
and nature of the initial natural cheese, the
c
nature
and
amount
of
the
emulsifying
agents, the manufacturing
procedure
and
where a =% total solids of young Cheddar
additional
factors
(Carie et al, 1985). The
cheese; b = amount of young cheese to be re-
emulsifier
plays a very important
role in
placed (g); c = % total solids of WPC.
producing desirable body and texture char-
Young and old Cheddar cheeses were kept at
acteristics,
and melting and slicing proper-
room temperature overnight, cleaned, quartered
ties in the finished cheese products. Three
and grated. The calculated amount of Cheddar
cheese, WPC, salt and water for preparing 1 kg
major categories
of extensively
employed
product were added in a 2.5-1 semi-spherical
emulsifying
salts are: citrates,
monophos-
stainless steel kettle. The water added also in-
phates
and polyphosphates
(Kosikowski,
cluded the subsequent water loss (175 ml) due to
1982; Shimp, 1985).
evaporation during heat processing of cheese.
The contents in the kettle were heated with con-
ln the present investigation,
an attempt
tinuous stirring and scraping of the surface. As
has been made to add WPC in the formu-
the temperature approached 49 "C, the emulsify-
lation of processed
cheese
foods and to
ing salt either after dissolving in water or in dry
standardize
their manufacturing
process.
form was slowly added and thoroughly mixed.

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1\)
o
c.>

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204
VK Gupta, H Reuter
Heating was continued to 82 oC, and the temper-
and 1-way analysis of variance without interac-
ature maintained for 3-4 min. The entire process-
tion as per the procedure of Snedecor and Co-
ing period lasted 15 min. The hot product was
chran (1967). Critical difference was also calcu-
then immediately poured into plastic cups (Bella-
lated from the r-value.
piast, Art No 810) which were secured with air-
tight Iids. Cups '1ere maintained overnight at
18 oC and then moved to cold store maintained
RESULTS
at6 oC.
Effect of different emulsifying
salts
Chemical analysis
WPC were analysed for their chemical composi-
Pracessed cheese foods (43-44% mois-
tion as follows:
ture) were prepared by replacing 7-20% of
- total solids by gravimetric procedure;
young cheese solids with WPC solids. Dur-
- protein by the Kjeldahl method (AOAC, 1970),
ing heat processing, there was no free fat
protein factor 6.38;
release as was otherwise the case when
- fat by the Gerber method;
no WPC was added. This indicated suffi-
cient emulsification of fat even with 7%
- ash by AOAC (AOAC, 1970);
WPC. Flavour and appearance scores of
- calcium and lactose using a Technicon Autoa-
the final food were on average 5, but the
nalyser;
texture was chalky and sandy, as a result
- pH using a pH meter (E 5000, Metrohrn,
of which the consistency score was below
Swltzerland) .
4 and the total acceptance score on aver-
Cheddar cheese, processed cheese and pro-
age 4. The use of diafiltered WPC (WPCD,
cessed cheese foods were analysed for mois-
ture by gravimetric method.
23.6) with lactoselTS as low as 9.5% did
not prevent the sandiness in the processed
cheese foods, suggesting that lactose was
Sensory evaluation
of processed
not responsible for the defective texture.
cheese foodslprocessed
cheeses
Emulsifying salts (Joha: S-8, 1.2% and
S-10, 0.8%), which are widely utilized in
Products were evaluated for flavour, consisten-
Germany, when used at the 2% level did
cy, appearance and overall acceptability by a 7-
not improve the consistency of the pro-
member panel. The cheese samples were kept
cessed cheese foods with added WPC.
at 18 oC overnight preceding sensory evalua-
Trisodium citrate and disodium phosphate
tion. The order of testing was randomized. To
emulsifiers added in equal proportion at
assist the judges in describing defects, the
scores sheet included a list of suggested f1a-
2.0, 2.5 and 3.0% levels also failed to irn-
vour, consistency and appearance defects. The
prave the texture of cheese foods. The
judges were asked to give an overail score
sandiness
appeared
in
ail
processed
ranging between 1-7, where 7 = excellent, 6 =
cheese food samples even with a low 5%
very good, 5 = good, 4 = fair, 3 = poor, 2 = very
WPC solids.
poor and 1 = extremely poor.
Other measures such as addition of
WPC 0.5 h before heat processing, just be-
Statistical analysis
fore pracessing or during heat pracessing
had no effect on preventing sandy or
.: The data were analysee. wherever necessary,
chalky texture in cheese foods. An attempt
for 2-way analysis of vatiance with interaction
to manufacture pracessed cheese foods in

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Processed
cheese with WPC
205
a Stephan Universal Machine, employing
a
ry scores of processed
cheese foods. Dif-
high-speed
cutting device (3 000 rpm) and
ferent WPC affected
the flavour
and con-
direct steam injection, succeeded
in giving
sistency scores of processed
cheese foods
a smooth textured
product, but only under
highly significantly
(P < 0.01). Amongst the
conditions
of more than 55% moisture.
At
different
WPC used, WPCD
(16.5) irnpart-
that high moisture
level, the cheese
food
ed a significantly
better flavour
score (CD
was very weak in body and unacceptable
= 0.253)
to the final product,
while WPC
to the judges.
(18.3) and WPC (26.1) resulted
in signifi-
Lastly, an attempt was made using triso-
cantly
better
consistency
scores
(0
=
dium citrate alone as emulsifier, as is done
0.335) compared
to WPCD
(13.0).
For a
in India. This emulsifier
when used at the
higher level of WPC incorporation,
a higher
3% level prevented
the. development
of a
UF concentration
was necessary
to bring
sandy
texture
in the cheese
foods
even
the moisture
content
to within acceptable
when
up to 25% cheese
solids were re-
upper limits in processed
cheese foods. To
placed
with
WPC
solids
(table
III). The
avoid extra moisture,
salts and emulsifying
stage at which WPC was added, as men-
salts were added in- dry form, and this did
tioned earlier, did not affect the quality of
not affect the sensory
quality
of the final
the final product.
product.
The addition
of diafiltered
WPC tended
to have a negative effect on the consisten-
EffectofdifferentWPC
cy of processed
cheese foods. The effect
was more prominent
at higher levels (15-
Table Il shows the effect of different WPC
25%)
of WPC
addition
(table
III). When
replacing 10% cheese solids on the sense-
WPCD (23.6) and WPC (26.1) were corn-
Table
Il. Average
sensory
scores of processed
cheese foods with 10% cheese solids replaced
with
different WPC.
Influence
du remplacement
de 10% de la matière sèche fromagère
par différents
CPL sur les carac-
téristiques
sensorielles
des fromages
fondus.
Characteristics
Type of WPC used
of processed
cheese foods
WPC (18.3)
WPC (26.1)
WPCD (13.0)
WPCD (16.5)
Moisture (Olof
43.5
44.9
45.2
45.3
Flavour
4.9
4;9
5.1
5.4
Consistency
5.9
5.8
5.2
5.6
Appearance
5.8
5.9
6.0
5.9
Overall
5.8
5.8
··5.4
5.6
acceptability

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206
VK Gupta, H Reuter
Table III. Effect of diafiltered
WPC on the average sensory scores of processed
cheese foods.
Effet de la diafiltration
des CPL sur les caractéristiques
sensorielles
des fromages
fondus.
Characteristics
WPCD(23.6)
WPC (26.1)
of processed
cheese foods
15%
20%
22.5%
20%
22.5%
25%
Moisture (%)
45.1
46.1
47.6
47.2
46.9
47.4
Flavour
5.8
4.5
3.2
6.0
6.0
5.8
Consistency
6.0
3.5
2.5
5.5
5.1
4.5
Appearance
6.0
5.8
5.1
6.0
5.2
5.0
Overall
acceptability
6.0
4.1
3.2
5.8
5.5
5.1
pared at 20 and 22.5% levels of addition in
WPC, processed cheese foods scored
processed cheese foods, their flavour,
5.7-6.0 in the vicinity of 44.9, 45.9 and
consistency
and
overall
acceptability
46.7% moisture content respectively. A
scores were observed to be affected high-
higher moisture level than this resulted in a
Iy significantly (P < 0.01) with the type and
softer product while a lower moisture level
levels of WPC addition. The higher level
made the body of the product harder and
and diafiltration of WPC showed substan-
brittle.
tial adverse effects on the sensory quality
of processed cheese foods.
Effect of different levels
of trisodium citrate
Effect of different moisture content
ln order to determine the optimum level of
Figure 1 illustrates the consistency scores
trisodium citrate, processed cheese foods
of processed cheese foods with different
were prepared with 1.5, 2.0, 2.5 and 3.0%
moisture content when prepared with 3%
trisodium citrate. The amount of trisodium
trisodium citrate emulsifier and a varying
citrate added affected ail the sensory indi-
amount of cheese solids replacement with
ces of processed cheese foods (table IV)
WPC. It was observed that for better con-
highly significantly (P < 0.01). Processed
sistency (score, 5.7-6.0), the control sam-
cheese foods with 2.5 and 3.0% trisodium
pie had to have 41.4% moisture, whereas
citrate were judged to be much 'better in
for the same good consistency the mois-
consistency, appearance and overall ac-
ture content in processed cheese foods
ceptability than with 1.5 and 2.0% trisodi-
had to be increased proportionally with the
um citrate. On a flavour score basis, the
increaseof WPC addition. With 10, 15 and
product with 2.5% trisodium citrate was
20%
cheese
solids
replacement
with
judged to be best. It was observed that at

---

Processed
cheese with WPC
207
~
~
26
<.J
~ 24
CONSISTENCY
:%:
22
SCORE
...
i 20
0
5-7- 6-0
0
--- 5-0-5-2
~ 18
u
«
..J
16
Il.
~
œ 14
CIl
0
12
::::;
0
10
CIl
~
8
~
~
6
:%:
<.J
4
2
o
40
41
44
45
46
47
48
49
50
MOISTURE
(%1
Fig 1. Consistency
score of processed
cheese foods as affected
by different
amounts
of WPC and
moisture.
Consistence
des fromages fondus suivant l'apport de CPL et l'humidité.
Table IV. Effect of trisodium citrate level on the average sensory scores of processed
cheese foods.
Effet du taux de citrate trisodique sur les caractéristiques
sensoriel/es
des fromages
fondus.
Characteristics
Trisodium citrate (%)
of processed
cheese foods
1.5
2.0
2.5
3.0
Moisture (%)
44.0
44.5
44.6
45.3
Flavour
4.8
4.8
5.3
4.9
Consistenèy
3.1
4.2
5.2
5.1
Appearance
4.1
4.3
5.9
5.8
Overall acceptability
4.1
4.2
5.4
5.1
1.5 and 2% level of trisodium citrate, the
Standardized processed cheese foods
product was mostly sandy. At a 2.5% level
of trisodium
citrate,
the
product
was
A number of processed cheese foods were
smooth in consistency and was almost
prepared by replacing 20% cheese solids
comparable to cheese foods with 3.0% tri-
with WPC (26.1). Trisodium citrate in dry
sodium citrate.
form was added at 2.5 and 3.0% level and

---

208
VK Gupta, H Reuter
the moisture content in the final product
NDRI processed cheese from India and 3
maintained between 41.8 and 49.5%. It
Kraft processed
cheeses
(Kraft sliced
was observed that the consistency score
Chester, 45% fat; Kraft cream, 50% fat,
of := 6 was obtained at about 45.2 and
and Kraft Velveta, 20% fat in dry matter
46.5%
moisture content in processed
(DM)), from the German market (table V).
cheese foods prepared with 2.5 and 3.0%
The product scored slightly better than
trisodium citrate respectively (fig 2). At
even the control processed cheese. Ali the
higher or lower moisture content than this,
sensory indices of cheese foods were be-
the consistency scores were low.
tween 5.5 to 6.0 out of 7, showing their
good to very good acceptability. NDRI pro-
cessed cheese lacked typical cheese fla-
Comparative sensory quality
vour and had hard, crumbly and slightly
of standardized processed cheese food
mealy consistency. Ali Kraft cheeses also
with commercial processed cheeses
lacked typical cheese flavour and had a
very soft body. Amui processed cheese
The standardized processed cheese food
from India, because of its rich flavour and
prepared with 2.5% trisodium citrate and
smooth and firm consistency, scored best
20% WPC solids scored much better over
(6.0) in ail sensory indices.
TRI-SODIUM
CITRATE
6
2·50/0
3-0 0/0
'"
a:
o
o
III
5
>
o
Z
'"
...
III
III
Z
o 4
o
3
~(,'o
1
1
1
1
1
1
1
1
1
1
"
42
43
""
45
46
47
48
'9
50
MOISTURE
(010
)
Fig 2. Consistency
score of processed
cheese foods as affected by different
amounts of trisodium
ci-
trate and moisture.
Consistence
des fromages fondus suivant la teneur en citrate trisodique
et l'humidité.

---

Table V. Comparative
sensory scores of processed
cheese food and commercial
processed
cheeses.
Comparaison
des scores sensoriels
du fromage fondu expérimental
par rapport à ceux du commerce.
Characteristics
Processed
Control
Amui
NDRI
Kraft
Kraft
Kraft
""U
ël
cheese
processed
sliced
cream
Valveta
0
CD
food
cheese
Chester
(50% fat
(20% fat
(J)
(J)
(45% fat
in DM)
(in DM)
CD
c.
in DM)
0
zr
CD
CD
(J)
CD
Moisture (%)
45.2
41.3
45.4
41.8
48.4
50.8
59.4
§.
5'
Flavour
5.5
5.1
6.0
3.2
3.1
4.1
4.0
:E
""U
0
Consistency
5.8
5.4
6.0
4.1
4.1
5.2
4.2
Appearance
5.8
5.0
6.0
5.9
3.2
5.1
4.1
Overall acceptability
5.6
5.3
6.0
4.2
3.5
5.1
4.1
N
o
ID

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210
VK Gupta, H Reuter
DISCUSSION
duced by high speed rotating knives may
have increased the surface area of fat.
This, combined with high moisture content,
Effect of different emulsifying
salts
might have helped in the improved emulsi-
ficaton of proteins.
With the addition of WPC, the ratio of pro-
The better results obtained by using tri-
tein to fat in cheese becomes higher. In
sodium citrate as compared to other emul-
normal cheeses, where enough fat as weil
sifiers in the present study supports the
as water is present, one end of the protein
earlier findings of a number of workers
will dissolve inthe fat, the other end will
(Templeton and Sommer,
1930, 1932;
dissolve in the water and a homogenous
Gupta et al, 1984) that sodium citrate was
product will result. In the absence of suffi-
a better emulsifier than disodium phos-
cient fat, the excess or unemulsified pro-
phate. It is possible that the addition of this
tein separates into grainy or chalky water
emulsifying salt increased the surface area
phase deposits (Shimp, 1985). One way to
of fat to a greater degree.
increase the available fat is to increase the
degree of emulsification by adding emulsi-
fying salts. This increases the total surface
Effect of different
WPC
area of the fat without changing the
amount of fat present.
With the increase in UF concentration of
Joha emulsifying salts have been used
whey, protein, fat, ash and calcium content
in the
processed
cheese
industry
in
on a DM basis are increased in WPC (Hid-
Europe with great success for over 60
dink et al, 1981; Gupta and Reuter, 1987).
years. At the moment, there are about 20
So, with the use of WPC with higher total
different Joha emulsifying salts available
solids, greater amounts of these constitu-
for different processed cheeses. However,
ents
are
incorporated
into
processed
in most factories only a few of these 20 dif-
cheese foods. For a greater amount of pro-
ferent salts are used (Meyer, 1973). S-8
tein and calcium, better emulsifying action
and
S-10
are such
emulsifying
salts
is required in the processed cheese food
(Prokopek, 1986; personal communica-
systems for smooth consistency. Diafiltra-
tion). It may be possible to obtain good
tion of WPC further increases its protein
quality cheese food with some combina-
and calcium content (Gupta and Reuter,
tion of Joha salts, but the main difficulty
1987). The emulsifier has to retain cal-
with these salts is that their formulations
cium, solubilize protein and increase hy-
are kept secret by the company. Failure of
dration and swelling to facilitate emulsifica-
S-8 and S-10 Joha salts and combination
tion of fat during processing (Caric et al,
of trisodium citrate and disodium phos-
1985). As the amount of calcium phos-
phate emulsifying salts indicated that they
phate is increased, the solubility of casein
could not increase the emulsifying power
in water is decreased and so is its emulsi-
of fat sufficiently to take care of ail the pro-
fying capability. With higher UF concentra-
teins in the system. The sandiness and
tion, which is necessary for greater incor-
chalkiness in cheese foods are probably
poration of WPC solids
in processed
due to the separation of unemulsified pro-
cheese foods without undue increase in
teins.
moisture,
increased protein content
in
ln the Stephan Universal Machine, it is
WPC is inevitable. But the calcium content
possible that the homogenizing èffect pro-
can be kept low with suitable preheating

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