Cl

RSa

Pb

c

d

a

KEEPC

GM

d+

0h

Small Ruminant Research 106S (2012) S43–S48

Contents lists available at SciVerse ScienceDirect

Small Ruminant Research

journa l homepage: www.e lsev ier .com/ locate /smal l rumres

onsumer acceptability of ovine cheese from ewes fed extrudedinseed-enriched diets�

. Branciari a, A. Valianib,∗, M. Trabalza-Marinucci c, D. Miragliaa, D. Ranuccia, G. Acuti c,. Espostod, L. Mughetti c

Dipartimento di Scienze Biopatologiche ed Igiene delle Produzioni Animali ed Alimentari, Università degli Studi di Perugia, via S. Costanzo, 4, 06100erugia, ItalyIstituto Zooprofilattico Sperimentale dell’Umbria e delle Marche, via G. Salvemini 1, 06126 Perugia, ItalyDipartimento di Patologia, Diagnostica e Clinica Veterinaria; Università degli Studi di Perugia, via S. Costanzo, 4, 06100 Perugia, ItalyDipartimento di Scienze Economiche-Estimative e degli Alimenti, Università degli Studi di Perugia, via S. Costanzo, 06100 Perugia, Italy

r t i c l e i n f o

eywords:xtruded linseedweecorino cheeseonsumer acceptability

a b s t r a c t

The aim of this experiment was to study consumer acceptability and composition ofPecorino cheese obtained from ewes fed an extruded linseed-enriched diet. Sixty lactat-ing Sarda ewes were randomly assigned to 3 dietary treatments: (1) control concentrate(CTR); (2) concentrate enriched with 100 g/kg of extruded linseed (EL-10); (3) concentrateenriched with 200 g/kg of extruded linseed (EL-20), that were all administered along withad libitum alfalfa hay. Cheeses were made with the bulk milk obtained from the 3 groups.The results showed that the diet affected cheese composition after 60 days of ripening.Linseed supplementation decreased protein and fat content while it increased the concen-tration of monounsaturated, polyunsaturated and long-chain fatty acids in both EL-10 andEL-20 cheeses. The extruded linseed-enriched diets improved the n-3 fatty acid and conju-gated linoleic acid contents and decreased the n-6/n-3 fatty acid ratio. A consumer panelevaluated the cheeses for color, eyeness, toughness, Pecorino cheese odor, Pecorino cheeseflavor, extraneous odors and flavors and overall acceptability. Although EL-10 and EL-20cheeses differed from the CTR cheese for some sensory profile attributes, all groups provedsimilar for overall acceptability and presence of extraneous odors and flavors. A triangle

test showed no differences among dietary treatments. Furthermore, when a MOS sensorarray, composed of six metal oxide sensors, was used to evaluate the three types of cheeses,no differences were found among groups. Extruded linseed supplementation seems there-fore a possible strategy for improving the nutritional quality of lipids in Pecorino cheesewithout affecting its sensory properties.

© 2012 Elsevier B.V. All rights reserved.

� This paper is part of a supplement titled “SIPAOC Congress 2010”uest Edited by Antonello Carta, Maria Teresa Manfredi, Giuseppeoniello and Massimo Trabalza-Marinucci.∗ Corresponding author at: Istituto Zooprofilattico Sperimentaleell’Umbria e delle Marche, via G. Salvemini 1, 06126 Perugia, Italy. Tel.:39 075343282; fax: +39 07535047.

E-mail address: a.valiani@izsum.it (A. Valiani).

921-4488/$ – see front matter © 2012 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.smallrumres.2012.04.032

1. Introduction

Ewe milk compared with bovine and caprine milk ischaracterized by a high fat and total solids content, mak-ing it ideal for cheese production (Zangh et al., 2006a).

However, ovine milk fat contains a high saturated fattyacid (SFA) level that is regarded as undesirable as somefatty acids (FA) (C12:0; C14:0; C16:0) are associated withincreased serum cholesterol which, in turn, is associated

inant Research 106S (2012) S43–S48

Table 1Chemical composition of the concentrates used in the experimental diets.

Component Experimental concentrates

CTR EL-10 EL-20

Dry matter (g/100 g) 88.16 88.98 89.40Crude protein (g/100 g) 16.66 16.43 16.75Ether extracts (g/100 g) 3.63 7.53 11.70Ash (g/100 g) 6.77 7.23 7.34Neutral detergent fibre (g/100 g) 17.38 20.30 26.13Acid detergent fibre (g/100 g) 5.26 6.77 8.97Acid detergent lignin (g/100 g) 1.22 1.62 2.71Ca (g/100 g) 1.39 1.47 1.55P (g/100 g) 0.65 0.68 0.70C16:0 16.51 11.19 9.54C18:0 2.22 3.00 3.29C18:1 cis9 23.80 19.71 18.12C18:2 cis9 cis12 51.31 30.75 22.95C18:3 cis9 cis12 cis15 4.44 33.12 43.48

S44 R. Branciari et al. / Small Rum

with an increased risk of heart disease (Bhat and Bhat,2011).

The ever-growing consumer awareness and the need torespond to the increasing demand for healthier foods, hasinduced animal nutritionists to revise dairy animal feed.Some studies in literature report the use of linseed or otheroil supplements in the diet of dairy ewes (Luna et al., 2005;Zangh et al., 2006b; Gómez-Cortés et al., 2009). These dietshave proven able to modify the FA composition of milkand cheese, obtaining a reduction of the SFA content alongwith an increase of the monounsaturated and polyunsatu-rated FA content. Furthermore, the increased concentrationof certain unsaturated FA such as n-3 FA and conjugatedlinoleic acids (CLA) is considered particularly beneficial tohuman health. However, alterations in milk FA composi-tion may have a deep effect on the physical and processingproperties of milk and dairy products (Palmquist et al.,1993). Furthermore, it could determine the modificationof the organoleptic characteristics of the cheeses, due tolipolysis and oxidation processes (Campbell et al., 2003;Sympoura et al., 2009). Sensory properties play a key rolein determining consumer acceptability for dairy products.Various studies evaluated bovine cheeses obtained frommilk with a high unsaturated FA content and only reportedminor effects of the diet on the organoleptic propertiesof both milk and cheese (Jones et al., 2005; Khanal et al.,2005; Lynch et al., 2005; Sympoura et al., 2009). Allredet al. (2006) observed a decreased acceptability of Cheddarcheese obtained from cows fed palm oil and fish calciumsalts, alone or combined with either extruded soybeans orsoybean oil. There is little information concerning sensorycharacteristics and consumer acceptability of n-3 FA andCLA-enriched sheep cheese (Luna et al., 2008).

Pecorino cheese, produced according to traditionaltechniques, and characterized by a ripening period of atleast two months, is a very well known ovine cheese in Italyand some Pecorino varieties have been given the recogni-tion of “Protected Denomination of Origin” (Cevoli et al.,2011). The main objective of this study was to evaluatethe effects of a dietary supplementation with extruded lin-seed on consumer acceptability and flavor characteristicsof Pecorino cheese.

2. Materials and methods

The University of Perugia Bioethics Committee gave approval for thisexperiment.

2.1. Animals and dietary treatments

Sixty pluriparous Sarda ewes in an early lactation stage were ran-domly divided into three groups of equal size, balanced for body weightand body condition score, and fed isoenergetic and isonitrogenous diets.Three concentrates were formulated: a control concentrate (CTR), with noextruded linseed, and two experimental concentrates containing, respec-tively, 100 g/kg (EL-10) and 200 g/kg (EL-20) of ground and extrudedlinseed (Table 1). Animals were fed 800 g per head per day of concen-trate, administered in two equal portions during milking. Alfalfa hay

(crude protein: 12.3 g/100 g; NDF: 53.4 g/100 g; ADF: 38.0 g/100 g) wasprovided in box feeders ad libitum. Experimental diets were adminis-tered from late pregnancy to day 100 of lactation. Sheep were housed ina stable with access to an outdoor paddock and machine-milked twice aday.

Fatty acid values are given as g/100 g total fatty acids. CTR, control; EL-10,10 g extruded linseed/100 g; EL-20, 20 g extruded linseed/100 g.

2.2. Cheesemaking

Two batches of Pecorino cheese were made from each treatmentgroup using small-scale manufacturing facilities. Bulk milk collected dur-ing week 9 and week 12 of lactation was used for cheese production. Thepecorino cheeses from the various treatment groups (CTR, EL-10, EL-20)were each manufactured separately. Whole raw ewe milk was pasteur-ized (68 ◦C, 10 min), cooled to 37 ◦C and a lyophilized mixed-strain starterculture was added (Fermenti lattici, Laboratorio Prodor, Bobbio, PC, Italy).The milk was ripened for 30 min, before adding a liquid calf rennet (30%chymosin, 70% pepsine, 1:10,000 strength) (Caglio Liquido, LaboratorioProdor, Bobbio, PC, Italy). Coagulation was allowed to take place over30–45 min. When the coagulum had developed the desired firmness, eval-uated subjectively, the curd was cut into small granules (about 5 mm insize), cooked at 41 ◦C for 5 min and pressed into cylindrical forms. To facil-itate whey draining, the forms were maintained at 30 ◦C, until the pHreached the value of 5. The curd was then dry salted and stored for ripen-ing at 12 ± 1 ◦C and 80 ± 5% relative humidity for 60 days. The cheeseswere sent to the laboratory under refrigeration (4 ◦C) and immediatelyanalyzed.

2.3. Chemical analyses

During the trial, alfalfa hay and concentrates were collected and ana-lyzed for chemical composition. Dry matter was evaluated following AOAC(2000) method 934.01. Crude protein, crude fat and ash were determinedaccording to AOAC methods 976.06, 920.39 and 942.05, respectively(AOAC, 1990). The methods of Van Soest et al. (1991) were used in theanalyses of NDF, ADF and ADL. Sodium sulphite was used in the NDF proce-dure and both NDF and ADF were expressed inclusive of ash. Calcium andphosphorous concentrations were determined following AOAC methods985.35 (Julshamn et al., 1998) and 965.17 (AOAC, 1996), respectively.

Chemical analyses were performed after 60 days of ripening on 6cheeses per group (3 cheeses per cheese manufacturing session). Drymatter was evaluated by gravimetric methods (IDF, 1982). Total nitrogenwas determined by the Kjeldahl method 991.20 (AOAC, 2000) and proteincontent was obtained by multiplying total N by a factor of 6.38. Fat con-tent was determined by the Mojonnier method 995.19 (AOAC, 2000); ashcontent was evaluated using the muffle furnace method 935.42 (AOAC,2000); salt was determined by the Volhard method 935.43 (AOAC, 2000).Finally, pH was measured using a puncture electrode probe connectedto a portable pH meter (model MP120 Mettler Toledo Inc., Columbus,USA). Cheese fatty acids were extracted according to Phillips et al. (1997)and the lipids were then esterified according to the method describedby Christie (1982). Fatty acid methyl esters were separated and quan-

tified using a VARIAN 3400 gas chromatograph equipped with a flameionization detector (FID) and a split-splitless injector. Analyses wereperformed with CP-SIL column 88, 50 m × 0.22 mm i.d., 0.20 �m filmthickness (Chrompack, Varian, Inc., CA). The injection volume was 1 �L.The carrier gas was high purity helium with flow rate of 1 mL/min. The

inant Research 106S (2012) S43–S48 S45

it1waP1bU

2

owaprssttlHePii2pcsw

swfttpfit

2

(o(pwfwtbsowftrrtg1vps

X

wt

Table 2Effect of linseed supplementation on chemical composition of cheesesafter 60 days of ripening.

Cheese composition Dietary treatment SEM

CTR EL-10 EL-20

Dry matter (g/100 g) 55.88a 55.79a 55.35b 0.06Fat (g/100 g) 27.37a 27.13b 26.99b 0.05Protein (g/100 g) 25.31a 24.98b 24.69c 0.08Ash (g/100 g) 3.68a 3.68a 3.21b 0.03NaCl (g/100 g) 1.19 1.21 1.21 0.02pH 5.37a 5.18b 5.30c 0.03

Means within a row with different superscript differ (P < 0.05). CTR, con-

R. Branciari et al. / Small Rum

njector and detector temperatures were kept at 290 ◦C. The column ovenemperature was programmed at 120 ◦C increasing by 3.2 ◦C/min up to70 ◦C and then increasing by 2.1 ◦C/min from 170 ◦C to 225 ◦C. Fatty acidsere identified via a comparison with a standard obtained by mixingstandard (37-Component FAME Mix) distributed by Supelco (Supelco

ark, Bellefonte, PA, USA) and a CLA isomer (cis 9 trans 11 and trans 10 cis2) standard obtained as described by Maurelli et al. (2009) and providedy Dipartimento di Scienze Economiche ed Estimative e degli Alimenti,niversity of Perugia.

.4. Sensory evaluation of cheeses

Staff and students of the Veterinary Medicine School of the Universityf Perugia were recruited as members of a consumer panel. Consumersere asked to complete a questionnaire that included information about

ge, sex and the frequency of consumption of Pecorino cheese. The finalanel consisted of men and women, aged 18–60, who consumed cheeseegularly (regular consumers were those who had a frequency of con-umption of at least once a week). Evaluation was conducted in 2 differentessions with 39 and 61 consumers in the 1st and 2nd session, respec-ively. Before each session, the definitions of attributes were explainedo the consumers. The test was performed using a 10 cm (1 = extremelyow; 10 = extremely high) unstructured scale (Johnson and Vickers, 1987;ein et al., 2008) for the evaluation of the following attributes: color,yeness, toughness, Pecorino cheese odor, extraneous odors and flavors,ecorino cheese flavor, overall acceptability. The attributes were selectedn a previous experiment (Trabalza Marinucci et al., 2011) and specificallyntegrated to meet the objectives of the experiment. Cheeses ripened formonths (6 cheeses per group) were allowed to equilibrate at room tem-erature (22 ◦C) for 1 h prior to evaluation in order to achieve optimumonditions for sensory evaluation and to obtain homogeneous cuts. Cheeseamples (10 g) were served in white plastic plates at room temperatureith random code numbers assigned to each sample.

A group of panelists consisting of 12 assessors was recruited for aeries of triangle tests evaluating CTR, EL-10 and EL-20 cheeses. Panelistsere researchers and employees of the University of Perugia, already

amiliar with the triangle evaluation techniques (Servili et al., 2011). Prioro sensory evaluation, they took part in briefing sessions. They were askedo choose the odd cheese in a series of 6 triangle tests. EL-10 samples wereresented against CTR, EL-20 samples were presented against CTR andnally EL-20 samples were presented against EL-10 to determine whetherhere was any significant difference among them.

.5. Mos Sensor Array (electronic nose)

An Electronic Olfactory System (EOS835) built by Sacmi IndustrySacmi Industry, S.r.l., Imola, Italy), composed of a chamber with six metalxide sensors was used to try to discriminate the three types of cheesesCTR, EL-10, EL-20). During analysis the sensors were maintained at a tem-erature range of 350–450 ◦C. Ten grams of grated cheese for each sampleere separately placed into a 100 ml glass bottle and maintained at 37 ◦C

or 15 min. The EOS835 was connected to the top of the bottle, equippedith a pierceable silicon/Teflon cap, by a steel feeler for head space that

ransfers the cheese headspace from the bottle to the MOS array cham-er. The duration of each measurement was programmed by the EOS835

oftware. Each headspace measurement conducted by EOS835 consistedf four steps: before (60 s) = period before real analysis: at this time thereas no data registered; during (60 s) = the cheese head space was trans-

erred in the MOS array chamber: this was the time the real measurementook place and the data collected by each sensor during this step wasecorded using the EOS835 software; after (108 s) = a recovery phase toestore the original MOS conditions; wait (240 s) = this was the necessaryransition time before new monitoring could begin. The headspace of therated cheese was conducted into the EOS835 chamber with an air flow of00 sccm and an injection flow of 1 cc/min. Ambient air filtered with acti-ated silica and charcoal was used as reference gas during the recoveryhase of the measurement cycle. The sensor response extracted by eachensor consisted of the following expression:

= R

R0

here R0 was the initial resistance of the sensor balanced in the air, R washe resistance of the sensor in the presence of the volatile compounds

trol; EL-10, 10 g extruded linseed/100 g concentrate; EL-20, 20 g extrudedlinseed/100 g concentrate.

emitted from the grated cheese (which decreased compared to R0), and Xwas the response recorded by each sensor, expressed in ohms.

2.6. Statistical analysis

Cheese FA and gross composition data were analyzed according to thegeneral linear model procedure (SAS, 2001) with diet and cheese manu-facturing session as fixed factors. The final model used for cheese sensoryevaluation scores included the effects of diet, testing session age, andgender of panelists. Data were reported as least square means ± standarderror mean. Overall differences between treatment means and their inter-actions were tested according to the Tukey test (SAS, 2001) and consideredto be significant when P ≤ 0.05.

The significance of the differences obtained from the triangle test wasdetermined using the expanded statistical tables of Roessler et al. (1978).

The electronic nose data were extracted and analyzed with the sta-tistical package “Nose Pattern Editor”. This software was elaborated bySacmi Industry (Sacmi Industry, s.r.l., Imola, Italy). The sensor data wereelaborated by principal component analysis (PCA) in order to obtain dataclusters related to dietary treatment.

3. Results and discussion

3.1. Cheese composition

The mean values related to cheese constituents aredetailed in Table 2.

Milk production did not vary among experimentalgroups (CTR: 0.65; EL-10: 0.70; EL-20: 0.68; SE: 0.03). Ewediet supplementation with extruded linseed decreased thefat and protein content in cheese. The negative effect onmilk (data not reported) and cheese fat content observedin the current study is in agreement with previous resultsobtained in cow cheese (Jones et al., 2005) and sheep milk(Zangh et al., 2006b) using lipid-supplemented rations.Nevertheless, to our knowledge, there are no studies inliterature reporting negative effects of linseed supplemen-tation on fat content in ewe milk. A lower milk proteincontent was reported by Gómez-Cortés et al. (2008) andmay be due to insufficient aminoacids in the mammarygland, probably due to a reduced microbial activity in therumen (Pulina et al., 2006). In contrast with the currentstudy, Zangh et al. (2006b) and Caroprese et al. (2011)observed a positive effect on milk fat content and no effectson milk protein concentration, when feeding extruded lin-

seed to sheep. The source of the fat supplemented, as wellas its physical form, may account for the different resultsobtained in the various studies (Pulina et al., 2006).

S46 R. Branciari et al. / Small Ruminant Research 106S (2012) S43–S48

Table 3Effect of linseed supplementation on the fatty acid composition of cheesemade with raw milk from ewes fed the experimental diets after 60 daysof ripening.

Itema Dietary treatment SEM

CTR EL-10 EL-20

SFA 72.06a 62.84b 56.84c 0.33SCFA (C4:0–C10:0) 19.30a 15.72b 13.64c 0.26MCFA (C11:0–C17:0) 48.76a 40.15b 35.22c 0.16LCFA (>C18:0) 27.54a 37.17b 42.12c 0.35MUFA 18.39a 23.57b 26.27c 0.23PUFA 4.90a 6.38b 7.65c 0.04n-6 PUFA 2.97a 3.18b 3.31c 0.03n-3 PUFA 1.22a 1.68b 2.09c 0.02n-6:n-3 2.45a 1.90b 1.58c 0.02C18:2 cis9 trans 11 (CLA) 0.71a 1.52b 2.25c 0.02Atherogenic index 3.42a 2.24b 1.75c 0.03Thrombogenic index 3.01a 2.15b 1.73c 0.02

Means within a row with different superscript differ (P < 0.05). Fatty acidvalues are given as g/100 g total fatty acids methyl esters. CTR, con-

Table 4Sensory properties of cheese after 60 days of ripening as perceived byconsumers.

Dietary treatment SEM

CTR EL-10 EL-20

Color 4.80 5.16 4.84 0.25Eyeness 2.38b 1.71b 4.73a 0.25Pecorino cheese odor 4.54a 3.49b 3.60b 0.25Extraneous odors 1.09 1.37 1.84 0.25Toughness 3.72b 4.41a 4.45a 0.19Pecorino cheese flavor 2.90b 3.97a 3.49a,b 0.24Extraneous flavors 2.07 1.67 1.93 0.31Overall acceptability 4.25 5.04 4.25 0.28

trol; EL-10, 10 g extruded linseed/100 g concentrate; EL-20, 20 g extrudedlinseed/100 g concentrate; SFA, saturated fatty acids; MUFA, monounsat-urated fatty acids; PUFA, polyunsaturated fatty acids.

The content of 9 groups of FA, in particular SFA,short chain fatty acids (SCFA) (C4:0–C10:0), medium chainfatty acids (MCFA) (C11:0–C17:0), long chain fatty acids(LCFA) (>C18:0), monounsaturated fatty acids, polyunsat-urated FA (PUFA), n-6 PUFA, n-3 PUFA, CLA in cheesesis reported in Table 3. Furthermore, 3 FA indexesare also reported: n-6/n-3 ratio, atherogenicity index(C12:0 + 4xC14:0 + C16:0)/(MUFA + PUFA) and thrombo-genicity index (C14:0 + C16:0 + C18:0)/(0.5 MUFA + 0.5 n-6PUFA + 3 n-3 PUFA + n-3 PUFA/n-6 PUFA). A lower SCFAand MCFA and a higher LCFA content were observed inboth EL-10 and EL-20 cheeses. These results are consistentwith data reported by Zangh et al. (2006b). The SCFA andMCFA reduction may be the result of the negative effectof fat supplementation on the de novo synthesis of milkfat (Bauman and Griinari, 2001). Feeding PUFA to rumi-nants alters rumen fermentation, leading to incompletebiohydrogenation and to the production of specific LCFAswhich inhibit the de novo synthesis of milk FA. Linseedsupplementation increased the concentration of PUFA andparticularly n-3 PUFA, markedly decreasing the n-6:n-3 FAratio in the EL-10 and EL-20 cheeses. Similar findings werereported by Gómez-Cortés et al. (2009). The cis 9 trans 11CLA content increased more than 2 fold in the EL-20 groupcheeses compared to the control diet cheeses. Gómez-Cortés et al. (2009) hypothesized that this increase may bedue to the amount and to the physical form of the extrudedlinseed. One of the most common nutritional concernsregarding cheese is that it is proatherogenic due to thehigh SFA content (Lock and Bauman, 2004; Gómez-Cortéset al., 2009; Bodas et al., 2010). Linseed supplementationmarkedly decreased the atherogenicity and thrombogenic-ity indexes both in the EL-10 and EL-20 cheeses. This resultis in agreement with previous research showing the ben-eficial effect of dietary oil supplementation on decreasing

the thrombogenic and atherogenic indexes of dairy prod-ucts (Gómez-Cortés et al., 2009; Cieslak et al., 2010). Thereduction observed in the treated groups, and especiallyin the EL-20 group, has a potentially significant impact in

Means within a row with different superscript differ (P < 0.05). CTR, con-trol; EL-10, 10 g extruded linseed/100 g concentrate; EL-20, 20 g extrudedlinseed/100 g concentrate.

terms of human health (Cieslak et al., 2010; Osmari et al.,2011).

3.2. Cheese sensory analysis

Consumer tests indicated that EL-20 cheeses had amore pronounced eyeness than the CTR and EL-10 groups(Table 4). The EL-10 and EL-20 cheeses, according to theassessors, presented a less pronounced Pecorino odor,while a more intense Pecorino flavor was perceived in theEL-10 compared to CTR cheeses. In general, young subjects(<30 years old) perceived less (P < 0.01) Pecorino cheeseflavor than older people (>30 years old). In a study bySympoura et al. (2009), feeding extruded linseed to cowsresulted in decreasing the “milk” note of the Saint-Nectairecheese flavor and odor, but these effects were consid-ered minor when compared to the strong effect relatedto the cheesemaking date. No significant differences wereobserved concerning the presence of extraneous odors,flavors and overall acceptability. Similarly, no differencesin flavor, aroma or overall impression between experi-mental groups were found by Jones et al. (2005) whenevaluating CLA-enriched bovine cheeses. Untrained pan-elists were unable to detect flavor differences betweencontrol and treated samples when evaluating cow milkwith high levels of vaccenic acid, cis-9 trans-11 CLA anda high degree of unsaturation (Lynch et al., 2005). Khanalet al. (2005) reported that both open and trained panelistsdid not find remarkable flavor and texture modifications inCLA-enriched milk and cheese from cows grazing on pas-ture. Other studies found no detrimental consequences onthe organoleptic characteristics of ewe cheeses containinghigher levels of n-3 FA and CLA (Luna et al., 2008; Gómez-Cortés et al., 2009).

A higher degree of toughness was observed in EL-10 andEL-20 cheeses with an effect due to the assessor’s sex, withfemales giving higher (P < 0.01) scores than males (4.51 vs.3.87, respectively). Contrary to the results obtained in thepresent work, Jones et al. (2005) found that highly CLA-enriched Caerphilly cheeses were significantly less firm and

less crumbly than the control cheeses.

The results of the sensory analysis based on a triangletest, aimed at differentiating CTR, EL-10 and EL-20 cheeses,are shown in Table 5. No significant differences were found

R. Branciari et al. / Small Ruminant Re

Table 5Triangle test results.

Number of correct judgments P

Batch 1 5 nsBatch 2 6 nsBatch 3 3 nsBatch 4 4 nsBatch 5 5 nsBatch 6 3 ns

Differences among cheeses are significant if P < 0.05 (95% confidencelevel); ns, not significant. Batch 1 and Batch 4, comparison between CTRa2c

bbc

foapctwh

isrcue2wanpo

Fe

nd EL-10 cheese; Batch 2 and Batch 5, comparison between CTR and EL-0 cheese; Batch 3 and Batch 6, comparison between EL-10 and EL-20heese.

etween the three cheeses, considering that, for the test toe significant, at least 8 out of 12 assessors must select theorrect sample.

The PCA model (Fig. 1) shows the data elaboration per-ormed by the electronic nose software (with the exceptionf one sample from the EL-20 group, considered outlier)nd explains 92% of total variance (69.86% for the first com-onent and 21.71% for the second component). The lack oflustering of the cheeses according to the different milkhey were produced with, shows that the electronic noseas not able to recognize any remarkable difference in theead spaces of the analyzed samples.

The electronic nose used in this experiment is annstrument comprising an array of electronic chemicalensors with partial specificity and an appropriate pattern-ecognition system, capable of recognizing simple oromplex odors. The electronic nose has been successfullysed to classify cheeses by geographical origin (Pillonelt al., 2003), variety and ripening stage (Contarini et al.,001; Cevoli et al., 2011). Cevoli et al. (2011), in a researchhere 60 different Pecorino cheese samples were evalu-

ted by an electronic nose coupled with an artificial neuraletwork, reported a very high prediction capability thatroved more effective than that based on GC–MS analysisf volatile compounds.

ig. 1. Diagram of the PCA obtained from electronic nose analysis of thexperimental cheeses after 60 days of ripening.

search 106S (2012) S43–S48 S47

4. Conclusions

Ewe diet supplementation with extruded linseed effi-ciently modifies the FA composition of Pecorino cheese,in particular by reducing the SFA and increasing the CLAcontent. A variation of the aromatic properties might, how-ever, represent an obstacle for consumer acceptability eventhough there is an ever higher concern for healthy products.Results from the current study suggest that the enrichedcheese acceptability was similar to the control, further-more neither a trained panel through a triangle test noran electronic nose were able to discriminate among exper-imental groups. In conclusion, based on the results of thepresent work, there seems to be no specific reason againstthe use of extruded linseed in sheep diets.

Conflict of interest

None of the authors have any financial or personalinterest that would inappropriately influence or bias thecontents of this paper.

Acknowledgments

The authors would like to thank F. Canalicchio and E.Cassetta for help in laboratory analyses and L. Burani andG. Tenerini for technical assistance and care of the ani-mals. This project was sponsored by the Italian Ministryof Agriculture (MiPAAF), DM 293/7303/05.

References

Allred, S.L., Dhiman, T.R., Brennand, C.P., Khanal, R.C., McMahon, D.J.,Luchini, N.D., 2006. Milk and cheese from cows fed calcium salts ofpalm and fish oil alone or in combination with soybean products. J.Dairy Sci. 89, 234–248.

AOAC, 1990. Official Method of Analysis, 15th ed. Association of OfficialAnalytical Chemists Inc., Arlington, VA.

AOAC, 1996. Official Methods of Analysis, 16th ed. Association of OfficialAnalytical Chemists, Washington, DC.

AOAC, 2000. Official Method of Analysis, 17th ed. Association of OfficialAnalytical Chemists Inc., Arlington, VA.

Bauman, D.E., Griinari, J., 2001. Regulation and nutritional manipulationof milk fat: low-fat milk syndrome. Livest. Prod. Sci. 70, 15–29.

Bhat, Z.F., Bhat, H., 2011. Milk and dairy products as functional foods: areview. Int. J. Dairy Sci. 6, 1–12.

Bodas, R., Manso, T., Mantecón, A.R., Juárez, M., De la Fuente, M.A., Gómez-Cortés, P., 2010. Comparison of the fatty acid profiles in cheeses fromewes fed diets supplemented with different plant oils. J. Agric. FoodChem. 58, 10493–10502.

Campbell, W., Drake, M.A., Larick, D.K., 2003. The impact of fortificationwith conjugated linoleic acid (CLA) on the quality of fluid milk. J. DairySci. 86, 43–51.

Caroprese, M., Albenzio, M., Bruno, A., Fedele, V., Santillo, A., Svevi, A.,2011. Effect of solar radiation and flaxseed supplementation on milkproduction and fatty acid profile of lactating ewes under high ambienttemperature. J. Dairy Sci. 94, 3856–3867.

Cevoli, C., Cerretani, L., Gori, A., Caboni, M.F., Gallina Toschi, T., Fabbri, A.,2011. Classification of Pecorino cheeses using electronic nose com-bined with artificial neural network and comparison with GC–MSanalysis of volatile compounds. Food Chem. 129, 1315–1319.

Christie, W.W., 1982. A simple procedure for rapid transmethylation ofglycerolipids and cholesteryl esters. J. Lipid Res. 23, 1072–1075.

Cieslak, A., Kowalczyk, J., Czauderna, M., Potkanski, A., Szumacher-Strabel,M., 2010. Enhancing unsaturated fatty acids in ewe’s milk by feeding

rapeseed or linseed oil. Czech J. Anim. Sci. 11, 496–504.

Contarini, G., Povolo, M., Toppino, P.M., Radovic, B., Lipp, M., Anklam, E.,2001. Comparison of three different techniques for the discrimina-tion of cheese: application to the ewe’s cheese. Milchwissenschaft 56,136–140.

inant Re

S48 R. Branciari et al. / Small Rum

Gómez-Cortés, P., Bach, A., Luna, M., Juarez, M., de la Fuente, M.A., 2009.Effects of extruded linseed supplementation on n-3 fatty acids andconjugated linoleic acid in milk and cheese from ewes. J. Dairy Sci. 92,4122–4134.

Gómez-Cortés, P., Frutos, P., Mantecon, A.R., Juarez, M., de la Fuente, M.A.,Hervas, G., 2008. Addition of olive oil to dairy ewe diets: effect on milkfatty acid profile and animal performance. J. Dairy Sci. 91, 3119–3127.

Hein, K.A., Jaeger, S.R., Tom Carr, B., Delahunty, C.M., 2008. Comparison offive common acceptance and preference methods. Food Qual. Prefer.19, 651–661.

IDF, 1982. Cheese and processed cheese. Determination of the total solidscontent. International Dairy Federation, FIL-IDF Standard 4A, Brussels,Belgium.

Johnson, L., Vickers, Z., 1987. Avoiding the centering bias or range effectwhen determining an optimum level of sweetness in lemonade. J.Sens. Stud. 2, 283–292.

Jones, E.L., Shingfied, K.J., Kohen, C., Jones, A.K., Lupoli, B., Grandison, A.S.,Beever, D.E., Williams, C.M., Calder, P.C., Yaqoob, P., 2005. Chemical,physical, and sensory properties of dairy products enriched with con-jugated linoleic acid. J. Dairy Sci. 88, 2923–2937.

Julshamn, K., Maage, A., Wallin, H.C., 1998. Determination of magne-sium and calcium in foods by atomic absorption spectrometry aftermicrowave digestion: NKML collaborative study. J. AOAC Int. 81,1202–1208.

Khanal, R.C., Dhiman, T.R., Ure, A.L., Brennand, C.P., Boman, R.L., McMahon,D.J., 2005. Consumer acceptability of conjugated linoleic acid-enriched milk and cheddar cheese from cows grazing on pasture. J.Dairy Sci. 88, 1837–1847.

Lock, A.L., Bauman, D.E., 2004. Modifying milk fat composition of dairycows to enhance fatty acids beneficial to human health. Lipids 39,1197–1206.

Luna, P., Bach, A., Juarez, M., de la Fuente, M.A., 2008. Influence of dietsrich in flax seed and sunflower oil on the fatty acid composition ofewes’ milk fat especially on the level of conjugated linoleic acid, n-3and n-6 fatty acids. Int. Dairy J. 18, 99–107.

Luna, P., Fontecha, J., Juarez, M., de la Fuente, M.A., 2005. Changes in themilk and cheese fat composition of ewes fed commercial supplementscontaining linseed with special reference to the CLA content and iso-mer composition. Lipids 40, 445–454.

Lynch, J.M., Lock, A.L., Dwyer, D.A., Noorbakhash, R., Barbano, D.M.,Baumann, D.E., 2005. Flavor and stability of pasteurized milk withelevated levels of conjugated linoleic acid and vaccenic acid. J. Dairy

Sci. 88, 489–498.

Maurelli, S., Blasi, F., Cossignani, L., Bosi, A., Simonetti, M.S., Damiani, P.,2009. Enzymatic synthesis of structured triacylglycerols containingCLA isomers starting from sn-1,3-diacylglycerols. J. Am. Oil Chem. Soc.86, 127–133.

search 106S (2012) S43–S48

Osmari, E.K., Cecato, U., Macedo, F.A.F., Souza, N.E., 2011. Nutritional qual-ity indices of milk fat goat on diets supplemented with differentroughages. Small Rumin. Res. 98, 128–132.

Palmquist, D.L., Beaulieu, A.D., Barbano, D.M., 1993. Feed and ani-mal factors influencing milk fat composition. J. Dairy Sci. 76,1753–1771.

Phillips, K.M., Tarragò-Trani, M.T., Grove, T., Grun, I., Lugogo, R., Harris,R.F., Stewert, K.K., 1997. Simplified gravimetric determination of totalfat in food composites after chloroform–methanol extraction. JAOCS74, 137–142.

Pillonel, L., Ampuero, S., Tabacchi, R., Bosset, J.O., 2003. Analytical methodsfor the determination of the geographic origin of Emmental cheese:volatile compounds by GC/MS-FID and electronic nose. Eur. Food Res.Technol. 216, 179–183.

Pulina, G., Nudda, A., Battacone, G., Cannas, A., 2006. Effects of nutrition onthe contents of fat, protein, somatic cells, aromatic compounds, andundesiderable substances in sheep milk. Anim. Feed Sci. Technol. 131,255–291.

Roessler, E.B., Pangborn, R.M., Sidel, J.L., Stone, H., 1978. Expandedstatistical table for estimating significance in paired-preference,paired-difference, duo-trio and triangle tests. J. Food Sci. 43, 940–947.

SAS, 2001. Statistical Software and User’s Guide, Version 8.2. SAS Inst., Inc.,Cary, NC, USA.

Servili, M., Rizzello, C.G., Taticchi, A., Esposto, S., Urbani, S., Mazzacane, F.,Di Maio, I., Selvaggini, R., Gobbetti, M., Di Cagno, R., 2011. Functionalmilk beverage fortified with phenolic compounds extracted from olivevegetation water, and fermented with functional lactic acid bacteria.Int. J. Food Microbiol. 147, 45–52.

Sympoura, F., Cornu, A., Tournayre, P., Massouras, T., Berdagué, J.L., Mar-tin, B., 2009. Odor compounds in cheese made from the milk of cowssupplemented with extruded linseed and �-tocopherol. J. Dairy Sci.92, 3040–3048.

Trabalza Marinucci, M., Miraglia, D., Valiani, A., Ranucci, D., Acuti, G.,Esposto, S., Branciari, R., 2011. The effect of somatic cell counton Pecorino cheese sensory properties. Ital. J. Anim. Sci. 10 (S1),667.

Van Soest, P.J., Robertson, J.B., Lewis, B.A., 1991. Methods for dietary fiber,neutral detergent fiber, and non-starch polysaccharides in relation toanimal nutrition. J. Dairy Sci. 74, 3583–3597.

Zangh, R., Mustafa, A.F., Zhao, X., 2006a. Effect of flaxseed supplemen-tation to lactating ewes on milk composition, cheese yield, andfatty acid composition of milk and cheese. Small Rumin. Res. 63,

233–241.

Zangh, R.H., Mustafa, A.F., Zhao, X., 2006b. Effect of feeding oilseeds rich inlinoleic and linolenic fatty acids to lactating ewes on cheese yield andon fatty acid composition of milk and cheese. Anim. Feed Sci. Technol.127, 220–233.