EFFECT OF ADDING LEEK AS A NATURAL SOURCE OF NITRITE ON THE PROCESSING AND QUALITY PROPERTIES OF CAMEL SAUSAGE DURING FROZEN STORAGE

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*Corresponding author: Email: angyfayz@yahoo.com;
Original Research Article
Journal of Advances in Food Science & Technology
5(1): 27-33, 2018
ISSN: 2454-4213
EFFECT OF ADDING LEEK AS A NATURAL SOURCE OF
NITRITE ON THE PROCESSING AND QUALITY
PROPERTIES OF CAMEL SAUSAGE DURING
FROZEN STORAGE
ENGY, F. ZAKI
1*
AND MOHAMED, F. KHALLAF
2
1
Meat Production and Technology Unit, Department of Animal Breeding, Desert Research Center,
Cairo, Egypt.
2
Department of Food Science, Faculty of Agriculture, Ain Shams University, Cairo, Egypt.
AUTHORS’ CONTRIBUTIONS
This work was carried out in collaboration between both authors. Author EFZ designed the study, performed the
statistical analysis, wrote the protocol, and the first draft of the manuscript. Authors MFK managed the analyses
of the study, managed the literature searches and revised the final draft of the manuscript. Both authors read and
approved the final manuscript.
ARTICLE INFORMATION
Editor(s):
(1)
Zhao Chen, Clemson University, USA.
Reviewers:
(1)
Małgorzata Gniewosz, Warsaw University of Life Science, Poland.
(2)
Enver Baris Bingol, Istanbul University, Turkey.
Received: 27
th
December 2017
Accepted: 5
th
March 2018
Published: 14
th
March 2018
__________________________________________________________________________________
ABSTRACT
The objective of this research was to determine the effect of adding various levels of leek as a natural source of
nitrite in the manufacturing of camel sausage and investigated its impact on the quality characteristics of the
prepared product compared to camel sausage formulated with nitrite. The nitrite content increased as the level of
leek increased. The level of leek had no effect on the cooking loss of sausage samples. T.B.A values of
formulated samples were significantly deceased after 45 days and such increase was continued as the time of
frozen storage increased. Formula (1) recorded the lower shrinkage followed by formula (2). No significant
differences in (a*) value during frozen storage for all sausage samples. The overall acceptability of formula (1)
and (3) had the higher score compared to control sausage samples.
Keywords: Camel sausage; leek; quality characteristics.
1. INTRODUCTION
The role of nitrites in curing of meat
products contributes to the development of a
characteristic cured meat color. Also, nitrite plays a
key role in cured meat as a bacteriostatic
and bacteriocidal agent. Nitrite is strongly
inhibitory to anaerobic bacteria, most importantly
Clostridium botulinum and contributes to control
of other microorganisms such as Listeria

Zaki et al.; JAFSAT, 5(1): 27-33, 2018
28
monocytogenes [1]. It is also a potent antioxidant
[2]. Over the last 20 years dietary nitrite
has been associated with methemoglobinemia and
formation of carcinogenic nitrosamines in human.
This has led to restrictions of nitrate and nitrite levels
in food [3].
Fresh leeks are a good source of nitrates, flavonoids,
polysaccharides and glucosinolates in addition to
numerous organosulfur components contributing to
their rich flavor [4-6]. Epidemiological and laboratory
studies have suggested that Allium vegetables have
tumor-inhibitory properties. The consumption of leeks
reduces risk of prostate, colorectal, stomach and
breast cancer [7,8]. The anti-carcinogenic action may
be related to the high content of organosulfur
compounds and other biophenols with high
antioxidant activity [9-11]. Among Allium genus, the
wild leek or broadleaf wild leek (Allium
ampeloprasum L.) is native to the Mediterranean
region (south Europe, northern Africa to west Asia). It
is a specie closely related to leek (Allium porrum L.),
that have been traditionally considered as its wild
progenitor.
Camel meat is known to be more beneficial for health
because it contains lower fat and cholesterol levels
than other red meats [12]. Generally, consumers are
prejudiced against fresh camel meat. If camel meat
could be converted into processed products such as
burger and sausage, it might be more acceptable to
domestics’ consumers. [13]. However, no research
has been conducted to investigate the effect of
added leek on the quality characteristics of camel
sausage.
This study aims to investigate the effect of added leek
on camel sausage to determine the optimum level to
improve the quality characteristics of camel sausage
during frozen storage.
2. MATERIALS AND METHODS
The present work was carried out at Desert Research
Center (DRC), Ministry of Agriculture and Land
Reclamation, and Food Science Department, Faculty
of Agriculture, Ain-Shams University.
2.1 Preparation of Camel Sausage
Camel meat and humped fat obtained from local
slaughter house were used in this study. Left round
(Biceps femoris muscle) of 3-4 years aged camel was
pooled to form an experiment unit, with three batches
of lean ground meat being prepared from each
sausage formulation. All knives –separable fat was
removed from muscles and used with humped fat as
fat source. Lean meat was ground through a 3mm
plate grinder. The ground meat was transferred to
bowl chopper and the following additives (Table 1)
were added and mixed as described by Zaki [14].
Each formula was stuffed into natural casings (sheep
intestines). Sausage was tiered into 10 cm length and
placed in plastic foam trays, packed in polyethylene
bags and frozen at -18ºC±1 for 90 days.
2.2 Physical Analysis
2.2.1 pH
Camel sausage pH was measured as described by
Hood [15].
2.2.2 Cooking measurements
Sausages were roasted in a preheated oven for 10 min.
All cooking measurements were carried out on three
replicates of each treatment. Cooking yield percent
was determined by calculating weight deference of
samples before and after cooking. The cooking yield
was determined as reported by Naveena et al. [16] as
follows:
Cooking yield (%) = (Cooked sample weight) / (Uncooked sample weight) ×100
Shrinkage measurement: Raw and cooked samples were measured for diameter and thickness as described by
Berry [17] using the following equation:
Reduction in width (%) = (Uncooked sample width) - (Cooked sample width) ×100
(Uncooked sample width)
Reduction in length (%) = (Uncooked sample length) - (Cooked sample length) ×100
(Uncooked sample length)
Shrinkage (%): Dimensional shrinkage was calculated using the following equation as reported
by Murphy et al. [18] = [(Raw length - Cooked length) + (Raw width - Cooked width)] ×100
(Raw length +Raw width)

Zaki et al.; JAFSAT, 5(1): 27-33, 2018
29
Table 1. Camel sausage formulations
Ingredients
Treatments
Control (-) Control (+) Formula (1) Formula (2) Formula (3)
Camel meat(g)
1400
1400
1400
1400
1400
Camel fat(g) 240 240 240 240 240
1
Leek
----
----
150
250
350
2
Nitrite ---- 150 ---- ---- ----
Onion(g) 100 100 100 100 100
Salt(g) 60 60 60 60 60
Ice(g) 10 10 10 10 10
3
Ascorbic acid
500
500
500
500
500
4
Spices mix(g) 30 30 30 30 30
1
Leek: (nitrite 204.67 ppm);
2
Nitrite (Sodium nitrite 150 ppm);
3
Ascorbic acid: (ppm);
4
Spices mixture consists of: (30 g
black pepper, 8 g red pepper, 8 g ginger, 8 g carnation, 8 g coriander, 8g cubeb, 15 g Cinnamon and 15g spices).
2.2.3 Color measurements
Meat color was measured by Chroma meter (Konica
Minolta, model CR 410, Japan) calibrated with a
white plate and light trap supplied by the
manufacturer. Color was expressed using the CIE L,
a, and b color system CIE [19]. A total of three
spectral readings were taken for each sample on
different locations. Lightness (L*) (dark to light), the
redness (a*) values (reddish to greenish). The
yellowness (b*) values (yellowish to bluish) were
estimated.
2.3 Chemical Analysis
2.3.1 Measurement of lipid oxidation
The extent of lipid oxidation in camel sausage was
assessed by measuring 2- thiobarbituric acid reactive
substances (TBARS), as described by AOCS [20].
2.3.2 Nitrite content
Nitrite content in plant tissues and camel sausage was
determined by A.O.A.C. [21].
2.4 Sensory Evaluation
Camel sausage was subjected to organoleptic
evaluation as described by A. M. S. A. [22]. Ten
panelists of staff members of Food Science
Department, Faculty of Agriculture, Ain-Shams
University were scored appearance, texture, juiciness,
flavor, tenderness and overall acceptability using a 9-
point hedonic scale. The mean scores of the obtained
results of organoleptic evaluation were then
statistically analyzed.
2.5 Statistical Analysis
All data generated from each treatment were analyzed
using statistical analysis system SAS, [23]. Two- way
ANOVA was applied for pH, TBA, color, nitrite
content, cooking loss and shrinkage measurements. In
case of sensory evaluation one – way ANOVA was
applied.
3. RESULTS AND DISCUSSION
The pH values of camel sausage formulated with
different levels of leek were showed in Table (2).
Sausage formulated with leek had a higher pH value
than control (+ and/or -) groups. Also, it can be
noticed that pH value was increased as the level of
leek increased. During frozen storage pH value of
control groups (-/+) and formula (1) remained almost
constant after 45 days of storage and decreased after
90 days of frozen storage. While, pH value of formula
(2) and (3) was decreased as frozen storage time
increased. These differences in pH value may be due
to the higher carbohydrates content in fresh leek
which used in formula (2) and (3) in higher levels
Magra et al. [24].
The nitrite content of camel sausage (Table 3) was
significantly affected by leek level and storage time.
The nitrite content increased as the level of leek
increased. Also, the nitrite content of all camel
sausage was significantly decreased as the time of
frozen storage increased. At the end of frozen period,
the reduction of nitrite content in sausage formulated
with different levels of leek was higher than control
ones. Therefore, the use of fresh leek as a natural
source of nitrite in the formulation of camel sausage,
resulting in low concentration of nitrite in the final
products during storage time. These results are close
to that obtained by [24] they found that sausage
manufacture with fresh leek had the lowest nitrite
content.
T.B.A value of control and formulated sausages
stored under frozen storage were presented in Table
(4). Formula (2) and (3) had higher T.B.A value than
other groups. These results are close to that obtained
by [3,24]. During frozen storage, T.B.A value of

Zaki et al.; JAFSAT, 5(1): 27-33, 2018
30
control (-) sample significantly increased after 90days
of frozen storage. While, T.B.A value of control (+)
and formulated samples were significantly deceased
after 45 days and such increase was continued as the
time of frozen storage increased.
The decrease in T.B.A value of control (+) sample
may be due to antioxidant activity of both nitrite and
ascorbic acid during manufacturing. While, the
reduction in T.B.A value of formulated samples may
be due to antioxidant activity of leek which diffused
during storage to sausage sample. In addition,
decreasing and /or increasing of T.B.A. values may be
due to the instability of produced malonaldehyde
and/or the oxidation of different types of lipid at
different storage time Munoz et al. [25].
Table (5) showed the cooking loss and shrinkage
measurement of control and formulated camel sausage
during frozen storage. At zero time, cooking loss % of
control sausage sample recorded the higher cooking
loss than sausage formulated with leek. The level of
leek had no effect on the cooking loss of sausage
samples. Cooking loss increased as the time of frozen
storage increased for both control and formulated
sausage samples. However, the increase of cooking
loss during frozen storage is probably due to the
excessive fat separation and water released, which
occurred from breaking the emulsion during cooking
as reported by Trius et al. [26]. From the same table,
sausage of formula (1) had the lowest reduction in the
length and in the width, while the higher reduction in
both length and width were found in formula (3).
Formula (1) recorded the lower shrinkage followed by
formula (2). Generally, shrinkage % increased as the
time of frozen storage increased for all sausage
samples.
Table 2. pH value of camel sausage during frozen storage at 18ºC
Treatments Storage period (day)
0 45 90
Control (-) 6.03±0.04
Ca
6.01±0.04
Cab
5.95±0.07
BCb
Control (+) 6.08±0.01
Ca
6.07±0.01
BCa
6.01±0.01
Bb
Formula (
1
)
6.16±0.01
Ba
6.13±0.01
Ba
5.90±0.02
Cb
Formula (2) 6.24±0.02
Aa
6.16±0.02
ABb
6.01±0.02
Bc
Formula (3) 6.28±0.01
Aa
6.19±0.01
Ab
6.07±0.02
Ac
a-c
different superscripts in the same row are significantly different (P =.05).
A-C
different superscripts in the same column are significantly different (P =.05).
Means± standard deviation of analysis in triplicate.
Table 3. Nitrite content of camel sausage during frozen storage at 18ºC
Treatments Storage period (day)
0 45 90
Control (-) - - -
Control (+) 127.50±2.50
Aa
69.45±1.09
Ab
37.44±1.04
Ac
Formula (
1
)
14.44±1.76
Da
15.50±2.70
Da
4.60±1.36
Bb
Formula (2) 44.61±1.39
Ca
35.50±2.72
Bb
6.09±1.16
Bc
Formula (3)
63.48±1.74
Ba
28.39±1.03
Cb
3.02±0.99
Bc
a-c
different superscripts in the same row are significantly different (P =.05).
A-D
different superscripts in the same column are significantly different (P =.05).
Means± standard deviation of analysis in triplicate.
Table 4. T.B.A value of camel sausage during frozen storage at 18ºC
Treatments Storage period (day)
0 45 90
Control (-) 0.040±0.002
CDb
0.008±0.005
Bc
0.083±0.002
Ca
Control (+) 0.052±0.005
Ca
0.018±0.001
Bb
0.044±0.003
Da
Formula (
1
)
0.038
±0.002
Db
0.017
±0.001
Bc
0.114
±0.008
Ba
Formula (2) 0.083±0.005
Ab
0.016±0.001
Bc
0.126±0.008
Aa
Formula (3)
0.068
±0.008
Bb
0.033
±0.004
Ac
0.131
±0.004
Aa
a-c
different superscripts in the same row are significantly different (P =.05).
A-D
different superscripts in the same column are significantly different (P =.05).
Means± standard deviation of analysis in triplicate.

Zaki et al.; JAFSAT, 5(1): 27-33, 2018
31
Table 5. Cooking loss and shrinkage measurements of camel sausage during frozen storage at 18ºC
Treatments Storage period (days)
0 45 90
Cooking loss (%)
Control (-) 32.66±0.09
Ab
37.56±1.64
Aab
39.44±1.20
Aa
Control
(+)
35.39±1.21
Aa
36.40±1.25
Aa
38.80±0.95
Aa
Formula (1) 22.97±2.63
Bb
28.72±0.63
Ba
30.53±0.58
Ba
Formula (
2
)
23.01±0.57
B
b
26.54±0.16
Bab
28.87±0.11
Ba
Formula (3) 20.41±1.41
Bb
25.47±3.05
Ba
27.13±3.25
Ba
Reduction in length (%)
Control (-) 13.09±1.68
Ba
13.85±1.68
BCa
15.33±0.63
Ba
Control
(+)
12.27±0.68
Bb
14.45±0.31
Bab
15.31±1.31
Ba
Formula (1) 8.49±1.02
Ca
9.73±0.29
Ca
10.75±1.39
Ca
Formu
la (
2
)
10.23±0.50
BCb
12.12±1.22
BCab
12.94±0.28
BCa
Formula (3) 17.20±0.97
Ab
19.09±2.17
Aab
19.84±0.74
Aa
Reduction in width (%)
Control (-) 23.55±2.04
Aa
24.17±2.03
Aa
27.04±0.96
Aa
Control
(+)
21.32±5.20
ABa
21.12±2.77
Aa
23.63±3.63
Aa
Formula (1) 14.93±3.56
B
a
15.72±1.70
Ba
17.54±1.08
Ba
Formula (
2
)
15.10±0.88
Ba
15.47±3.88
Ba
16.28±0.45
Ba
Formula (3) 11.58±0.31
BCa
15.93±3.77
Ba
17.19±3.81
Ba
Shrinkage (%)
Control (-) 13.93±0.85
Ab
19.00±0.44
Aa
16.90±3.95
Bab
Control
(+)
15.07±0.58
Ab
17.01±0.77
Aab
18.59±1.22
ABa
Formula (1) 11.73±1.33
Bb
14.04±1.25
Bab
16.18±2.44
Ba
Formula (2) 12.27±0.48
Ab
14.91±0.25
ABab
16.14±0.53
Ba
Formula (3) 14.48±0.48
Ab
17.05±0.39
Aab
19.34±0.43
Aa
a-b
different superscripts in the same row are significantly different (P =.05).
A-C
different superscripts in the same column are significantly different (P =.05).
Means± standard deviation of analysis in triplicate.
Table 6. Color measurements of camel sausage during frozen storage at 18ºC
Treatments Storage period (days)
0 45 90
L*
Control (-) 41.59±0.19
Ab
43.82±0.76
Aa
42.69±0.58
Ab
Control (+) 36.33±0.22
Dc
41.35±0.26
Ba
39.80±0.07
Cb
Formula (
1
)
38.77±0.49
Cb
40.41±0.60
Ba
40.86±0.17
Ba
Formula (2) 37.30±0.67
Db
40.38±0.37
Ba
40.35±0.27
Ba
Formula (3)
40.10±0.61
Bb
40.65±0.76
Bab
41.36±0.13
Ba
a*
Control (-) 7.68±0.02
Aa
7.57±0.02
Aa
7.87±0.14
Ba
Control (+) 7.75±0.14
Ab
8.08±1.74
Aab
9.29±0.07
Aa
Formula (
1
)
1.79±0.16
Ba
1.31±0.02
Ba
1.68±0.01
Ca
Formula (2) -0.90±0.16
Ca
-1.65±0.05
Ca
-1.27±0.15
Da
Formula (3)
-
3.10±0.09
Da
-
2.29±0.05
Da
-
2.94±0.09
Ea
b*
Control (-) 9.06±0.01
Bb
10.53±0.08
Aa
10.10±0.18
Ca
Control (+) 7.11±0.09
Cc
8.47±0.15
Cb
9.54±0.09
Da
Formula (
1
)
9.06
±0.16
Bb
10.53
±0.27
Aa
10.10
±0.06
Ca
Formula (2) 8.78±0.52
Bc
10.19±0.15
Ab
11.56±0.03
Aa
Formula (3)
11.57
±0.24
Aa
10.61
±0.08
Ab
10.81
±0
.10
Bb
a-c
different superscripts in the same row are significantly different (P =.05).
A-D
different superscripts in the same column are significantly different (P =.05).
Means± standard deviation of analysis in triplicate.

Zaki et al.; JAFSAT, 5(1): 27-33, 2018
32
Table 7. Sensory evaluation of camel sausage
Treatments Appearance Texture Juiciness Flavor Tenderness Overall
acceptability
Control
(
-
)
7.77
±
0.53
b
7.44
±
0.67
ab
7.77
±
0.52
b
7.55
±
0.71
b
7.55
±
0.52
b
7.55
±
0.63
b
Control (+) 8.50±0.82
a
7.70±0.53
a
8.60±0.67
a
8.40±0.52
a
8.50±0.52
a
8.22±0.53
a
Formula (1) 6.60±0.70
c
6.70±0.67
c
7.30±0.67
bc
7.30±0.67
bc
7.10±0.88
b
7.20±0.92
bc
Formula (2)
6.90
±
0.32
c
7.00
±
0.47
bc
6.70
±
0.32
c
6.90
±
0.32
c
7.00
±
0.47
b
6.90
±
0.32
c
Formula (3) 7.20±0.79
bc
7.00±0.82
bc
7.20±0.79
bc
7.00±0.70
bc
7.20±0.63
b
7.60±0.52
b
a-c
means within the same column with different superscripts letters are different (P =.05).
Means± standard deviation
Color measurements of control and formulated camel
sausage during frozen storage were presented in Table
(6). Sausage of control (+) had the lowest lightness
(L
*
value), while control (-) had the highest one.
Addition of leek had significant effect on the redness
of sausage samples. Sausage formulated with leek had
lower redness a* value than control. This is due to the
green color of fresh leek which affects the redness of
the prepared sausage. These results are close to that
obtained by [3] they found that sausage formulated
with high levels of leek had lower redness. No
significant differences in (a
*
) value were detected
during frozen storage for all sausage samples. Sausage
of formula (3) had higher (b*) value than other
sausage samples. No significant differences were
found in (b*) value between control and other
formulated ones.
Sensory evaluation of camel sausage formulated with
various levels of leek are shown in Table (7). The
control (+) had the highest score for appearance than
other groups. No significant differences were found in
formula (1) and (2). Also, it can be found that no
significant differences were found in tenderness score
for formulated sausage which means that the level of
leek had no effect on the tenderness of sausage. For
overall acceptability of formula (1) and (3) had the
highest score compared with control sausage samples.
4. CONCLUSION
Addition of leek in the formulation of camel sausage
improved the cooking measurements, reducing the
nitrite content and T.B.A values in the final product
during frozen storage. Also, it can be found that no
significant differences were found in tenderness score
for formulated sausage which means that the level of
leek had no effect on the tenderness of sausage. For
overall acceptability of formula (1) and (3) had the
highest score compared with control sausage samples.
Leek can successfully used as a natural source of
nitrite in meat products.
COMPETING INTERESTS
Authors have declared that no competing interests
exist.
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