Advance Journal of Food Science and Technology 2(6): 335-339, 2010
ISSN: 2042-4876
© M axwell Scientific Organization, 2010
Submitted date: October 16, 2010
Accepted date: November 15, 2010
Published date: November 30, 2010
Improving the Processed Cheese Quality by the Addition of Natural Spice Extracts
1
K. K rumov, 2 G. Ivanov, 3 A. Slavchev and 4 N. Nenov
Department of Techno logy of M ilk and Dairy Products,
2
Department of Food Preservation and Refrigerated Technology,
3
Departm ent of Org anic Chemistry and M crobiolog y, Technolo gical Faculty,
University of Food Techno logies, Plovdiv , Bulgaria
4
Extractum L td., Plovdiv , Bulgaria
1
Abstract: The aim of the present study was to establish the possibilities for improv ing the processed cheese
quality by the addition of natural spice extracts. Four batches of processed cheese were produced by using of
Piper nigrum L., Satureja ho rtensis L. and their natural extracts. Control and test samples w ere stored at 5±1 ºC
for 10 da ys. Ea ch ba tch of processed cheese was analyzed for dry matter, p H, titrable acidity, fat and salt
content. Microbiological analysis of spices, spice extracts and processed cheese samples was p erformed.
Sensory evaluation of all batches was also performed. A similarity in the composition of control and test
samples was established. Total aerobic colony count of test samples was approximately 10 times lower than
in the controls. Processed chee ses produ ced by u sing of spice ex tract had higher sensory evaluation coefficients
than the controls. It was concluded that the replacem ent of Piper nigrum L. and Satureja ho rtensis L. spices
with their extracts improved significantly the processed cheese microbiological and sensory quality.
Key w ords: Microbial contamina tion, processe d che ese, sensory quality, shelf-life, sp ice extracts
INTRODUCTION
Processed cheese is a food product made by heating
a mixture of cheese, water, emulsifying salts and further
optional ingredients such as butter or spices. Production
of processed cheese and fac tors influe ncing its
characteristics have been described in many publications
(Caric and K alab, 1997; Guinee, 2004). Acc ording to
Chambre and Daurelles (1997), processed cheese products
usua lly retain the ir good quality for up to 6-12 months at
room temperature. Processed cheese is not a preserved
food, but a ‘semi-preserved food’ with a limited shelf-life
(Berger et al., 1989 ).
Mo st of the problems of the shelf-life and storage of
processed cheese were associated with problems caused
by microbial contamination. Microbiological hazards
during processed cheese production can be eliminated by
UHT processing: even temperature-resistant spores such
as Clostridium butyricum, Clostridium tyrobutyricum,
Clostridium sporogenes can be destroyed (Schar and
Bosset, 2002). Po st-sterilization infection could be
prevented by hot filling (85-95±1ºC) into the packing
(Sturm, 199 8).
The spices added are the main source of
contamination during manufacture of processed cheese. In
the available literature there were not reports for
application of spic e extracts fo r decre asin g
microbiological contamination of processed cheese. In
some cases milk ingredients used for processed cheese
mixture formulation could also be a source of
microbial contamination (Bhowmick et al., 2006;
Kumbhar et al., 2009). Usu ally these microorganism s did
not survive melting process.
The aim of the present study was to establish the
possibilities for improving the proce ssed cheese quality
by the addition of natural spice extracts.
MATERIALS AND METHODS
Processed cheese making: The ex periments were
performed during 2010 in the lab oratories of U niversity of
Food Technology, Plovdiv, Bulgaria. Processed cheese
samples were manufactured from blends of Kashkaval
cheese, curd, butter, water and em ulsifying salt (sodium
c i t r a te s , s o d i u m o r th o phosp hates or sodiu m
polypho sphates). The mixture was heated in a batch
cooker with constant agitation, until a homogene ous mass
is obtained. The melting temperature of processed cheese
was 85±1ºC and the total melting time was 15 min from
the beginning of heating to the beginning of discharge.
The spices and spice extracts w ere added to the mixture
after 5 and 10 min of heating, respectively. Portions of
100 g melted cheese were poured into PET cups with
sealab le lids. The filled cups were divided into four pa rts
Corresponding Author: G. Ivanov, Department of Food Preservation and Refrigerated Technology, Technological Faculty,
University of Food Technologies, 26 Maritza blvd., 4002 Plovdiv, Bulgaria
335
Adv. J. Food Sci. Technol., 2(6): 335-339, 2010
according to the spices or spice extracts added: processed
cheese with Satureja ho rtensis L. - control sample 1 (C1),
processed cheese with Piper nigrum L. - con trol sam ple
2 (C2), processed cheese with Satureja hortensis L.
extract - test sam ple 1 (T 1) and proce ssed cheese w ith
Piper nigrum L. extract - test sample 2 (T 2). Thereafter,
these samples w ere cooled d own to the temperature of
10±1ºC and w ere stored at 5±1ºC for 10 d ays.
Tab le 1: F ive p oint h edo nistic s cale
Sensory properties
Extremely dislike
Dislike
Neither like nor dislike
Like
Extremely like
Spices and spice extracts: For flavoring of processed
chee se the fo llowin g spices and extracts were used:
Sens ory
Sens ory
Sens ory
properties Significance evaluation
properties scores
coefficient
scores (SES)
Color
N3
C
Aroma
N5
A
Flavor
N8
F
Body
N4
B
Total Sensory Evaluation Score (TSES)
(from 20 to 100)
Total S enso ry Qu ality Co efficient (TS QC )
(from 1 to 5)
C
C
Score
1
2
3
4
5
Table 2: Calculation of sensory quality coefficient
Ground black pepper fruits (Piper nigrum L.),
country of origin Vietnam, crop 2009, bulk density
600 g/L
Dried savory herb (Satureja ho rtensis L.), country of
origin Bulgaria, crop 2009
Standardized extracts Botfex T M Black pepper and
Botfex T M Savory produced by Extractum Ltd., Bulgaria.
The extracts were derived on semi-industrial scale
extraction unit using sub-critical liquefied gas 1,1,1,2tetrafluoroethane (CAS-No. 811-97-2, Solkane 134a) as
food grade solvent according to EU flavoring regulations.
The extraction raw materials were the same as used for
cheese flavoring.
The standardized extract BotfexT M Black pepper has
the following technical data: INCI-Name (CTFA) Piper
Nigrum Extract, CAS-No. 84929-41-9, EINECS-No. 284524-7, appearance - brown clear oily liquid with yellow
crystals, pungent taste and strong characteristic smell of
raw material, volatile o il content - min.50% (v/w), piperin
content - min. 40% (w/w ), yield 25-32 Kg raw material per
kg extract, solvent residue - less than 0.1 g solvent/kg
extract. The extraction parameters: extraction time 60
min, temperature 20-23o C.
The standardised extract Botfex T M Savory has the
following technical data: IN CI-N ame (CTFA ) Sature ia
Hortensis Extract, CAS-No. 84775-98-4, EINECS-No.
283-922-8, appearance - dark brown viscous liquid w ith
strong characteristic smell of raw material, volatile oil
content - min.60% (v/w), yield 400-500 Kg raw material
per kg extract, solvent residue - less than 0.1 g solvent/kg
extract. The extraction parameters: extraction time 90
min, tem peratu re 20-2 3ºC.
Sens ory
Quality
Coefficient
(SQ C)
(from 1 to 5)
(C/20)
(A/20)
(F/20)
(B/20)
3 ( C , A, F, B )
(TSES/20)
processed cheese with 0.1 N NaOH using ph enolphthalein
as indicator; fat content was determined by the
acidobu tyric method of van Gulik according to ISO
3433:2008; salt con tent w as determined according the
meth od described b y Reddy and Marth (19 93). The
chemical analysis of processe d cheese samp les were
performed after 10 days of storage in a refrigerator at
6±2ºC. Chemical analyses were conducted in triplicate.
Microbiological analysis: The following microbiological
analy sis of spices and spice extracts were performed:
aerob ic colony count according to ISO 4833:200 4, yeasts
and moulds according to ISO 7954:200 2, Escherichia coli
according to ISO 16649-2:2002 , Salm onella spp.
according to ISO 6579:2002, coliforms according to ISO
16649-2:2002,
coagulase-positive
staph ylococci
according to ISO 6888-1:2005+A 1:200 5, anaerobic
sulfite-reducing bacteria according to ISO 15213:2003.
Processed cheese samples w ere analyzed for aerobic
colony count according to ISO 6610:2002, yeasts and
moulds according to ISO 6611:2002, coagulase-positive
staphylococci according to ISO 6888-1:2005+A1:2005
and anaerobic sulfite-reducing bacteria according to ISO
15213:2003 at the first day of the cold storage.
Sensory analysis: Processed cheese samp les were coded
and served in randomized order. Samples were presented
to the sen sory p anel at room temperature (20±2ºC). A
panel of 30 customers evaluated the follow ing sensory
properties: color, aroma, flavor and texture by using of
five points hedo nistic scale (Table 1). Sensory evaluation
was performed by calculating a sensory quality coefficient
for each cheese sam ple (Table 2).
Chem ical analysis: Each batch of processed cheese was
analy zed for dry m atter, pH , titrable acidity, fat and salt
content. Dry matter content was determined by drying at
102±2ºC to a constant weight according to ISO
5534:2004; pH was measured by pH-meter MS 2011
(Microsyst, Plovdiv, B ulgaria), with glass electrode (pH
electrode Sensoret, Garden Grove, CA, USA) at 20±2ºC;
titratable acidity was expressed as % lactic acid and was
determined by titration of water solution of 10 g
Statistical analysis: Statistical analyses were carried out
on the averages of the triplicate results. Data were
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Adv. J. Food Sci. Technol., 2(6): 335-339, 2010
Table 3. Physicochemical analysis of processed cheese samples
Phy sicoch emical p arame ters
---------------------------------------------------------------------------------------------------------------------------------------------------------Sam ple
pH
L ac tic ac id (% )
D ry ma tte r (% )
F at (% )
N aC l (% )
C1
5.54±0.06 a
1.23± 0.04 a
46 .5± 0.5 a
16 .2± 0.7 b
2.2 ±0 .3 c
G1
5.73±0.03 b
0.88+0.05 b
45 .8± 0.7 a
15 .4± 0.5 b
2.1 ±0 .1 c
C2
5.63±0.04 a
1.18+0.03 a
46 .2± 0.4 a
15 .5± 0.8 b
2.4 ±0 .3 c
G2
5.74±0.04 b
0.93+0.04 b
45 .6± 0.6 a
16 .5± 0.7 b
2.1 ±0 .2 c
a, b, c: means within same column bearing a common superscript did not differ significantly (p<0.05)
Table 4: Microbiological quality of spices and spice extracts used for processed cheese making
Sam ple
------------------------------------------------------------------------------------------------------------------------------Ground black pepper
Standardized extract
Dried savo ry herb
Standardized extract
fruits (P ip er ni gr um L.)
Botfex T M Black pepper
(Satureja hortensis L.)
Botfex T M Savo ry
Microorganisms groups
CF U/g
CFU /cm 3
CF U/g
CFU /cm 3
Aerobic colony count
1.7x10 6
2.5x10 2
3.4x10 3
<10 1
Moulds
<10 1
<10 1
2x10 1
<10 1
Ye asts
2x10 3
<10 1
<10 1
<10 1
Esc her ichia coli
<10 2
<10 2
<10 2
<10 2
Salm one lla
ND
ND
ND
ND
Coliforms
<10 2
<10 2
4x10 2
<10 2
3
2
2
Coagulase-positive staphylococci
1.3x10
<10
<10
<10 2
An aero bic su lfite-red ucin g ba cteria
8x10 1
<10 1
<10 1
<10 1
ND : not d etecta ble
analyzed by the analysis of variance (one-way ANOVA)
method with a significant level of p#0.05 (Draper and
Smith, 1998). The Duncan’s multiple comparison test
(SPSS) with a significant difference set at p#0.05 was
used to compare sample means. Significant differences
between means less than 0.05 were considered
statistically significant (Kenward, 1987). All statistical
procedures were computed using the Microsoft Excel and
Sigma Plot 2001 software.
microbial grow th and activity during storage period. The
results obtained (Tab le 3) for pH values and lactic acid
content of con trol sam ples did not differ significantly
(p<0.05). Similar tendency was foun d for the test sam ples.
Microbiological analysis: Results from microbiological
analy sis of natural spices and spice extracts (Table 4) used
for processed cheeses production showed similarity of
Escherichia coli and Salm onella counts in all studied
samples. Small differences were found in moulds, yeasts,
coliforms, coagulase-positive staphylococci and anaerobic
sulfite-reducing bacteria counts of all studied samples. It
was found that ground black paper samples had higher
con tamina tion w ith ye a s ts , c oa gula s e -po sitive
staphylococci and ana erobic sulfite-reducing bacteria in
comparison with the dried savory samples. Results
obtained (Table 4) showed hig her co ntamination with
moulds and coliforms of dried savory samples in
comparison with their natural extracts. Most significant
difference between spices and their natural extracts was
established for aerobic colony count. Aerobic colony
counts of ground black paper and dry savory were with 4
and 3l g, resp ectively high er in compa rison w ith their
extracts. All these results allow a conclusion to be made,
that the microbiological contamination of spice extracts is
significa ntly lower than that of the corresponding natural
spices. As it is evident from the results for aerobic colony
count, the spices cou ld be an imp ortant source of
processed cheese m icrobial contam ination. In contrast to
them the spice extracts had significantly lower microbial
contamination.
Evaluation of the effect of replacemen t of spice s with
natural spice extracts on processed cheese microbiological
RESULTS AND DISCUSSION
Chem ical analysis: The results obtained from the
chemical analysis showed similarities in the composition
of control and experimental batches of processed cheese
(Table 3). The dry m atter, fat and salt contents of control
and test processed cheese samples did not differ
significa ntly (p<0.05). A ccording to Schar and
Bosset (2002) the main factors influencing the changes in
processed cheese d uring storage are product composition,
processing, packaging and storage conditions (time and
temperature). The similarity in chemical composition of
all studied samples found in present study could be
explained with the uniformity of the factors mentioned
above. Minor differences were observed in pH values and
lactic acid content of control and test samples (Table 3).
The pH values of samples C1 and C2 were lower than
those of samples T1 and T2 w ith 0.19 and 0.11,
respectively. In correspondence with these results the
lactic acid content of control samples C1 and C2 was
higher with 0.35 and 0 .25 % , respectively in comparison
with the test sample s T1 and T 2. These ten dencies co uld
be explained w ith the higher microbial contamination of
control samples (T able 5) contributing for more intensive
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Adv. J. Food Sci. Technol., 2(6): 335-339, 2010
Table 5: M icrobiological quality of processed cheese sa mples
Sam ple
---------------------------------------------------------Microorganisms
C1
T1
C2
T2
groups
CF U/g
CF U/g
CF U/g
CF U/g
Aerobic colony count 3.6 N10 4
2N10 3
3x10 3
2x10 2
M ould s, Ye asts
<10 1
<10 1
<10 1
<10 1
Coagulase-positive
<10 2
<10 2
<10 2
<10 2
staphylococci
Anaerobic sulfite<10 1
<10 1
<10 1
<10 1
redu cing bac teria
quality was performed by determination of microbial
contamination of control and test sam ples (Table 5).
Results obtained showed, that there were not significant
(p<0.05) differences in coagulase-positive staphylococci
and anaerobic sulfite-reducing bacteria counts of the
studied samples. That fact could be explained with the
effect of melting temperature (85±1ºC) on the
microorganisms presented in processed cheese mixture.
Evidently, the microorganisms groups mentioned above
did not survived during processed cheese production.
Different tendency was established for aerobic colony
count of studied sam ples. R esults obtained (Table 5)
showed, that total microbial contamination of test samples
was approximately 10 times lower than in the controls. It
could be explained with the presence of thermo-durable
microorganism, which spores could survive during
processed cheese manufacture. Higher aerobic colony
count of control samples in comparison with test
processed cheeses could be attributed to some spices of
genus Bacillus which are common contaminants of spices.
It could be assumed, that the lower total microbial
contamination of test samples (Table 4) in comparison
with th e con trols to the great extend is due to these heatresistible microorganisms. Besides, some molds also
could survive melting procedure. Regardless of the
similarity in yeast and molds count at the first day of the
cold storage (Table 5) an intensive molds growth on the
control samples surface was observed at the 10-th day of
experiment. Probably, some heat resistible m ould spores
have germinated d uring this period. Sim ilar results were
found by Nour El-Diam and El-Zubeir (2006) who
compared the microbiological quality of processed and
non processed Sudanese white cheese. The results
obtained (Table 4 and 5), showed that replacement of
Piper nigrum L. and Satureja hortensis L. sp. w ith their
extracts improved significantly the processed cheese
micro biolog ical quality.
Fig. 1: Sensory evaluation of processed cheese samples
produced with Piper nigrum L. and Satureja hortensis
L. sp. and spice extracts
(p<0.05). The main difference between control and test
samples was found in sensory evaluated color. The color
SQC of T1 and T2 samples was higher than the control
samples C1 and C 2 with 0.6 and 0.4, respectively. Th ere
are several factors influencing color changes during
storage of processed cheese: nonenzymatic browning,
oxidation, enzy matic activity as we ll as interactions with
packaging material. According to Kristensen et al. (2001)
the light exposure had little if any influence on processed
cheese browning. The authors reported for absence of
browning of processed cheese during storage at 5ºC. In
the present study were not found significant differences in
chemical composition of all tested samp les (Table 3).
Therefore, it could be assumed that microbial activity was
respo nsible for the negative color changes during storage
of control samples. This statement is confirmed by the
intensive molds growth, observed on the surface of
control samples at the end of the experiment (10th day of
cold storage ). Evidently, reduced microbial contamination
of test samp les (Table 5) contribu ted to better preservation
of proce ssed cheese sen sory q uality during cold storage.
It was found that test samples had higher flavor and taste
SEQ than the controls, while the body SEQ of alls studied
samples did no t differ sign ificantly (p<0.05). According
to Piska and Stetina (2004), cheese ripening and rate of
cooling of the processed cheese mixture influenced
significa ntly rheological properties of processed cheese.
In the present study these factors, as well as the cheese
composition were identica l. This could be an explanation
for the similarity of body SEQ of control and test samples.
Sensory analysis: Results obtained from sensory
evaluation of studied samples showed, that replacement
of Piper nigrum L. and Satureja hortensis L. sp. with their
extracts had significant effect on the processed cheese
sensory quality (Fig. 1). TSQC of test samples T1 and T2
was higher than the control samples C1 and C2 with 0.41
and 0.43, respectively, w hich w as statistica lly significant
CONCLUSION
It could be conclude d that replacem ent of Piper
nigrum L. and Satureja ho rtensis L. sp. w ith their extracts
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Adv. J. Food Sci. Technol., 2(6): 335-339, 2010
improved significantly processe d che ese quality. A
decreased microbiological contamination and better
sensory properties of test processed cheese sam ples were
established.
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ACKNOWLEDGMENT
The authors express their gratitude to the company
Extractum Ltd. Plovdiv, Bulgaria for the technological
and financial support of the present research.
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