# Some parameters to process camel milk into cheese

Gaukhar Konuspayeva, Benedicte Camier, Frederic Gaucheron, Bernard Faye

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Gaukhar Konuspayeva, Benedicte Camier, Frederic Gaucheron, Bernard Faye. Some parameters to process camel milk into cheese. Emirates Journal of Food and Agriculture, 2014, 26 (4), 10.9755/ejfa.v26i4.17277. hal-01209483

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Some parameters to process camel milk into cheese

Gaukhar Konuspayeva<fnref n="1" />,<fnref n="2" />*, Benedicte Camier<fnref n="3" />, Frederic Gaucheron<fnref n="3" /> and Bernard Faye<fnref n="2" />,<fnref n="4" />

Abstract

Cheese from camel milk was never produced by traditional way. However, Hansen® (Denmark) delivered recently new coagulant agent named “Chy-Max M” containing transgenic camel chymosine. In the present study, impact of calcium, lactation stage and curd acidification were investigated. Camel milk was shared into 6 samples (100g each) submitted to 3 types of treatment (1. calcium chloride solution (500 g/L diluted 1/10 water); 2. powder of calcium phosphate; 3. no calcium) and 2 temperatures (20°C/36°C). Rennet 50 µL/L (Chy-Max) was added in all samples. Milk coagulation was faster at 36°C and renneting pH lower. No difference in clotting time and curd firmness after calcium addition was observed. The curd firmness at 36°C was stronger than at 20°C. For measuring impact of lactation stage, coagulation capacity and curd yield on milk was tested in milk provided by one camel from 12th to 25th day postpartum. Milk was coagulated by Chy-Max (50 µL/L/20°C). No coagulation was observed in the first days of experiment. Then curd start to be formed, but with low yield. The curd was correct and ready to use for cheese making only from the 20th day post-partum. Acidification of camel cheese curd without starters was measured at 20°C and 36°C during 10 hours. Milk pH and curd pH were measured during all cheese processing. At the beginning, milk pH was 6.38 whatever the temperature. Acidification was faster at 36°C than at 20°C. At the time of coagulation, pH of 20°C curd was 5.80 vs 5.08 at 36°C.

Key words: Camel Cheese, Fermentation, Calcium, Lactation stage

Introduction

In the world, camel milk is better known for its
fermented products: shubat – in Kazakhstan; chal –
in Turkmenistan; khoormog – in Mongolia; gariss
– in Sudan; suusac – in Kenya, zrig -in Mauritania,
rather than for its types of cheeses: chuku – in
Niger or caravan – in Mauritania, fresh camel
cheese – in Morocco (Bengoumi et al., 2002;
Konuspayeva and Faye, 2010; Benkerroum et al.,
2011). In the literature, there are some data on the
use of bovine rennet, or rennet agent coming from
vegetal sources for camel cheese making (Ramet,
1989; Boudjenah-Haroun et al., 2011; Boudjenah-
Haroun et al., 2012; Ahmed and El Zubeir, 2011).
Regarding bovine rennet, a lot of parameters

(rennet quantity, time of coagulation, curd
description, pH value) for technological production
of cheese from camel milk were studied by Ramet
(1985).

However, Hansen™ (Denmark) delivered
recently new coagulant agent named “Chy-Max M”
containing camel chymosine (Sorensen et al.,
2011). With such camel rennet, no data about
power and time of coagulation, acidification of
curd, impact of physiological and environmental
factors to coagulation of camel milk, was available.
In the present study, impact of calcium and of
lactation stage on coagulation to produce cheese,
and then curd acidification of coagulated camel
milk were investigated.

**Material and Methods**

Camel milk and early milk were sampled from
healthy dromedary camels from Camel and Range
Research Center, Al-Jouf, KSA at mid of lactation
stage and between 12th to 25th days of lactation
respectively. Percentage of fat and total protein was
determined by automatic milk analyzer device

Received 26 May 2013; Revised 03 July 2013; Accepted 09
September 2013; Published Online 11 October 2013

<footnote n="1">¹Department of Biology and Biotechnology, Al-Farabi Kazakh National University, 71 av. Al-Farabi, 050040 Almaty, Kazakhstan</footnote>

<footnote n="2">²Al-Kharj FAO Camel Project, Center for Agriculture Project, P. O. Box n°761 Al-Kharj 11942, Saudi Arabia</footnote>

<footnote n="3">³INRA, UMR Science & Technology of Milk and Egg, 65 rue de Saint Brieuc, 35042 Rennes, France</footnote>

<footnote n="4">⁴CIRAD-ES, TA C-Dir/B Campus International de Baillarguet, Cedex, 34398 Montpellier, France</footnote>

<footnote>*Corresponding Author</footnote>

<footnote>Gaukhar Konuspayeva
Camel and Range Research Center, P.O. Box 322, Al-Jouf,
Sakaka, Saudi Arabia</footnote>

<footnote>Email: konuspayevags@hotmail.fr</footnote>
(Lactoscan MCC) calibrated for camel milk. The ultrasonic technology used by Lactoscan allowed direct measurement of fat, proteins, lactose and salts. Lactoscan determined also the freezing point of each sample and the quantity of added water. The freezing point was calculated automatically from the components it depends on.

For clotting camel milk, specific liquid chymosin for camel milk – ChyMax M (Hansen®, Denmark) was used. Dose 50 µL/L was added with preliminary dilution 1/20.

## Coagulation properties

Camel milk was shared into 6 samples of 100 g each submitted to 3 treatment: (i) calcium chloride solution (500 g/L diluted 1/10 water); (ii) powder of calcium phosphate; and (iii) control with no calcium. Two temperatures 20°C and 36°C were tested. After 30 min of heating or not, 50 µL/L of rennet Chy-Max M (strength 1000 IMCU, international milk coagulating units) was added in all samples. The pH value was measured. Then visual determination of clotting time was done and after 60 min, the curd was cut and filtration through cloth was achieved. The weight of the curd (gross yield) was measured 1h 30 after clotting. Corrected yield was calculated as:

Corrected yield (DM curd=30% and DM whey= 6). Gross yield = [(DM curd- DM whey)/ (30 - 6)], with DM = dry matter.

## Impact of lactation period

For measuring impact of lactation stage, coagulation capacity and curd yield on milk was

tested in milk provided by one camel from 12th to 27th day postpartum. Milk was coagulated by Chy-Max M (50 µL/L/20°C).

## Natural acidification of camel cheese curd

The pH value was measured at 20°C and 36°C during 10 hours with Ph-meter Hanna Instruments HI221 pH/mV/ORP

## Results

### Coagulation properties

Before testing the milk, its gross physico-chemical composition was analyzed (Table 1) and its microbiological status was assessed (total flora and coliforms).

<table><caption>Table 1. Global composition of camel milk (g/100g).</caption><thead><tr><th>Parameters</th><th>Mean and SD</th></tr></thead><tbody><tr><td>Fat</td><td>2.72 ± 0.17</td></tr><tr><td>Solid non-fat</td><td>9.37 ± 0.12</td></tr><tr><td>Protein</td><td>2.83 ± 0.04</td></tr></tbody></table>

Milk coagulation was faster at 36°C and pH renneting lower (Table 2). No difference in clotting time and curd firmness between calcium treatments was observed. The curd firmness at 36°C was stronger. The molding was more effective with the curd obtained at 36°C.

The effect of calcium salt quantity was also tested at 36°C (Table 3). There was no effect on type of calcium source and of the dose on the time of coagulation, pH value and on curd yield comparatively to control.

<table><caption>Table 2. Coagulation characteristics as function of type of calcium added.</caption><thead><tr><th rowspan="2">Parameters</th><th colspan="3">20°C</th><th colspan="3">36°C</th></tr><tr><th>Control</th><th>Ca phosphate<br>(1g/kg)</th><th>Ca chloride<br>(0.1mL/kg)</th><th>Control</th><th>Ca phosphate<br>(1g/kg)</th><th>Ca chloride<br>(0.1mL/kg)</th></tr></thead><tbody><tr><td>pH renneting</td><td>6.26 ± 0.05</td><td>6.25 ± 0.05</td><td>6.25 ± 0.05</td><td>5.78 ± 0.11</td><td>5.75 ± 0.11</td><td>5.75 ± 0.07</td></tr><tr><td>Coagulation time<br>(min)</td><td>14 ± 0</td><td>14 ± 0</td><td>14 ± 0</td><td>6 ± 0</td><td>6 ± 0</td><td>6 ± 0</td></tr></tbody></table>

<table><caption>Table 3. The dose of different calcium source on coagulation of camel milk at 36°C.</caption><thead><tr><th></th><th>pH<br>renneting<br>36°C</th><th>Coagulation<br>Time (min)</th><th>Yield(g/100g)<br>1h30after<br>moulding</th><th>Dry matter<br>Curd<br>(g/100g)</th><th>Corrected yield<br>(g/100g)</th></tr></thead><tbody><tr><td>Control</td><td>6.40</td><td>8</td><td>14.80</td><td>27.46</td><td>13.07</td></tr><tr><td>Phosphate Ca 2g/L</td><td>6.40</td><td>8</td><td>12.91</td><td>31.10</td><td>13.45</td></tr><tr><td>Phosphate Ca 4 g/L</td><td>6.40</td><td>8</td><td>13.26</td><td>31.33</td><td>13.97</td></tr><tr><td>CaCl<sub>2</sub> 0.2mL/L</td><td>6.37</td><td>8</td><td>14.35</td><td>28.94</td><td>13.65</td></tr></tbody></table>
<figure><img src="image_2.png" /><figcaption>Figure 1. Curd yield according to stage of lactation of camel from 12th *postpartum* day.</figcaption></figure>

**Impact of lactation stage on coagulation capacity and curd yield**

No coagulation was observed before 12th day of lactation (Figure 1). At 12th *postpartum* day, first coagulation induced the formation of a very weak curd and low yield. At 14th day no coagulation was observed and consequently, and no curd was obtained. Then curd became better, with increase of

curd yield. The milk at 25-27th *postpartum* day was acceptable to get curd and was ready to use for cheese making.

**Natural acidification of camel cheese curd**

At the beginning, milk pH was 6.38 whatever the temperature (Figure 2). Acidification was faster at 36°C. At the end (when coagulation occurred), pH of 20°C milk was 5.80 vs 5.08 at 36°C.

<figure><img src="image_3.png" /><figcaption>Figure 2. Acidification curves of camel milk at 20°C and 36°C.</figcaption></figure>
Discussion

The physico-chemical composition of camel
milk was analyzed before starting the
experimentation. The fat and protein contents of
our camel milk were in the range of the normal
values reported in the literature (Farah, 1993;
Konuspayeva et al., 2009).

To transform milk into cheese, the gel obtained
after coagulation play important role. For cow
milk, calcium ions help to attend this gel stable in
all types of milk. Usually calcium phosphate or
calcium chloride is used, mainly on milk after heat
treatment. It is stated that to get firmness curd of
camel milk, 10-15 g of calcium chloride per 100 kg
of milk have to be added when bovine rennet is
used (Ramet, 1985, Benkerroum et al., 2011).
Indeed, in our trial, camel milk was not heated. In
such conditions, camel milk showed no effect of
adding of calcium ions, whatever the form,
phosphate or chloride on clotting time and yield. In
all published data, the described trials used heat
treated camel milk.

The effect of lactation stage on cheese making is known mainly with cow, goat or ewe milk. With camel milk no data was available in the literature. It is stated that at the first month *post-partum*, the quality of protein in milk undergoes important changes: immunoglobulins and some other whey proteins decreased and proteins from complex casein increased. For cheese making, only casein proteins are of main interest. The optimal time for cheese making will be after 25 days *post-partum*.

In the case of preparation of different types of cheese from camel milk, it is necessary to know the acidification patterns, how many times it takes before attend determined pH value. For coagulation of milk, 3 types of coagulation are described: rennet-coagulation, lactic coagulation and mixed coagulation (Goudedranche et al., 2001). For camel milk, only bovine rennet was tested or extract of young camel stomach (Boudjenah-Haroun et al., 2011). In the literature, no data on coagulation with pure camel rennet is available.

Only one reference using Chymax of Hansen
company were used, but it was bovine one
(Benkerroum et al., 2011). In our trial, only 50µl
was used (Chymax M strength 1000 IMCU) per
liter of raw milk instead 170 µl (Chymax-bovine
strength 600IMCU) per liter of pasteurized milk by
Benkerroum et al. (2011). Also, regarding the type
of coagulation, these authors used lactic
coagulation for preparing soft cheese from camel
milk. Milk acidification in their trial was faster in
the presence of *Streptococcus thermophilus* and

*Lactobacillus bulgaricus*. The pH value decreased below 5 after 240 minutes in room temperature. In our trial, such decreasing needed more than 500 minutes, because no starters were used and the acidification was natural.

These technological parameters of camel milk
processing into cheese by camel rennet represent
informative steps for further trials and could be
useful for industrial scale cheese processing of
camel milk.

Acknowledgment

This study has been achieved within FAO
camel project UTF/SAU/021/SAU with the support
of Camel and Range Research Center (CRRC). The
authors thank Mr. Sallal Issa Al-Mutairi, head of
the CRRC for his encouragements and support. We
thank also the staff of the camel farm (Mrs. Hassan
and Surish) for the monitoring of the camel.
Thanks also to FAO team leader at Riyadh, Dr. A.
Oihabi and the FAO regional officer, Dr.
Bengoumi who supported this project from the
beginning.

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