A global visual method for measuring the deterioration of strawberries in MAP

(1)

HAL Id: hal-02619959

https://hal.inrae.fr/hal-02619959

Submitted on 25 May 2020

HAL is a multi-disciplinary open access

archive for the deposit and dissemination of

sci-entific research documents, whether they are

pub-lished or not. The documents may come from

teaching and research institutions in France or

abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est

destinée au dépôt et à la diffusion de documents

scientifiques de niveau recherche, publiés ou non,

émanant des établissements d’enseignement et de

recherche français ou étrangers, des laboratoires

publics ou privés.

Distributed under a Creative Commons Attribution| 4.0 International License

A global visual method for measuring the deterioration

of strawberries in MAP

Celine Matar, Sébastien Gaucel, Nathalie Gontard, Stéphane Guilbert, Valérie

Guillard

To cite this version:

Celine Matar, Sébastien Gaucel, Nathalie Gontard, Stéphane Guilbert, Valérie Guillard. A global

visual method for measuring the deterioration of strawberries in MAP. MethodsX, Elsevier, 2018, 5,

pp.944-949. �10.1016/j.mex.2018.07.012�. �hal-02619959�

(2)

Method

Article

A

global

visual

method

for

measuring

the

deterioration

of

strawberries

in

MAP

Céline

Matar,

Sébastien

Gaucel,

Nathalie

Gontard,

Stéphane

Guilbert,

Valérie

Guillard

*

JointResearchUnit,AgropolymersEngineering&EmergingTechnology,UM–INRA–Supagro&CIRAD,2 PlacePierreViala,Bat31,34060MontpellierCedex01,France

ABSTRACT

Evaluatingthequalitychangesofpackedstrawberriesduringstoragerequiresmultiple,timeconsumingand costlymeasurementssuchassensorial,chemicalanddecayidentification.Inordertoefficientlyassessthequality ofstrawberriesinModifiedAtmospherePackaging(MAP)whilereducingthenumberofanalysisdone,we proposetogatherthemainvisualqualitychangesunderoneunique,overallmeasurement.Forthisend,aprotocol associatedtoadeteriorationgridwasbuilttoevaluatesurfacedeteriorationasafunctionoftimeconsidering colorchange,texturesofteningandmicroorganismdevelopment.Thedevelopedmethodhaspermittedtobuild thedeteriorationkineticofstrawberriespackedindifferentconditions(MAPornoMAP).Itallowstomimicthe qualityanalysismadebytheconsumer,ataglance,duringpurchase.Tothebestofourknowledge,thepresented methodis a breakthroughunlike most commonusualmethods mainlyrelyingon thenumberof spoiled strawberries.

Global measurement of the deterioration encompassing microorganism development, color changeand texturesoftening.

An annotation gridbuilt tobe used asreference for theattribution of the percentageof strawberries’ deterioration.

Measurementsofapercentageofsurfacedeteriorationwasfoundmoreaccuratethancountingthenumberof rottenstrawberries.

ARTICLE INFO

Methodname:Globalvisualdeteriorationassessmentofstrawberries

Keywords:Assessingdeterioration,Deteriorationgrid,Texturesoftening,Colorchange,Microorganismdevelopment

Articlehistory:Received13April2018;Accepted18July2018;Availableonline20July2018

*Correspondingauthor.

E-mailaddress:valerie.guillard@umontpellier.fr(V.Guillard).

https://doi.org/10.1016/j.mex.2018.07.012

ContentslistsavailableatScienceDirect

MethodsX

(3)

SpeciﬁcationsTable

Subjectarea AgriculturalandBiologicalSciences Morespeciﬁcsubjectarea AssessingproductdeteriorationinMAP

Methodname Globalvisualdeteriorationassessmentofstrawberries

Methodologybackground

Assessing the quality of strawberries as a function of time is an important step for the characterizationofproducts’shelflife.Sofar,manyqualityparametersaremeasuredinparallelto assesstheoverallqualityofstrawberriessuchastotalsolublesolids(TSS),ﬁrmness,color,decayonthe fruit, etc. However, these multiple measurements are time consuming, require sophisticated equipmentandahighamountofstrawberries.Inthispaper,wepresentglobalvisualevaluationofthe strawberries’qualityexpressedasthepercentageofdeterioratedsurfacearea,namelypercentageof deterioration. This visual percentage of deterioration encompass color change and/or texture softeningand/ormicroorganismdevelopment,similarlytotheanalysismadebytheconsumerat purchase.Intightpackedsystem,asinModiﬁedAtmospherePackaging,onlyvisualassessmentcould bedone.Thismethodologyaimsatmimickingthisactofpurchase.

Methoddetails Materials

-Strawberriesofthevariety“Charlotte”,grownoff-ground,(Mauguio,SouthofFrance) -Filmpackagingmadeoflowdensitypolyethylene(LDPE)(BBAemballages,Lunel–France) -Polypropylene (PP) trays (Attitud’Pack, Chatuzange Le Goubet-France) with dimensions of

0.140.0950.025m

-Memmertincubatorsforcontrollingthetemperature(Memmert,Schwabach–Germany) -Digitalcameraforpicturesacquisition(CanoncameraEOS450D–Japan)

Method

Deteriorationgrid

AgridformeasuringthepercentageoffruitsurfacedeteriorationwasbuiltbasedonCtiﬂstudies [1,2].Thedeteriorationisexpressedthroughapercentageofvisualsurfacedeteriorationofthefruit. Duringtime,thispercentageofsurfacedeteriorationwillevolvewiththevisualaspectofthefruit duetothesofteningofthetexture,colourchangeanddevelopmentofmicroorganismonthesurface. Onlyvisualaspectswereincludedwhilebuildingthegridasitistheonlywayforaconsumertocheck thequalityofthefruitspackedinMAPforpurchasedecision.

Thepercentageofthedeteriorationisidentiﬁedonthepicturesusing3circlesofdecreasingsizes asindicatedinTable1.TheradiusRofthebigcirclewassetsothattheareaof10bigcirclesrepresents thewholesurfaceofthestrawberries.Eachbigcirclethencorrespondsto10%ofdeterioratedsurface. Inordertohaveamoreaccurateestimationofthedeterioration,mediumandsmallcircleswerealso consideredwithradiusR/2andR/10andassociatedpercentagesofdeteriorationequalto2.5%and 0.1%respectively.

Toestimateapercentageofdeterioration,thelargedamagedsurfacesareﬁrstidentiﬁedusingbig circlesfollowedbylowerdamagedsurfacesusingmediumandsmallones.Notethatallcirclesshould bepairwisedisjointi.e.withoutintersection.

ThetotalpercentageofdeteriorationDtot(%)isexpressedthroughthefollowingequation:

(4)

withnBCthenumberofbigcircles,nMCthenumberofmediumcircles,nscthenumberofsmallcircles,

DBC,DMCandDscthepercentageofdeteriorationassociatedrespectivelytothebig,themediumand

thesmallcircles.ExamplesofannotationaregiveninFig.1fordifferentlevelsofdeterioration. Experimentaldesign

1 Strawberrieswereharvestedinthemorningofexperiments,cooledto5Cattheproducerfacilities, thenpicked upto thelaboratory around5hafterharvestwhere they were storedat desired temperaturesfor3h.

2 Harvestedstrawberriesweresortedaccordingtomaturity:overripenedi.e.fruitswithsofttexture, damagedorrottenwereeliminatedandunderripenedfruitsi.e.fruitswithgreen,notfullymature, spotswerediscarded.Sortingwasalsodoneaccordingtoshape:oversizedfruitsorverysmallones comparedtothebatchfruitsizeswereeliminated.

3 Intotal42traysof100gofstrawberrieswereprepared,6traysofstrawberrieswerepackedin macroperforatedLDPEandwereusedasthecontrolsituationrepresentingnoMAPconditionand 36wereputinMAPconditionsatthesametimet=0usinganon-perforatedLDPEﬁlmpackagingof 0.030.150.11mdimensionsand50.5₁₀6_m_thickness₍_Table₂_).

4 Aﬁrstmeasurementofthedeteriorationusingthegridwasdoneforthe36traysatt=0rightbefore packingtheproductinMAPconditions.

5 After t=0, every measurement of the deterioration in MAP is a destructive one. Indeed, the estimationofthepercentageofsurfacedeteriorationwasdoneafterremovingtheﬁlmpackaging, tobeabletoseeclearlythesurfaceofthefruitandthusafterbreakingtheMAPcondition.In consequence,eachoneofthe36traysinMAPconditionwereforsingle-use.However,fornoMAP condition,thesame6trayswereassessedforthewholedurationoftheexperimentsincethegases surroundingtheproductisalwaysequaltotheatmospherecompositionandwillnotaffectthe deteriorationoftheproduct(Table2).

6 Measurementsofthedeteriorationisdonetwiceaday,inthemorningandintheafternoonduring6 days,forMAPandnoMAPconditions.Foreachmeasurement,threereplicates,correspondingto threetrays,wereevaluated(Table2).

Notethat,apictureoftheopenedtraysistakenrightafterbreakingtheMAPconditionandwill laterbeexaminedandcomparedtothepercentageofdeteriorationidentiﬁedinthedeteriorationgrid (Fig.1).

7 Inparallel,asurveywasconductedtoidentifythetimeatwhichtheconsumerwillstoppurchasing the product. For this end, a panel of 30 untrained consumers annotated the trays used for deteriorationassessment,twiceadayinthemorningandintheafternoonfor6days.Thequestion askedtoeachconsumerofthispanelwas‘Justbylookingatthestrawberriesinthetray,areyou willingtobuytheproductornot?’the2possibleanswersare‘Yes’or‘No’.Whenmorethan50%of theconsumeranswered‘No’,theproductisconsiderednotmarketableanymore.

Table1

Circlessizesusedtoestimatethepercentageofdeterioration.

Sizeofthecircle %ofsurfacedeterioration

Big DBC=10%

Medium DMC=2.5%

(5)

Fig.1.Examplesofdeteriorationannotationusingsmallcirclescorrespondto0.1%ofdeterioration,mediumcirclesto2.5%of deteriorationandbigcirclesto10%ofdeterioration.

(6)

Methodvalidation

Inordertovalidatethevisualevaluationofthestrawberries’deteriorationinMAP,wecomparedit tothecommonvisualdecaymethodusedintheliterature.Theaforementionedmethodisbasedona visualmeasurementofthe%ofdecayorspoilagei.e.bycountingthenumberofstrawberriesshowing visiblemoldlesionsonthesurfaceexpressedasapercentageofthetotalnumberofstrawberriesinthe tray[3–5].Decayisthusexpressedinpercentageasfollow:

S¼ðninfec100Þ=ntot ð2Þ

whereSisthedecayin%,ninfecisthenumberofmoldedstrawberriesinthepackage,ntotisthetotal

numberofstrawberriesinthepackage.

Theevaluationofdecay(basedoncountingspoiledstrawberries[3–5])anddeterioration(basedon surface(methoddevelopedinthisarticle))wereconductedsimultaneously,onthesamesamples usingtheexperimentalplanexplainedinExperimentaldesignsection,forstrawberriespackedinMAP andnoMAPconditionsat20C.

Experimentalvaluesofdecay(Fig.2(a))anddeterioration(Fig.2(b))inMAP()ornoMAP(*) conditions as a function of time showed a sigmoidal behavior from 0% to 100% of decay or deterioration.

However,inFig.2(a)theexperimentalpointsinMAP(*)andnoMAP()fordecayleadtoquasi superpositionofthetwosigmoidalcurves,depictingthesamebehaviorinMAPandnoMAPcondition. Therefore,differentiationbetweenMAPandnoMAPisdifficulttoassess.Thus,annotationbasedona percentageof decay was notsufficientonits own in theidentificationof thequality difference betweenMAPand noMAPresults. In fact,decay was identified throughthenumber of molded strawberriesinbothMAPandnoMAPconditionsbutnodiscriminationwasmadeonthelevelof fruit’sdecay.

Whereas,inFig.2(b),thepercentageofdeteriorationinMAPandnoMAPareseparatedintwo independent sigmoidal curves. MAP condition result in a slight inhibition of the deterioration comparedtonoMAPcondition.At5.25days, 100%ofthestrawberriespackedinnoMAPareaffectedas comparedto82%ofstrawberriesinMAPcondition.Unlikedecaymethod,thedeteriorationgridwas abletodifferentiatebetweenMAPandnoMAPconditionbecausethedeteriorationmethodtakesinto accountthesurfaceofthefruitaffectedbyatexturesofteningand/ormicroorganismdevelopment and/orcolorchangeatthesametime.

ResultsofthesurveyshowedthattraysinnoMAPconditionswerenotmarketablefromday2 (morning)wheremorethan50%oftheconsumersanswered‘No’totheaskedquestion.However, traysinMAPconditionwerejudgedacceptablebytheconsumersuntilday3(morning).Therefore, consumersurveyconﬁrmsthatthekineticofdegradationofstrawberriesisslowerinMAPcondition thaninnoMAP.Thisdifferenceofbehaviorofstrawberriesqualityintwostorageconditions,hereMAP andnoMAP,iswelldescribedbythedeteriorationfactorwhiledecayfactorleadstoacontradictory conclusion.

Table2

Experimentalplanindicatingthelabelofthetrayanalyzedatthecorrespondingdays,formeasurementdoneinMAPandno MAPconditionsinthemorningandintheafternoon.

Storagecondition Number ofthemeasurement Control (noMAP) MAP

Day1 Day2 Day3 Day4 Day5 Day6 1st

(Morning)

Tray1 Tray7 Tray13 Tray19 Tray25 Tray31 Tray37 Tray2 Tray8 Tray14 Tray20 Tray26 Tray32 Tray38 Tray3 Tray9 Tray15 Tray21 Tray27 Tray33 Tray39 2nd

(Afternoon)

Tray4 Tray10 Tray16 Tray22 Tray28 Tray34 Tray40 Tray5 Tray11 Tray17 Tray23 Tray29 Tray35 Tray41 Tray6 Tray12 Tray18 Tray24 Tray30 Tray36 Tray42

(7)

Acknowledgements

Thisworkwas conductedin thecontextof thePack4Freshproject fundedbytheINRA-CIRAD MetaprogramGloFoodSandoftheFP7-ERA-NET618107EcoBerries.

References

[1]P.Vaysse,P.Reynier,C.Granado,M.Castaing,EvolutiondelaqualitédelafraiseCharlotte,INFOSCTIFLN:271,(2011)May. [2]P.Vaysse,P.Reynier,C.Granado,F.LeBarber,Qualitédelafraise:Suividelastationjusqu’aupointdevente,INFOSCTIFL

N:312,(2015) June.

[3]G.S.Riad,J.K.Brecht,Validationofthetwo-levelMAPsystemincommercialstrawberrydistributionandsimulatedretail handling,ActaHortic.1071(2015)613–618.

[4]M.S.Aday,C.Caner,Theshelflifeextensionoffreshstrawberriesusinganoxygenabsorberinthebiobasedpackage,LWT– FoodSci.Technol.52(2)(2013)102–109.

[5]M.L.A.T.M.Hertog,H.A.M.Boerrigter,G.J.P.M.VanDenBoogaard,L.M.M.Tijskens,A.C.R.VanSchaik,Predictingkeeping qualityofstrawberries(cv.‘Elsanta’)packedundermodiﬁedatmospheres:anintegratedmodelapproach,PostharvestBiol. Technol.15(1)(1999)1–12.

Fig.2.Visualassessmentofapercentageofdecay(a)usingmethodfromtheliteratureandapercentageofdeterioration(b) usingmethodologypresentedinthecurrentmanuscript,asafunctionoftimeindays,forstrawberriespackedinMAP()andno MAPcondition(*)at20C.