enrichment of yogurt made from camel milk with allium

Abstract

The influence of Allium sativum andCinnamomum verum water extracts on thewater holding capacity (WHC), susceptibilityto syneresis (STS), exopolysaccharides (EPS)and rheological properties of yogurt during 0,7, 14 and 21 days of refrigerated storage (4°C)were investigated. The WHC of yogurt inpresence of C. verum or A. sativum wassignificantly higher than plain-yogurt overallstorage period. The highest WHC showed onday 21 of storage with 24.5±1.6% and17.3±1.5% for C. verum- and A. sativum-yogurts respectively. The STS uniformlyreduced (p<0.05) in presence of herbs comparedto in absence. ESP in plain- and herbal-yogurtsincreased during refrigerated storage. However,both plain- and A. sativum-yogurt decreased(p<0.05) on day 21 of storage. Amplitudesweep showed liquid like behaviour for bothherbal and plain-yogurt during storage.However, addition of C. verum or A. sativumin yogurt showed remarkable improvement inthe structure of yogurt on day 21 of storage.Both herbal- and plain-yogurts showed shearthinning behaviour. Refrigerated storage up to21 days showed less shear thinning behaviour

Camel- International Journal of Veterinary Science : 1(1):51-63. January, 2013

Enrichment of yogurt made from camel milk withAllium sativum and Cinnamomum verum: Influence onsyneresis, water holding capacity, exopolysaccharides

and rheological properties

Shori, A.B. 1*, Baba, A.S.1, Misran, M.2 and Tan, H.W.2

1Division of Biochemistry, Institute of Biological Sciences, Faculty of Science,University of Malaya, 50603 Kuala Lumpur, Malaysia

2Colloid Research Group, Division of chemistry, Faculty of Science, University ofMalaya, 50603 Kuala Lumpur, Malaysia

*Corresponding Author:[email protected]

Paper No. 5: MS Received: 19 May, 2012 MS Accepted: 12 September, 2012

as compared to 0 day for both plain- and C.verumyogurt but not for A. sativum-yogurt.

©2012 New Delhi Publishers. All rightsreserved

Keywords: Yogurt, Cinnamomum verum,Allium sativum, Water holding capacity,Susceptibility to syneresis, Rheology.

IntroductionYogurt is a healthy dairy productproduced by bacterial fermentation ofmilk. The potential to increaseconsumer’s satisfaction bydevelopment of yogurt products withnew flavors, health benefits and goodquality has been increased.

Viscoelastic properties of yogurt are oneof the main rheological parameters useto characterise the texture that may leadto define the quality of yogurt and

Shori et al., Enrichment of yogurt made from camel milk with Allium sativum and C. verum:


ensure the consumer acceptability(Benezech and Maingonnat, 1994).

Milk coagulation during fermentation byacid with consequence of removal ofcalcium bond between casein micellescauses destabilization of casein lead toaggregates and form a curd (Shaker etal., 2000). This gelation process startswith the aggregation of whey proteinsassociated with caseins (â-lactoglobulin)that denatured to a certain degree byfermentation (Heertje et al., 1985 andLee and Lucey, 2010). The mechanismof gelation process as described by Xuet al. (2008) suggests two maininteractions that occur between wheyproteins and casein micelles afterfermentation that is a direct interactionof â-lactoglobulin with casein micellesvia ê-casein binding and a reactionbetween á-lactalbumin and â-lactoglobulin with the micelles throughan intermediate formed between the twowhey proteins in solution. Thus,crosslinking or bridging of denaturedwhey proteins associated with the caseinmicelles results in an increase in numberand strength of bonds between proteinparticles (Corredig & Dalgleish, 1999;Schorsch et al., 2001; Guyomarc’h etal., 2003; Lee and Lucey, 2004).

Camel’s milk is different from otherruminant milk and it does not formcoagulum in acidic environment(Wangoh, 1993). Thus, fermentedcamel milk products are difficult toproduce because of the problem in milkcoagulation. Mohamed and Larsson-

Raznikiewicz et al. (1990) found thatcamel milk coagulum failed to reach agel-like structure even after 18 hincubation with lactic acid culture.Likewise, Jumah et al. (2001) study theeffect of milk source including milkfrom ovine, caprine, bovine and camelon the rheological properties of curdduring the gelation process of yogurtand found that the lowest value forviscosity was showed by yogurt madefrom camel milk. Attia et al. (2001)reported that the anti-coagulation factorsin camel milk is lead to difficulty ofproducing firmed structure offermented camel milk because thestarter culture showed a longer lagphase and an earlier decline phaseresulting in a fragile coagulum. Anotherstudy by Hashim et al. (2009) showedthat camel milk yogurt fortified by 1%gelatin or 0.75% alginate + 0.075%calcium has the highest intensities forfirmness and body. Recently in vitrostudy, camel milk yogurt enriched withA. sativum or C. verum water extractsshowed therapeutic values such asantioxidants and anti-diabetic activity(Shori and Baba, 2011a; b) and improvedlactic acid bacteria (LAB) growth (Shoriand Baba, 2012). However, to the bestof our knowledge there are noresearches on the effect of physical andrheological properties of camel milkyogurt during refrigerated storage.Therefore, the aim of this research wasto study the effect of A. sativum or C.verum water extracts on the physicaland rheological properties of camel milkyogurt during refrigerated storage at


Camel- International Journal of Veterinary Science : 1(1):51-63. January, 2013 53

4°C.

Materials and Methods

1 Materials and chemicalsCommercial pasteurized full creamcamel milk (Al-Turath) was purchasedfrom local supermarket in Saudi Arabia.C. verum bark and A. sativum powder(McCormick®, Malaysia) werepurchased from local store.Commercial yogurt bacteria mixture(Chris-Hansen, Denmark) waspurchased from a local distributor. Eachsachet of yoghurt mix containsLactobacillus acidophilus LA-5 (4billion), Bifidobacterium Bb-12 (4billion), Lactobacillus casei LC-01 (1billion) and Streptococcus thermophilusTh-4 (1 billion). Probiotic mixture (Bio-Life, Malaysia) was purchased from alocal. One capsule contained 5 billioncfu of mix probiotic bacteria such asLactobacillus acidophilus, L.delbrueckii ssp. Bulgaricus, L. casei, L.rhamnosus, Bifidobacterium bifidum,B. infantis, B. longum in the ratio of1:1:1:1.

2 Water Extraction of herbsThe mixture of C. verum or A. sativumpowder (10g) in 100 mL of distilled H

2O

was incubated overnight in a water bathat 70 °C (Haake Model SWD 20). Themixture was centrifuged (Eppendorf5804 R; 10000 rpm) for 15 minutes at4oC and carefully remove thesupernatant to use as C. verum or A.sativum water extract in preparation ofyogurt.

3 Preparation of Starter CultureThe pasteurized full cream milk (1 L)was pre-heated to 41°C. One sachet ofyogurt bacteria mixture and a capsuleof probiotic mix were added and mixedthoroughly with the pre-heated milkprior to an overnight incubation at 41°C.The yogurt formed was refrigerated(4°C) and used as starter culture within3 days (Rashid et al., 2007).

4 Preparation of YogurtsTo prepare 100 mL of C. verum- or A.sativum-yogurt: 85 mL of pasteurizedfull cream milk was heated to 41 °Cfollowed by addition of 10 mL of herbalwater extract from C. verum or A.sativum and 5 g of starter culture (Shah,2003). The mixture was mixedthoroughly prior to incubated at 41°C.The fermentation process was stoppedat pH 4.5 by placing the yogurts in ice-bath for 60 minutes. Yogurt was thenkept in the refrigerator at 4°C forpredetermined period (21 days) prior toanalysis. The same procedures werecarried out to prepare plain yogurt(control) except 10 mL of distilled H

2O

was used in place of C. verum or A.sativum water extract.

5 Water holding capacityThe water holding capacity (WHC)of yogurts samples was determined asdescribed by Harte et al. (2003) withslight modifications. Yogurt sample (10g) was placed in a centrifuge tube andcentrifuged at 4°C (10000 rpm) for 15minutes. The separated whey was



pipetted out and weighed. The followingformula was used to calculate WHC%:

Where: W1 = Weight of whey after

centrifugation, W2 = Yogurt weight.

6 Susceptibility to syneresis (STS)Susceptibility to syneresis was carriedout as described by Isanga & Zhang,(2009). Yogurt sample (10 g) wasplaced on a filter paper (Whatman No.41) placed on top of a funnel. After 6hours of drainage, the volume of thewhey collected in a beaker wasmeasured and used as an index ofsyneresis. The following formula wasused to calculate STS:

Where: V1 = Volume of whey collectedafter drainage; V2 = Volume of yogurtsample.

7 Isolation and quantification ofexopolysaccharidesExopolysaccharides (EPS) was isolatedfrom yogurt samples using a modifiedprocedure as described by Elin et al.(2010). Yogurt sample (25ml) wasdiluted with dH

2O in the ratio of 1:1.

The mixture was boiled at 100°C for10 min followed by cooling down foranother 10 min. Then, 4ml of 20% (w/v) trichloroacetic acid (TCA) was addedto the solution and kept for 2 hour at

room temperature. After centrifugation(10000×g for 30 min at 4°C) to removethe precipitated proteins and bacterialcells, the pH of the supernatant wasadjusted to 6.8 using 40% (w/v) NaOH.The solution was subjected tocentrifugation again (10000×g for 30min at 4°C). The supernatant was mixedwith a double volume of cold ethanoland then stored at 4°C for 24 hour. Theprecipitated EPS was collected bycentrifugation (10000×g for 30 min at4°C), dissolved in 10 ml dH

2O and

mixed with a double volume of coldethanol and stored at 4°C for 24 hour.The precipitate EPS with ethanol wasrecovered by centrifugation at 4°C(10000×g for 30 min). Total EPS(expressed as mg/L) was estimated ineach sample by phenol sulphuricmethod (Dubois et al., 1956) usingglucose as a standard (Torino et al.,2001).

8 Rheological properties of yogurtDynamic oscillatory measurements ofyogurts were carried out using BohlinVOR controlled strain Rheometer(Malvern Instrument UK), with a cone-plate geometry, in which the rotatingcone was 40 mm in diameter, and coneangle of 4° with a gap of 0.150 mm.Temperature maintenance at 20±0.1 °Cwhich achieved with Peltier Platesystem (-40 to +180oC, Peltier Platesystem from Bohlin Instrument Ltd.)that acts as temperature controller.Yogurt samples were gently stirred 10times by spoon prior to rheologicalanalysis in order to avoid the differences



due to structural breakdown duringhandling of the yogurt. Amplitudesweeps were carried out at 20°C tocharacterize the viscoelastic linearregion of yogurt samples. Strain rangingfrom 0.0005 to 0.1% was used at aconstant frequency of 0.5Hz. The elasticmodulus (G’), the viscous modulus(G’’) and the loss tangent defined astan d = (G”/G’) were obtained fromthe equipment software in all cases.Shear viscosity profiles of yogurtsamples were measured as a functionof shear rate sweep (0.010 - 80.000 s-

1). All the measurements wereperformed on day 0, 7, 14, 21 days.

Statistical AnalysisAll Analyses were performed in threebatches for WHC and STS analysis andtwo batches for rheological

measurements during 0, 7, 14 & 21 daysof storage at 4 °C. The average wastaken and data were expressed as mean± standard. The significance wasestablished at p<0.05. Data analysis wasdone using SPSS® version 17.0.

Results

1 Water holding capacity (WHC)The presence of A. sativum or C. verumin yogurt resulted in higher WHC thanplain yogurt during storage at 4°C(Figure. 1). The WHC in fresh plainyogurt was 0.41± 0.3% whereas thisvalue showed increased in the presenceof C. verum (p<0.05) or A. sativum to2.7±0.1% and 0.57±0.1% respectively(Figure 1). Refrigerated storage to 21days showed higher increase (p<0.05)of WHC both in presence of A. sativumand C. verum than plain yogurt. The

Fig.1: water holding capacity (%) vs storage period (day) during 21 days refrigerated storageat 4 °C. Values are presented as mean ± SEM (n=3).



highest WHC was recorded on day 21of storage with 24.5±1.6% and17.3±1.5% for C. verum- and A.sativum-yogurts respectively.

2 Susceptibility to syneresis (STS)The presence of A. sativum and C.verum in yogurt uniformly reduced STScompared to plain yogurt both in fresh(0 day) and refrigerated stored yogurt.Refrigerated storage increased (p<0.05)

STS both in plain- and A. sativum-yogurts whereas the reverse was truefor C. verumyogurt. However, thelatter showed the highest increased(p<0.05) on day 21 of storage with23.5±3.1%.

3 Microbial exopolysaccharidesproductionThe EPS isolated from fresh plain

Fig.2: Susceptibility to syneresis (%) vs storage period (day) during 21 days refrigeratedstorage at 4 °C. Values are presented as mean ± SEM (n=3).

Fig. 3: Exopolysaccharides (EPS) concentration (mg/L) vs storage period (day) during 21days refrigerated storage at 4 °C. Values are presented as mean ± SEM (n=3).



yogurt was 278.6± 0.3 mg/L (Fig. 3).The presence of A. sativum or C. verumin yogurt non significantly increasedEPS to 297±0.2 mg/L and 296.4±0.3mg/L respectively. The first week ofrefrigerated storage increased (P<0.05)EPS of A. sativum- and C. verum-yogurts (418.2±0.4 mg/L and472.2±0.2 mg/L respectively) comparedto plain-yogurt (283.8 ±0.4 mg/L; Fig.3). Prolonged storage of yogurt to moretwo weeks had significant effect on EPSof plain- and A. sativum-yogurts but notin C. verum-yogurt. However, bothplain and A. sativum-yogurts decreased(p<0.05) on day 21 of storage (Fig. 3).

4 Dynamic rheologyYogurt samples in the presence orabsence of A. sativum or C. verumshowed a drop in both elastic modulus(G’) and viscous modulus (G’’) overthe whole strain% range measuredduring the 21 days of storage (Figure4). The viscous modulus (G’’) wasdominant over the elastic modulus (G’)during throughout the storage period.However, plain yogurt showed higherG’ values than G’’ on 0 day over shortrange of strain (0.05-0.08%) prior toG’ and G’’ crossed over (Fig. 4a). Inthe presence of A. sativum or C. verumin yogurt refrigerated storage up to 14days showed no effect on the changesof yogurt structure. However, extendthe storage to 21 days enhanced thestructure in A. sativum yogurt only over0.05-0.17% of strain (Fig. 4b) and inC. verum yogurt over the whole strainrange (Fig. 4c).

5 Apparent viscosityViscosity profiles of yogurts duringstorage were measured as a functionof shear rate sweep (Fig. 5). Both plain-and herbal-yogurts exhibited shear-thinning behaviour, i.e., the apparentviscosity decreases with shear rate.Refrigerated storage had remarkableeffect on the viscosity profiles of plainyogurt (Fig. 5a) that showed increasein viscosity with extended storageperiod. Viscosity profiles for C. verumyogurt showed improved duringrefrigerated storage compared to 0 day(Fig. 5c) whereas A. sativum yogurtshowed no changes during storage(Fig. 5b). However, A. sativum- and C.verum-yogurt showed the highestviscosity on day 14 of storage.

DiscussionThe increase of water holding capacityof yogurt in the presence of A. sativumor C. verum extract was lead todecrease undesirable syneresis. A higherconcentration of EPS in herbal-yogurtthan plain-yogurt could be related toincrease of WHC and decrease of STSbecause EPS produced by LAB can helpprevent whey separation of yogurt(Girard and Schaffer-Lequart, 2007;Purwandari et al., 2007). Recently,Shori and Baba, (2012) reported that,presence of A. sativum or C. verum inyogurt made from camel milk hasenhanced the growth of LAB whichcould lead to increase the concentrationof EPS in yogurt. In addition, theinteraction between EPS and free water



Fig. 4: Elastic modulus (G’) and viscous modulus (G’’) vs. strain % during 21 days refrigeratedstorage at 4 °C. (a) plain yogurt, (b) A. sativum yogurt , and (c) C. verum yogurt. Values arepresented as mean (n=2).



Fig. 5: Apparent viscosity vs. Shear rate (1-s) during 21 days refrigerated storage at 4 °C. (a)plain yogurt, (b) A. sativum yogurt , and (c) C. verum yogurt. Values are presented as mean(n=2).



in yogurt may cause textureimprovement (De Vuysi and Degeest,1999 and Hassan et al., 2002).

Shear strain sweep in yogurts showedviscous behaviour (G’ < G’’) over thewhole range of strain% (Fig. 4)indicated liquid like behaviour. LowerG’ values than G’’ in camel milk yogurtsthrough the 21 days of storagesuggested due to extensive particlerearrangement during structureformation lead to creation large poresassociated with greater whey separation(Skriver, 1995 and Lucey et al., 2004).The increase in whey separation(syneresis) causes the linear decreasein both G’ and G’’ values during increasethe strain% overall the storage periodresulted in fragile structure that showedto breakdown easily even at lowerstrain% (Tunick et al., 1990).However, the dominate of elasticmodulus over viscous modulus in A.sativum- and C. verum- yogurts on day21 of storage indicated that the presenceof these herbal extracts in yogurt couldimprove the structure (solid likebehaviour) by decreasing the syneresisin yogurt (Figure 2). In addition,increase EPS in presence of herbalextract in yogurt could be attributed toincrease colloidal linkage between milkproteins micelles resulted in moreintense network of yogurt (Pyo andSong, 2009). Moreover, the higher EPSin C. verum yogurt than A. sativumyogurt on day 21 of storage couldexplain the improvement of C. verumyogurt texture that can withstand the

breaking down during increase ofstrain%. However, this indicated thatboth yogurts behave as a very weak gel,much closer to a concentrated solutionthan to a true gel. A. sativum- yogurtshowed ability to turn into liquid likebehaviour by increased the tan d valuesto more than 1 (data not shown). Theweakness in the network of yogurtincrease the sedimentation of caseinaggregates that lead to syneresisoccurred and causes slippage in themodulus (Haque et al., 2001). This canbe overcome by strengthening theyogurt structure with stabilizers suchas gelatin or alginate (Hashim et al.,2009).

The linear decrease of the elastic andviscous modulus corresponds to atypical shear thinning profile. The lowviscosity in yogurt is in agreement withJumah et al. (2001) who related that tosmall amount of casein which is notsufficient to make a complete matrix.Al-Alawi and Laleye (2011) found thatthe amount of different proteins inpasteurized market camel milk such asê-casein and â-lactoglobulin is very low(744.00 and 248.00 mg/L respectively)compared to pasteurized market cowmilk (3,554.67 and 2,397.33 mg/Lrespectively). These two proteins areimportant in gelation process of yogurt(Xu et al., 2008). However, theimprovement of herbal-yogurt viscosityduring refrigerated storage suggestedrefers to release of more â-lactoglobulinand ê-casein during proteolysis activityof yogurt starter culture. Further



studies need to be carried out forisolation and quantification the proteinof milk present in yogurt duringrefrigerated storage. Moreover, thefurther reduction in pH of herbal-yogurtcompared to plain-yogurt duringrefrigerated storage (Shori and Baba,2011a,b) might enhance further therearrangement of the protein network(Ross-Murphy, 1990) because ofremoving calcium and neutralizing thenegative charges of casein micelleswhich aggregates and forms a curd(McMahon et al., 1984).

ConclusionThe WHC of yogurt in presence of C.verum or A. sativum was significantlyhigher than plain-yogurt overall storageperiod. In addition, increase theconcentration of EPS in the presenceof herbal extract can lead to significantSTS reduction compared to in theabsence. Rheological properties showedliquid like behaviour for both herbal andplain-yogurt during storage. However,addition of C. verum or A. sativum inyogurt enhanced the structure of yogurton day 21 of storage. The shear thinningbehaviour of yogurt improved duringrefrigerated storage for plain- and C.verumyogurt but not for A. sativum-yogurt compared to fresh yogurt.

AcknowledgementsWe acknowledge the financial supportof University of Malaya Research Grant(RG023-090BIO).

ReferencesAl-Alawi AA. and Laleye LC. 2011.

Characterization of CamelMilkProtein Isolates as Nutraceutical andFunctional Ingredients. CollaborativeResearch Project SQU/UAEU CL/SQU-UAEU/01/08 SQU/UAEU 01-06-60/08.

Attia H., Kherouatou N. and Dhouib A. 2001.Dromedary milk lactic acidfermentation: Microbiological andrheological characteristics. J. Ind.Microbiol. Biotechnol. 26:263–270.

Benezech T. and Maingonnat JF. 1994.Characterization of the rheologicalproperties of yoghurt – a review. JFood Eng, 21: 447–472.

Corredig M.and Dalgleish DG. 1999. Themechanisms of the heat inducedinteraction of whey proteins withcasein micelles in milk. InternationalDairy J. 9: 233–236.

De Vuyst L.and Degeest B. 1999..Exopolysaccharides from lactic acidbacteria: Technological bottlenecks andpractical solutions. Macromol. Symp.140:31–41.

Girard M. and Schaffer-Lequart C. 2007..Gelation and resistance to shearing offermented milk: role ofexopolysaccharides. Int Dairy J., 17:666–673.

Guyomarc’h F., Queguiner C., Law AJR.,Horne DS and Dalgleish DG. 2003.Role of the soluble and micelle-boundheat induced protein aggregates onnetwork formation in acid skim milkgels. J. Agric Food Chem, 51:7743–7750.

Haque A, Richardson RK and Morris ER.2001. Effect of fermentationtemperature on the rheology of set andstirred yoghurt. Food Hydrocolloid,15: 593–602.

Harte F, Luedecke L., Swanson BG. andBarbosa-Cánovas GV. 2003. Low fat



set yogurt made from milk subjectedto combinations of high hydrostaticpressure and thermal processing. JDairy Sci, 86:1074–1082.

Hashim IB., Khalil A H. and Habib H. 2009.Quality and acceptability of a set-typeyogurt made from camel milk. J DairySci, 92:857–862.

Hassan AN., Ipsen R., Janzen T. and. QvistKB. 2003. Microstructure andrheology of yogurt made with culturesdiffering only in their ability toproduce exopolysaccharides. J. DairySci., 86:1632–1638.

Heertje I., Visser J. and Smits P. 1985.Structure formation in acid milk gels,Food Microstructure, 4: 267-277.

Isanga J. and Zhang, G. 2009. Production andevaluation of some physicochemicalparameters of peanut milk yoghurt.LWT- Food Sci. Technol., 42: 1132-1138.

Jumah RY., Skaker RR. and Abu-Jdayil B.2001. Effect of milk source on therheological properties of yogurt duringthe gelation process. Int. J. DairyTechnol. 54:89–93.

Lee WJ. and Lucey J. 2004. Rheologicalproperties, whey separation, andmicrostructure in set-style yogurt:effects of heating temperature andincubation temperature. J. TextureStudies, 3:515-536.

Lee WJ. and Lucey J.A. 2010. Formation andPhysical Properties of Yogurt. Asian-Aust. J. Anim. Sci., 23:1127 – 1136.

McMahon DJ., Brown RJ., RichardsonGH.and Ernstrom C.A. 1984. Effectsof calcium, phosphate, and bulk culturemedia on milk coagulation properties.J Dairy Sci, 67:9309-938.

Mohamed MA. and Larsson-RaznikiewiczM. 1990. Hard cheese making fromcamel milk. Milchwissenschaft, 45:716-718.

Purwandari U., Shah N.P. and Vasiljevic T.2007. Effects of exopolysaccharide-

producing strains of Streptococcusthermophilus on technological andrheological properties of set-typeyoghurt. Int Dairy J., 17:1344-1352.

Pyo YH and Song SM. 2009. Physicochemicaland Sensory Characteristics of aMedicinal Soy Yogurt ContainingHealth-Benefit Ingredients.Agric. FoodChem., 57:170–175.

Rashid H., Togo K., Ureda M. and MiyamotoT. 2007. Probiotic characteristicsof lactic acid bacteria isolated fromtraditional fermented milk ‘Dahi’ inBangladesh, Pakis J Nutrition 6:647–652.

Ross-Murphy SB. 1995. Rheologicalcharacterization of gels. J. Texture Stud.26:391-400.

Schorsch C., Wilkins DK., Jones MG. andNorton IT. 2001. Gelation of casein–whey mixtures: effects of heating wheyproteins alone or in the presence ofcasein micelles. J. Dairy Res., 68:471–481.

Shah NP. 2003. Yogurt: the product and itsmanufacture. In: B. Caballero, L.C.Trugo and P.M. Finglas, Editors (2nded.), Encyclopedia of food science andnutrition 10, Academic Press, London.

Shaker RR., Jumah R.Y. and Abu-Jdayil B.2000. Rheological properties of plainyogurt during coagulation process:impact of fat content and preheattreatment of milk. J Food Engg,44:175–180.

Shori A.B. and Baba AS. 2011a. Comparativeantioxidant activity, proteolysis and invitro a-amylase and a-glucosidaseinhibition of Allium sativum-yogurtsmade from cow and camel milk. J. SaudiChemical Society, In Press.

Shori A B. and Baba AS. 2011b. Cinnamomumverum improved the functionalproperties of bioyogurts made fromcamel and cow milks, J Saudi Societyof Agric Sci, 10:101-107.

Shori AB. and Baba AS. 2012. Viability of lactic



acid bacteria and sensory evaluation inCinnamomum verum and Alliumsativum-bio-yogurts made from cameland cow milk. Journal of theAssociation of Arab Universities forBasic and Applied science, 11:50-55.

Skriver A. 1995. Characterization of stirredyoghurt by rheology, microscopy andsensory analysis. Ph.D thesis. TheRoyal Veterinary and AgriculturalUniversity, Frederiksberg, Denmark.

Tunick MH., Nolan EJ., Shieh, JJ., Basch JJ.,Thompson MP and Maleeff BE. et al.1990. Cheddar and cheshire rheology.J Dairy Sci, 73:1671–1675.

Wangoh J. 1993. What steps towards camelmilk technology? Int J.Ani Sci, 8:9-11.

Xu ZM., Emmanouelidou DG., RaphaelidesSN. and Antoniou KD. 2008.. Effectsof heating temperature and fat contenton the structure development of setyogurt. J Food Engg, 85:590–597.

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