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    FATTY ACID PROFILES OF GOAT MILK AND DOMIATICHEESE AS AFFECTED BY PASTURE

    FEEDING AND STAGE OF LACTATION

    K.A. SORYAL, S.S. ZENG, B.R. M M , S.P. HART and K. TESFAI

    E {Kika)de la G arza American Institute f o r Goat ResearchLangston University

    Langston, Oklahoma 73050

    Received for Publication March 12,2003Accepted for Publication March 29,2003

    ABSTRACT

    Twenty lactating Alpine goats w ere random ly allocated into fo u r groups toinvestigate the e fe c t offeeding regimes with concentrates on at ty acid profilesofgoat milk and Domiati cheese at diferent stages of lactation. Pooled m il kf io meach group was collected twice monthly f o r Domiati cheese making. Cheesewas sampled Pesh and at 1 and 2 months of pickling in whey. Caproic,caprilic and capric acids in goa t milk were recorded at 1.9 5.5 and 25.1 ,ug/g

    of fat, respectively, and accounted f o r 13.27 of total fa tty acids. Totalunsaturated at ty acids represented 28.87 of totalfatty acids. In Domiati cheese,caproic, caprilic and capric acids were 4.2, 7.4 and 31.4 pg/g of fa t, respectively,and accounted for 11.21 of total fatty acids. Total unsaturated fa tty acidsrepresented 26.83 of total fa tty acids. Fatty acid composition of both milk andcheese was afec te d by eeding treatments andstages of lactation. All the at ty acidsof milk and cheese were lower when goats were pasture-fed compared to oth ergroups except linolenic and stearic acids in goat m ilk and linolenic acid in cheese.Concentrations of caproic, caprilic, capric, palm itic, myristic and oleic ac ids

    fluctuated throughou t lactation with the highest values at mid lactation. The aboveobservations indicate that pasture feed ing during m id-lactation could result inimproved quality and nutritionally healthy goat milk and cheeses.

    INTRODUCTION

    Goat milk and goat milk products possess a characteristic flavor and tastemainly due to their unique fatty acid profile and concentration. Many factors such

    ' Corresponding author. P.O. o x 1730. TEL: (405)466-3836; FAX: (409466-31 38; EMAIL:[email protected]

    Journal of Food Lipids 10 (2003) 219-236. A l l Rights Reserved.opyright 2003 by Food & Nurrition Press, h e . . Trumbull, Connecticut. 219

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    220 K.A. SORYAL, S.S. ZENG, B.R. MM, S P HARTand K. TESFAI

    as feeding system , fatty acid composition of diet, stage of lactation, processingtechnique, and cheese age, have been reported to have a profound impact o n fattyacid composition in cow milk and cow m ilk products (Grummer 1991; Palmquist

    et al. 1993; Dartt et al. 1999; Jensen 2002; Ward et al. 2002). The fatty acidcontent in diets not only affects the type but also the proportionof fatty acids inmilk (Grummer 1991). Lipids in milk play an important rolein cheese yield andfirmness, as well as in the color and flavor of dairy products (Delacroix-Buchet andLambert 2000). In addition, fatty acids are potentially involved as positive ornegative predisposing factors for human health (Parodi 1999; Williams 2000).

    Com pared to cowmilk, goat milk is slightly higher in caproic (C6),caprilic ( C , )and capric (C],,) acids and slightly lower in butyric(C ,) and palmitic (C1 6) cids(Barber et al. 1997; Chilliard et al. 2000). This was explained by differentregulation of mammary cells between goats and cows in the elongation process offatty acids synthesizedin the mammary gland by the fatty acid synthase complex(Barber et al. 1997). The h igh level of hydrogenation of dietary fatty acids in therumen is the reason for the low level of polyunsaturated fatty acids in goat milk(Chilliard et al. 2000).

    Fatty acid profile of milk can be affected by the energy balance in lactatinganimals. Stage of lactation, milk yield as well as diet composition and nutrientdensity determine if an animal is in positive or negative energy balance. Whenenergy balance is negative, animals mobilize lipids from adipose tissue which arerich in palmitic, stearic and oleic acids (Baset aI. 1987). It is reported that50% ofthe variability of stearic and oleic acids content in milk of goats receiving hay plusconcentrate diets during the first4 months of lactation was linked to changesinenergy balance (Baset al. 1987).

    Although concentrate supplementation (17.5% crude protein and 2.6 Mcalmetabolizable energy) to grazingdairy goats has been reported to enhance milkproduction (Landauet al. 1993), changing feeding system and diet compositionmay induce changesin goat milk fatty acids. Potential effects on other aspectsof

    milk and cheese quality such as flavor, taste, health and nutritive value warrantfurther investigation. Therefore, the present study was designed to investigate theeffects of different feeding regimes and lactation periods on fatty acid compositionof milk and Domiati cheese.

    MATERIALS AND METHODS

    Experimental Procedure

    Forage. This experiment was conducted on the dairy goat farm at theE (Kika)de la Garza American Institute for Goat Research, Langston University, Langston,OK from April to September 2001. Eight mixed vegetative forages (0.75 hapaddocks) were rotationally grazed by goats. The paddocks containedwheatherseem clover, ryelchicory, sudan grasdcrabgrass. Residence time in each

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    FATTY ACID PROFILE OF GOAT MILK AN D DOMIATI CHEESE 221

    paddock varied, but averaged 7 days and was adjusted to maintain a minimum dailyforage allowances of 2 to 4 kg DWday. Herbage mass was measured before andafter grazing and samples of forage on offer (cut to ground level) was collected.

    Samples of diet selected (hand plucked) were obtained as described by Min et al.1999). Plucked samples were used to estimate organic matter (OM) digestibilityfor calculation of organic matter intake (OMI). Concentrate feed offered and ortswere weighed and feed samples from both feed on offer and orts were collected at5 day intervals and composited for each month. Chemical composition and invitro organic matter digestibility (OMD) of forage and concentrate feed arepresented in Table 1.

    TABLE 1

    CHEMICAL COMPOSITION ANDIN VZTRO ORG AN IC MATTER DIGESTIBILITY

    REFUSALS BY GOATSOF PASTURE AND CONCENTRATE FED AND FEED

    Pasture Suuplementation SEMVariable

    Pre-graz ing Post-grazing Concentrate' Alfalfa refusals

    Dry matter 91.3 93.2 89.5 93.5 89.2 0.62

    Organic matter 87.1 85.5 86.1 87.1 84.3 2.13

    Crude protein 13.5 9.7 11.7 16.5 13.7 1.01

    Acid detergent fiber 29.4 32.5 6.5 37.7 21.6 2.04

    Non-digestible fiber 26.4 45.8 13.8 39.7 28.8 2.04

    Organic matterDigestibility 85.4 84.3 94.4 71.7 82.3 1.48

    'Concentrate com position:74.5 rolled corn, 5 whole cotton seed, 16% soybean m eal,2 sodium bicarbonate,0.2 di-calcium phosphate,1.6% limestone with trace m inerals,Vitamin A, D and E.

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    222 K.A. SORYAL, S.S .ZENG, B.R. MIN, S.P. HARTand K. TESFAI

    Experimental Animals. Twenty mixed age Alpine goats(55 f 11 kg B W)were allocated into four groups. Group A was supplemented with 0.66 kgconcentratemixture (per1.5kg of milk/day), and was confined withno grazing and

    fed alfalfa hay. Groups B, C and D were rationally grazed with m ixed vegetativeforages and received concentrate mixture as following: Group B receiving a highlevel of concentrate (0.66kg); Group C receiving a low levelof concentrate (0.33kg), and Group D without concentrate and on pasture feeding only. The animalswere milked twice daily at0700 ad 1600 h. These goats were 30-49 days-in-milk(DIM) when the fust batch ofmilk for cheese processing was collected.

    Processing of Domiati Cheese

    Ten kilograms of goat m ilk from each group (five goats) was collected forprocessing Domiati cheese twice monthly from April to Septmeber 2001. Thecheese manufacturing procedure was described in detail by Soryalet al (2003).

    Fa tty Acid Composition

    Approximately 10mL of pooled goatmilk samples and approximately1 g offreeze-dried (Dura-Stop Tray Dryer, FTS Systems, Stone Ridge,N Y Domiaticheese samples were used for fat extraction following the method of Folchet al.(195 1). Fatty acid methyl esters were prepared by saponificationusing KOH (0.68M in methano l) followed by transesterificationwith20 boron trifluoride(BF,) inmethano l and analysis by gas chromatog raphy (Agilent Techno logies,Wilmington, DE). The instrument used was a HP6890 with flame ionizationdetector. Column was HP-INNO Wax 19091N-133 Polyethylene Glycol30 m x0.25 mm x 0.25 pm id, Agilent Techno logies, Wilmington,DE). The column oventemperature was held for2 min at 60C, then programmed at a rate of 6C/min to afinal temperature 2 1OC and he ld for2 min. injector and detector temperatures were

    250C, and the injector part was equipped with a50:1 split ratio. Th e flow rate ofthe nitrogen carriergas was adjusted to 31 psi pressure (20 mL/rnin), air at 450mL./min, hydrogen at 40mL/min and nitrogen (as make-up gas) at 45mllminIntegration for each fatty acid was performed by a Hewlett-Packard HP6890-Chem station Software (Agilent Technologies, Wilmington,DE). Identification ofthe peaks was madeon the basis of the retention times of standard methy l esters ofindividual fatty acids. Final fatty acid concentrations were derivedon fat base ofgoat milk and Domiati cheese(&g of fat).

    Sta tistica l Analysis. A randomized complete block design (RCBD) was usedin this experiment. The following statistical model included feeding treatments,cheese age and lactation period as independent variables, and m ilk and cheeseparameters as dependan t variables. Data were statistically analyzed using thegeneral linear model (GLM ) procedure of statistical analysis system (SA S 1990).

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    FATTY ACID PROFILE OFGOAT MILK A N D DOMIATI CHEESE 223

    If there were significant effects, means separations were performed using the leastsquare difference (LSD) test.

    Where Yijkl = observation, p = overall mean, Ti = effect of treatment, Lj =effect of lactation period, Ak = effect of cheese age, n interactionbetween treatment and lactation period, TAik = interaction betweentreatment and cheese age, LAjk = interaction between lactation periodand cheese age, TLAijki=interaction mong treatment, lactation periodand cheese age, and random error.

    TAB LE 2.FATTY ACID COM POSITION (MEAN+SD ) OF POOLED GOAT MILK FOR

    CHEESEMAKING DURING AN ENTIRE LACTA TION (N=44)

    Dependent variables M ean f SD %ofto ta l Rangefatty acids

    Total fatty acids pg lg of fat)

    Caproic acid (CS0)

    Caprilic acid (CS 0Capric acid (Clo 0)

    Lauric acid (Clz 0)

    M yristic acid (C14 0 )

    Palmitic acid (C16 0)

    Steanc acid (CIS0)

    Oleic acid Cl8 I

    Linoleic acid Cl8 2 )

    Linolenic acid (C18 3)

    Total satura ted fatty acids(yg/g of fat)

    245.3 f 42.68

    1.9 f 3.15

    5.5 + 4 . 0 9

    25 .1 f7 .19

    11.3 f 2.62

    27.5 f 4.96

    73.5 f 14.26

    28.1 f 4.25

    59 .1 f8 .05

    10.7 1.73

    0.3 0.82

    172.9

    Total unsaturated fatty acids(&g of fat) 70.1

    SD - standard deviation.

    0.78

    2.24

    10.22

    4.59

    11.22

    29.95

    11.46

    24.08

    4.38

    0.13

    71.13

    28.87

    0 8.3

    0 - 12.7

    10.8 - 42.8

    5.6 - 17.8

    14.6 38.0

    34.3 97.6

    20.7 - 34.4

    37.2 - 72.9

    7.5 - 13.1

    0 - 2.5

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    224 K.A. SORYAL, S S ZENG, B.R. MM, S.P. HART and K. TESFAI

    RESULTS AND DISCUSSION

    The overall means of fatty acid concentrations of Alpine goat milk for cheesemanufacturing during an entire lactation are shown in Table 2. The concentrationof fatty acids ranged from 0.3 (linolenic acid) to 73.5 ( p a h t i c acid) pg/g of milkfat. Butyric acid was not detected in any samples. The shorter chain fatty acids(caproic, caprilic and capric) represented 13.27 of total fatty acids. Values ofthese acids in the present study are slightly lower than those reported by Lu (1993)in Alpine goat milk fat (16.84 ) and Sam Sampelayo et al. (2002) in Granadinagoat milk fat (17.45 ). These fatty acids in goat milk were higher than those ofcow and sheep milk fat (5.9 and 12.6 , respectively) (Glass etal 1967; Jenness1980). These authors suggested that the difference between goats and cows was

    TABLE 3.FATTY ACID COM POSITION (MEANf SD') OF DOMIATI CHEE SE DURING AN

    ENTIRE LACTATION (N=44)

    Dependent variables M ea n f SD of total Rangefatty acid s

    Total fatty acids pg/g of fat) 279.9 f 43.30 96.5 - 349.7

    Caproic acid cg 0 4.2 f 3.44 1.49 0 10.3

    Caprilic acid c8.0) 7.4 3.42 2.64 0 14.8

    Capric acid (Clo 0 31 4 f 4 . 9 9 11.21 18.3- 39.9

    Lauric acid ( C I ~o ) 13.0 1.75 4.63 9. 6 16.5

    Myristic acid c14 0 ) 31.7 *5.18 11.32 10.7 - 42.0

    Palrnitic acid (Cl6 0 ) 84.5 f 13.62 30.19 21 .4- 106.2

    Stearic acid CIS0 33.1 f 7.96 11.83 2.8 - 48.5

    Oleic acid c18 1 62.7 f 12.98 22.40 5.9 82.6

    Linoleic acid(CIS 2) 12.2 f 2.99 4.36 3.6 - 18.1

    Linolenic acid(Cl8 : 3) 0.3 f 0.95 0.12 0 4.5

    Total saturated fatty acids( g of fat)

    Total unsaturated fatty acids pg/g of fat)

    205.2 40.1

    75.2 f 12.54

    73.17

    26.83

    'SD - standard deviation.

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    FATTY ACID PROFILEOF GOA T MILK AND DOMIATI CHEESE 225

    attributed by the different regulation in the mammary cells, particularly in theelongation process of fatty acids which are synthesized de novo by the fatty acidsynthase complex. The lack of fatty acid elongation above 16 carbons and the

    presence of mechanisms for terminating elongation in the fatty acid synthasecomplex (Moore and Christie 1981) increase these fatty acids in goat milk. Thepresence of relatively high levels of these acids in goat milk lipids could beresponsible for its characteristic flavor (Parkash and Jenness 1968; Skjevdall979).Arora and Singh (1986) suggested that the higher values of these fatty acids in goatmilk fat compared to cow's milk could be responsible for the unique flavor and thegreasy texture in goat dairy products.

    The lauric and myristic fatty acids values of the present study (4.59 and11.22%, respectively) were slightly higher than those reported by Glass et al.(1967) and Jenness (1980) in goat milk fat (3.3 and 10.3%, respectively) and thosein cow milk fat (3.1 and 9.50%, respectively). The pa h t i c acid value of thepresent study (29.95%) was similar to those in Granadina goat milk fat reported bySanz Sampelayo et al. (1998,2002). However, Glass et al. (1967) and Ward et al.(2002) reported lower values of palmitic acid in cow milk fat (26.5 and 24.87%,respectively). Some saturated fatty acids, particularly lauric, myristic and palmiticacids, are considered to be cholesterol-raising in human nutrition (Berner 1993).The stearic acid value (1 1.46%) in goat milk was lower than that of cow milk

    (Glass et al. 1967, 14.6%; Ward et al. 2002, 13.57%) but was comparable to thatof Granadina goat milk fat ( S a mSampelayo et al. 1998,10.34%; S a m Sampelayoet al. 2002, 8.5%). The oleic acid content represented 24.08% of total fatty acidsand 84.21% of total unsaturated fatty acids which is lower than those of cow'smilk (26.22%) (Glass et al. 1967; Ward et al. 2002) and Granadina goat milk(25.55%) (Sanz Sampelayo et al. 1998). The total unsaturated fatty acids contentof the present study represented 28.87% of total fatty acids which was similar tothat of Granadina goat milk fat (27.9%, S a n z Sampelayo et al. 1998,28.9%, SamSampelayo et al. 2002) and that of Alpine goat milk fat (26.98%, Lu 1993). Our

    result showed a lower value of total unsaturated fatty acids than that of cow milkfat (33.58%, Ward et al. 2002 and 34.6%, Jenness 1980) and a higher value thanthat of sheep milk fat (24.3%, Jenness 1980). These long-chain unsaturated fattyacids have been associated with decreasing heart diseases (Albert et al. 1988).

    Table 3 shows the mean composition of fatty acids in Domiati cheese during awhole lactation. The concentrations of individual fatty acids in cheese were similarto those of goat milk (Table 2), ranging from 0.3 (linolenic acid) to 84.5 (palmiticacid) pg/g of cheese fat. Among the shorter chain fatty acids (C,o or less), capricacid represented the highest value (1 1.2 1 ). A similar trend was observed byAttaie and Richter (1996). These researchers reported the highest value of capricacid in Cheddar-ldce hard goat cheese. The fatty acids C6-C,o) epresented 15.7%of total fatty acids, which was higher than hat in cow milk cheeses (Gomez et al1987). Gomez and coworkers compared the fatty acid composition of differentvarieties of cheese made with different milks and found that cheese made with

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    226 K.A. SORYAL, S S ZENG, B.R.MIN, S.P. HART and K. TESFAI

    either goat or ewe milk had higher amounts of short-chain fatty acids than cheesemade from cow milk. They attributed this observation to the higher amounts ofcapric and caprilic acids in goat milk. The higher level of these fatty acids in the

    naturally homogeneous goat milk as well as the higher level ofmoisture content arellkely to have greater lipolytic effects during cheese ripening than cow milkcounterparts (Park 2001).

    The total unsaturated fatty acids represented 26.83% of total fatty acids inDomiati cheese. Linoleic acid accounted for a significant amount (1 6.25%) of totalunsaturated fatty acids. During storage and distribution, lipolysis is a primaryprocess in cheese ripening with a variety of biochemical changes includingliberation of linoleic acid. Linoleic acid plays an important role in cheese ripeningas its derivative, 10-undecenoicacid, at 5 ppm attributes to soapy and sweetcharacteristics Attaie and Richter 1996). Among the unsaturated fatty acids, oleicacid was the highest (83.49%) and linolenic acid was the lowest (0.45%).

    Tables 4 and 5 show the effect of feeding treatments on fatty acid compositionof goat milk and cheese, respectively. The concentrations of fatty acid compositionwere affected by feeding treatments in the same way in both milk and cheese.Caprilic and capric acids were significantly lower in group D (pasture only) thanother groups (P < 0.05). A similar trend existed in the long chain fatty acids withsignificantly lower values of lauric and linoleic acids in group D compared to othergroups (P < 0.05). The total fatty acids content of milk fat was the lowest in groupD compared to other groups. However, group D showed a significantly highervalue of linolenic acid in both milk (Table 4) and cheese (Table 5 ) . The results ofStorry et al. (1 974) agreed the above findings. They compared the effect of feedinga high roughage diet (8 kg hay and 9 kglday concentrate per cow) and a lowroughage diet (1 kg hay and 11-16 kg/day concentrate per cow) on milk fattyacids. The concentrations of all fatty acids were reduced with an exception oflinoleic acid in the low roughage diet. In the present study, animals of group Dseemed to be under nutritional stress and were unable to synthesize fatty acids due

    to lack of energy from pasture roughage. This could be explained by changes inrumen fermentation that alter the endocrine status that partitions nutrients towardadipose tissue resulting in a reduction in the availability of precursor for fatty acidtriacylglycerol synthesis (Grummer 1991).

    Also shown in Tables 4 and 5 , group D had a significantly lower value of stearicacid in goat milk than group C and in Domiati cheese than groups B and C. Asimilar result in cows was observed by Stony et al. (1974). They attributed theobservation to the incomplete hydrogenation of polyunsaturated fatty acids andthus less stearic acid reaching the duodenum. White et al. (2001) designed a trialto compare fatty acid composition in cows fed a total mixed ration (confined) orgrazing (pasture). In contrast to our results, pasture-fed cows producedsignificantly more C,o, C,2, C,, and confined cows produced significantly moreC,8 . In accordance with our findings, pasture-fed cows produced significantlymore C, , and significantly less CI8

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    FATTY ACID PROFILE OF GOAT MILK AND DOM IATICHEESE 227

    TABLE 4.EFFEC T OF FEEDING TREATMENTSON FATTY AClD COM POSITION

    OF GOAT MILK FOR CHEESEMA K MG

    Dependent variables

    Feeding treatments'

    A B C D SEM'

    Total fatty acids (&g of fat)

    Caproic (c6 0 )

    Caprilic (CS 0 )

    Capric (CIO 1

    Launc (CU01

    Myristic (c14 0 )

    Palmitic (c16 0)

    Stearic (CIS 0 )

    Oleic (CIS I )

    Linoleic (C IS2 )

    Linolenic ( C IS3)

    Total saturated fatty acids ( p g g of fat)

    246.2

    1.8

    5.6ab

    26.9b

    12.4b

    28.1

    72.7

    28.1a

    59.5

    10.7b

    0.2a

    175.7

    Total unsaturated fatty acid s (&g of fat) 70.5

    243.6

    1.8

    5.1ab

    23.0ab

    10.oab

    27.1

    75.0

    35.3bC

    58.0

    8.0b

    0.48

    177.3

    66.4

    254.9

    2.0

    5.7b

    24.4ab

    10.Sb

    28.2

    75.2

    3 8 s

    60.8

    8.6b

    l . l a

    184.4

    70.5

    220.8

    I .6

    3.6'

    20.4'

    8.5'

    25.5

    69.8

    30.8ab

    51.6

    5.4O

    3.sb

    160.8

    60.6

    13.22

    0.61

    0.65

    1.75

    0.82

    1.50

    3.94

    2.12

    2.96

    1.17

    0.35

    'Groups A, B, C and D were supplemented with0.66 (groups A & B), 0.33 (group C),and 0 kg concentrate (group D) per kg of milk over1 5 kg/d. Mixed vegetative forageswere rotationally grazed bythe dairy goats exceptfor group A (confined and fed alfalfahay).*SEM - standard error of m ean.a . b Means n a r o w with different letters differ(P < 0.05).

    The melting point of the fat is an important consideration in cheese processing.Palrmtic and oleic acids are the major fatty acids affecting the melting point. Tables4 and 5 show that total C,,fatty acids recorded the highest vaIues in groups B andC. Because of the relatively specific action of stearoyl coA desaturase, increasingthe content of C fatty acids will increase that of oleic acid and decrease the denovo synthesis of palmitic acid (Banks et al. 1984).

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    228 K.A. SORYAL, S.S. ZENG, B.R. MM, S.P. HART and K. TESFAI

    TABLE 5 .EFFECT OF FEEDING TREATMENTSON DOMIATI CHEESE FATTY ACID

    COMPOSITION

    Dependent variables Feeding treatmen ts'

    A B C D SEM

    Total fatty acids ( p g / gof fat)

    Caproic (C, 0 )

    Caprilic ( C S 0 )

    Capnc I )

    Lauric (C12 0

    Myristic (CM0

    Palmitic (c16 0

    Stearic (CIS 0 )

    Oleic CIS 1)

    Linoleic ( C IS2 )Lino lenic (CIS 3)

    Total saturated fatty acid s( p g / gof fat)

    Total unsaturated fatt y acids( p g / gof

    fat)

    281.4

    4.4

    7.9

    3 1.3'

    12.9'

    3 1.9b

    84.7

    33.1a

    62.6b

    12.2b0.3

    206.4

    75.1

    276.5

    3.9

    6.8

    27.2b

    10.9b

    3 1 .4ab

    83.9

    38.6'

    62.gb

    9.5'2.5b

    202.7

    74.9

    282.0

    4.0

    7.2

    28.2b

    10.9'

    30.0ab

    84.2

    42.7b

    62.9'

    10.9b

    2.7b

    207.3

    76.5

    258.0

    3.9

    6.6

    24.3'

    9.7'

    28.9

    78.5

    32.8

    54.6'

    6.6'3.7c

    184.8

    64.8

    7.71

    0.46

    0.46

    0.82

    0.33

    0.94

    2.42

    1.59

    1.93

    0.950.34

    'Group A, B, C and D w ere supplemented with0.66 (groups A & B), 0.33 (grou p C), and0 kg concentrate (grou p D) per kg of milk over1.5 kg/d. Mixed vegetative forages wererotationally grazed by the dair y goats except for grou pA (confined and fed alfalfa hay).2SEM - standard error of mean.

    . M eans in a row with different letters differ(I < 0.05).

    The effect of cheese age on fatty acid composition of cheese is shown inTable 6. Domiati cheese is a soft cheese ripened in the whey solution and keptrefrigerated ( 0.05). All fatty acids of cheese except caprilic and myristic slightly decreased(4.3 1 1.06%) after 2 months pickling. This observation might be attributed to breakdowns of these fatty acids by a bacterial or enzymatic action during pickling.Linolenic acid lost 21.72% of its content in the whey solution after 2 monthspickling. It is suggested that some of this trienoic acid might have been converted

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    FATTY ACID PROFILEOF GOAT MILK AND DOMIATI CHEESE 229

    to stearic, oleic or linoleic acids. The importance of this process is that this longerchain fatty acid can split to other compounds like 10-undecenoic acid, whichcontributes to a soapy and sweet aroma at 5 ppm. Similar results were obtained in

    studying the biochemical characteristic of three types of goat cheese (Martin-Hernandez and Juarez 1992). In that study, the mean fatty acid composition of theglyceridic fraction in the milk, curd, and cheese did not exhibit any significantalterations in any of the cheeses till 90 days of storage and ripening. Ponce deLeon-Gonzalez et al. (2002) also reported that the concentration of free fatty acidsdid not increase significantly during the ripening time in reduced-fat Muenster-typecheese made from a mixture of bovine skim milk and bovine whole milk.

    TABLE 6.EFFECT OF CHEESE AGE ON FATTY A CID COM POSITION

    OF DOMIATI CHEESE

    Cheese age

    Dependent variables Fresh O ne m on th Tw o S E M Imonths

    Total fatty acids pgg of fat) 276.5 270.5 276.4 6.67

    Caproic (c6 0) 4.4 3.5 4.2 0.39

    Caprilic (C S. ) 7. 7.1 7.2 0.40

    Capric (CIO1 28.1 27.6 27.5 0.71

    Lauric (CIZ.1 11.3 11.0 11.1 0.28

    Myristic ( C I ~0) 31.2 30.4 36.6 3.76

    Palmitic (C16:o) 84.1 82.5 82.0 1.68

    Stearic (CIS0) 37.1 36.7 35.8 1.oo

    Oleic (CIS .) 61.2 60.2 60.6 1.47

    Linoleic ( C I ~2 9.7 9.1 9.4 0.30

    Linolenic (Cia : 3 2.4 2.4 1.9 0 26

    'SEM - standard errorof mean.

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    230 K.A. SORYAL, S.S.ZENG, B.R. MIN, S.P. HARTand K. ESFAI

    The changes of fatty acid concentrations in goat milk and in D omiati cheeseduring lactation are illustrated in Fig. 1 and 2, respectively . A m axim um value oftotal fatty acids in both goat milk and Dom iati cheese was recorded during 5th-6th

    lactation period (mid-lactation).During the 1st lactation stage, contents of cap roic,caprilic, capric, and m yristic acids in goat milk were the lowest an d increasedthereafter to significantly higher values( P < 0.05) by the 6 th stageof lactation (F ig.I . These results agreed with those of Auldist and coworkers (1998) obtained incows. Auldist and coworkers reported that milk from early lactation contained lessC, to C,, than those from middle and late lactation stages. Sim ilar results w ere alsoobtained by Banskalieva2001), with the lowest values ofC,, Cl0, nd Clz during3-10 days after kidding and the highest values during 60 -90 days in the milk ofthree goat breeds. The lower valuesof short chain fatty ac ids at the1st stage couldbe explained by the physiological inability of goats in early lactation to consum eenough ry matter to m eet energy requirements. During early lactation, energybalance decreases and becomes negative. Dietary supply of acetate decreases,resulting in a lower synthesis of short-chain fatty acids by mam mary tissue and anincreased mobilizationof adipose tissue fatty acids (Palmquistet al. 1993). Anotherexplanation was provided by Bauman and Davis (1974) and Belyea and Adam s(1990). At the initiationof lactation, animals are in negative energy balance,causing mobilizationof adipose tissue fatty acids and incorporationof these long

    chain fatty acids into milk fat, which lnhibits de novo synthesis of short cha in fattyacids by m ammary tissue.Palmitic acid in both milk and cheese had a low er value at the beginningof

    lactation, a significan tly higher value at the 6 th lactation stage( P < 0.05), andmaintained at this level thereafter till the endof lactation (Fig.1 and 2). Studiessuggest that approximately one halfof the palmitic acid is derived from the firstsource, i.e. de novo fatty acid synthesis, while the reminderis derived from thesecond source, i.e., circulating blood lipids. Blood lipids may be derived fromdigestion and absorption of dietary fat or from m obilization of fatty acids fromadipose tissue. Since animals arein a negative energy balance during the earlylactation, the result is a lower synthesis of half the amo unt o f palmitic acid, whichcorresponds to the lower content of palrmtic acid during the early lactation . At thesame time, stearic acid supply from adipose tissue in the early lactationismaintained until the 10th and 1 th stages of lactation (late lactation), when the acidstart to decrease markedly. The decreaseof stearic acid at the late lactation wasassociated with the increase of palmitic acid. A similar trend was found byBanskalieva (2001) with low values at early lactation and m aximum values after

    60 days in Nubian and Toggenburg goats and after 90 daysin Saanan goats.Theoleic acid content was maintained during an entire lactation with slight changes a tearly lactation. Decreased values were ob served during the 4th and 5th lactationperiods and a maximum value was obtained at the 6th lactation period (Fig.1 and2). When short-chain fatty acids were in short supply during early lactation, Hawkeand Taylor (1983) reported that it makes up the difference by providing o leic acid

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    FATTY AC ID PROFILE OF GO AT MILK AND DOM IATI CHE ESE 23 1

    I-e L au r ic (C12) +Myist ic (C14) +Myris l ic (C14)i - t w m i t i c c i 6 ) +Steam (cia)

    FIG. I . CHA NGE S OF FATTY ACID CONCENTRATIONp glg OF FAT) IN GOAT MILK FORCHEESE MANUFACTURINGDURING LACTATION (15 DAY INTERVALS)

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    232 K.A. SORYAL, S.S. ZENG, B.R. MM, S.P. HART and K. TESFAI

    FIG. 2. CHAN GES OF FATTY ACID CONCEN TRATION @g/g OF FAT) IN DOMIATICHEESE DURING LACTATION 1 5 DA Y INTERVALS)

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    FATTY ACID PROFILEOF GO AT MILK AND DOMIATICHEESE 233

    at the sn-3 position of the triacylglycerol molecule and thus oleic acid is the maincompensation for short-chain fatty acids changes. Banskalieva (2001) reported highlevels of oleic acid inmilk fat in three goat breeds during the first month after

    kidding w hch could be the result of elevated mobilization fiom adipose tissue. A slactation advanced, oleic acid content decreased sharply due to a decreasedmobilization of body reserves.

    In conclusion, fatty acid profiles ofboth goat milk and Domiati cheese wereaffected by feeding treatments and stages of lactation. All the fatty acids of goatm lk and cheese were lower when goats were pasture-fed compared to other groupswith an exception of linolenic acid. Total C,, fatty acids in bothmilk and cheesewere higher when the goats were pasture-grazed with high and low concentratesupplementations, respectively. Concentrations of caproic, caprilic, capric,p a h t i c , myristic and oleic acids fluctuated throughout lactation with the highestvalues at mid lactation. There was no significant effect of cheese age on fatty acidsof cheese except caprilic and myristic acids which decreased after 2 monthspickling. The above observations indicate that pasture feeding during mid-lactationcould result in improved quality and nutritionally healthy goat milk and cheeses.

    ACKNOWLEDGMENT

    This study was funded by the 1890 Land-Grand Institution Teaching andResearch Capacity Building Grant Program of USD NS CR EES(OKLX-1999-041 14). A sincere appreciation is given toMr. B. Bah, Drs. E. Pononum and J. Luofor their laboratory and statistical assistance.

    REFERENCES

    ALBERT,C.M.,HE EKENS, C.H., O'DONNELL, C.J.,AJAIN, U.A., CAREY,V.J., WILLET, W.C., RUSKIN, J.N. and MA NSON, J.E. 1988. Fishconsum ption andrisk of sudden cardiac death. J.Am. Med. Assoc. 279,23-28.

    AROR A, K.L. and SINGH ,S. 1986. Effect of blending goat and buffalo milk onsensory characteristics of ghee. Indian J. Dairy Sci.39, 488-490.

    ATTAIE, R. and RICHTER, R.L. 1996. Formation of volatile free fatty acidsduring ripening of Cheddar-like hard goat cheese. J. Dairy Sci. 79,717-724.

    AULDIST, M.J., WALSH, B.J. and THOMSON, N.A. 1998. Seasonal and

    lactational influences on bovinemilk composition in New Zealand. J. DairyRes. 65 ,401-41 1.BANK S, W., CLAPPER TON, J.L., MUIR, D.D., POWELL, A.K. and

    SWEETSUR, A.W.M. 1984. The effect of dietary-induced changesin milkurea levels on the heat stability ofmilk. . Sci. Food Agric.35, 165-172.

  • 8/10/2019 Fatty Acid Profiles of Goat Milk and Domiati Cheese as Affec

    16/18

    234 K.A. SORYAL, S.S. ZENG, B.R. MIN, S.P. HART and K. TESFAI

    BANSKALIEVA, V. 2001. Fatty acid composition of milk fat triacylglycerols inthree breedsof goat during lactation. Comptes rendus de lacademie bulgare desSciences. Tome 54, 75-78.

    BARBER, M.C., CLEGG, R.A.,TRAVERS, M.T. and VERNON, R.G.1997.Lipidmetabolism in the lactatingmammary gland. Biochem. Biophys. Acta1347,

    BAS, P., CHILLIAARD, Y., MORAN D-FEHR , P., ROUZEAU, A. andMANDRA N, N.1987.Composition des principaux tissus adipeux de la chevreAlpine en fin de lactation.Ann. Zootech. 36, 361-374.

    BAUM AN, D.E. and DAVIS, C.L.1974. Biosynthesis of milk fat. InLactation-AComprehensive Treatise.Vol. 2 , (B.L. Larson and V.R. Smith, eds.) pp. 3 1 ,Academic Press, New York.

    BELYEA, R.L. andA D A M S , .W. 1990.Energy and nitrogen utilization of highversus low producing dairy cows.J. Dairy Sci. 73,1023-1030.

    BERNER, L.A. 1993. Round table discussion on milk fat, dairy foods, andcoronary heart disease risk. J. Nutr.123, 1175-1 184.

    CHILLIARD, FERLAY, Y., MANSBRIDGE, A.R.M. and DOREAU, M.2000.Ruminant milk fat plasticity: nutritional control of saturated, polyunsaturated,trans, and conjugated fatty acids. A m . Zootech.49, 181-205.

    DARTT, .A., LLOYD, J.W., RADKE,B.R., BLA CK, J.R. and KAN EENE, J.B.

    1999. A comparison of profitability and economic efficiencies betweenmanagement-intensive grazing and conventionally managed dairiesinMichigan. J. Dairy Sci.82, 2412-2420.

    DELACR OIX-BUCHET, A. and LAMBERT, G.2000. Sensorial properties andtypicity of goat Dairy products. In7*hn?. Con on Goa ts ,Tome, Vol. 2, pp.559-563, Tours, France.

    FOLCH, J., LEES, O.A.M., MEATH, J.A. and LEBERON ,F. M. 1951.Preparation of lipid extracts from brain tissue. J. Biol. Chem .191, 833-841.

    GLASS, R.L., TROLIN,H. and JENNESS, R. 1967. Comparative biochemicalstudies of milk. IV. Constituent fatty acids ofmilk fats. Comp. Biochem.Physiol. 22,415-425.

    GOM EZ, R., FERNANDEZ SALGU ERO, J. and MA RCOS, A.1987.Composicion en acidos libres y combinados de algunas variedades de quesoscomerciales. Grasas Aceites.38, 23-26.

    GRUM MER , R.R.1991 . Effect of feed on the composition of milk fat. J. DairySci. 74,3244- 3257.

    HAW KE, J.C. and TAYLOR, M.W. 1983. Influence of nutritional factors onthe

    yield, composition and physical properties of milk fat. InDevelopmentsinDairy C he m is e- 2. Lipids,(P.F. Fox, ed.) pp. 37, Applied Science, New York.JENNESS, R. 1980. Com position and characteristics of goat m ilk: review1968-

    1979. J. Dairy Sci.63, 1605-1630.JENSEN, R.G. 2002. T h e composition of bovine milk lipids: January1995 to

    December 2002. J. Dairy Sci.85 295-350.

    101-126.

  • 8/10/2019 Fatty Acid Profiles of Goat Milk and Domiati Cheese as Affec

    17/18

    FATTY AC ID PROFILE OF GOA T MILK AND DOMIATI CHEESE 235

    LANDAU,S., VECHT, J. and PEREVO LOTS KY, A. 1993. Effects oftwo levelsof concentrate supplementation on milk production of dairy goats browsingMediterranean scrub land. Small Rumin. Res. 11 ,227-237 .

    LU, C.D. 1993. Implications of feeding isoenergetic diets containing animal fat onmilk composition of alpine does during early lactation.J. Dairy Sci. 76 1137-1147.

    LYNCH, J.M., BARBANO, D.M., BAUMAN, D.E., HARTNELL, G.F. andNEMETH , M.A. 1992. Effect of a prolonged-release formulation of n-methionyl bovine somatotrophin (sometribove) on milk fat. J. Dairy Sci.75,1794-1809.

    MA RTIN-HERNA NDEZ, M.C. and JUAREZ, M. 1992. Biochemicalcharacteristics of three types of goat cheese.J. Dairy Sci. 75 1747-1752.

    MIN, R.B., BARRY, T.N., McNABB, W.C. and KEM P, P.D. 1999. The effect ofcondensed tannins inLotus corniculatus upon reproductive efficiency and woolproduction in sheep during late summer and autumn. J. Agric. Camb. 1 32,323-334.

    PALM QUIST, D.L., BEAULIEU, A.D. and BARB ANO, D.M. 1993. Feed andanimal factors influencing milk fat composition.J. Dairy Sci. 76 1753-1771.

    PARK, Y.W. 2001. Proteolysis and lipolysis of goat milk cheese. J. Dairy Sci.84(E. Suppl.), E84-E92.

    PARKASH, S. and JENNESS, R. 1968. The composition and characteristics ofgoat milk: eview. J. Dairy Sci.30, 67-72.PARODI, P.W. 1999. Conjugated linoleic acid and other anticarcinogenic agents

    of bovine milk fat. J. Dairy Sci. 82, 1339-1349.

    THOM AS, D.L., JAEGGI, J.J. andHOU CK , K.B. 2002. Influence ofbo vin emilk in mixture with bovinemilk on the quality o f reduced fat Muenster-typecheese. J. Dairy Sci. 85,36-42 .

    SAN Z SAM PELA YO, M.R., PEREZ, L., BOZA,J. and AMIGO, L. 1998. Forage

    ofdifferent physical formsin the diets of lactating Granadina goats: Nutrientdigestibility andmilk production and composition. J. Dairy Sci. 81,492-4 98.

    SANZ SAM PELAYO , M.R., PEREZ, L., MAR TIN ALON SO,J.J., AMIGO, L.and BOZA,J. 2002. Effects of concentrates with different contents of protectedfat rich in PUFAs on the performance lactating Granadina goats. Part 11: Milkproduction and composition. Small Ruminant Res.4 3 , 141-148.

    SAS, 1990. SASU ser's Guide: Statistics, Version6 Edition. SASInst., C a y , NC.SKJEV DAL, T. 1979. Flavor of goat milk. A review of studies on the sources of

    its variations. L ivest. Prod. Sci.6 397-405.SOR YAL, K.A., ZENG,S.S. ,MIN, B.R. and HAR T, S.P. 2003. Effect of feeding

    treatments and lactation stages on com position and organoleptic quality of goatmilk Dom iati cheese. Small Rum in. Res. (in press).

    PONCE DE LEON-GONZALEZ, L., WENDOFWF, W.L., INGHAM, B.H.,

  • 8/10/2019 Fatty Acid Profiles of Goat Milk and Domiati Cheese as Affec

    18/18

    236 K.A. SORYAL, S.S. ENG, .R. MIN, .P. HART and K. TESFAI

    STORRY, J.E., BRUMBY, P.E., HALL, A.J. and JOHNSON,V.W. 1974.Responses in rumen fermentation and milk-fat secretion in cows receivinglow-roughage diets supplemented with protected tallow. J. DairyRes. 41, 165-173.

    WARD, A.T., WITTENBERG,K.M. and PRZYBYLSKJ,R. 2002. Bovine milkfatty acid profiles producedby feeding diets containing solin, flax, and canola.J. Dairy Sci. 85, 1191-1 196.

    WH ITE,S.L.,BERTR AND, J.A, WADE,M.R., WASH BUR N, S.P.,GREEN, J.T.and JENKINS,T.C. 2001. Com parison of fatty acid content ofmilk from Jerseyand Holstein cows consuming pasture or a total mixed ration.J. Dairy Sci. 84,

    WILLIAMS, C.M. 2000. Dietary fatty acids and human health. Ann. Zootech.2295-2301.

    49, 165-180.