PaPer Ital. J. Food Sci., vol. 27 - 2015 357 - Keywords: camel milk, kefir, grain, traditional method, chemical properties, microbial properties, flavor profile analysis - KEFIRS MANUFACTURED FROM CAMEL (Camelus dramedarius) MILK AND COW MILK: COMpARISON OF SOME ChEMICAL AND MICRObIAL pROpERTIES G. KAvAS Department of Dairy Technology, Faculty of Agriculture, Ege University, 35100 İzmir, Turkey *Corresponding author: Tel. +90 232 3111420, email: gokhan.kavas@ege.edu.tr AbstrAct this study examined the production possibilities of kefir from fresh camel milk fermented with grain. the findings were then compared with kefir manufactured from cow’s milk. cow’s milk was fermented with 2.5% grains. the 1% (v/w) glucose enriched camel’s milk was fermented with 10% grains and left in an incubator at 25°c. Physical-chemical and sensorial analyses of the kefir sam- ples were measured on day one (18 hours) of storage and microbiological analyses were meas- ured on days one, three and five. some physical-chemical parameters were found to be higher in camel milk and its kefir than in cow milk and its kefir, some were found to be close and some were found to be lower. Addition of 1% glucose and 10% grains to the camel milk affected the ti- tration acidity and viscosity of kefir to significant levels. the kefir produced from camel milk was perceived as sourer, whereas its other properties were found to be close to those of cow milk. the cholesterol levels of camel milk and its kefir were detected to be higher when compared to those of cow milk and its kefir, but the cholesterol level decreased in both examples after the produc- tion of kefir. In terms of the composition of fatty acids, it was determined that sFA and the small, medium chain fatty acids ratio was low in camel milk and its kefir, but MUFA and the long chain fatty acids ratio was high. PUFA ratio was high in camel milk but low in its kefir. In microbiolog- ical analysis, yeast levels increased in kefir samples with the Lactobacillus ssp. strains, and the increase in the number of yeasts was higher than in the cow milk kefir. In kefir samples, Lacto- bacillus ssp. strains increased on day one and three of storage, but diminished after day three. 358 Ital. J. Food Sci., vol. 27 - 2015 IntrodUctIon Kefir is a dairy product that has been pro- duced for years in Eastern Europe and Mon- golia, before spreading to caucasia (GAWArE et al., 2011). Kefir is produced by adding specif- ic amounts of the kefir grain (traditional meth- od) or the modified culture (industrial method) manufactured from this grain (PoGAČIĆ et al., 2013) into the milk of various animals. Ethyl alcohol and lactic acid fermentations are de- veloped together during the product formation, thus causing it to taste somewhat acidic. Kefir grains are off-white and slightly yellowish, irreg- ular in shape and with a circumference taken up by polysaccharide matrixes that (JIAnZHonG et al., 2009) compose 25% of the dry weight solu- ble in water (PoGAČIĆ et al., 2013), and a diame- ter of 0.3cm -2 cm (bEsHKoVA et al., 2002). Ho- mofermentative lactobacilli make up 65-80% of the flora. In the grain flora, homofermentative and heterofermentative lactic acid streptococ- ci make up 20%, and lactose-fermentative and non-fermentative yeasts make up a further 5%. the percentage of acetic acid bacteria (in pro- duction with grain) is relatively small (IrIGoY- En et al., 2005). species of the microorganisms in the grain, their proportion to each other and their numbers change according to the origin of the grain and conditions of use (FErrEIrA et al., 2010). today, kefir is regarded as a fermented dairy beverage that is anti-bacterial and anti- inflammatory (LoPItZ-otsoA et al., 2006), an- ti-tumoral (sHIoMI et al., 1982), anti-apoptotic (MAtsUU et al., 2003), anti-allergic (UMEdA et al., 2005), anti-oxidant, and anti-mutagenic (LIU et al., 2005). It also lowers systolic and diastolic blood pressure and bad cholesterol (AGErbAEK et al., 1995), adjusts lactose dyspepsia (HErt- ZLEr and cLAncY, 2003), and contains bioactive peptides, exopolysaccharides and their bacterio- sis, and has a strong probiotic effect on human health (rAttrAY and o’connELL, 2011). camel milk differs from the milk of other rumi- nant animals in its composition and physiolog- ical properties. camel milk is rich in long chain fatty acids, but contains low amounts of short chain fatty acids (GorbAn and IZZELdIn 1999). Vitamins A, b2, E, c and minerals ca, na, K, Zn, Mg and Fe are far more abundant in camel’s milk than in cow’s milk. Lactose intolerant people (EL- HAtMI et al., 2007) can consume camel milk. due to camel milk not containing β-lactoglobulin and some casein derivatives, it is similar to human milk with its hypoallergenic (sHAbo et al., 2005), immunoglobulin content. It is anti-diabetic effec- tive (HAMAd et al., 2011) and because it contains more peptidoglycan recognition proteins (PGrP) and natural protective proteins than other ru- minant milk, it has an antimicrobial and antivi- ral effect (EL-AGAMY et al., 1992). not to mention that camel milk is anti-carcinogenic and anti-hy- pertensive (HAMAd et al., 2011) and renoprotec- tive, it reinforces immunity, increases metabo- lism and muscle mass, is bone-forming and also has therapeutic effects on some diseases such as hepatitis b, autism (LAILA et al., 2013) and tuberculosis (AGrAWAL et al., 2004). today, we know that yoghurt, probiotic yoghurt (AttIA et al., 2001; EL-AGAMY et al., 1992), stabilizer aug- mented yoghurt (MULIor et al., 2013) and many mild cheeses whose clotting is poor due to enzy- matic coagulation (MEHAIA, 1993; rAMEt, 1987) can be produced from camel milk. our research utilized kefir that was man- ufactured from camel (Camelus dramedarius) milk (caM). Kefir made from cow’s milk (coM) was used as the control sample. the physical- chemical properties in raw milks were analyzed, along with these properties in the cow milk ke- fir (coMK) and camel milk kefir (caMK) sam- ples. sensorial tests were conducted as of the eighteenth hour of day one and microbiological analyses were made on day one, three and five of storage. MAtErIALs And MEtHods Camel milk, kefir grain camel (Camelus dramedarius) milk was procured from a native camel farm in deniz- li sarayköy (turkey). cow milk and kefir grain were procured from the department of dairy technology Pilot dairy Plant, Ege University Ag- ricultural Faculty. Kefir production In this study, kefir was produced from camel and cow milk using the traditional (grain) meth- od as shown in Fig. 1. Physical-chemical analyses In the raw milk and kefir samples, dry matter (binder Ed-53 Germany) and ash (Protherm PFL 110/6 turkey) were calculated via a gravimeter, fat with the Gerber method, pH value of the ti- tration acidity in terms of lactic acid with a ss-3 Zeromatic (beckman Instruments Inc., califor- nia, UsA) brand pH meter, protein with the Kjel- dahl method (AoAc, 1990), lactose value with an Atago Polax x 2L (Japan) model polarimeter (HorWItZ, 1965), viscosity value with a brook- field digital Viscometer, ModEL dV-II+Pro (UsA) model viscometer as cP [at speed 180 mPa, be- tween 15.7% and 67.7% torque]. Determining the fatty acid composition in samples and preparation of fat extraction and fatty acid methyl esters Each homogenized sample was extracted us- ing the Gerber method, thus fat was obtained Ital. J. Food Sci., vol. 27 - 2015 359 Fig. 1 - Kefir Production with the traditional (Grain) Method. ** the glucose and grain ratio added to camel milk and cow milk was determined as a result of preliminary study. ***physical-chemical and sensorial analyses were measured at day one (18 hours) of storage and microbiological analyses were measured at days one, three and five. (Iso 11870:2009 - IdF 152:2009) and fatty acid methyl esters were prepared pursuant to Aocs (2009), after which they were examined in the gas chromatograph (Gc). [chromatography is a supelco sP-2380 fused silica capillary column (60 m 0.25 mm i.d., 0.2 mm film thickness; su- pelco Inc., bellefonte, PA, UsA) and flame ioniza- tion detector Hewlett-Packard Gc (model 6890). Injection volume was 1 µL. Gc furnace temper- ature was set to reach 220°c from 100°c when 4°c/minute. Injector and detector temperature was 300°c, carrier gas was Helium and the flow rate was 1 mL/min]. Determining the cholesterol level in samples In samples, the cholesterol level was ana- lyzed according to the findings of ossA et al., (1995); and then examined by gas chromatog- raphy (Gc). [chromatography was a HP-5 silica capillary column (25 m 0.32 mm i.d., 0.52 mm film thickness; Hewlett-Packard, UsA) and FId 360 Ital. J. Food Sci., vol. 27 - 2015 (flame ionization detector) Hewlett-Packard Gc (model 6890). Injection volume was 1µl. Gc fur- nace temperature was set to 300°c, injector tem- perature to 280°c, colon temperature to 270°c for 15 minutes. carrier gas was Helium and the flow rate was 1.5 mL/min. Microbiological analyses For counting Lactobacillus ssp., de Mann ro- gosa sharpe (Mrs) Agara (Merck darmstadt, Germany) (sHArPE et al., 1966) was used. Lac- tococcus ssp. was cultured on M l7 Agara (Mer- ck darmstadt, Germany) (tErZAGHI and sAnd- InE, 1975). For yeast, Glucose-salt Agara (Anon- YMoUs, 1990) plantation was done. Isolation and census of lactic acid bacteria were conduct- ed according to IdF standard 149 A (1997) and IdF standard 163 (1992). Yeasts were incubat- ed at 25°c for three to five days. After this peri- od, colonies that had developed in petri dishes were counted as cfu/mL on days one, three and five of storage. Sensory evaluation the sensory evaluation was made by a panel of nine individuals who evaluated kefir samples in terms of consistency and flavor on a scale from 1 to 5. For ALtUĞ and ELMAcI (2011), the method of Flavor Profile Analysis was utilized. Statistics two different milk and two different kefir sam- ples were analyzed in three parallels and two rep- etitions. sPss statistics analysis software (IbM sPss statistics) was used. data that gained im- portance were analyzed using the variance anal- ysis AnoVA based on the duncan multiple com- parison test on a p<0.01 level. rEsULts And concLUsIons In the caM sample, compared to the coM sample, fat and lactose values were found to be table 1 - Physical-chemical properties of raw camel milk, raw cow milk and of kefirs produced from these milks. Analyses Milk samples Kefir samples CaM CoM CaMK CoMK Dry matter 12.73±0.12A 12.80±0.09B 11.10±0.02C 10.70±0.03D Fat (%) 3.60±0.08A 3.50±0.06B 3.20±0.02C 3.30±0.01D Titratable Acidity 0.127±0.02A 0.132±0.02B 0.92±0.01C 0.81±0.02D pH 6.46±0.32A 6.44±0.27B 4.10±0.10C 4.55±0.14D Protein (%) 3.05±0.03A 3.21±0.03B 2.82±0.03C 3.09±0.03D Ash (%) 2.932±0.10A 1.461±0.09B 1.423±0.05C 1.068±0.05D Lactose (%) 6.22±0.05A 6.20±0.51B 3.45±0.07C 3.54±0.02D A, B, C, D: The differences between the values in the same rows are statistically significant (p < 0.01). higher; there was twice as much ash and similar pH and dry matter values. In addition, protein, titration acidity in terms of lactic acid (table 1) and viscosity values were detected to be lower. In the research, it was determined that results regarding the pH value 6.46 pH, fat (3.60%), pro- tein (3.05%), lactose (6.22%), total dry matter (12.73%), ash (2.932%) and titratable acidity in terms of lactic acid (0.12%) of camel milk were within the boundaries found in the literature, and that the lactose and ash levels were high- er in our studies (FAo, 1982; EL-AMIn and WIL- coX, 1992). PH values of kefir samples were de- termined to correspond with the turkish Food codex (2009/25) and WsZoLEK et al. (2006). Lac- tic acid was detected to be higher in the caMK sample (0.92%LA) than in the coMK sample (0.81%LA), whereas for viscosity, it was vice ver- sa. With the addition of 1% (v/w) glucose into the caM sample, simulating the development of lactic acid bacteria, we aimed to increase the ti- tration acidity and viscosity. to this end, the ef- fect that the addition of 1% glucose (v/w) and 10% grain into the caM sample has on titration acidity and viscosity was found to be significant (p<0.01), and lactic acid and viscosity were de- tected to have increased. However, viscosity in the caMK sample was lower than the coMK sam- ple. In addition, the glucose and grain ratio added to camel milk was determined as a result of pre- liminary study. In that preliminary study, some portion of the caM sample was inoculated with yeast grains in ratios of 2.5%, 5%, 7.5% and 10% without the addition of glucose, while the other portion of the sample had the same process with the addition of glucose. Afterwards, viscosity val- ues and titration acidity were detected in kefir samples, and viscosity values are given in tables 2 and 3. Grain being added into camel milk by 2.5% did not have a major effect, and since the 2.5% grain addition into the coMK sample pro- vided the desired viscosity value, other grain ra- tios were not tested. All in all, with the 1% glucose (v/w) and 10% grain addition into camel milk, a four times greater increase was reached in vis- cosity than in the one with just the grain addi- tion, and the titration acidity diminished from Ital. J. Food Sci., vol. 27 - 2015 361 4.78 pH (in the sample with grain addition only) to 4.10 pH. results correspond with the litera- ture (LEWIs, 1986). In this study, problems that might occur in fer- mentation were associated with low viscosity val- ue obtained from the caMK sample, lower serum protein content of camel milk than cow milk (FA- rAH, 1996), poor interaction between denature serum proteins of camel milk and k-casein, lack of β-lactoglobulin from serum proteins and dif- ferent derivatives of β-casein, low amounts of ca- table 2 - Viscosity values of the kefir samples produced by injecting grain in certain amounts in caM with/without glucose addition and the ones produced from coM without glucose addition (cP). Grain ratio (%) CaMK (Gra) CaMK (Gra+G) CoMK (Gra)   viscosity (cP) viscosity (cP) viscosity (cP)  2.5 5.21aA 5.87 aB 111.475C 5 5.46bA 8.44 bB NT 7.5 7.12cA 18.81 cB NT 10 9.28dA 37.18 dB NT NT:Not-tested ; Gra: Grain ;G+Gra: Glucose +Grain a, b, c, d, e: The differences between the values in the same column are statistically significant (p < 0.01). A, B, C, D: The differences between the values in the same rows are statistically significant (p < 0.01). sein and its derivatives (LALEYE et al., 2008) and the anti-bacterial effect of camel milk (HAsHIM and KHALIL, 2004). Many factors (content of pro- tein and denature serum proteins, casein ratio and its content, interactions between denature serum proteins and k-casein) may affect viscos- ity (PUVAnEntHIrAn et al., 2002). based on the pH change, these factors might also affect the micelle surface area and size, micelle content and water binding capability in casein micelles (AnEMA and KLostMEYEr, 1996; dALGLEIsH and table 3 - Fatty acid compositions of kefir samples made from camel/cow milk (g/100g) Name of Fatty Acid Methyl Ester (g/100g) and Formula of Molecule CoM CoMK CaM CaMK Butyric Acid Methyl Ester (C4:0) 0.064 0.043 ND ND Caproic Acid Methyl Ester (C6:0) 0.264 0.422 0.140 0.121 Caprylic Acid Methyl Ester (C8:0) 0.037 0.024 0.003 0.002 Capric Acid Methyl Ester (C10:0) 0.085 0.061 0.004 0.003 Undecanoic Acid Methyl Ester (C11:0) 0.007 0.009 ND ND Lauric Acid Methyl Ester (C12:0) 0.127 0.101 0.021 0.021 Tridecanoic Acid Methyl Ester (C13:0) 0.002 0.017 0.005 0.004 Myristic Acid Methyl Ester (C14:0) 0.386 0.303 0.321 0.309 Myristoleic Acid Methyl Ester (C14:1) 0.051 0.034 0.050 0.050 Pentadecanoic Acid Methyl Ester (C15:0) 0.021 0.013 0.029 0.029 cis-10- Pentadecanoic Acid Methyl Ester (C15:1) 0.012 0.036 0.013 0.010 Palmitic Acid Methyl Ester (C16:0) 0.901 0.740 1.049 0.967 Palmitoleic Acid Methyl Ester (C16:1) 0.063 0.027 0.292 0.268 Heptadecanoic (Margaric) Acid Methyl Ester (C17:0) 0.015 0.011 0.020 0.018 cis-10-Heptadecanoic Acid Methyl Ester (C17:1) 0.016 0.074 0.024 0.019 Stearic Acid Methyl Ester (C18:0) 0.430 0.361 0.507 0.457 Oleic Acid Methyl Ester (C18:1n9c) 0.840 0.581 0.843 0.715 Linoleic Acid Methyl Ester (C18:2 n6c) 0.088 0.072 0.107 0.099 γ-Linolenic Acid Methyl Ester (C18:3 n6) 0.034 0.177 0.053 0.036 Arachidic Acid Methyl Ester (C20:0) 0.028 0.017 0.028 0.023 cis-11- Eicosenoic Acid Methyl Ester (C20:1) ND ND 0.013 0.010 cis-11,14-Eicosadienoic Acid Methyl Ester (C20:2) ND ND 0.009 0.005 Arachidonic Acid Methyl Ester (C20:4n6) 0.012 0.067 0.028 0.017 Behenic Acid Methyl Ester (C22:0) 0.016 0.094 0.023 0.009 Other fatty acids ND 0.017 0.017 0.007 Short-chain fatty acids (4-6C) 0.33 0.46 0.14 0.12 Medium-chain fatty acids (8-12C) 0.26 0.20 0.03 0.03 Long-chain fatty acids (>12C) 2.92 2.62 3.41 3.05 Saturated fatty acids (SFA) 2.38 2.22 2.15 1.96 Monounsaturated fatty acids (MUFA) 0.98 0.75 1.24 1.07 Polyunsaturated fatty acids (PUFA) 0.13 0.32 0.20 0.16 ND: Non-detected. 362 Ital. J. Food Sci., vol. 27 - 2015 LAW, 1988, 1989). the drop in pH causes the in- teraction between serum proteins and case mi- celles and the viscosity to increase (AnEMA et al., 2004). However, in the current study it was de- termined that based on the drop in pH (4.10 pH) in the caMK sample, the viscosity value was low- er than in the coMK samples. this is thought to result from the effect of one or more of the pa- rameters given above (AnEMA and LI, 2003) Also, the camel milk is low in casein and serum pro- teins and the composition of these. It was found that the milk type in kefir samples has an impor- tant effect on titration acidity, pH and viscosity; the effect of titration acidity on viscosity is vital as well (p<0.01). Protein, lactose and fat in the caMK sample were found to be higher than in the coMK sample, whereas dry matter and ash were found to be lower. In general, effect of the milk type on dry matter, fat, protein and lactose was established as significant, as well as the ef- fect of glucose addition into milk and grain ratio on titration acidity (p<0.01). caM and coM, and fatty acid compositions of kefirs produced from these milks are given in ta- ble 3. In caM and caMK samples, it was deter- mined that the short (c4:0-c6:0) and medium (c8:0-c12:0) chain fatty acids ratio, as well as the saturated fatty acids (sFA) ratio were lower than in coM and coMK samples, but the long chain fatty acids ratio and the monounsaturat- ed fatty acids (MUFA) ratio were higher. It was also established that the ratio of polyunsatu- rated fatty acids (PUFA) in the caM sample was higher than the coM sample; however, its ratio in the caMK sample (0.16 g/100 g) was lower than in the coMK sample (0.32 g/100 g). thus, the conclusion: camel milk and its kefir contain some fatty acids that affect our health positive- ly in terms of fatty acid composition in higher amounts than cow milk and its kefir. the camel milk fatty acid composition chang- es pursuant to the species and the diet of that specific camel, as well as its region and the cli- mate of that region (cHILLIArd et al., 2000; Ko- nUsPAYEVA et al., 2008). the results we obtained from this research were similar to the results of other researchers (AGrAWAL et al., 2004; sHAM- sIA, 2009). In the caM, coM, caMK and coMK samples, cholesterol levels were different and an impor- tant relationship between the milk type and the cholesterol level was detected (p<0.01) (table 4). Along with this, it was determined in the re- search that the cholesterol level decreased after production of kefir by using different milks, and the effect that kefir production has on the drop in cholesterol levels was regarded as significant (p<0.01). According to some researchers (Gor- bAn and IZZELdIn, 1999; GoUdJIL et al., 2003; KonUsPAYEVA et al., 2008; sIEbEr, 2005), cho- lesterol level of kefir production was higher than cow milk, but it was also found to be lower ac- cording to some other researchers (ALAbdULKA- rIM, 2012; AGrAWAL et al., 2004). Initially, in the grain, Lactobacillus ssp. strains were found to be as 1.93 x107 cfu/mL, Lactococ- cus ssp. strains as 5.54 x107 cfu/mL and yeast as 1.68x106 cfu/mL. In the study, Lactobacillus ssp. strains (Fig. 2a) and yeast levels (Fig. 2b) increased in both kefir samples throughout the storage process. In addition, the increase in the Lactobacillus ssp. strains in the caMK sample was found to be higher. Lactococcus ssp. strains (Fig. 2c) were detected to have increased in kefir samples at day one and three of storage, but to have decreased after day three. Levels of Lacto- bacillus ssp. strains in kefir samples were close to one another at the inception of storage, but the one in the caMK sample took the lead after day one of storage. Lactobacillus ssp. strains in the caMK sample at days one, three and five of storage increased, in comparison with the start- ing level, respectively at levels of 0.99 cfu/mL, 1.71 cfu/ml and 2.59 cfu/mL. However, in the coMK sample, it was respectively: 0.91 cfu/ mL, 1.28 cfu/mL and 2.18 cfu/mL. Lactococ- cus ssp. strains in the coMK sample at days one and three of storage increased, in compari- son with the starting level, respectively at levels of 0.05 cfu/mL and 1.02 cfu/mL. However, this lessened in day five by 0.41 cfu/mL compared to day three of storage. development of Lacto- coccus ssp. strains in the caMK sample was the same as the coMK sample at day one; how- ever, its increase after day one of storage was lower than the one in the coMK sample. In the caMK sample, an increase respectively at lev- els 0.04 cfu/mL and 0.8 cfu/mL was detected in day one and three of storage in comparison with the starting level, whereas after day five, a decrease took place. this decrease was ten times more than the coMK sample. Yeast level increased in both kefir samples throughout the storage process, but the one in the coMK sam- ple was approximately three times higher than the caMK’s. Generally, it was concluded that mi- croorganism levels in caMK and coMK samples in storage were above the minimum values set forth by “turkish Food codex, communiqué on Fermented Milks” (turkish Food codex, com- muniqué no: 2009/25). table 4 - cholesterol levels of kefirs samples made from camel/cow milk (mg/100g). Cholesterol levels (mg/100g) CoM CoMK 14.60aA 7.97aB CaM CaMK 21.28bA 18.24bB a, b, c, d, e: The differences between the values in the same column are sta- tistically significant (p < 0.01). A, B, C, D: The differences between the values in the same rows are statisti- cally significant (p < 0.01). Ital. J. Food Sci., vol. 27 - 2015 363 Fig. 2 - Lactobacillus ssp. (a), yeast (b) and Lactococcus ssp. (c) levels in kefirs produced from camel and cow milks. research helped discover an important rela- tionship between the milk type and the storage period on microorganism levels. In addition, the effect that glucose has on microorganism devel- opment was established as significant (p<0.01). In the caMK sample produced with the addi- tion of 1% glucose, increase in the Lactobacillus ssp. strains was higher than in the coMK sam- ple, but this was vice versa for the increase in the yeast level. Progress of the increase (Lactobacillus ssp., yeast), also the decrease (Lactococcus ssp.) in the microorganism levels in the caMK sample after day three of storage show parallels with the coMK sample (KoroLEVA et al., 1978; KoroLEVA and bAVInA, 1978; onEr et al., 2010). In the re- search, microbial flora in the caMK sample went through a different development. this result cor- responds with the literature data regarding oth- er fermented dairy products of camel milk (AbU- tArboUsH, 1996; AttIA et al., 2001; JUMAH et al., 2001; AbdEL rAHMAn et al., 2009). In addition, the research pinpointed that the usage of grain in producing kefir from camel milk was more ef- fective (AbU-tArboUsH, 1996; AbdEL rAHMAn et al., 2009; MEHAIA, 1993). In the flavor profile evaluation of kefir sam- ples, panelists determined that sour, sweet, salty, bitter, fermented milk, cream, greasy, cheesy, sharp, gas, alcohol, metallic and burnt milk flavor densities were perceived differently between the caMK and coMK samples (Fig. 3). In the flavor profile evaluation, it was detected that the caMK sample was sourer, cheesier and had a sharper aroma than the coMK sample. con- sistency and appearance in the caMK sample were detected to be lower than the coMK sam- ple. In general, the caMK sample was appreci- ated by the panelists and was defined as “sour- er” than the coMK sample. Fig. 3 - Flavor profile evaluation of the caMK and coMK samples. 364 Ital. J. Food Sci., vol. 27 - 2015 concLUsIons In the current research, an increase was ob- tained in the viscosity value in the kefir produced by adding 1% (v/w) glucose and 10% grain into camel milk. dry matter, ash and titratable acid- ity in the camel milk kefirs were higher than in cow milk kefirs; whereas fat, pH, protein and lac- tose values were lower. cholesterol level of camel milk and its kefir product was found to be high- er than that of cow milk and its kefir. Along with this, it was detected in this study that propor- tion of camel milk and its kefir to cow milk and its kefir in terms of sFA is low. However, it is high in terms of MUFA. the PUFA ratio of cam- el milk is high compared to cow milk. However, the PUFA ratio in the camel milk kefir was de- fined to be lower than the one in the cow milk kefir. Lastly, it was also confirmed in the study that some compounds, which have positive ef- fects upon metabolism in camel milk and its ke- fir, have a higher impact than on the cow milk kefir’s metabolism. rEFErEncEs Abdel rahman İ.A., dirar, H.A. and osman M.A. 2009. Mi- crobiological and biochemical changes and sensory evalu- ation of camel milk fermented by selected bacterial start- er cultures. Afr. J. Food sci. (12)3: 398-405 Abu-tarboush H.M. 1996. comparison of associative growth of yogurt starter in whole milk from camels and cows. J. dairy sci. 79 (3): 366-371. Agerbaek M., Gerdes L.U. and richelsen b. 1995. Hypocho- lesterolaemic effect of a new fermented milk product in healthy middle-aged men. Eur. J. clin. nutr. 49: 346-52. Agrawal r.P., Kochar d.K., sahani M.s., tuteja F.c. and Ghrui s.K. 2004. Hypoglycaemic activity of camel milk in streptozotocin induced diabetic rats. Int. J. diab. dev. countries. 24: 47-49. Alabdulkarim b. 2012. Effect of camel milk on blood glu- cose, cholesterol, triglyceride and liver enzymes activ- ities in female albino rats. World App. sci. J. 17 (11): 1394-1397. Altuğ t. and Elmacı Y. 2011. sensorial evaluation in food. no :010-1b. sidas Medya Ltd.sti., İzmir, turkey 27s. Anema s.G. and Klostmeyer H. 1996. δ Potentials of casein Micelles from reconstitued skim milk Heated at 120ºc. I. dairy J. 6: 673-687. Anema s.G. and Li Y. 2003. Association of denaturated Whey Proteins with casein Micelles in Heated reconsti- tuted skim milk and Its Effect on casein Micelle size. J. dairy res. 70: 73-83. Anema s.G., Lowe E.K. and Li Y. 2004. Effect of pH on the viscosity of heated reconstituted skim milk. I. dairy J. 14: 541-548. Anonymous. 2001. FAo/WHo. codEX standard for Fer- mented Milks. 243. Anonymous. 1990. Milk and milk products enumeration of yeast and moulds colony count technique at 25°c. IdF standart 94. AoAc (Association of official Analytical chemists) 1990. official Methods of Analysis of the Association of official Analytical chemists. thirteenth Edition. Association of official Analytical chemists (publisher), Washington, dc 20044, UsA, 1018 p. Aocs, 2009. Aocs American oil chemists’ society offi- cial Method. ce 2-66. Preparation of Methyl Esters of Fatty Acids. Attia H., Kherouatou n. and dhouib A. 2001. dromedary milk lactic acid fermentation: microbiological and rheo- logical characteristics. J. Industrial Microbiol. biotech- nol. 26(5): 263-270. beshkova d.M., simova E.d., simov Z.I., Frengova, G.I. and spasov Z.n. 2002. Pure cultures for Making kefir. Food Microbiol. 19: 537-544. chilliard Y., Ferlay A., Mansbridge r.M. and doreau M. 2000. ruminant milk fat plasticity: nutritional control of sat- urated, polyunsaturated, trans and conjugated fatty ac- ids, Ann. Zootech. 49: 181-205. dalgleish d.G. and Law A.J.r. 1988. pH induced dissocia- tion of casein micelles. I. Analysis of liberated caseins. J. dairy res. 55: 529-538 dalgleish d.G. and Law A.J.r. 1989. pH induced dissoci- ation of casein micelles. II. Mineral solubilization and its relation to casein release. J. dairy res. 56: 727-735 El-Agamy E.I., ruppanner r., Ismail A., champagene c.P. and Assaf r. 1992. Antimicrobial and antiviral activity of camel milk protective proteins. J. dairy res., 59: 169-175. El-Amin F.M. and Wilcox c.J. 1992. Milk composition of Ma- jaheem camels. J. dairy sci. 75: 3153-3157. El-Hatmi H., Girardet J.M., Gaillard J.L., Yahyaoui M.H. and Attia H. 2007. characterisation of whey proteins of camel (Camelus dromedarius) milk and colostrum. small rum. res. 70: 267-271. FAo. 1982. camels and camel milk. Food and agrıculture organızatıon of the Unıted nations. rome. Farah Z. 1996. camel milk properties and products, 1st Edi- tion. swiss centre for development. cooperation in tech- nology and Management, Vadianstrasse 42, cH- 9000 st. Gallen, switzerland. Ferreira I.M., Pinho o., Monteiro d., Faria s., cruz s., Per- reira A., roque A.c and tavares P. 2010. Effect of kefir grains on protolysis of major milk protins. J. dairy sci. 93: 27-31. Gaware V., Kotade r. and dolas K. 2011. the magic of kefir: a review History of Kefir. Pharmacologyonline. 1: 376-386. Gorban A.M.s. and Izzeldin o.M. 1999. study on cholesteryl ester fatty acids in camel and cow milk lipid, Int. J. Food sci. technol. 34: 229-234. Goudjil H., torrado s., Fontecha J.,Martinez-castro I., Fra- ga J. and Juarez M. 2003. composition of cholesterol and its precursor in ovine milk, Lait 83: 153-160. Hamad E.M., Abdel-rahim E.A. and romeih E.A. 2011. beneficial Effect of camel milk Liver and kidneys func- tion in diabetic sprague-dawles rats. I. J. dairy sci. 6 (3): 190-197. Hashim I.b. and Khalil A.H. 2004. dairy sci. J. 87 suppl. 1: 282-386. International dairy Federation (IdF) (1988). Fer- mented milks, science and technology. IdF bulletin 227. Hertzler s.r. and clancy s.M. 2003. Kefir improves lactose digestion and tolerance in adults with lactose maldiges- tion. J. Am. diet. Assoc. 103: 582-7. Horwitz W. 1965. official methods of analysis of the asso- ciation of official agricultural chemists. 10th Ed., p. 224, Publishing by the association official agricultural chem- ists. benjamin Franklin station, Washington d.c. 20044. IdF standard 149 A. 1997. dairy starter cultures of Lac- tic Acid bacteria (LAb) – standard of Identity. brussels, belgium: International dairy Federation. IdF standard 163 1992. General standard of Identity for Fermented Milks. brussels, belgium: International dairy Federation. Irigoyen A., Arana I., castiella M., torre P. and Ibánez F.c. 2005. Microbiological, Physicochemical and sensory characteristic of Kefir during storage. Food chem. 90: 613-620. Iso 11870:2009 (IdF 152:2009). Milk and milk products- determination of fat content-General guidance on the use of butyrometric methods. Jianzhong Z., Xiaoli L., Hanhu J. and Mingsheng d. 2009. Analysis of the microflora in tibetan kefir grains using denaturing gradient gel electrophoresis Food Microbiol. 26: 770-775. Ital. J. Food Sci., vol. 27 - 2015 365 Jumah r.Y, shaker r.r. and Abu-Jdayil b. 2001. Effect of milk source on the rheological properties of yoghurt dur- ing the gelation process. J. dairy tech. 54(3): 89. Konuspayeva G., Lemarie E., Faye b., Loiseau G. and Montet d. 2008. Fatty acid and cholesterol composition of camel’s (Camelus bactrianus, Camelus dromedarius and hybrids) milk in Kazakhstan. dairy sci. technol. 88: 327-340. Koroleva n.s., bavına n.A. and rozhkova I.V. 1978. chang- es in the Microflora of kefir during storage XX. Int. dairy cong France-1978 Publishing by congrilait Paris 1978 Vol. E. (844). Koroleva n.s. and bavina n.A. 1978. basıc Factors Affect- ing the Microflora and Quality of Kefir. XX Int. dairy cong France 1978. Publishıng by congrılait Paris 1978. Vol. E (844). Laila Y. Ayadhi A.L. and Elamin n.E. 2013. camel Milk as a Potential therapy as an Antioxidant in Autism spectrum disorder (Asd). Evidence based complementary and Al- ternative Medicine 8: 11-17 Laleye L.c., Jobe b. And Wasesa A.A.H. 2008. comparative study on heat stability and functionality of camel and bovine milk whey proteins. J. dairy sci. 91: 4527-4534. Lewis J.M. 1986. Physical properties of dairy products. In: Modern dairy technology (Ed. r.K. robinson) Elsevier Ap- plied science Publishers, London, UK. Liu J.r., chen M.J. and Lin c.W.2005. Antimutagenic and antioxidant properties of milk-kefir and soymilk-kefir. J. Agric. Food chem. 53: 2467-74. Lopitz-otsoa F., rementeria A., Elguezabal n. and Garaizar J. 2006. Kefir: A symbiotic yeast-bacteria commu¬nity with alleged healthy capabilities. revista Iberoamerica- na de Micologia. 23: 67-74. Maeda H., Zhu X., suzuki s., suzuki K. and Kitamura s. 2004. structural characterization and biological activi- ties of an exopolysaccharide kefiran produced by Lacto- bacillus kefiranofaciens Wt-2bt. J. Agric. Food chem. 52: 5533-5538 Marshall V.M. and cole W.M. 1985. Methods for making kefir and fermented milks based on kefir. J. dairy res. 52: 451-456 Matsuu M., shichijo K., okaichi K., Wen c.Y., Fukuda E., nakashima M., nakayama, t., shirahata s., tokumaru s. and sekine I. 2003. theprotective effect of ferment- ed milk kefir on radiation-induced apoptosis incolonic crypt cells of rats. J. dairy res. (tokyo) 44(2): 111-115. Mehaia M.A. 1993. Fresh soft white cheese (domiati type) from camel’s milk: composition, yield and sensory eval- uation. J. dairy sci. 20: 2845-2855. Muliro P.s., shalo P.L. and Kutima P.M. 2013. optimization of camel milk coagulum formation and consumer prefer- ence. Afr. J. Food sci. and tech. 4(8): 176-181. oner Z. and Karahan A.G., Çakmakçı M.L. 2010. Effects of different milk types and starter cultures on kefır. Food J. 35 (3): 177-182. ossa E.M., Huber W., Molero A. and Pereyra c. 1995. de- termination of cholesterol in milk fat by supercritical flu- id chromatography. J. chromatography A. 715:333-336. Pogačić t., Šinkos., Zamberlin s. and samaržija d. 2013. Microbiota of kefir grains. Mljekarstvo 63(1): 3-14. Puvanenthiran A., Williams r.P.W. and Augustin M.A. 2002. structure and visco-elastic properties of set yo- ghurt with altered casein to whey protein ratios. I. dairy J. 12: 383-391 ramet J.P. 1987. Use of bovine calf rennet to coagulate raw camel milk. World Anim. rev. 61: 11-26. rattray F.P. and o’connell M.J. 2011. Kefir. Encyclopedia of dairy science., Elsevier, Ltd. 518-524. shabo Y., barzel r., Margoulis M. and Yagil r. 2005. cam- el milk for food allergies in children. Immunol. and Al- lergy .7 :796-798. shamsia s.M. 2009. nutritional and therapeutic properties of camel and human milks. I. J. Genetics and Molecular biol. 1(2): 052-058. sharpe M.E., Fryer t.F. and smith d.c. 1966. Identifica- tion of the Lactic Acid bacteria. In: Gibbs b.M. and skin- ner P.A.: Identification Methods for Microbiologists, Part A, 65-79. shiomi M., sasaki K., Murofushi M. and Aibara K. 1982. An- titumor activity in mice of orally administered polysaccha- ride from Kefir grain. Jpn. J. Med. sci. biol. 35: 75-80. sieber r. 2005. oxidised cholesterol in milk and dairy prod- ucts. Int. dairy J. 15:191-206. terzaghi b.E. and sandine W.E. 1975. Improved medium for Lactic streptococci and their bacteriophages. App. Mi- crobiol. 29 (6): 807-8l3. turkish Food codex. 2009. communiqué no: 2009/25. Femented milk product. 6.02.2009-27143 teblig no: 2009/25 Umeda c., sonoyama K., Yamaguchi n., saito r., Akashi K., Motoshima, H. and Kawabata J. 2005. oral administra- tion of freeze-dried kefir reduces intestinal permeation of and oral sensitization to ovalbumin in mice. biosci bio- technol biochem. 69(1): 249-251. Wszolek M., Kupiec-teahan b., skov Guldager H. and tamime A.Y. 2006. Production of kefir, koumiss and other related products. In: tamime A.Y. (Ed.) Fermented milks. blackwell science Ltd, oxford, pp. 174-198. Paper Received September 4, 2014 Accepted November 5, 2014