Web-based survey of consumer preferences for the visual appearance of meat from suckling kids

Full Te ms & Condi ions o access and use can be ound a h ps://www. and online.com/ac ion/jou nalIn o ma ion?jou nalCode= jas20 I alian Jou nal o Animal Science ISSN: (P in ) 1828-051X (Online) Jou nal homepage: h ps://www. and online.com/loi/ jas20 Web-based su ey o consume p e e ences o he isual appea ance o mea om suckling kids Guille mo Ripoll, Ma ía J. Alcalde, Anas asio A güello & Begoña Panea To ci e his a icle: Guille mo Ripoll, Ma ía J. Alcalde, Anas asio A güello & Begoña Panea (2019) Web-based su ey o consume p e e ences o he isual appea ance o mea om suckling kids, I alian Jou nal o Animal Science, 18:1, 1284-1293, DOI: 10.1080/1828051X.2019.1649990 To link o his a icle: h ps://doi.o g/10.1080/1828051X.2019.1649990 © 2019 The Au ho (s). Published by In o ma UK Limi ed, ading as Taylo & F ancis G oup. View supplemen a y ma e ial Published online: 15 Aug 2019. Submi you a icle o his jou nal A icle iews: 57 View ela ed a icles View C ossma k da a PAPER Web-based su ey o consume p e e ences o he isual appea ance o mea om suckling kids Guille mo Ripoll a ,Ma  ıa J. Alcalde b , Anas asio A g€ uello c and Bego~ na Panea a a Unidad de P oducci on y Sanidad Animal. Cen o de In es igaci on y Tecnolog  ıa Ag oalimen a ia de A ag on, Ins i u o Ag oalimen a io de A ag on –IA2 CITA, Uni e si yo Za agoza, Za agoza, Spain; b Depa amen o de Ciencias Ag o o es ales, Uni e si y o Se illa, Se illa, Spain; c Depa amen o de P oducci on Animal, Uni e si y o Las Palmas de G an Cana ia, Las Palmas, Spain ABSTRACT Mos suckling kids a e aised on a ms o ien ed owa d cheese p oduc ion, and many goa a m- e s’ ea kids wi h milk eplace s. The aim o he cu en s udy was o in es iga e he consume p e e ences o he isual appea ance o mea om suckling kids ea ed wi h milk eplace s o na u al milk. Mea colou was he majo c i e ion used o selec mea . The mea o Cab a del Guada ama ea ed wi h milk eplace s was p e e ed by 72% o consume s and had a p e e ed ligh ness and hue angle. The ea ing sys em did no in luence p e e ence h ough he ime o display. Web-based su eys p o ided simila in o ma ion o in o ma ion eco ded wi h li e su - eys using ac ual p oduc s ins ead o pic u es. Mea colou appea s o be a ecu ing in insic cue o assess consume p e e ence. In gene al, consume s p e e ed mea o ligh suckling kids ea ed on milk eplace s because his mea had a high ligh ness and hue angle as well as a low ch oma. HIGHLIGHTS Mea colou was he majo c i e ion used o choose mea . Rea ing sys em did no in luence consume ’s p e e ence h ough ime o display. Consume s p e e ed mea wi h high ligh ness and hue angle, and low ch oma. ARTICLE HISTORY Recei ed 19 Feb ua y 2019 Re ised 30 May 2019 Accep ed 25 July 2019 KEYWORDS Rea ing sys em; milk eplace ; colou ; isual app aisal; muscles; choice In oduc ion Consume beha iou is complex and is de e mined by psychological, ma ke ing and senso y ac o s, and is- ual appea ance is one ype o senso y ac o (Fon -i- Fu nols and Gue e o 2014). The choice o mea a he poin o pu chase is de e mined by isual appea ance cha ac e is ics, such as colou and ma bling, because hese in insic quali y cues a e highly ela ed o expec a ions o mea quali y (Bano i c e al. 2012). F om hese cues, he appea ance o eshness and col- ou has been epo ed o be he mos impo an (Be nu es e al. 2012; G acia and de Magis is 2013; Ripoll e al. 2018b). Mea colou is de ined by he con- cen a ion and chemical s a e o he muscle pigmen , which can be measu ed using he hue angle (h ab ) and ch oma (C ab) pa ame e s o CIE Lab(Rene e 1982). The e a e some s udies ela ing CIE Labcolou o consume p e e ences, bu mos a e ocussed on bee o hea y lambs (Khliji e al. 2010; Holman e al. 2016). Howe e , consume colou p e e ences a e di e en when assessing ed mea and ligh mea and conse- quen ly use di e en colou cues. Thus, consume s o hea y lambs p e e ed he eddes mea (Khliji e al. 2010), while consume s o ligh lambs p e e ed pale mea (Be nu es e al. 2012; Ripoll e al. 2018b). In bee , ap o ides he bes p edic ion o he consume accep ance o colou (Holman e al. 2016), while C ab is an impo an indica ion o colou (Ripoll e al. 2012). Albe  ıe al. (2002) used an a i icial in elligence algo- i hm o ind a unc ion yield a sco e bee om 1 (ligh pink mea ) o 5 (da k ed mea ). The unc ion ound selec ed Land h ab as he mos explana o y a iables. Also, Liu e al. (1996) ecommend he use o h ab because i is p ecise and easily unde s andable. The ela ionship be ween consume s isual app aisal and ins umen al colou emains unclea . Howe e , in CONTACT D . Guille mo Ripoll [email p o ec ed] Cen o de In es igaci on y Tecnolog  ıa Ag oalimen a ia de A ag on (CITA), A da, Mon a~ nana 930, 50059 Za agoza, Spain. Supplemen al da a o his a icle can be accessed he e. ß2019 The Au ho (s). Published by In o ma UK Limi ed, ading as Taylo & F ancis G oup. This is an Open Access a icle dis ibu ed unde he e ms o he C ea i e Commons A ibu ion License (h p://c ea i ecommons.o g/licenses/by/4.0/), which pe mi s un es ic ed use, dis ibu ion, and ep oduc ion in any medium, p o ided he o iginal wo k is p ope ly ci ed. ITALIAN JOURNAL OF ANIMAL SCIENCE 2019, VOL. 18, NO. 1, 1284–1293 h ps://doi.o g/10.1080/1828051X.2019.1649990 o de o gain g ea e knowledge on he subjec , a s udy should be ca ied ou wi h a g ea e a ie y o ypes o mea . Hence, Lis he mos impo an CIE Lab pa ame e used o he consume judgemen o ligh suckling kid mea (Ripoll e al. 2018a). This mea is cha ac e ised by high Land h ab and low C ab (Mo ales-De la Nuez e al. 2011; De Palo e al. 2015). Spain is a g ea p oduce o kid mea , and 80% o his kid mea o igina es om he ligh suckling kid ca - ego y (MAPAMA 2016). Mos o he suckling kids a e aised on milk a ms o ien ed owa d cheese p oduc- ion. When goa s a e suckling hei kids, he milk p o- ein and a quan i y and quali y dec ease (Ca a aca e al. 2004). As a esul , some goa a me s emo e he kids om hei dams a a e y young age and ea hem wi h milk eplace s. Howe e , some a me s s ill ea kids wi h hei dams because hey belie e ha he mea om suckled kids is mo e ende han he mea om kids ea ed on a i icial suckling sys ems (A g€ uello e al. 2005). The p oxima e composi ion o milk could modi y kid mea colou , and, consequen ly, his could a ec he consume p e e ence (Ripoll e al. 2018a). Some s udies ha e shown ha he leg chops o kids ea ed wi h milk eplace s we e p e e ed by consume s because he mea was pale and dull, wi h a g ea e hue angle and a lowe edness and ch oma (Ripoll e al. 2018a). Mos o he s udies examining consume isual app aisal a e ca ied ou wi h eal p oduc ; ne e he- less, his echnique is expensi e and ime-consuming, and, because o his, o he echniques ha e been de eloped in ecen yea s. Web-based su eys using pic u es ha e been demons a ed as a alid me hod o ela e he ins umen al colou o mea o consume isual app aisal (Holman e al. 2016). A he same ime, he lack o ep esen a i eness o he s udied popula ion, which was he p incipal weakness o web su eys, is quickly disappea ing each yea as mo e people a ound he wo ld gain in e ne access (E ans and Ma hu 2005,2018). Consequen ly, he aim o he cu en s udy was o s udy consume p e e ence o he isual appea ance o mea om suckling kids ea ed wi h milk eplace s o na u al milk as well as o de e mine he choice c i- e ia used du ing he p ocess. Ma e ials and me hods Ca case sampling All p ocedu es we e conduc ed acco ding o he guidelines o Di ec i e 2010/63/EU on he p o ec ion o animals used o expe imen al and o he scien i ic pu poses (E.U. 2010). Suckling male kids o he Cab a del Guada ama, Majo e a, Palme a, and Tine e~ na b eeds ea ed wi h milk eplace s (MR) o na u al milk om hei dams (NM) we e selec ed om wo a ms o each b eed. Six een kids pe b eed we e ed NM; and 15 kids we e ed MR o Guada ama and Palme a while, and 16 kids we e ed MR o Majo e a and Tine e~ na. The kids we e slaugh e ed ollowing s anda d comme cial p o- cedu es acco ding o he Eu opean no ms o he p o- ec ion o animals a he ime o killing (E.U. 2009). The kids had a li e weigh o 8.2 ± 0.1 kg and an age o 40–45 days old. A head-only elec ical s unning (1.00 A) was applied o he kids, and hey we e hen exsanguina ed and d essed. The kids had an a e age ho ca case weigh o 4.5 ± 0.1 kg. The ca cases we e hung by he Achilles endon and chilled o 24 h a 4C in o al da kness. The igh hind leg was sepa- a ed om he ca case, acuum packed and s o ed a –20 C un il sampling. Ins umen al colou measu emen o he chops The shel li e o he mea o suckling lambs and kids is app oxima ely one week (Alcalde e al. 2017). Because o he e y small size o he kid legs, only ou o he leg chops we e su icien ly la ge enough o measu e he colou o he di e en muscles. Wi h hese boun- da ies, we used a e e sed s o age design (Gim enez e al. 2012). Hence, he 126 ozen legs we e sliced in o ou 2-cm hick chops and assigned o 8, 6, 3, and 1 days be o e aking a pic u e (day 0). On he assigned day, he chops we e hawed and placed in expanded polys y ene ays co e ed wi h e ac ile oxygen-pe meable plas ic ilm (wa e apou pe me- abili y: 10 g m 22 24 21 h, oxygen ansmission a e: 200 cm 3 m 22 24 21 h, CO 2 ansmission a e: 650 cm 3 m 22 24 21 h; LINPAC Packaging Limi ed, Fea he s one, UK). Then, he chops we e s o ed o 24 h a 4 C in o al da kness un il he day o pic- u e cap u e. Muscle colou s we e measu ed a 0% UV wi h an obse e angle o 10and ze o and whi e calib a ion using a Minol a CM-2006d spec opho ome e (Konica Minol a Holdings, Inc., Osaka, Japan) in CIE Lab 1986 space wi h he specula componen included. The measu emen a ea (diame e o 8 mm) was co - e ed wi h a CM-A149 dus co e (Konica Minol a Holdings, Inc., Osaka, Japan). The illuminan used was D65. The ligh ness (L), edness (a) and yellowness (b) indexes we e eco ded using he so wa e ITALIAN JOURNAL OF ANIMAL SCIENCE 1285 Spec aMagic NX (Minol a Co. L d., Osaka, Japan), and he hue angle hab ¼ an1b a  180 p hi and ch oma C ab ¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi a ðÞ 2þb ðÞ 2 q  we e calcula ed. The colou o he semimemb anosus,semi endinosus and biceps emo is leg muscles we e measu ed because hey ep- esen mos o he chop a ea. Colou measu emen s we e epea ed h ee imes, and he spec opho om- e e was o a ed on he ho izon al plane be o e each measu emen . The mean o he h ee eadings was used o s a is ical analysis. Cap u e o he images o he chops Following each measu emen , he chops we e indi- idually posi ioned in a Cubeli e Las oli e po able s u- dio (Vi ec Imaging Dis ibu ion UK, Leices e shi e, UK) abo e a black backg ound. The s udio was placed benea h wo ligh bulbs wi h i e C omali e bulbs (C omali e S.L, Ba celona, Spain). Each ligh bulb con- ained 28 W, 5.200 K, and 1.600 lm, deli e ing 1.200 a e age lx o he sample su ace. An Olympus Pen E- PL1 12.3 Mpx came a wi h a M. Zuiko digi al 14–42mm 1:3.5–5.6 L lens (Olympus Imaging Co p., Shinjuku-ku, Tokyo) was placed o e head he sample wi h a ipod. The came a’s exposu e se ings we e manually adjus ed o an ISO o 400, a lens ape u e o F5.6 and a shu e speed o 1:125. All images we e downloaded in aw o ma , and no lash, il e s o o he lenses we e applied. Addi ionally, no o he image edi ing o p ocessing o manipula ion was applied o he han he c opping o he image. When he chop colou was measu ed and all chops we e pho og aphed, an asso men o pic u es was selec ed o he su eys. The chops wi h L,h ab and C ab alues ep esen a i e o hei b eed and ea ing sys ems we e selec ed o isual app aisal by consum- e s. L,h ab and C ab we e chosen because hese pa ame e s a e simila o he colou pe cep ion o human beings (Ripoll e al. 2012). Su ey design and dissemina ion Two su eys we e designed o his s udy. The geo- g aphical scope o he su eys was es ic ed o Spain, uling ou he esponses o consume s om o he coun ies. This s udy was conduc ed using an online su ey se ice (www.encues a acil.com), and he su - ey da a we e con e ed o an MS Excel shee . The ques ionnai es we e es ed by esea che s who may o may no ha e been in ol ed in he s udy and adap ed un il he inal e sion was app o ed. Mo eo e , a comp omise had o be eached be ween ho ough- ness, simplici y, and sho ness. The ques ionnai es we e dis ibu ed using social media websi es, uni e si y mailing lis s and su ey mailing lis s. A di ulga ion message was included ha asked ecei e s o u he b oadcas he web link o o he pe sons in hei espec i e elec onic mailing lis s. Fo hose ecei e s willing o pa icipa e in he su ey, he su ey welcome page was immedia ely accessible a e hey clicked on he web link. The ques ionnai e was anonymous o gua an ee a highe le el o pa icipa ion and hones y. Pe sonal da a, such as iden i ica ion o elec onic mail add ess, we e no equi ed, and he e was no inancial compensa ion. Pa icipan s we e clea ly in o med o he aim o he s udy and ga e implici consen o he use o hei supplied in o ma ion in he esea ch acco ding o Eu opean egula ions (U.E. 2010). This s udy was con- duc ed acco ding o he Decla a ion o Helsinki o s udies on human subjec s. The su eys comp ised se e al se s o pic u es o chops om di e en ea ing sys ems and imes o dis- play bu o simila b eeds, and he esponden had o choose he pic u e wi h hei p e e ed chop. The e ec s o he ea ing sys em and ime o display we e es ed wi h he i s su ey (Su ey RS þTD). This su - ey only used pic u es o Cab a del Guada ama, and eigh se s o ou pic u es each we e shown o esponden s. The ime o display was compa ed in ou se s o pic u es, and he ea ing sys em wi hin each ime o display was compa ed in he o he ou se s o pic u es. A second su ey (Su ey RS) was con- duc ed o s udy he e ec o he ea ing sys em in ol ing he ou b eeds a 1 days o display. The e o e, ou se s o wo pic u es we e shown, and consume s we e asked o choose be ween he ea ing sys ems wi hin each b eed. The chop shape and size we e balanced wi hin and be ween he pic u e se s. Ques ionnai e and pic u es a e shown in Supplemen a y Apppendix A. Bo h su eys had a com- mon sociodemog aphic sec ion. The in o ma ion ga h- e ed in his sec ion included gende (woman, man), age (<25 yea s, be ween 26 and 40 yea s, be ween 41 and 55 yea s, and >55 yea s), li ing en i onmen , ‘Ha e you e e as ed mea om ligh suckling kids?’ (yes/no), and ‘I he esponse is yes, do you like i ?’ (yes/no). A las ques ion common o bo h su eys asked abou he choice c i e ia used o selec he pic- u e o he p e e ed chop. The op ions we e (a) mea colou , (b) a colou , (c) mea b igh ness, (d) chop size, and (e) chop shape. 1286 G. RIPOLL ET AL. S a is ical analysis Fo bo h su eys, he 2 es was used o analyse he equencies o consume answe s (gende , age, he c i- e ia used o choose he pic u es, he equency o consume s who had p e iously as ed mea om ligh suckling kids, and he equency o people who liked he mea om ligh suckling kids). Pic u e selec ion acco ding he ea ing sys em, ime o display and b eed we e also es ed using he 2 es , as we e he c i e ion used o pic u e selec ion acco ding o b eed. The le el o signi icance was 0.05. When one o he cells had a equency o less han i e, which makes he use o he 2 s a is ic unad isable, he likelihood a io s a is ic was used a he same p obabili y le el. To in e p e he pa e ns o associa ion be ween he s udied a iables, he co ec ed s anda dised esidual be ween he obse ed and expec ed cases wi hin each cell g ea e han j1.96jwas conside ed. Ins umen al colou a iables we e analysed wi h an analysis o a iance wi h ea ing sys em, muscle and b eed as ixed e ec s. The Duncan es was used o compa e means, and he le el o signi icance was p<.05. Resul s Sample cha ac e isa ion and he choice c i e ia used by consume s The su ey RS þTD, which in es iga ed he e ec s o he ea ing sys em and ime o display, was comple ed by 186 consume s, and he su ey RS, which in es i- ga ed he e ec s o he ea ing sys em, was com- ple ed by 399 consume s. The gende dis ibu ions in he RS þTD and RS su eys we e simila ( 2 ¼0.02; p<.9), wi h 59% and 60% women, espec i ely. Simila ly, bo h su eys had he same dis ibu ion o ages ( 2 ¼3.2; p¼.3). The e we e 14% and 19% o people be ween 18 and 25 yea s, 30% and 29% o people be ween 26 and 40 yea s, 40% and 34% o people be ween 41 and 55 yea s and 17% and 18% o people olde han 55 yea s in he RS þTD and RS su - eys, espec i ely. Popula ion o Spain we e 51% woman, and he e we e 10% o people be ween 18 and 25 yea s, 27% o people be ween 26 and 40 yea s, 30% o people be ween 41 and 55 yea s and 25% o people olde han 55 yea s (INE 2016). The e o e, younge people and olde people we e unde - and o e ep esen ed al hough bo h in e media e seg- men s we e well ep esen ed. Eigh y-eigh pe cen o he esponden s had as ed mea om ligh suckling kids, and he e was no di e ence in his numbe be ween he su eys ( 2 ¼1.26; p¼.3). F om hese esponden s, 94% con i med ha hey liked his mea , also wi hou di e ences be ween he su eys ( 2 ¼1.9; p¼.2). The c i e ia used by he esponden s o choose hei p e e ed chops a e shown in Figu e 1. The choice c i e ia we e di e en o each su ey ( 2 ¼23.5; p<.001), bu mea colou was he majo c i e ion o bo h su eys. A signi ican ly highe pe - cen age o esponden s in su ey RS (82%) used mea colou as a c i e ion han ha in su ey RSþTD (60%). Howe e , mo e esponden s o su ey RS þTD used a colou (12%) and chop shape (11%) as c i e ion han did he esponden s o su ey RS (6% and 3%, espec i ely). Mea b igh ness and chop size we e less equen ly used and did no show di e ences (p>.05) be ween he su eys, wi h 5% and 3% o esponden s, espec i ely. The choice c i e ion was no condi ioned by gende , age o he li ing en i onmen o he con- sume on bo h su eys (p>.2). Consume p e e ence and he ins umen al colou o he chops displayed o 8 days The pe cen age o he chops p e e ed by he su ey RS þTD esponden s acco ding o he ea ing sys em and ime o display a e shown in Figu e 2. The esponden s simila ly chose bo h ea ing sys ems h ough he ime o display (p>.05), bu he ea ing sys em and he ime o display a ec ed he pe cen - age o p e e ed chops (p<.0001). The chops a 7 days o display we e signi ican ly less p e e ed (p<.05) han he chops a o he display imes. The chops displayed o 3 days we e he mos p e e ed, al hough his p e e ence was no s a is ically ele an 4 5 3 6 82 2 5 11 12 69 0 1020304050607080 Chop size Mea b igh ness Chop shape Fa colo Mea colo Pe cen age o esponden s Su ey RS+TD Su ey RS * * * Figu e 1. Choice c i e ia used by he esponden s wi hin each su ey. Su ey RS þTD compa ed he ea ing sys ems and ime o display, and su ey RS compa ed he ea ing sys ems. The dis ibu ion o equencies o each su ey was independ- en ( 2 ¼23.5; p<.001). The obse ed equencies wi h as e - isks a e signi ican ly di e en (p<.05) be ween su eys. ITALIAN JOURNAL OF ANIMAL SCIENCE 1287 (p>.05). The chops om he kids ed MR we e p e- e ed in 72% o consume s, while 28% p e e ed he chops om he kids ed NM (p<.0001). The ea ing sys em p e e ence was no a ec ed (p>.4) by age, gende , o he li ing en i onmen o consume s a any ime o display. The ins umen al colou o he chops shown o he consume s in su ey RS þTD is shown in Table 1. The e we e no signi ican in e ac ions be ween he s udied e ec s (p>.05) o any a iable. The ea ing sys em a ec ed all a iables (p<.05). The mea om he kids ed MR had a g ea e L,b h ab and a lowe aand C ab:The e o e, he di e ence in colou be ween MR and NM was DE ab¼4. The ime o dis- play also a ec ed all colou a iables (p<.05). Ligh ness inc eased sligh ly om 1 o 8 days (p<.05). Con e sely, edness dec eased s eadily o e he ime o display, wi h signi ican di e ences om 1 o 8 days (p<.05). Yellowness and hue angle showed simila pa e ns, wi h a sligh dec ease om 1 o 6 days (p>.05) and an inc ease om 6 o 8 days (p<.05). The ch oma dec eased om 3 o 6 days (p<.05) and inc eased om 6 o 8 days (p<.05). The h ee muscles had simila Land a(p>.05). The BF and SM muscles had simila b,h ab and C ab (p>.05), while he ST muscle was di e en om bo h he BF and SM muscles (p<.05). Consume p e e ence and he ins umen al colou o he chops om he ou b eeds The pe cen age o he chops p e e ed by he su ey RS esponden s acco ding he ea ing sys em and choice c i e ia a e shown in Table 2. The o al pe cen - age o he selec ion o NM was highe (52.3%) han ha o MR ( 2 ¼6.7; p¼.009). Howe e , he p e e ence o he ea ing sys em was no he same o each b eed ( 2 ¼84.1; p<.0001). As a esul , con- sume s p e e ed he chops om he Cab a del Guada ama ed NM and he chops om he Palme a and Tine e~ na ed MR (p<.05). The e was no p e e - ence o he ea ing sys em o Majo e a (p>.05). The p e e ence o he ea ing sys em was no a ec ed (p>.5) by age, gende , o he li ing en i onmen o consume s a any ime o display. Howe e , he choice c i e ia also a ec ed he pe cen age o p e e ed chops. The e o e, he consume p e e ence, using Table 1. Ins umen al colou o he leg chops om he Cab a del Guada ama kids ea ed wi h milk eplace (MR) o na u al milk om hei dams (NM). Labh ab C ab Rea ing sys em MR 42.70 7.34 6.77 40.85 10.80 NM 39.54 9.98 5.84 29.74 11.60 SE 0.395 0.254 0.254 1.291 0.260 Time o display 1 day 40.30 b 9.91 a 6.71 ab 34.31 ab 12.14 a 3 days 40.96 b 8.86 ab 6.11 ab 34.39 ab 10.95 a 6 days 41.12 ab 8.17 b 5.43 b 32.99 b 9.95 b 8 days 42.20 a 8.49 b 6.90 a 39.35 a 11.17 a SE 0.586 0.375 0.376 1.910 0.351 Muscle Biceps emo is 41.18 8.60 5.65 b 32.86 y 10.40 y Semimemb anosus 40.59 8.74 5.94 b 34.55 y 10.66 y Semi endinosus 41.59 9.23 7.32 x 38.48 x 11.92 x SE 0.472 0.301 0.302 1.537 0.310 Signi icance † Rea ing sys em <0.001 <0.001 0.006 <0.001 0.001 Time o display 0.041 0.025 0.018 0.019 0.009 Muscle 0.283 0.265 <0.001 0.023 0.001 Pic u es o hese leg chops we e used on su ey RS þTD ( ea ing sys em and ime o display). a : edness; b: yellowness; C ab :ch oma; hab :hue angle; L: ligh ness; SE: s anda d e o : † In e ac ions we e no signi ican (p>.05). Di e en supe sc ip s (a and b) indica e signi ican di e ences be ween imes o display (p<.05). Di e en supe sc ip s (x, y) indica e signi ican di e ences be ween muscles (p<.05). hab ¼ an1b a  180 p;C ab ¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi a ðÞ 2þb ðÞ 2 q Table 2. Pe cen ages o he p e e ence o he ea ing sys- ems in he gene al sample ( 2 ¼84.1; p<.0001) and he consume s ha used mea colou ( 2 ¼80.4; p<.0001) and a colou ( 2 ¼13.0; p¼.005) as decision c i e ia. Choice c i e ia Gene al sample Mea colou Fa colou B eed MR NM MR NM MR NM Cab a del Guada ama 29.3 70.726.5 73.544.0 56.0 Majo e a 48.1 51.9 48.5 51.5 32.0 68.0 Palme a 60.439.6 58.541.5 80.020.0 Tine e~ na 52.947.1 53.047.0 60.040.0 To al 47.7 52.3 46.6 53.4 54.0 46.0 MR: milk eplace ; NM: na u al milk. Pe cen ages highe om he expec ed (p<.05). 0 10 20 30 40 50 60 70 80 1368 Time o display, d * 30.4 41.9 22.0 5.6 28 72 NM MR Rea ing sys em * * Figu e 2. Pe cen age o he Cab a del Guada ama chops p e- e ed by consume s acco ding o he ime o display ( 2 ¼208.4; p<.0001) and ea ing sys em ( 2 ¼144.6; p<.0001). NM, na u al milk; MR, milk eplace . The obse ed equencies wi h as e isks a e signi ican ly di e en (p<.05) om he expec ed equencies. 1288 G. RIPOLL ET AL. mea colou as a c i e ion, was di e en acco ding o he b eed ( 2 ¼80.4; p<.0001). Consume s also p e- e ed he chops om he Cab a del Guada ama ed NM and he chops om he Palme a and Tine e~ na ed MR (p<.05), bu wi h di e en p opo ions han he o al consume sample. Howe e , when conside - ing a colou ( 2 ¼13.0; p¼.005), consume s also p e- e ed he Palme a and Tine e~ na ed MR (p<.05) bu p e e ed he Majo e a ed NM (p<.05). Addi ionally, he consume s did no show a p e e ence o any ea - ing sys ems when choosing he chops o Cab a del Guada ama (p>.05). Finally, when conside ing mea b igh ness ( 2 ¼4.2; p¼.2), chop shape ( 2 ¼1.7; p¼.6) and chop size ( 2 ¼1.1; p¼.8), consume s did no p e e one ea ing sys em mo e han ano he . The ins umen al colou a 1 day o display o he chops shown o he consume s in su ey RS is shown in Table 3. The e we e no signi ican in e ac ions be ween he s udied e ec s (p>.05) o any a iable. The ea ing sys em a ec ed all a iables (p<.05) excep b(p¼.4). The mea om he kids ed MR had a g ea e L,b ,h ab , and a lowe aand C ab: The e o e, he di e ence in he colou be ween MR and NM was DE ab¼2.4. In gene al, hese esul s a e consis en wi h hose o su ey RS þTD. The b eed a ec ed all a iables (p<.05). Cab a del Guada ama was clea ly di e en compa ed wi h he o he b eeds because hey had a lowe L, b, and h ab , and a highe a and C ab (P<0.05). Majo e a, Tine e~ na and Palme a had simila band h ab (P>0.05). Majo e a and Palme a had di e en L,a , and C ab (p<.05), while Tine e~ na had in e media e alues among he b eeds (p>.05). The e we e di e ences in L,b , and C ab (p<.05) be ween he muscles. As in he esul s no ed when chops we e shown o consume s in su ey RS þTD, he di e ences be ween he SM and BF muscles we e highe han he di e ences be ween he BF and SM. Hence, ST had a highe L,a , and C ab (p<.05) han SM, while BF had in e media e alues o C ab (p>.05) and simila alues o Land b o SM (p>.05). Discussion The e is a well- ounded consensus in he li e a u e ha he p incipal c i e ion used in mea choice is col- ou due o i s ela ionship wi h eshness (Kubbe ød e al. 2002; Be nu es e al. 2012; G acia and de Magis is 2013; Ripoll e al. 2018b). Howe e , isible a con en is also a main cue used o assess mea quali y (Kubbe ød e al. 2002; Bano i c e al. 2016). Ne e heless, mea om ligh suckling kids has no appa en a . Consequen ly, in bo h su eys, colou was he mos impo an cue. Mea om ligh suckling kids has high Land low aand b alues. The e o e, his mea is ligh e , pale and dulle (Mo ales-De la Nuez e al. 2011; De Palo e al. 2015) han he mea o hea y suckling kids (Ozcan e al. 2014; Yakan e al. 2016) and o concen a e- ed kids (Emami e al. 2015). Because o his paleness, i could be expec ed ha ‘mea b igh ness’was used as a c i e ion by mo e con- sume s, as L(ligh ness) has been epo ed as he main colou a iable used by consume s o assess suckling kid mea (Ripoll e al. 2018a). In addi ion o L, consume s assessed he appea ance o he whole chop a he han he indi idual muscles and ocussed on h ab (Ripoll e al. 2018a). The ela ionship be ween he isual app aisal o mea colou and Lhas been epo ed p e iously (Eikelenboom e al. 1992; Denoyelle and Be ny 1999; Hulsegge e al. 2001). In con as , bis no na u ally associa ed wi h mea col- ou (Mancini e al. 2005; Ripoll e al. 2012), and i s use by human beings is unclea (O’Sulli an e al. 2003). Khliji e al. (2010) only used Land a o sco e lamb mea . Holman e al. (2017) epo ed aas he bes p edic o o consume accep ance o bee , bu h ab and C ab inc eased he p edic ion p ecision. Table 3. Ins umen al colou o he leg chops om he kids o he ou b eeds ea ed wi h milk eplace (MR) o na u al milk om hei dams (NM) a 1 days o display. Labh ab C ab Rea ing sys em MR 45.48 6.03 8.22 54.89 10.45 NM 43.59 7.54 8.00 47.44 11.32 SE 0.462 0.337 0.225 1.770 0.240 B eed Cab a del Guada ama 40.27 c 9.88 a 6.68 b 34.34 b 12.04 a Majo e a 45.07 b 6.53 b 8.74 a 53.52 a 11.02 b Palme a 46.87 a 4.95 c 8.31 a 59.98 a 9.87 c Tine e~ na 45.93 ab 5.78 bc 8.60 a 56.82 a 10.59 bc SE 0.618 0.466 0.307 2.494 1.5630 Muscle Biceps emo is 44.15 y 7.05 8.09 y 50.04 11.01 xy Semimemb anosus 43.53 y 6.77 7.17 z 48.23 10.24 y Semi endinosus 45.92 x 6.54 9.01 x 55.22 11.41 x SE 0.350 0.397 0.174 2.122 0.288 Signi icance† Rea ing sys em 0.003 0.002 0.400 0.040 0.014 B eed <0.001 <0.001 <0.001 <0.001 <0.001 Muscle 0.006 0.664 <0.001 0.060 0.017 Pic u es o hese leg chops we e used on su ey RS ( ea ing sys em). a: edness; b: yellowness; C ab :ch oma; hab :hue angle; L: ligh ness; SE: s anda d e o : † In e ac ions we e no signi ican (p>.05). Di e en supe sc ip s (a, b, and c) indica e signi ican di e ences be ween imes o display (p<.05). Di e en supe sc ip s (x, y, and z) indica e signi ican di e ences be ween muscles (p<.05). hab ¼ an1b a  180 p;C ab ¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi a ðÞ 2þb ðÞ 2 q ITALIAN JOURNAL OF ANIMAL SCIENCE 1289 The esul s o su ey RS þTD showed a clea p e e - ence o consume s o MR mea , demons a ing ha he kid mea wi h g ea e Land h ab and low C ab is p e e ed. Howe e , su ey RS was no so clea because he di e ence in colou (D ab) be ween he ea ing sys ems was conside ably highe o su ey RS þTD (D ab¼4.0) han ha o su ey RS (D ab¼2.4). This la e colou di e ence is close o he concep o he ‘jus no iceable di e ence’be ween wo s imuli epo ed by some au ho s (S okes e al. 1992; ISO 2004). Howe e , de ining a isually de ec able h esh- old is di icul because i depends la gely on whe e he wo compa ed colou s a e loca ed in he colou space (Lee 2005). Ab il e al. (2001) epo ed ha D ab o bee >0.9 we e isually de ec ible. Howe e , heo - e ically, when D ab is below 2.2, he s imuli a e no dis- c iminable di e en om each o he (S okes e al. 1992). O he au ho s epo ed ha D ab below 1 is impe cep ible and di e ences be ween 1 and 4 may o may no be pe cep ible (Ebne 2007). Also is impo an he physical and empo al dis ance be ween he s imuli (Wyszecki and S iles 1982). In ac , Babike e al. (1990) epo ed ha goa and lamb mea wi h D ab¼1.97 was no de ec ed by consume s when no a e showed oge he . Ca asco e al. (2009) epo ed ha ained e alua o s we e no able o di e en ia e a colou s wi h D ab¼5.2 because colou s imuli we e no e alua ed nex o each o he . In addi ion, he ea - ing sys ems compa ed on su ey RS had alues o L abo e 40.77, which has been epo ed as he i s h eshold o assess suckling kid mea (Ripoll e al. 2018a). The e o e, acco ding o hese la e au ho s, bo h ea ing sys ems would achie e simila is- ual app aisal. Die s ongly a ec s he mea colou o p e umi- nan s, such as suckling lambs and kids (Joy e al. 2012; Ozcan e al. 2014). Mea ligh ness is in luenced by pH and p o ein s uc u es (MacDougall 1982) mo e han die (Rene e 1982). Hence, some au ho s epo ed ha milk eplace s do no a ec he Lo esh kid mea , independen o he measu ed muscle (Ba~ n on e al. 2006; Zu i a-He e a e al. 2013; De Palo e al. 2015). Howe e , in ag eemen wi h Ripoll e al. (2018a), ozen/ hawed mea could show a di e en beha iou due o he dena u alisa ion o sa coplasmic p o eins. In ag eemen wi h ou esul s, De Palo e al. (2015) ound ha he mea o kids ed wi h na u al milk had lowe band h ab han ha o hose ed wi h milk eplace s. Addi ionally, he au ho s also did no ind di e ences in C ab:Compa ed wi h he use o na - u al goa milk, he use o milk eplace s a ec s he colou o he semimemb anosus muscle by dec easing b(Zu i a-He e a e al. 2013). Howe e , he compos- i ion o goa milk is dependen on he eeding/man- agemen sys em o he goa s (Raynal-Lju o ac e al. 2008), and his in luences he colou o mea , espe- cially a. Some au ho s explained ha he mea om kids ea ed wi h na u al milk has lowe aand g ea e h ab because na u al goa milk o is poo in Fe (Sa~ nudo e al. 2012). Howe e , a highe le el o Fe was ound in he kids ed wi h milk eplace (Wi ek 2002). In con as wi h he Fe insu iciency, Ba~ n on e al. (2006) and A g€ uello e al. (2005) epo ed ha he mea om kids ea ed wi h MR had g ea e h ab and he same L as hose ea ed wi h NM, bu he esul s disag ee con- ce ning C ab:Zu i a-He e a e al. (2013) epo ed he same L,a , and bin bo h ea ing sys ems. To ou cu en knowledge, he e a e no s udies in he li e a u e examining he isual app aisal o pu - chase in en ions o kid mea h ough imes o display. Howe e , some au ho s ha e epo ed ha consume s signi ican ly ejec he mea o ligh (Panea e al. 2005; Joy e al. 2012) o hea y lambs a e 5 days (Kennedy e al. 2004). Mea discolou a ion is impo an because discolou ed mea canno be easily sold (Liu e al. 1995). Mea discolou a ion is p oduced du ing s o age as deoxymyoglobin is con e ed o me myoglobin. A s onge ela ionship be ween isual assessmen and h ab ,C ab and he a o b a io has been epo ed, a he han wi h he s andalone ich oma ic coo di- na es (Lee e al. 2005; Mo issey e al. 2008; Ripoll e al. 2012). The e o e, inc eases in h ab and dec eases in C ab ha e been used as indica o s o ed mea dis- colou a ion (MacDougall 1982; Albe  ıe al. 2005; Lee e al. 2005; Ripoll e al. 2011,2012; De Palo e al. 2015; Holman e al. 2017). The b owning o bee has been ela ed o he dec ease o ch oma (Rene e and Mazuel 1985). This inding is in ag eemen wi h he esul s o ou s udy, as he discolou a ion o he kid mea and he ejec ion om consume s we e ela ed o a dec ease o C ab a he han h ab due o he pale- ness o his ype o mea . Howe e , Ozcan e al. (2014) s udied he mea colou o Gokceada suckling kids and concluded ha while aand bseemed o no change om 1 o 5 days, Ldec eased sligh ly. Mo ales-De la Nuez e al. (2011) did no epo changes in Land ao he mea om Majo e a kids s o ed o 7 days; howe e , band hab inc eased while C ab dec eased. The changes in h ab and C ab obse ed wi h s o age ime can be a esul o myoglo- bin oxida ion o me myoglobin and he loss o hem- inic pigmen s due o he eeze/ haw p ocess. 1290 G. RIPOLL ET AL. Conclusions The jus no iceable di e ence in he consume colou de ec ion was simila when he consume assessed pic u es o mea ins ead o ac ual mea samples. Consequen ly, web-based su eys p o ided simila in o ma ion compa ed wi h su eys using ac ual p od- uc ins ead o pic u es. Mea colou appea s as a ecu ing cue o assess consume p e e ence, and his cue is used consis en ly ac oss he sociodemog aphic cha ac e is ics o he consume . Howe e , a mino i y o consume s choose o he kinds o mea because hey use o he cues, such as a colou and chop shape/size. In gene al, consume s p e e ed he mea o ligh suckling kids ea ed on milk eplace s because his mea has an inc eased ligh ness, hue angle and low ch oma. Howe e , when he mea o bo h ea ing sys- ems has ligh ness le els abo e 40.77 and small di e - ences in colou , he consume p e e ence o a ea ing sys em is dependen on he b eed. Finally, he ela- ionship be ween ins umen al colou o mea and consume isual app aisal emains unclea , especially in suckling ligh goa kids because he li e a u e ocussed on his opic is sca ce. Disclosu e s a emen The au ho s decla e ha hey ha e no con lic o in e es . Funding This s udy was suppo ed by he Depa men o Science and Technology, Minis y o Science and Technology (RTA2012- 0023-C03). B. 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