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The purpose of this research was to study the effect of freeze-drying process on camel's milk nutritional characteristics compared with fresh milk. The results showed that the protein, casein, whey proteins, lactose and ash percentage were significantly higher (P< 0.05) in freeze-dried skim milk than fresh milk. The average of mineral contents in reconstituted freeze-dried skim camel's milk was slightly higher than that of fresh camel milk except Ca, K and P contents. On the other hand, freeze-dried skim camel's milk had a slightly higher concentration of water-soluble vitamins except vitamin C. Vitamins B, A, D and E showed relatively stable values after freeze-drying treatment. Freeze-drying process skim camel's milk was characterized by slightly higher contents of all amino acids. Freeze-dried whole milk showed higher contribution of Protein efficiency ratio, Biological value and Net protein utilization than that of fresh whole milk. Freeze-dried process had a little effect on fatty acid profile in camel milk fat. Nutritional properties of lyophilized camel's milk remained basically unchanged compared with fresh milk.
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*Corresponding author.
Email: salaha.khalifa@gmail.com
Tel: 0020552282360; Fax: 0020552287567
International Food Research Journal 22(4): 1438-1445 (2015)
Journal homepage: http://www.ifrj.upm.edu.my
1Ibrahim, A. H. and 2*Khalifa, S. A.
1Department of Animal and Poultry Breeding, Desert Research Center, Cairo, Egypt
2Food Science Department, Faculty of Agriculture, Zagazig University, Zagazig 44519, Egypt
Effect of freeze-drying on camel’s milk nutritional properties
Abstract
The purpose of this research was to study the effect of freeze-drying process on camel’s milk
nutritional characteristics compared with fresh milk. The results showed that the protein, casein,
whey proteins, lactose and ash percentage were signicantly higher (P< 0.05) in freeze-dried
skim milk than fresh milk. The average of mineral contents in reconstituted freeze-dried skim
camel’s milk was slightly higher than that of fresh camel milk except Ca, K and P contents. On
the other hand, freeze-dried skim camel’s milk had a slightly higher concentration of water-
soluble vitamins except vitamin C. Vitamins B, A, D and E showed relatively stable values
after freeze-drying treatment. Freeze-drying process skim camel’s milk was characterized by
slightly higher contents of all amino acids. Freeze-dried whole milk showed higher contribution
of Protein efciency ratio, Biological value and Net protein utilization than that of fresh whole
milk. Freeze-dried process had a little effect on fatty acid prole in camel milk fat. Nutritional
properties of lyophilized camel’s milk remained basically unchanged compared with fresh milk.
Introduction
Camel milk is highly nutritious so that many
generations of our ancestors survived on this
beverage alone. Camel milk is almost a complete
food consisting of proteins (mainly casein), fat, salts
and lactose as well as vitamins and minerals (Sawaya
et al., 1984). Camel milk and bovine milk had
similar amino acid composition. Camel milk casein
contained most of the essential amino acids in high
ratios. Glutamic acid was the most abundant amino
acid followed by Leucine, Lysine and Aspartic acid
(Abu-Tarboush and Ahmed, 2005). In Africa and
the Middle East, camel milk is used therapeutically
against dropsy, jaundice, problems of the spleen,
tuberculosis, asthma, anemia, piles, diabetes and
against Hepatitis C Virus (Rao, et al., 1970; El-
Fakharany et al., 2008). Benecial role of raw camel
milk in chronic pulmonary tuberculosis patients has
been observed (Mal et al., 2001). Treatment of type–I
diabetes with oral supplementation of raw camel milk
was reported to be effective and reduces the insulin
daily doze from 30 to 35% (Agrarwal et al., 2003).
Research has demonstrated the presence of potent
anti-bacterial and anti-viral factors in camel milk.
Antimicrobial properties were partially attributed
to well characterize proteins, such as lactoferrin,
lactoperoxidase, lysozyme and immunoglobulin
G. These proteins were shown to have higher
concentrations or higher activity in camel milk (El-
Agamy et al., 2009). In addition, camel milk could
have signicant therapeutic attributes such as anti-
cancer (Magjeed, 2005).
Egypt considered as one of the world’s highest
Hepatitis C. There are several traditional medicines
used by different Egyptian patients sectors. The most
popular one is the camel milk, 50% of the patients
shown a marked improvement in general fatigue (El-
Fakharany et al., 2008). Considering the health effect
of camel milk proteins and its bioactive peptides, it
could be the ‘super food’ of the future. Traditional
dehydration processes usually cause physical and
structural changes in the dried products due to heat
application. In fact, caramelization, discoloration,
loss in texture and physical form, loss of volatile
flavoring characteristics, and poor rehydration ability
of many dried foods have left an imprint on the
mind of consumers (Desrosier, 1977). Freeze-drying
or lyophilization is a process in which a solvent is
removed from a frozen solution by sublimation.
This process minimizes the degradation reactions
and maintains adequate physical, chemical, and
biological stability of the product during long-
term storage at ambient temperature (Fonseca et
al., 2004). Being a cold process, freeze-drying is
especially useful for drying heat sensitive foods.
Freeze-drying is recognized as the best method of
producing drier material of high quality. The dried
products obtained from freeze-drying processes have
good flavour appearance, and a high preservation of
Keywords
Camel milk
Freeze-drying
Lyophilization
Nutritive value
Article history
Received: 24 July 2014
Received in revised form:
27 November 2014
Accepted: 10 December 2014
1439 Ibrahim, A. H. and Khalifa, S. A./IFRJ 22(4): 1438-1445
nutrition. Moisture level as low as 2% can be reached
with freeze-drying. It can be benet to produce
freeze-dried camel milk to take advantage of its
nutritional and therapeutic properties. In spite of all
these nutritional and therapeutic properties of camel
milk, the changes in physical and chemical properties
of freeze-drying camel milk is still unknown. The
objective of this study was to investigate the effects
of the lyophilization (freeze-drying) treatment on
physical, chemical and nutritional characteristics of
camel’s milk.
Materials and Methods
Camel’s milk
Fresh whole camel milk from healthy and
uninfected Magrabi camels (Camelus dromedarius)
was obtained from Sidi-Barani areas Matrouh
Governorate, North West Coast, Egypt. The
udder was cleaned and washed with disinfectant
solution (Safflon 20%), before collection of milk.
Autoclaveable plastic containers (1000 mL) were
used for the collection of samples. Containers were
sterilized at 120°C for 15 min and kept ready for milk
collection from different sites (Omer and Eltinay,
2009).
Preparation of freeze-dried camel’s milk samples
Batches of skimmed milk were prepared from
fresh camel milk by centrifugation at 4000 g for 10
min at 15°C. Freeze-drying of whole and skim camel
milk was performed in a Freeze Dryer (Thermo-
Electron Corporation-Heto power dry LL300 Freeze
Dryer, Czech Republic). The freeze-dryer was
programmed to operate for 1 h initial freezing at
-45°C followed by primary drying at 30°C at 0.10
mbar pressure for 48 h and secondary drying at 5°C
for 3 h at the same pressure. After the end of freeze-
drying cycle, the vials were sealed under vacuum and
stored at 5°C until analyzed (Ivanova, 2011).
Raw whole and skimmed milk - freeze-dried whole
and skimmed milk
Proximate analysis (total solids, fat, total nitrogen,
ash content and titratable acidity %) for raw whole
and skimmed milk was determined as described
by Ling (1963). The casein and whey protein was
determined by micro Kjeldahl method as mentioned
by Rowland (1938). Lactose content was determined
by the phenol-sulfuric spectrophotometeric method
as reported by Barnett and Abd-El-Tawab (1957).
The total solids in freeze-dried whole and
skimmed milk was determined according to the
IDF procedure (1993), fat (Rose Gottlieb method),
ash content, titratable acidity and total protein
(Kjeldahl) in freeze-dried whole and skimmed milk
were determined as mentioned in AOAC, (1997).
Lactose determination in freeze-dried whole and
skimmed milk samples were estimted according
to the modied phenol-sulfuric acid procedures
described by Lawrence (1968) using a Jenway 6850
spectrophotometer (Jenway Instruments, Beacon
Road, Stone, Staffordshire, ST15 OSA, UK) at a
wave length of 490 nm . The casein and whey
proteins were determined by micro Kjeldahl method
as mentioned by Rowland (1938).
Vitamins determination
Water-soluble vitamins such as vitamin C and
vitamin B complex (B1, B2, B3, B5, B6, B9 and B12)
and fat soluble vitamins such as vitamins A, D and E
were determined by the method of Albala-Hurtado et
al. (1997) and Paixao and Campos (2003), respectively.
Prepared samples were analyzed for vitamins C, A,
D, E and B complex (B1, B2, B3, B5, B6, B9 and
B12) group by liquid phase chromatography HPLC
(Dionex UltiMate 3000 RS systems –Thermo
Scientic system). The sample (20 µL) was injected
into the HPLC with a syringe (Hamilton, Reno, NV,
USA). The HPLC column used was a reversed-phase
Discovery C18 (150 mm × 4.6 mm, 5 µm) from
Supelco (Bellefonte, PA, USA). The column eluate
was monitored with a photodiode-array detector at
265 nm for vitamins C, 325 for A, 295 for E, 260 for
D, 234 nm for thiamine, 266 nm for riboflavin, 324
nm for pyridoxine, 282 nm for folic acid, 204 nm
for cobalamin, 261 nm for niacin, and 204 nm for
pantothenic acid. Identication of compounds was
achieved by comparing their retention times and UV
spectra with those of standards stored in a data bank.
Concentrations of the water-soluble and insoluble
vitamins were calculated from integrated areas of the
sample and the corresponding standards.
Minerals determination
Minerals were determined in ash solution
(Srivastava, 2010). Calcium, magnesium, phosphorus,
manganese, cupper, iron and zinc concentrations were
determined using atomic absorption spectrophotometer
(Unicam Analytical System, Model 919, Cambridge,
UK) while sodium and potassium concentrations was
determined using flame photometer (Jenway PF7 Flame
Photometer, Essex, UK).
Amino acid composition
Milk samples were prepared by acid hydrolysis
(6N HCl) for 24 h at 110°C and the nal mixture was
ltrate using Whatman lter paper no. 42. About 0.2
mL of ltration was evaporated at 140°C for one hour
Ibrahim, A. H. and Khalifa, S. A./IFRJ 22(4): 1438-1445 1440
and nally adds 1ml of diluting buffer to the dried
sample. Hydrolyzes were analyzed by Beckman
Amino Acid Analyzer, Model 119CL as mentioned
by Nagasawa et al. (1970).
Analysis of fatty acids by Gas Chromatography
Fatty acid methyl esters FAMES were prepared
as described in AOAC (1990) method 969.33. A GC
equipped with a flame ionisation detector and an auto
sampler (model 7673, Hewlett–Packard, Palo Alto,
CA, USA), was used for analyzing FAMES. The GC
conditions were: column oven temperature was 70°C
for 1 min, increased to 200°C (20°C/min) and kept at
200°C for 1 min, then increased to 220°C (1°C/min)
and kept at 220°C for 20 min, Injector temperature
and detector temperature was 260°C, flow rate 1.1
ml/min (He) and the split ratio used was 1:25. A
FAME Standard (mixture 463) was used to identify
the FAME, and the FA amount was expressed as
percent of total FAs.
Nutritive value
Protein efciency ratio (PER) based on the
amino acid contents of camel milk were calculated
according to the recommendations of Alsmeyer et al.
(1974) using the following equations:
PER1= -0.684+0.456 (leucine) – 0.047 (proline)
PER2= -0.468+0.454 (leucine) – 0.105 (tyrosine)
PER3= -1.816+0.435 (methionine) + 0.78 (leucine) +
0.211 (histidine) – 0.944 (tyrosine)
Biological value (BV) and net protein utilization (NPU)
were calculated using the equations suggested by
Block and Mitchell (1946): BV= 49.9 + 10.53 PER
NPU= BV× Digestibility (protein 95%).
Total energy in all sample of camel milk was
expressed in calories (Watt and Merrill, 1963), and
calculated using the following equation:
Calories= (protein × 4.27) + (fat × 8.78) + (lactose × 3.87).
Statistical analysis
Experimental data were analyzed as Complete
Random Design (CRD) according to SPSS package
(SPSS v.20, 2012). Standard error of the means
was derived from the error mean square term of
the ANOVA, which was used the least signicant
difference (LSD) test. Differences were considered
signicant at (P<0.05). All measurements were
performed in triplicate.
Results and Discussion
Data presented in Table (1) show the chemical
composition of fresh and freeze-dried camel’s milk.
The results indicated that the moisture content of
whole and skim freeze-dried camel milk was lower
as a result of freeze-drying. Thus, moisture level as
low as 2% can be reached with freeze-dried foods
(Dalgleish, 1990), this makes the products much
lighter than those dried by other drying methods and
they do not require refrigeration. In general, total
protein, caseins, whey proteins, lactose and ash %
were signicantly higher (P< 0.05) in freeze-dried
skim milk than freeze-dried whole camel milk.
Changes in the composition of some constituents in
freeze-dried milk can be explained as a function of
the freeze-dried process. These changes coincided
with changes in moisture content (Kumar and Mishra,
2004). However, no signicant differences in total
energy for both freeze-dried and fresh milk (Table 1).
Mineral content in camel milk were found here
(Table 1) was within the range with values reported
by various researchers (Elamin and Wilcox, 1992;
Gorban and Izzeldin, 1997; Haddadin et al., 2008).
The average of all major and trace element contents in
reconstituted freeze-dried camel’s milk was slightly
higher than those of fresh camel milk, thus might
be due to freeze-dried possess except Ca, K and P
contents were signicantly differences (P< 0.05). In
contrast, the influence of process of freeze-dried on
trace element was not signicant.
Milk is a valuable source for both water-soluble
and fat-soluble vitamins. Therefore, we compare the
concentration of vitamins in fresh and reconstituted
freeze-dried camel’s milk (Table 2). The results
showed that freeze-dried skim camel’s milk was
a slightly higher concentration of water-soluble
vitamins except vitamins C. Lyophilization process
signicantly affected the amount of vitamin C in
milk (Vincenzetti et al., 2011). Further, freeze-dried
yoghurt showed reduction in levels of ascorbic acid
(Karadimov and Karadimova, 1979). On the other
hand, vitamins B group were relatively stable in all
samples with no signicant differences (P< 0.05)
between all samples. Vitamins B group are relatively
stable to most food-processing operations and
storage (Fox and McSweeney, 1997). Fresh whole
camel’s milk had a slightly higher concentration of
fat-soluble vitamins (A, D and E) than freeze-dried
whole camel’s milk.
Table (3) shows the amino acid concentration
of fresh and reconstituted freeze-dried camel’s milk
(g/100 g protein). The results indicated that Glutamic
acid (Glu) was the major amino acid in all milk
1441 Ibrahim, A. H. and Khalifa, S. A./IFRJ 22(4): 1438-1445
Table 1. Chemical composition of fresh and freeze-dried camel's milk
*Reconstituted freeze-dried whole camel's milk (Dry matter 12.1%) and freeze-dried skim milk (Dry matter 9.3 %).
abc.. Means followed by different letter in the same row are signicantly different. (P <0.05)
Table 2. Vitamin concentrations in fresh and reconstituted freeze-dried camel's milk*
*Reconstituted freeze-dried whole camel's milk (Dry matter 12.1%) and freeze-dried skim milk (Dry matter
9.3 %)
abc.. Means followed by different letter in the same row are signicantly different. (P<0.05)
**ND=Not determined
Ibrahim, A. H. and Khalifa, S. A./IFRJ 22(4): 1438-1445 1442
Table 3. Amino acid concentration of fresh and reconstituted freeze-dried camel's milk (g/100 g protein) *
*Reconstituted freeze-dried whole camel's milk (Dry matter 12.1%) and freeze-dried skim milk (Dry matter 9.3 %)
abc.. Means followed by different letter in the same row are signicantly different. (P<0.05)
Table 4. Nutritive value of fresh and reconstituted freeze-dried camel's milk*
*Reconstituted freeze-dried whole camel's milk (Dry matter 12.1%) and freeze-dried skim milk (Dry matter 9.3 %)
1443 Ibrahim, A. H. and Khalifa, S. A./IFRJ 22(4): 1438-1445
treatments. These values are in accordance with those
found by El-Agamy (2006), Kamal et al. (2007) and
Shamsia (2009). However, freeze-dried skim camel’s
milk was characterized by slightly higher contents
of all amino acids. The essential amino acids Ile,
Lys, Phe and Val were signicantly (P< 0.05)
higher in freeze-dried skim milk compared to their
amounts in the other milk treatments .In the case
of non-essential amino acids, all amino acids except
Glu and Ser were signicantly (P< 0.05) higher in
freeze-dried skim milk compared to their amounts
in the other milk treatments. Protein efciency
ratio (PER), biological value (BV) and net protein
utilization (NPU) of freeze-dried milk were higher
than those of fresh milk (Table 4). This result could
be attributed to the higher concentration of leucine in
the freeze-dried milk than in the fresh milk. On the
other hand, the nutritive values calculated for both
milk types using the third equation showed an equal
value. Data presented in (Table 5) shows the fatty
acid prole of whole fresh and freeze-dried camel’s
milk (g/100 g fat). In general, short-chain fatty acids
(C4:C12) in fresh and freeze-dried camel milk were
present in very small amounts compared with those
reported in cows’ milk (Abu-Lehia, 1989). However,
the concentrations of C14:0, C16:0, C18:0 and C18:1
is relatively high. Fresh and freeze-dried camel milk
has high amounts of linolenic acid (C18:3) and long-
chain polyunsaturated fatty acids compared with
those reported in cows’ milk. Our ndings are similar
to those reported by Abu-Lehia, (1989); Farah,
(1993). The main saturated fatty acids in freeze-dried
camel milk were 14:0 (12.2%), 16:0 (24.4%) and
18:0 acids (13.7%). The major unsaturated fatty acids
of fresh and freeze-dried camel milk triacylglycerol’s
were 18:1 and 16:1. The freeze-dried process had a
little effect on fatty acid prole in camel milk fat.
This result are in agreement with Karadimov and
Karadimova, (1976), who reported that there were
no changes in the fatty acids (C4: C12) of the dried
product.
Conclusion
Lyophilization of camel’s milk demonstrated that
the nutritional characteristics of this product remained
basically unchanged compared with fresh milk. The
results obtained also, conrmed the possibility of
producing freeze-dried camel milk with benecial
properties using camel’s milk as raw material and
lyophilized camel milk powder is easy to transport,
requires no special conditions for prolonged storage.
In addition, lyophilization of camel’s milk can help
in supplying camel’s milk on the market all-over the
year.
Acknowledgments
The present document was achieved in the frame
of PROCAMED project, supported by the European
Table 5. Fatty acid prole of whole fresh and reconstituted freeze-dried camel's milk (g/100 g fat)*
*Reconstituted freeze-dried whole camel's milk (Dry matter 12.1%) and freeze-dried skim milk (Dry matter 9.3 %)
Ibrahim, A. H. and Khalifa, S. A./IFRJ 22(4): 1438-1445 1444
Union (ENPI - Joint operational Programme of the
Mediterranean Basin -IEVP-CT). The contents of this
document are the sole responsibility of the ‘Division
of Animal Production, Animal Breeding Department,
Desert Research Center (Egypt) and can (under no
circumstances) is regarded as reflecting the position
of the European Union.
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... Samples (250 g) were weighed and frozen in the freeze dryer (Labconco FreeZone 18) at −50°C and vacuum applied at 133 × 10 −3 mbar for 48 h. After the freeze-drying cycle, the containers were sealed and stored at 5°C and analyzed following the method described by Ibrahim and Khalifa (2015). Freeze-drying augmented in longer shelf-life preservation of the solid over the liquid state of milk (Ibrahim & Khalifa, 2015). ...
... After the freeze-drying cycle, the containers were sealed and stored at 5°C and analyzed following the method described by Ibrahim and Khalifa (2015). Freeze-drying augmented in longer shelf-life preservation of the solid over the liquid state of milk (Ibrahim & Khalifa, 2015). ...
... The specific gravity of the samples followed the gravimetric method by weighing the known measure of milk. Moisture content (Equation (2)) was determined from the loss of mass freeze-drying in the Labconco-FreeZone18 Freeze Dryer (Ibrahim & Khalifa, 2015, Valentina et al., 2016. The milk samples were subjected to a prefreezing temperature between −15 and −23°C at 1.65 and 0.67 mbar vacuum set point, respectively, in the freeze dryer. ...
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In the light of the Covid‐19 pandemic outbreak, and the need‐of‐the‐hour to boost immunity to residents, especially those residing in an arid environment, a comparative study was made on the physical and biochemical properties of dairy milk. This novel study in Kuwait revealed the lesser consumed pseudoruminant camel milk as a better potential source of dietary inclusion and an immune booster over true ruminants—cow's and goat's milk. Analysis using a wide array of instruments determining the physical characteristics in camel's milk (pH, conductivity, specific gravity, moisture, and total solids), biochemical constituents (crude protein (CP), nonprotein (NP), and fat), and inorganic constituents (K‐919; Ca‐907; Zn‐4.2 mg/100 mg) revealed conducive properties that validate immunity to consumers when compared to the regularly used cow's milk (K‐841; Ca‐776; Zn‐2.43 mg/100 mg) and goat's milk (K‐914; Ca‐849; Zn‐2.45 mg/100 mg). Log‐transformed results revealed high vitamin C in camel's milk (0.42 mg/100 g), indicating high antioxidant properties compared to those of goat's milk (0.12 mg/100 g) and cow's milk (0.04 mg/100 g). Statistical tests by analysis of variance (ANOVA) revealed significant differences and the correlation coefficient between the three milk samples validating the multiple reasons to use camel's milk over the cow's and goat's milk. Furthermore, this study recommends the consumption of camel's milk due to its low concentrations of contaminants as well, their status below permissible limits in Kuwait, set by global standards over the other sampled milks. Following the analysis of three milk samples, this study revealed a novel validation to camel's milk edging over cow's and goat's milk in their elemental and biochemical properties, thus recommending the camel milk as an immune booster in the wake of the Covid‐19 pandemic.
... Protein is a very important parameter in the composition of donkey's milk, and an important factors in the diet and development of organisms (El-Hatmi et al., 2015). Ibrahim, 2015, realized study about the chemical composition of camel milk (fresh, dried and frozen). The content of total protein, casein, lactose and ash from skimmed and freeze-dried milk was higher compared to camel milk completely freeze dried. ...
... The content of total protein, casein, lactose and ash from skimmed and freeze-dried milk was higher compared to camel milk completely freeze dried. The results indicated that the moisture content of completely dried and frozen camel milk was lower due to the freeze-drying process (Ibrahim, 2015). Similar results about the physico-chemical parameters were reported by Kumar and Mishra, 2004. ...
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Currently, the extinction of donkeys (Equus asinus) worldwide is very limited, but donkey milk is recently getting popular in many countries due to its nutritional properties and chemical composition. For this reason, in our country, the farmers are encouraged to keep, to raise and increase the number of donkeys in their farms. Milk and donkey products are niche products, consumed by a small number of people, especially people suffering from various diseases (e.g. food allergies, children to whom breast milk should be substituted with milk similar in composition). Donkey milk brings benefits to consumers due to its chemical composition. Donkey milk storage depend on the chemical composition, antioxidant capacity and the biochemical degradation under heat treatment.
... • Nutritional characteristics of camel milk powder can be preserved Ibrahim & Khalifa (2015). ...
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The dairy industry could take advantage of camel milk to use the animals for milk production rather than as cargo carriers. The powder is a good way to increase the shelf life of milk, and by using camel milk powder, camels may be used and a source of milk other than cow and buffalo can be obtained by the dairy. Additionally, camel milk has a number of health advantages over cow milk, some of which go above and beyond expectations. Therefore, using camels and their milk can best be accomplished using camel milk.
... At 11.3 percent humidity, the produced powder was stable. Aimed to investigate the influence of freeze drying on the nutritional qualities of camel milk, specifically how the technique affects the fine composition of camel milk when compared to fresh milk [7] . Analyses revealed that most components (including minerals and vitamins) were very stable, indicating that the nutritional characteristics of camel milk powder were preserved. ...
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Camel milk is a relative newcomer to both Indian and as well to international milk markets. The recent processing technology emergence has coincided with a variety of processed products based on technology established for milk from other dairy animals. Technical improvements, on the other hand, have to be tailored to functional food products with a distinct behavior and composition. Camel milk powder can provide a great opportunity to dairy industries for introducing new products to the market of milk and milk products. This article gives a brief review regarding camel milk powder development technology, limitations and challenges to overcome.
... At 11.3 percent humidity, the produced powder was stable. Aimed to investigate the influence of freeze drying on the nutritional qualities of camel milk, specifically how the technique affects the fine composition of camel milk when compared to fresh milk [7] . Analyses revealed that most components (including minerals and vitamins) were very stable, indicating that the nutritional characteristics of camel milk powder were preserved. ...
... Moreover, Freeze-drying has been widely used for stabilizing biological and preservation of various types of food and biological materials (enzymes, proteins, vitamins, etc.), because this procedure is believed to be effective to maintain the biological activities of the material over a long period time (Adams, 1991 andKhalifa, 2015b). ...
... To extend the storage time and prevent deterioration, the samples were freeze-dried into powder with an NAI-T1-50 vacuum freeze dryer (Bo Yikang). Freeze-drying does not affect milk nutrients (Ibrahim and Khalifa, 2015;Cortez and Soria, 2016;Zhu et al., 2020). Calcium content was analyzed with an AA-7000 atomic absorption spectrophotometer (Shimadzu) following the method of Deshwal et al. (2020) with some modifications. ...
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The effect of milk on bone health is controversial. In this study, the effects of yak milk in mice with retinoic acid-induced osteoporosis (OP) were evaluated. Yak milk was provided to OP mice as a nutrition supplement for 6 wk. The results showed that yak milk significantly reduced bone turnover markers (tartrate acid phosphatase and alkaline phosphatase). The yak milk treatment was also associated with remarkably increased bone mineral density, bone volume, trabecular thickness, and trabecular number, as well as improved biomechanical properties (maximum load and stress) of the tibia. Furthermore, yak milk mitigated the deterioration of the network and thickness of trabecular bone in treated OP mice compared with the OP model group. The results indicated that yak milk could improve bone mass and microarchitecture through the inhibition of bone resorption in OP mice.
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The investigation was aimed at assessing anti-inflammatory and antioxidative activities along with the release of peptides with antioxidative properties during the fermentation of camel milk by Lacti�caseibacillus casei (NK9). Reverse-phase high-performance liquid chromatography (RP-HPLC) was used to separate the bioactive peptides of 3 and 10 kDa (permeates and retentates). Reverse-phase liquid chromatography–mass spectrometry (RPLC/MS) was used to identify and characterise the pure bioactive peptides, and the effect of fermented camel milk on inflammation produced by lipopolysaccharide (LPS)/endotoxin in RAW 264.7 (Ralph and William’s cell line) was also exam�ined. Furthermore, docking revealed that peptides (LLNEK and IYTFPQPQSL) were predicted to inhibit myeloperoxidase (nMPO) activity by engaging with different residues in and around the human myeloperoxidase (hMPO) active site
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Camel milk consists an essential macro/micronutrient for human nutrition in the arid and urban regions. This review study aimed to use of meta-analysis statistical techniques for assessment and correction of publication bias, exploration of heterogeneity between studies, and detailed assessment of the effect of a comprehensive set of moderators including breed, season, country, year of publication, and the interaction between composition elements. This could provide a single synthesis of the camel milk composition to warrant strong generalizability of results, examine variability between available studies, and analyze differences in camel milk composition among different exposures. Such a finding will aid future researchers and health professionals in acquiring a more precise understanding of camel milk composition and drawing more clinical implications. Six searching databases and bibliographic was used including PubMed/MEDLINE, ScienceDirect, Springer, EBSCOhost, Scopus, and Web of Science for from January 1980 to December 2021. The DerSimonian-Laird estimator was used to create the current random-effects meta-analysis. This systematic review and meta-analysis included a total of 7298 camel milk samples from twenty-three countries. This review comprises 79 studies published in English language on or after 1980, including a sub-group of 117 analyses consisting of seasons, sub-breeds, and countries. The contents of macro/micronutrients in camel milk were identified as follows: protein, 3.17%; fat, 3.47%; lactose, 4.28%; ash, 0.78%; and total solids, 11.31%; calcium, 112.93 mg/100g; iron, 0.45 mg/100g; potassium, 116.13 mg/100g; magnesium, 9.65 mg/100g; sodium, 53.10 mg/100g; zinc, 1.68 mg/100g; vit C, 5.38 mg/100g; vit A, 0.36 mg/100g; vit B1,0.05 mg/100g; vit B2, 0.13 mg/100g; vit B3, 0.51 mg/100g;vit B6, 0.09 mg/100g; and vit B12, 0.0039 mg/100g. Our meta-regression analysis found that fat and total solids were statistically significant moderator of protein; moreover, total solids content is statistically significant moderator of fat. Discrepancies observed in camel milk profiles are dependent upon several factors, including number of included studies, number of samples, different analytical techniques, feeding patterns, camel’s breeds, geographical locations, and seasonal variations.
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During the generation of functional food ingredients by enzymatic hydrolysis, parameters such as choice of enzyme, reaction pH and the drying process employed may contribute to the physicochemical and bio-functional properties of the resultant protein hydrolysate ingredients. This study characterised the properties of spray- (SD) and freeze-dried (FD) whey protein hydrolysates (WPHs) generated using Alcalase® and Prolyve® under pH-stat and free-fall pH conditions. The enzyme preparation used affected the physicochemical and antioxidative properties but had no impact on powder composition, morphology or colour. SD resulted in spherical particles with higher moisture content (~6%) compared to the FD powders (~1%), which had a glass shard-like structure. The SD-WPHs exhibited higher antioxidative properties compared to the FD-WPHs, which may be linked to a higher proportion of peptides <1 kDa in the SD-WPHs. Furthermore, the SD- and FD-WPHs had similar peptide profiles, and no evidence of Maillard reaction product formation during the SD processing was evident. The most potent in vitro antioxidative WPH was generated using Alcalase® under free-fall pH conditions, followed by SD, which had oxygen radical absorbance capacity and Trolox equivalent (TE) antioxidant capacity values of 1132 and 686 µmol TE/g, respectively. These results demonstrate that both the hydrolysis and the drying process impact the biofunctional (antioxidant) activity of WPHs.
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IVANOVA, S., 2011. Dynamical changes in the trace element composition of fresh and lyophilized ewe's milk. Bulg. J. Agric. Sci., 17: 25-30 The present study aims to investigate the trace element composition of fresh and lyophilized ewe's milk from sheep of the Karakachan breed raised in the region of the Middle Rhodopes. The analysis of trace elements in the native and lyophilized ewe's milk was made after ashing with atomic-absorption photometer AES-ICP "Varian-Liberty II". In the course of lactation a decrease of the content of the trace elements boron, barium, chromium, copper, iron, zinc, selenium and iodine and a good availability of manganese was observed in the native and freeze-dried milk.
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The aim of the present study was to characterize the changes occurring in amino acids profile of camel milk protein during the 1st month of lactation and seek to justify such dynamics of change in relation to the specific needs of growing neonates. Milk samples were collected from camels at varying stages of lactation from the 1st day till 30 day of parturition. Daily samples were tested for fat, protein, lactose, ash and total solids %. The respective mean values at parturition were 0.50±0.06, 12.99±0.20, 2.75±0.40, 0.96±0.037, 20.25±2.50, while at the 30 day the respective mean values were 3.78±0.68, 3.30±0.25, 5.85±0.43. 0.70±0.040, 15.06±1.45. The mean of different amino acid values at the 1st day were significantly increased then sharply decreased in the 3rd day and continuously decreased till reach to the 5th day after that slightly decreased in the 7th day. So, we noticed a non significant decreased in the reminder time, 10, 15, 21 and 30 day, respectively. While there is a significant increase in the level of serum insulin growth factor-1 at zero time and then began to decrease till 30 days. At the same time, concentrations of triiodothyronine and thyroxin were very high at birth and then decreased to relatively low concentrations on day 30. This study demonstrates that camel milk during the 1st month of lactation have important effects on clinical, metabolic and endocrine traits.