fruit volatile fingerprints characterized among four

Research ArticleFruit Volatile Fingerprints Characterized among FourCommercial Cultivars of Thai Durian (Durio zibethinus)

Wattana Aschariyaphotha1 Chalermchai Wongs-Aree23 Kitti Bodhipadma1

and Sompoch Noichinda 1

1Division of Agro-Industrial Technology Faculty of Applied Science King Mongkutrsquos University of Technology North BangkokBangsue Bangkok 10800 ampailand2Division of Postharvest Technology School of Bioresources and Technology King Mongkutrsquos University of Technology amponburiBangkhuntien Bangkok 10150 ampailand3Postharvest Technology Innovation Center Ministry of Higher Education Science Research and InnovationBangkok 10400 ampailand

Correspondence should be addressed to Sompoch Noichinda sompochnscikmutnbacth

Received 21 May 2021 Revised 18 August 2021 Accepted 24 August 2021 Published 6 September 2021

Academic Editor Dengyong Liu

Copyright copy 2021 Wattana Aschariyaphotha et al )is is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in anymedium provided the original work isproperly cited

Ripe durian fruits produce unique volatiles of pungent odor comprising esters alcohols ketones and sulfur-containingcompounds Recently ldquoChanthaburi 1rdquo hybrid bred from 2 famous commercial cultivars of ldquoChaneerdquo and ldquoMonthongrdquo claimed tobe less fragrant during ripening but there was no report )e present study compared the volatile profiles from 3)ai commercialcultivars of ldquoKanyaordquo ldquoChaneerdquo and ldquoMonthongrdquo compared to ldquoChanthaburi 1rdquo and the relationships of the cultivars wereorganized using the volatile fingerprints Out of 41 volatile compounds detected by SPMEGC-MS in ripe durian flesh 33compounds were esters but only 14 esters were found in ldquoChanthaburi 1rdquo Ripe flesh of most durian cultivars contains ethyl-2-methyl butanoate and ethyl hexanoate as the active volatiles ldquoChanthaburi 1rdquo contained fewer components with low odor activityvalue (OAV) of the volatiles ldquoChaneerdquo ripe flesh exhibited the strongest durian smell among the four varieties whereasldquoMonthongrdquo exhibited a strong apple-like fruity odor and ldquoKanyaordquo was more green fruity Diethyl disulfide and 3 5 dimethyl-12 4-trithiolane contributing pungent smells of garlic or onion were found only in ldquoChanthaburi 1rdquo and ldquoMonthongrdquo In terms ofdetected volatiles ldquoKanyaordquo and ldquoChaneerdquo were highly close when ldquoMonthongrdquo was apart PCA analysis revealed thatldquoChanthaburi 1rdquo contained ester compounds ancestrally related to the parents ldquoChaneerdquo in the component I and ldquoMonthongrdquo inthe component II )ese data could be beneficial for managing the status of )ai durians in global markets

1 Introduction

In )ailand durian plant collection was firstly reported for227 varieties However there currently are several cultivarsincluding ldquoChaneerdquo ldquoKanyaordquo and ldquoMonthongrdquo in thebusiness both in domestic and export markets [1] ldquoChaneerdquocomprises a moderate fruit size of 25ndash3 kg )e fruit shapeshows swelling in the middle and is blunt at the blossom endwith a big and short peduncle When ripening fruit is easilypeeled and the yellow flesh is a very soft fine texture butwith the thin flesh and an ample seed it is famous for

domestic markets ldquoKanyaordquo bears a moderate fruit size of3 kg showing a round fruit shape and a big and long pe-duncle)e ripe flesh has smoothly fine texture and is yellowand sweet ldquoMonthongrdquo the most famous variety exhibitsbig fruit of 3ndash4 kg Fruit is long having shoulders at the stemend and protruding at the blossom end )e ripe flesh is dryand thick with a lean seed [2ndash4] Ripe fruits of most typicaldurian varieties release a pungent solid smell resulting introuble for foreigners and under public assemblage Re-cently ldquoChanthaburi 1rdquo (ICNtimesM 5-1-1) bred fromldquoChaneerdquo and ldquoMonthongrdquo was officially approved and

HindawiJournal of Food QualityVolume 2021 Article ID 1383927 12 pageshttpsdoiorg10115520211383927

registered as a new variety by the Department of Agriculture)ailand on 9 October 2006 )e fruit is an early-seasonproduction with a harvesting time of 99ndash105 days afterpollination )e average fruit weight is 25ndash3 kg comprisingbright yellow flesh and a sweet delicate texture )e ripefruit of ldquoChanthaburi 1rdquo is claimed to have an extra-lowsmell [5] Nevertheless there is no analytical report yet forthe volatile characterization of the fruit

Aroma is a unique character of ripe durian fruit pre-ferred by some but annoying for many people Furthermoreit is seriously prohibited to take durian fruiteat duringpublic transportation or in assembly places such as hotels orconvention halls )is matter would be a significant obstaclefor the marketing of durians Ethyl esters (fruity esters andgeneral fruit) are the prominent esters in ripe ldquoMonthongrdquoflesh [6 7] Nevertheless this sweet smell is interrupted bysulfurous smells of sulfur-containing compounds Ethane-thiol diethyltrisulfide diethyldisulfide dimethyl sulfide 23-butanedithiol ethyl 1-methylethyl disulfide 3-methyl-thi-ozolidine methyl ethyl disulfide and 1-propanethiol aresuch sulfur-containing compounds found in ripe durianflesh [6ndash8] )ere is no report of the relationship of duriancultivars by the aroma volatile so far )ere have been manyreports of volatile components of ripe durians in ldquoMonth-ongrdquo [6ndash9] few in ldquoChaneerdquo [6] but there is no report inldquoKanyaordquo and ldquoChanthaburi 1rdquo Furthermore from thefruitrsquos visual appearance ldquoChanthaburi 1rdquo fruit shape is verysimilar to the shape of ldquoKanyaordquo leading to confusion byvisual appearance )us fruit volatile profiles between thecultivars compared as volatile fingerprints were brought inthe interest Here the present study was to identify odorcharacteristics of 4 commercial varieties Volatiles ofldquoKanyaordquo and ldquoChanthaburi 1rdquo were firstly reported and thevolatile relationship of these four varieties was theninvestigated

2 Materials and Methods

21 Plant Materials and Sample Preparation Mature durianfruits at 90 maturation from 4 cultivars ldquoChaneerdquo(19ndash22 kg) at 15 weeks after anthesis (WAA) ldquoKanyaordquo at18 WAA (17ndash20 kg) ldquoMonthongrdquo at 19 WAA (22ndash28 kg)and lsquoChanthaburi 1 at 14 WAA (14ndash18 kg) were harvestedfrom commercial orchards in Chanthaburi Province eastern)ailand between April and June 2018 Fruits were incu-bated at room temperature (25degC 70ndash75 RH) for naturalripening Fruit showing initial dehiscence at the blossom end(Supplementary Figure 1) referred to as full ripening was

peeled and the ripe flesh was used for volatile analysis )evisual appearance of the whole fruit and half-dehusked ofripe fruits of the four cultivars is shown in Figure 1

22Chemicals )e internal standard of volatile analysis wasthiophene (ge99 purity) (Sigma Chemical Co USA)

23 Volatile Trapping )e ripe aril of each cultivar wasfinely blended by using a high-speed homogenizer for 2minHomogenate at 5 g was put into a 20mL glass vial sealed witha screw cap having a silicone laminated with polytetra-fluoroethylene septum )e volatiles in the samplersquos head-space were trapped by SPME and analyzed by GC-MSmodified from [10] )e volatiles in the headspace of thesample in a vial were trapped by solid-phase microextraction(SPME) coated with 65 microm of PolydimethylsiloxaneDivinylbenzene (PDMSDVB) (1 cm length) while heated at50degC for 30min

24Analysis ofVolatiles inRipeDurianFlesh )e SPME wasinjected into a gas chromatogram (GC 6850 series AgilentTechnologies USA) equipped with an HP-5MS column (5phenyl-methylsiloane capillary column 30mtimes 0248mmID with 025 microm thickness) and an Agilent 5913 mass se-lective detector with the following condition 200degC of theinjection port (splitless mode) 50degC of the column oven for1min and increased at a rate of 5degCmiddotminminus1 to 120degC and thento 250degC at a 10degCmiddotminminus1 rate and 250degC of the detectorHelium was the carrier gas set to 2mLmiddotminminus1 at 159 psi

)iophene at 10 microLmiddotLminus1 was used as the internal standard)e spectra of the volatile profile were analyzed in theelectron impact (EI) mode with an electron energy of 70 eVa mass range of mz 45ndash450 a scan rate of 025 sscan and anelectron multiplier (EM) voltage of 3000V Spectra of thevolatile profile were compared to a mass spectral databasefrom the NIST V14 Llibrary values (Palisade Corp New-field NY USA) )ere were 3 replications for each analysis

25 Calculation of Volatile Compounds Each volatilecompound of the clear peak from the GC-MS chromatogramwas analyzed for the content compared to thiophene as theinternal standard Volatile content in ng thiophene per gfresh weight was estimated by the peak area of volatilesdivided by the peak area of internal standard (thiophene)and 10 microL internal standard solution (05 gmiddotLminus1 thiophene) to5 g durian homogenate prior to taking SPME [11]

Volatile content ng thiophene gminus 1FW1113872 1113873 peak area of volatilepeak area of internal standard

g durian aril homogenate (1)

2 Journal of Food Quality

Odor activity value (OAV) was obtained by dividingthe concentration of the compound in a matrix by itsodor threshold in that matrix )us it is generally as-sumed that the odorants with higher OAVs contributemore strongly to the overall aroma OAV of each volatilecompound was calculated using the following formula[12]

OAV concentration of the volatile content

odor theshold value (2)

26 Statistical Analysis )e volatile relationship of duriancultivars was analyzed using principal component analysis(PCA) by Minitabreg program ver17 (Minitab Ltd UK) )econtents and types of ester volatiles between cultivars wereanalyzed using multivariations of principal components byMinitabreg3 Results and Discussion

31 Volatile Profiles in Ripe Durians From our experiencehere was the first report of volatiles contributed in ripe fleshof ldquoKanyaordquo and a new hybrid ldquoChanthaburi 1rdquo bred fromldquoChaneerdquo as the female gamete and ldquoMonthongrdquo as the malegamete)ere were 41 major volatile compounds detected in

4 cultivars comprising 33 esters 2 sulfur-containing com-pounds 3 organic acids 2 phenolics and 1 aldehyde (Ta-ble 1) ldquoChanthaburi 1rdquo contained major 16 volatiles of 14esters and 2 sulfur compounds ldquoChaneerdquo contained mainly21 compounds of 17 esters 3 organic acids and 1 aldehydeldquoMonthongrdquo comprised 23 compounds of 19 esters and 2sulfur compounds and 2 organic acids ldquoKanyaordquo found 29volatiles including 23 esters 1 sulfur compound 1 phenolicacid 3 organic acids and 1 aldehyde

Fruit odor is a mixture of many volatile substances butthe main volatile component is the criteria used to determinethe odor matter Nowadays the odor threshold value of thatsubstance is academically used and can be described whereasOAV is calculated from the detected substance )e OAVvalue greater than 1 is the more important [13] From OAVethyl-2-methylbutanoate (2773) ethyl nonanoate (2257)ethyl octanoate (2049) and ethyl hexanoate (1150) were theactive volatiles of ldquoChanthaburi 1rdquo ripe flesh whereas diethyldisulfide was only 40 (Table 2) In ldquoChaneerdquo flesh 5 ethylesters ethyl octanoate (36136) ethyl dodecanoate (11262)ethyl-2-methylbutanoate (9232) ethyl hexanoate (3185) andethyl propanoate (1170) were among the major active vol-atiles (Table 2) In ldquoMonthongrdquo ripe flesh ethyl octanoate(41737) ethyl hexanoate (18088) methyl octanoate (8433)and ethyl-2-methylbutanoate (2783) were high in the OAV(Table 2) while ethyl octanoate (42419) ethyl dodecanoate

10 cm

(a)

10 cm

(b)

10 cm

(c)

10 cm

(d)

Figure 1 Appearances of the whole fruit (left) and flesh (right) of (a) ldquoChanthaburi 1rdquo (b) ldquoChaneerdquo (c) ldquoMonthongrdquo and (d) ldquoKanyaordquo

Journal of Food Quality 3

(41389) methyl octanoate (10774) ethyl hexanoate (7306)ethyl-2-methylbutanoate (6629) and ethyl propanoate(1964) were the active volatiles in ldquoKanyaordquo (Table 2) )erewere some volatile compounds detected only in each cultivarEthyl acetate (100) and ethyl nonanoate (2257) were only inldquoChanthaburi 1rdquo propyl-2-methylbutanoate (na) methyl

heptanoate (67) and ethyl-2-methyl pentanoate (na) wereonly in ldquoChaneerdquo methyl-2-methylbutanoate (na) methyl-2-hexenoate (na) ethyl-4-octenoate (na) and 2-methylbutylhexanoate (na) were only in ldquoMonthongrdquo and propylpropanoate (85) methyl hexanoate (lt1) and methyldodecanoate (6833) were only in ldquoKanyaordquo

Table 1 Volatile compounds released from ripe flesh of 4 )ai durian fruits corresponded to the GC-MS chromatogram profiles

Compound RTRelative content (ng thiopheneg FW)

ldquoChanthaburi 1rdquo ldquoChaneerdquo ldquoMonthongrdquo ldquoKanyaordquoEster

1 Methyl-2-methylbutanoate 04766 nd nd 071 nd2 Ethyl acetate 21226 881 nd nd nd3 Ethyl propanoate 29628 nd 339 nd 5704 Ethyl-2-methylpropanoate 36143 185 532 285 9715 Ethyl butanoate 43402 nd 108 207 2696 Propyl propanoate 45230 nd nd nd 2387 Ethyl-2-methylbutanoate 53346 8320 27697 8349 198868 Methyl-2-methyl-2-butenoate 57576 467 111 108 1079 Methyl hexanoate 57747 nd nd nd 73310 Ethyl-3-methyl-2-butenoate 65005 474 498 151 nd11 Propyl-2-methylbutanoate 65348 nd 4552 nd nd12 Ethyl-2-methyl-2-butenoate 75865 5087 830 nd 66113 Pentyl-2-methylbutanoate 77465 2658 nd nd 633114 Methyl-2-hexenoate 83524 nd nd 059 nd15 Ethyl hexanoate 92496 1035 2867 16279 657616 Methyl heptanoate 99754 nd 193 nd nd17 Ethyl-2-methylpentanoate 10227 nd 582 nd nd18 Propyl-2-methyl-(E)-2-butenoate 10296 1693 nd nd 31719 Ethyl-2-hexenoate 10547 105 nd 762 13220 Propyl hexanoate 11999 nd nd 1892 102921 Ethyl heptanoate 12096 nd 1550 820 89322 Methyl octanoate 12850 nd nd 2108 269423 Ethyl-4-octenoate 14548 nd nd 323 nd24 Ethyl octanoate 14931 820 14454 16695 1696825 Ethyl-2-methyl octanoate 15754 nd 316 nd 08026 Ethyl-(E)-2-octenoate 16302 085 nd 1135 31027 2-Methylbutyl hexanoate 16463 nd nd 116 nd28 Propyl octanoate 17543 nd 581 1061 162029 Methyl decanoate 18400 nd nd 308 59930 Ethyl decanoate 20252 293 437 2415 272531 Methyl dodecanoate 23424 nd nd nd 17832 Ethyl dodecanoate 25064 nd 225 nd 82833 Ethyl nonanoate 25076 226 nd nd nd

Total 22329 55874 53144 64713Sulfur compound

1 Diethyl disulfide 70606 469 nd 248 nd2 35-Dimethyl-124-trithiolane 13074 510 nd 114 166

Total 979 0 361 166Acid

1 Propanoic acid 27227 nd 102 nd 2912 Hexanoic acid 88038 nd 072 445 9923 Octanoic acid 14302 nd 347 286 1257

Total 0 521 731 2540Phenolic

1 24-Di-tert-butylphenol 23138 nd nd 172 nd25-bis (11-Dimethylethyl phenol) 23144 nd nd nd 180

Total 0 0 172 180Aldehyde

1 trans-2-Methyl-2-butenal 34086 nd 436 nd 961Total 34086 0 436 0 961


Table 2 Odor characteristics of ester sulfur acid phenolic and aldehyde containing compounds from ripe flesh of 4 )ai durian fruits

Compound Odor descriptionAromathreshold

values (ppb)

Odor activity values (OAV)ReferenceslowastldquoChanthaburi

1rdquo ldquoChaneerdquo ldquoMonthongrdquo ldquoKanyaordquo

Ester

1 Methyl-2-methylbutanoate

Sweet fruity apple-likeodor na mdash mdash na mdash mdash

2 Ethyl acetate Fruity sweet grape- andrum-like odor 088 10014 mdash mdash mdash D

3 Ethyl propanoate Green fruity apple-likeodor 0029 mdash 117048 mdash 19640 M

4 Ethyl-2-methylpropanoate Fruity 01 1850 53163 2847 9705 O

5 Ethyl butanoate Fruity pineapple 02 mdash 538 1035 1344 H

6 Propyl propanoate Sharp chemical pungentsweet fruity 028 mdash mdash mdash 848 M

7 Ethyl-2-methylbutanoate Fruity 03 277329 27697 27831 66288 N

8 Methyl-2-methyl-2-butenoate

Caramel note etherealrum 35 (in water) lt1 lt1 lt1 lt1 R

9 Methyl hexanoate Fruity pineapple ethereal 70 mdash mdash mdash lt1 O

10 Ethyl-3-methyl-2-butenoate na na na na na mdash mdash

11 Propyl-2-methylbutanoate Winey na mdash na mdash mdash mdash

12 Ethyl-2-methyl-2-butenoate Sweet fruity green notes na na na mdash na mdash

13 Pentyl-2-methylbutanoate na 12 222 mdash mdash 528 A

14 Methyl-2-hexenoate Fruity green bananahoney na mdash mdash na mdash mdash

15 Ethyl hexanoate Apple-like fruityaniseed-like sweet 009 115032 31854 180881 73063 H

16 Methyl heptanoateSweet fruity and greenwith a waxy apple-like

note029 mdash 667 mdash mdash B

17 Ethyl-2-methylpentanoate

Fruity green melon andwaxy with a fatty nuance na mdash na mdash mdash J

18 Propyl-2-methyl-(E)-2-butenoate na na na mdash mdash na mdash

19 Ethyl-2-hexenoate Fruity green pulpypineapple and apple 014 7462 mdash 5441 946 C

20 Propyl hexanoateSweet fruity juicypineapple green and

tropical70 mdash mdash lt1 lt1 E

21 Ethyl heptanoate Fruity pineapple cognacrum wine 024 mdash 6460 3416 3722 D

22 Methyl octanoateWaxy green sweetorange aldehydicvegetable herbal

0025 mdash mdash 84329 2694 I

23 Ethyl-4-octenoate na na mdash mdash na mdash mdash

24 Ethyl octanoate Pleasant fruity floralodor wine apricot note 004 20491 361361 417369 107742 K

25 Ethyl-2-methyloctanoate na na mdash na mdash na mdash

26 Ethyl-(E)-2-octenoate

Fruity green with a fattywaxy note na na mdash na na mdash

27 2-Methylbutylhexanoate Ethereal na mdash mdash na mdash mdash

28 Propyl octanoate na na mdash na na na mdash29 Methyl decanoate Oily winey fruity floral na mdash mdash na na mdash

30 Ethyl decanoate Fruity grape- cognac-and brandy-like odor 053 553 825 2415 5142 F


Ripe flesh of most durian cultivars contains ethyl-2-methylbutanoate (fruity note) and ethyl hexanoate (fruityapple green and tropical fruit odor) as the active volatilesshowing high OAV Both found in all four cultivars andmost commercial durians were blended with some high-OAV compounds to characterize the flavor of each durianvariety In general ripe durian flesh exhibits the fruity sweetfragrance of both compounds ldquoChanthaburi 1rdquo containedfewer components of volatiles as well as low OAV of thevolatiles )is indicates that the flesh of ldquoChanthaburi 1rdquoconducted very low intensity of odors during ripening Ethylheptanoate (fruity pineapple banana-like note) was foundin every cultivar except ldquoChanthaburi 1rdquo Ripe flesh ofldquoChaneerdquo exhibited the strongest durian aroma among 4varieties ldquoChaneerdquo exhibited aroma of ethyl octanoate(fruity floral odor wine apricot note) ethyl dodecanoate(waxy soapy nutty rummy) and ethyl propanoate (greenfruity apple-like) characterized as nutty rummy and greenapple-like ldquoMonthongrdquo exhibited strong apple-like fruityaldehydic waxy fragrance of ethyl octanoate (fruity floralodor wine apricot note) ethyl hexanoate (apple-like fruity)and methyl octanoate (waxy green sweet orange aldehydicvegetable) and ldquoKanyaordquo exhibited more complex waxynutty green apple-like fruity aroma of ethyl octanoate ethyldodecanoate (waxy soapy nutty rummy note) methyl

octanoate (waxy green sweet orange) and ethyl propanoate(green fruity apple-like)

Diethyl disulfide and 35-dimethyl-124-trithiolane foundin low levels in ripe durian pulp are the key compounds indurians Although sulfur-containing compounds exhibitedlow OAV compared to the esters they exhibit an annoyingpungent smell ldquoChanthaburi 1rdquo as well as ldquoMonthongrdquocontained sulfur-containing compounds of diethyl disulfideand 35-dimethyl-124-trithiolane which exhibit a garlic-likeonion-like pungent smell [32] In particular diethyl disulfidein ripe ldquoMonthongrdquo showing an OAV of 125 would releasethe pungent smell of ldquoMonthongrdquo durian as reported byLaohakunjit et al [8] and Niponsak et al [9] Previous studiesin Malaysia and Indonesia found that the indigenous varietiesexhibited a prominent smell of sulfur-containing compoundswhen fully ripe showing an unpleasant odor overall [32 33]

In 4 cultivars of )ai durian fruit ripe aril sharplyproduced a series of ethyl esters derived from ethyl alcoholand acyls CoA of straight carbons ranging from C4ndashC10(Table 1) Ethanol in the aril could be generated from an-aerobic respiration under a partial hypoxic condition in ariltissue Due to very high respiration of durian fruit duringripening fruit husk behaving like a gas barrier makes low gaspermeability to the aril Under partial hypoxia anaerobicrespiration was induced in the aril resulting in increased

Table 2 Continued


values (ppb)



31 Methyl dodecanoate Waxy soapy nuttycoconut mushroom 00026 mdash mdash mdash 68331 B

32 Ethyl dodecanoate Waxy soapy rummynutty floral 0002 mdash 112615 mdash 413890 B

33 Ethyl nonanoate

Slightly fatty oily fruitynutty reminiscent of

cognac with a rosy fruitynote

001 22568 mdash mdash mdash L

Sulphur compound1 Diethyl disulfide Onion garlic 2 397 mdash 125 mdash M

2 35-Dimethyl-124-trithiolane Sulphury onion meaty na na mdash na na G

Acid1 Propanoic acid Pungent acidic dairy 1 mdash 102 mdash 294 P2 Hexanoic acid Sour fatty sweaty cheesy 00047 mdash 15423 95657 213240 Q

3 Octanoic acid Fatty waxy rancid oilyvegetable cheesy 0011 mdash 31860 26270 115429 Q

Phenolic

1 24-Di-tert-butylphenol na na mdash mdash na mdash mdash

225-bis (11-Dimethylethyl

phenol)mdash mdash mdash na mdash

Aldehyde

1 trans-2-Methyl-2-butenal Strong green fruit na mdash na mdash na G

lowast)e capital letters represented the references of odor threshold value as follows A[14] Allison and Katz (1919) B[15] Backman (1917) C[16] Berger (1985) D

[17] Cometto-Muntildeiz et al (2005) E[18] Fan and Xu (2011) F[19] Ferreira et al (1998) G[20] Gemert (2011) H[21] Guth (1997) I[22] Karl et al (1994) J[23]Komthong (2006) K[24] Rychlik (1998) L[25] Schwarz (1995) M[26] Nagata (2003) N[27] Takeoka et al (1989) O[28] Takeoka et al (1990) P[29] van )rielet al (2006) Q[30] Wise et al (2007) and R[31] Yair (2012)


ethanol [34ndash37] Aliphatic and aromatic alcohols are typi-cally found in Malaysian durians whereas thiols are pro-duced in )ai durians and alcohols are not typicallyproduced in Indonesian and Filipino durians [37] On theother hand with a series of straight acyl CoA reacted withthe ethanol it is supposed that β-oxidation of fatty acidswould be involved in the process of ripe fruits [38] as durianpulps have high contents of fatty acids such as methylstearate (3593) methyl palmitate (3291) methyl pal-mitoleate (950) methyl octadecenoate (486) methyloleate (468) methyl myristate (252) and methyl li-noleate (220) [39] Furthermore amino acid metabolismplays a crucial role in ester production in durians For in-stance ethyl-2-methylbutanoate a primary volatile com-pound is derived from 2-methylbutanoyl-CoA throughisoleucine metabolism [40] )e origination of acyls CoA inthe ester production could be separated into two sourcesfrom the results When the acyl CoA of C4 could be derivedfrom amino acids acyl CoA above C6 could be from lipidoxidations Furthermore alcohol acyltransferase (AAT)which modifies alcohols and acyl CoA to esters could beessentially involved in the production of esters in mostdurians Although ATT has not yet been reported in durianit was reported to be essential for ester production duringripening in many fruits [41ndash43] However as a result offewer esters in ldquoChanthaburi 1rdquo the production of esters isapparently disturbed in the fruit probably by mutantfunctioning of the AAT or the substrate-enzymeincompatibility

32 ampe Relationship of Durian Cultivar Relied on AromaVolatiles All 4 varieties showed that ethyl esters were themajor components in the ripe flesh Ethyl acetate and ethylnonanoate were found in ldquoChanthaburi 1rdquo but not in theparent ldquoChaneerdquo and ldquoMonthongrdquo whereas on the otherhand ethyl butanoate and ethyl heptanoate found in theparent were not found in ldquoChanthaburi 1rdquo Methyl-2-meth-ylbutanoate was detected only in ripe ldquoMonthongrdquo flesh

Ester compounds as the major volatiles were taken tocalculate the relationship between cultivars )e differencesin essential substances between durian species may be due togenetics and the environment Genetic factors influence theformation of precursors enzymes and odor generation [44])e durian of ldquoChanthaburi 1rdquo a hybrid variety has overallodor characteristics related to the parent variety ldquoChaneerdquoand the father species is ldquoMonthongrdquo Nevertheless byconsidering the odor ldquoChanthaburi 1rdquo has a mild odor whilestill unripe similar to the odor of ldquoKanyaordquo Althoughidentifying the essential substances in ldquoChanthaburi 1rdquodurian exhibited a more minor odor type than the strongaroma varieties the essential substances (OAV) in theldquoChanthaburi 1rdquo exhibited characteristics related to bothldquoChaneerdquo and ldquoKanyaordquo)e relative content of the ester wasobtained according to the dendrogram (Figure 2) of eachessential substance )e volatile contents in ldquoChanthaburi 1rdquowere related to ldquoMonthongrdquo when considering the estercomposition )e ester compounds in ldquoChanthaburi 1rdquo werecorrelated well with the ldquoMonthongrdquo variety consistent with

the species characteristics that lsquoMonthongrsquo was the fatherHowever the relationship of ester compounds in ldquoChaneerdquowas close to that in ldquoKanyaordquo

Principal component analysis (PCA) using the estercompounds from Table 1 was operated to correlate andclassify the essential components of the four durian varietiesEster compounds were classified in the same componentwith an eigenvalue greater than 1 and the component wasequal to 2 (data not shown) with Minitabcopy 17 displayed inthe score plot and biplot (Figure 3) )e main componentand the secondary components were associated with theester compounds of the four durian varieties When lookingat themain components ldquoChanthaburi 1rdquo durian was relatedto ldquoChaneerdquo and from the secondary ldquoChanthaburi 1rdquo wason the other hand related to the ldquoMonthongrdquo variety whichcorresponds to the ester characteristics of the parents ButldquoKanyaordquo has characteristics that are clearly different fromthose of ldquoChanthaburi 1rdquo by both components In additionthe ester characteristics of ldquoChanthaburi 1rdquo as shown inFigure 3(c) were ethyl acetate ethyl nonanoate and methyl-2-methyl-2-butenoate which exhibit a rum-like grape andcognac as well as caramel note For ldquoChaneerdquo it can be seenfrom Figure 3(c) that the distinctive esters were propyl-2-methylbutanoate ethyl-2-methyl pentanoate and methylheptanoate showing winey apple pineapple green melonand waxy flavors cognac rum wine intensely fruity andorris-like In ldquoMonthongrdquo the ester characteristics weremethyl-2-methylbutanoate ethyl-2-hexenoate and methyl-2-hexenoate )e scent characteristics are sweet fruity ap-ple-like odor green pineapple apple green banana honeyOn the other side ldquoKanyaordquo exhibited a distinctive scent ofmethyl hexanoate propyl propanoate and methyl dodeca-noate showing fruity pineapple complex fruity odor appleand banana waxy soapy nutty and coconut mushroomWhen considering the OAV value of each durian species ifthe OAV is greater than 1 it can be expected to exhibit aunique aroma )e OAV value of ldquoChanthaburi 1rdquo wasclearly similar to that of ldquoChaneerdquo the mother variety andclose to that of ldquoKanyaordquo (Table 2 and Figure 4) )e OAVvalues showed that ldquoChanthaburi 1rdquo had the dominant es-ters ethyl acetate (100) and ethyl nonanoate (2257) whichexhibited fruity sweet grape and rum-like slightly fattyoily fruity scent characteristics of nutty reminiscent ofcognac with a rosy fruity note Nevertheless ldquoKanyaordquo hasoutstanding OAV values of ethyl octanoate (42419) andethyl dodecanoate (41389) at high which is likely to beanother distinctive scent characterized by long stemsshowing fruity fatty floral odor (wine apricot note) waxysweet musty pineapple dairy sweet waxy soapy rummyand nutty floral )e distinctive OAV value is of methylheptanoate (67) because it is found only in ldquoChaneerdquoshowing sweet fruity and green with a waxy apple-likenote )e higher levels of OAV were found in ldquoMonthongrdquoand ldquoKanyaordquo durians but less common in ldquoChanthaburi 1rdquowas ethyl octanoate (2049) which showed a pleasantlyfruity floral odor (wine apricot note) )e OAV values weredifferent from the ester relative content which was therelative content of the volatile compounds present in eachdurian species indicating that ldquoChanthaburi 1rdquo was


2

18

First Componentndash2 ndash1 0 1 2 3 4

Seco

nd C

ompo

nent

ndash4

ndash3

ndash2

ndash1

0

1

2

3

4

83310

Chanee

Kanyao

Score Plot of relationship between ester compounds

Monthong

Chanthaburi 1

21

2820

3022

17

11

251647 6233

932

9429

26511

(a)

Figure 3 Continued

4231

000

3333

6667

10000

Observations

Sim

ilarit

y

DendrogramDurian ester

Figure 2 Dendrogram of the relationship in the ester compound produced in 4 )ai durian cultivars (1 ldquoChanthaburi 1rdquo 2 ldquoChaneerdquo3 ldquoMonthongrdquo and 4 ldquoKanyaordquo)


Score Plot of ester compound component in ripe flesh of 4 ai durian fruits

First Component

ndash5 ndash4 ndash3 ndash2 0ndash1 1 2 3 4

Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthburi 1

Monthong

Chanee Kanyao

(b)

Biplot of ester compound component in ripe flesh of 4 durian fruits

First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthaburi 1

MonthongEthyl-2-hexenoate

2-Methylbutyl hexanoateEthyl -4-octenoate

Ethyl (E)-2-octenoate

Propyl hexanoateEthyl hexanoate

Methyl octanoate

Propyl octanoateEthyl heptanoate

Methyl hexanoateEthyl-2-methyl octanoateEthyl-2-methyl propanoateEthyldodecanoate

Ethyl-2-methylbutanoate Ethyl propanoate

Propyl propanoateMethyl dodecanoate

Pentyl-2-methylbutanoateEthyl octanoate

Ethyl butanoateMethyl decanoate

Ethyl decanoate

Methyl-2-methylbutanoateMethyl-2-hexenoate

Chanee

Ethyl nanonoate

Ethyl-3-methyl-2-butenoate

Ethyl-2-methyl-2-butenoatePropyl-2-methyl-(E)-2-butenoate

Methyl-2-methyl-2-butenoateEthyl acetate

Propyl-2-methylbutanoateMethyl heptanoate

Ethyl-2-methylpentanoate

Kanyao

(c)

Figure 3 Principal component analysis (PCA) relationship between 4)ai durian cultivars (a) Score plot of the relationship between 4)aidurian cultivars using the ester compounds (b) Score plot of the ester compound component in ripe flesh of 4 )ai durian cultivars (c)Biplot of the ester compound component relationship with 4 )ai durian cultivars


consistent with ldquoMonthongrdquo and ldquoChaneerdquo the father andmother respectively Nevertheless if the OAV value wasconsidered ldquoChanthaburi 1rdquo was close to ldquoKanyaordquo morethan ldquoMonthongrdquo (Figure 4) According to the observationfrom the odor characteristics the odor of ldquoChanthaburi 1rdquo ismild similar to that of ldquoKanyaordquo which the OAV value canexplain to some extent Based on information on thecomposition of these essential substances it could greatlybenefit the status of )ai durians in terms of the choice ofeating fresh fruit and the choices to use ripe durian pulp asan ingredient of food or dessert which requires the durianodor )e study could increase the opportunities of )aidurian transport channels to the world

4 Conclusions

)irty-three esters and three sulfur-containing com-pounds were the main volatiles found and affected theflavor character of the ripe pulp of four varieties of )aidurians ldquoChaneerdquo ldquoMonthongrdquo ldquoKanyaordquo and ldquoChan-thaburi 1rdquo Ethyl esters were the major esters as ethyl-2-methylbutanoate and ethyl hexanoate were the crucialessential substances found in all four varieties )e overallaroma character of the durian was a mixture combined offruity-like applepineapple with rum butter oily andwaxy odors Although ripe durians produced few sulfur-containing volatiles the compounds exhibit a sulfurouspungent smell Using the volatile ester profiles ldquoChan-thaburi 1rdquo correlated with ldquoChaneerdquo the mother breedand ldquoMonthongrdquo the father breed ldquoKanyaordquo was differentfrom ldquoChanthaburi 1rdquo However with high OAV valuesconcerned ldquoChanthaburi 1rdquo was obviously associated

with ldquoChaneerdquo but the odor character was more similar toldquoKanyaordquo than ldquoMonthongrdquo

Data Availability

)e data used to support the findings of this study are in-cluded within the supplementary information file

Conflicts of Interest

)ere are no conflicts of interest in this study

Acknowledgments

)e authors appreciate Assist Prof Kamontip Ekthamasutfrom the Department of Food Science and TechnologyFaculty of Science University of the )ai Chamber ofCommerce for her advice in the PCA interpretation )eauthors also acknowledge the United Graduate School ofAgricultural Science (UGSAS) Gifu University Japan forproviding them some apparatus facilities )is research wasfinancially supported by Graduate Development Scholarship2020 National Research Council of )ailand (NRCT)(Grant no 042563) )e authors appreciate the PostharvestTechnology Innovation Center Ministry of Higher Educa-tion Science Research and Innovation Bangkok forproviding them some scientific facilities

Supplementary Materials

Supplementary Figure 1 naturally ripe fruit at the initialdehiscence (red circle) at the blossom end (SupplementaryMaterials)

Ethyl octanoate

Pentyl-2-methylbutanoatePropyl propanoate

Ethyl acetate

100

Chanthaburi 1 Chanee Kanyao Monthong 100 6667 3333 0

895579096864

0 2100 4300

Methyl heptanoateEthyl butanoate

Ethyl -2-hexenoateEthyl decanoate

Ethyl-2-methylpropanoateEthyl heptanoateEthyl propanoateEthyl nonanoate

Methyl dodecanoateEthyl-2-methylbutanoate

Ethyl hexanoateMethyl octanoate

Ethyl dodecanoate

Figure 4 Heat map of odor activity value (OAV) which is greater than 1 of each durian species


References

[1] C Nualsri K Nakkanong A Chantanaorrapint R Rakkhanand S Chanaweerawan ldquoGenetic Diversity Analysis and Se-lection of Indigenous Durian in Southern ampailandrdquo Com-pleted Report Faculty of Natural Resources Print of SongklaUniversity Songkhla )ailand 2015

[2] M J Brown ldquoDuriondasha bibliographic reviewrdquo in IPGRI officefor South Asia R K Arora V R Rao and A N Rao EdsNew Delhi India 1997

[3] R Kongkachuichai R Charoensiri and P Sungpuag ldquoCa-rotenoid flavonoid profiles and dietary fiber contents of fruitscommonly consumed in )ailandrdquo International Journal ofFood Sciences amp Nutrition vol 61 no 5 pp 536ndash548 2010

[4] N A Husin S Rahman S Rahman R Karunakaran andS J Bhore ldquoA review on the nutritional medicinal molecularand genome attributes of durian (Durio zibethinus L) theking of fruits in Malaysiardquo Bioinformation vol 14 no 6pp 265ndash270 2018

[5] S Somsri ldquoCurrent status of durian breeding program in)ailandrdquo Acta Horticulturae vol 1024 no 1024 pp 51ndash592014

[6] J S Maninang C Wongs-Aree S Kanlayanarat S Sugayaand H Gemma ldquoInfluence of maturity and postharvesttreatment on the volatile profile and physiological propertiesof the durian (Durio zibethinus Murray) fruitrdquo InternationalFood Research Journal vol 18 pp 1067ndash1075 2011

[7] J Boonthanakorn W Daud A Aontee and C Wongs-AreeldquoQuality preservation of fresh-cut durian cv ldquoMonthongrdquousing microperforated PETPE filmsrdquo Food Packaging andShelf Lifevol 23 Article ID 100452 2020

[8] N Laohakunjit O Kerdchoechuen F B Matta J L Silva andW E Holmes ldquoPostharvest survey of volatile compounds infive tropical fruits using headspace-solid phase micro-extraction (HS-SPME)rdquo HortScience vol 42 no 2pp 309ndash314 2007

[9] A Niponsak N Laohakunjit and O KerdchoechuenldquoContribution to volatile fingerprinting and physico-chemicalqualities of minimally processed durian cv ldquoMonthongrdquoduring storage identification of a novel chemical ripenessmarkerrdquo Food and Bioprocess Technology vol 8 no 6pp 1229ndash1243 2015

[10] P Choosung W Utto P Boonyaritthongchai T Wasusriand C Wongs-Aree ldquoEthanol vapor releasing sachet reducesdecay and improves aroma attributes in mulberry fruitrdquo FoodPackaging and Shelf Life vol 22 Article ID 100398 2019

[11] P Schieberle ldquoNew developments in methods for analysis ofvolatile compounds and their precursorsrdquo in Characterizationof Food Emerging Methods A G Gaonkar Ed ElsevierScience )e Netherlands 1995

[12] A Laura V Luciano G Josep B Olga and M MontserratldquoChemical characterization of commercial sherry vinegararoma by headspace solid-phase microextraction and gaschromatography-olfactometryrdquo Journal of Agricultural andFood Chemistry vol 59 pp 4062ndash4070 2011

[13] J A Pino and S E Barzola-Miranda ldquoCharacterization ofodor-active compounds in pechiche (Vitex cymosa Berteo exSpeng) fruitrdquo Journal of Raw Materials to Processed Foodsvol 1 pp 33ndash39 2020

[14] V C Allison and S H Katz ldquoAn investigation of stenches andodors for industrial purposesrdquo Journal of Industrial andEngineering Chemistry vol 11 no 4 pp 336ndash338 1919

[15] E L Backman ldquoExperimentalla undersokningarofverluktsinnets fysiologirdquo Upsala Lakareforhandlingqarvol 22 pp 319ndash470 1917

[16] R G Berger F Drawert H Kollmannsberger S Nitz andB Schraufstetter ldquoNovel volatiles in pineapple fruit and theirsensory propertiesrdquo Journal of Agricultural and FoodChemistry vol 33 no 2 pp 232ndash235 1985

[17] J E Cometto-Muntildeiz W S Cain and M H Abraham ldquoOdordetection of single chemicals and binary mixturesrdquo Behav-ioural Brain Research vol 156 no 1 pp 115ndash123 2005

[18] W Fan and Y Xu ldquoDetermination of odor thresholds ofvolatile aroma compounds in baijiu by a forced-choice as-cending concentration series method of limitsrdquo LiquorMaking vol 38 pp 80ndash84 2011

[19] V Ferreira M Ardanuy R Lopez and J F Cacho ldquoRela-tionship between flavor dilution values and odor unit valuesin hydroalcoholic solutions role of volatility and a practicalrule for its estimationrdquo Journal of Agricultural and FoodChemistry vol 46 no 10 pp 4341ndash4346 1998

[20] L J van Gemert Odour ampresholds Compilations of Odourampreshold Values in Air Water and Other Media OliemansPunter amp Partners BV Utrecht )e Netherlands 2011

[21] H Guth ldquoOjectivation of white wine aromasrdquo )esis TUMunchen 1997

[22] V Karl J Gutser A Dietrich B Maas and A MosandlldquoStereoisomeric flavour compounds LXVIII 2- 3- and 4-alkyl-branched acids part 2 chirospecific analysis and sen-sory evaluationrdquo Chirality vol 6 no 5 pp 427ndash434 1994

[23] P Komthong S Hayakawa T Katoh N Igura andM Shimoda ldquoDetermination of potent odorants in apple byheadspace gas dilution analysisrdquo Lebensmittel-Wissenschaftund -Technologie- Food Science and Technology vol 39 no 5pp 472ndash478 2006

[24] M Rychlik P Schieberle and W Grosch Compilation ofOdor ampresholds Odor Qualities and Retention Indices of KeyFood Odorants Garching Germany 1998

[25] R Schwarz ldquoUber die Ricchscharfc der Honigbienerdquo Zeits-chrift fur Vergleichende Politikwissenschaft vol 37 pp 180ndash210 1995

[26] Y Nagata ldquoMeasurement of odor threshold by triangle odorbag methodrdquo in Odor Measurement Review pp 118ndash127Office of Odor Noise and Vibration Ministry of the Envi-ronment Government of Japan Tokyo Japan 2003

[27] G R Takeoka R G Buttery R A Flath et al ldquoVolatileconstituents of pineapple (Ananas comosus [L] Merr)rdquo in InFlavor Chemistry Trends and Develpments R TeranishiR G Buttery and F Shahidi Eds American Chemical So-ciety Washington NY USA pp 223ndash237 1989

[28] G R Takeoka R A Flath T R Mon R Teranishi andM Guentert ldquoVolatile constituents of apricot (Prunusarmeniaca)rdquo Journal of Agricultural and Food Chemistryvol 38 no 2 pp 471ndash477 1990

[29] C Van )riel M Schaper E Kiesswetter et al ldquoFromchemosensory thresholds to whole body exposures-experi-mental approaches evaluating chemosensory effects ofchemicalsrdquo International Archives of Occupational and En-vironmental Health vol 79 no 4 pp 308ndash321 2006

[30] P MWise T Miyazawa M Gallagher and G Preti ldquoHumanodor detection of homologous carboxylic acids and theirbinary mixturesrdquo Chemical Senses vol 32 no 5 pp 475ndash4822007

[31] M Yair Concepts in Wine Chemistry Board and BenchPublishing Corporation San Francisco CA USA 3rd edition2012


[32] W Hugo E K Wim and A Anton ldquoSulfur-containingvolatiles of durian fruits (Durio zibethinusMurr)rdquo Journal ofAgricultural and Food Chemistry vol 44 pp 3291ndash3293 1996

[33] X L Jia S Peter and S Martin ldquoldquoCharacterization of themajor odor-active compounds in )ai durian (Durio zibe-thinus L ldquoMonthongrdquo) by aroma extract dilution analysis andheadspace gas chromatographyminusolfactometryrdquo Journal ofAgricultural and Food Chemistry vol 60 pp 11253ndash112622012

[34] K Hongku N Laohakunjit and O Kerdchoechuen ldquoDurianflavor extracts and its volatile characteristicsrdquo AgriculturalScience Journal vol 42 no 2 pp 241ndash244 2011

[35] S C Tongdee A Suwanagul and S Neamprem ldquoDurian fruitripening and the effect of variety maturity stage at harvestand atmospheric gasesrdquo Acta Horticulturae vol 269 no 269pp 323ndash334 1990

[36] Y Y Voon N Sheikh Abdul Hamid G Rusul A Osman andS Y Quek ldquoVolatile flavour compounds and sensory prop-erties of minimally processed durian (Durio zibethinus cvD24) fruit during storage at 4degCrdquo Postharvest Biology andTechnology vol 46 no 1 pp 76ndash85 2007

[37] C Wongs-Aree and S Noichinda ldquoPostharvest qualityproperties of potential tropical fruits related to their uniquestructural charactersrdquo in In Postharvest Handling A SystemsApproach W J Florkowski R L Shewfelt B Brueckner andS E Prussia Eds Acedamic Press Cambridge MA USA 4thedition 2021

[38] R G der Agopian J P Fabi and B R Cordenunsi-LysenkoldquoMetabolome and proteome of ethylene-treated papayas re-veal different pathways to volatile compounds biosynthesisrdquoFood Research International vol 131 Article ID 108975 2020

[39] W Phutdhawong S Kaewkong and D Buddhasukh ldquoGC-MS analysis of fatty acids in )ai durian arilrdquo Chiang MaiJournal of Science vol 32 no 2 pp 155ndash158 2005

[40] A D Bauchot D S Mottram A T Dodson and P JohnldquoEffect of aminocyclopropane-1-carboxylic acid oxidase an-tisense gene on the formation of volatile esters in cantaloupecharentais melon (cv Vedrandais)rdquo Journal of Agriculturaland Food Chemistry vol 46 no 11 pp 4787ndash4792 1998

[41] B G Defilippi A A Kader and A M Dandekar ldquoApplearoma alcohol acyltransferase a rate limiting step for esterbiosynthesis is regulated by ethylenerdquo Plant Science vol 168no 5 pp 1199ndash1210 2005

[42] M M Khanom and Y Ueda ldquoBioconversion of aliphatic andaromatic alcohols to their corresponding esters in melons(Cucumis melo L cv Prince melon and cv Earlrsquos favoritemelon)rdquo Postharvest Biology and Technology vol 50 no 1pp 18ndash24 2008

[43] S Noichinda Y Ueda Y Imahori and K Chachin ldquo)ioesterproduction and thioalcohol specificity of alcohol acetyl-transferase in strawberry fruitrdquo Food Science and TechnologyResearch vol 5 no 1 pp 99ndash103 1999

[44] H Kelebek S Selli H Gubbuk and E Gunes ldquoComparativeevaluation of volatiles phenolics sugars organic acids andantioxidant properties of Sel-42 and Tainung papaya varie-tiesrdquo Food Chemistry vol 173 pp 912ndash919 2015


registered as a new variety by the Department of Agriculture)ailand on 9 October 2006 )e fruit is an early-seasonproduction with a harvesting time of 99ndash105 days afterpollination )e average fruit weight is 25ndash3 kg comprisingbright yellow flesh and a sweet delicate texture )e ripefruit of ldquoChanthaburi 1rdquo is claimed to have an extra-lowsmell [5] Nevertheless there is no analytical report yet forthe volatile characterization of the fruit

Aroma is a unique character of ripe durian fruit pre-ferred by some but annoying for many people Furthermoreit is seriously prohibited to take durian fruiteat duringpublic transportation or in assembly places such as hotels orconvention halls )is matter would be a significant obstaclefor the marketing of durians Ethyl esters (fruity esters andgeneral fruit) are the prominent esters in ripe ldquoMonthongrdquoflesh [6 7] Nevertheless this sweet smell is interrupted bysulfurous smells of sulfur-containing compounds Ethane-thiol diethyltrisulfide diethyldisulfide dimethyl sulfide 23-butanedithiol ethyl 1-methylethyl disulfide 3-methyl-thi-ozolidine methyl ethyl disulfide and 1-propanethiol aresuch sulfur-containing compounds found in ripe durianflesh [6ndash8] )ere is no report of the relationship of duriancultivars by the aroma volatile so far )ere have been manyreports of volatile components of ripe durians in ldquoMonth-ongrdquo [6ndash9] few in ldquoChaneerdquo [6] but there is no report inldquoKanyaordquo and ldquoChanthaburi 1rdquo Furthermore from thefruitrsquos visual appearance ldquoChanthaburi 1rdquo fruit shape is verysimilar to the shape of ldquoKanyaordquo leading to confusion byvisual appearance )us fruit volatile profiles between thecultivars compared as volatile fingerprints were brought inthe interest Here the present study was to identify odorcharacteristics of 4 commercial varieties Volatiles ofldquoKanyaordquo and ldquoChanthaburi 1rdquo were firstly reported and thevolatile relationship of these four varieties was theninvestigated

2 Materials and Methods

21 Plant Materials and Sample Preparation Mature durianfruits at 90 maturation from 4 cultivars ldquoChaneerdquo(19ndash22 kg) at 15 weeks after anthesis (WAA) ldquoKanyaordquo at18 WAA (17ndash20 kg) ldquoMonthongrdquo at 19 WAA (22ndash28 kg)and lsquoChanthaburi 1 at 14 WAA (14ndash18 kg) were harvestedfrom commercial orchards in Chanthaburi Province eastern)ailand between April and June 2018 Fruits were incu-bated at room temperature (25degC 70ndash75 RH) for naturalripening Fruit showing initial dehiscence at the blossom end(Supplementary Figure 1) referred to as full ripening was

peeled and the ripe flesh was used for volatile analysis )evisual appearance of the whole fruit and half-dehusked ofripe fruits of the four cultivars is shown in Figure 1

22Chemicals )e internal standard of volatile analysis wasthiophene (ge99 purity) (Sigma Chemical Co USA)

23 Volatile Trapping )e ripe aril of each cultivar wasfinely blended by using a high-speed homogenizer for 2minHomogenate at 5 g was put into a 20mL glass vial sealed witha screw cap having a silicone laminated with polytetra-fluoroethylene septum )e volatiles in the samplersquos head-space were trapped by SPME and analyzed by GC-MSmodified from [10] )e volatiles in the headspace of thesample in a vial were trapped by solid-phase microextraction(SPME) coated with 65 microm of PolydimethylsiloxaneDivinylbenzene (PDMSDVB) (1 cm length) while heated at50degC for 30min

24Analysis ofVolatiles inRipeDurianFlesh )e SPME wasinjected into a gas chromatogram (GC 6850 series AgilentTechnologies USA) equipped with an HP-5MS column (5phenyl-methylsiloane capillary column 30mtimes 0248mmID with 025 microm thickness) and an Agilent 5913 mass se-lective detector with the following condition 200degC of theinjection port (splitless mode) 50degC of the column oven for1min and increased at a rate of 5degCmiddotminminus1 to 120degC and thento 250degC at a 10degCmiddotminminus1 rate and 250degC of the detectorHelium was the carrier gas set to 2mLmiddotminminus1 at 159 psi

)iophene at 10 microLmiddotLminus1 was used as the internal standard)e spectra of the volatile profile were analyzed in theelectron impact (EI) mode with an electron energy of 70 eVa mass range of mz 45ndash450 a scan rate of 025 sscan and anelectron multiplier (EM) voltage of 3000V Spectra of thevolatile profile were compared to a mass spectral databasefrom the NIST V14 Llibrary values (Palisade Corp New-field NY USA) )ere were 3 replications for each analysis

25 Calculation of Volatile Compounds Each volatilecompound of the clear peak from the GC-MS chromatogramwas analyzed for the content compared to thiophene as theinternal standard Volatile content in ng thiophene per gfresh weight was estimated by the peak area of volatilesdivided by the peak area of internal standard (thiophene)and 10 microL internal standard solution (05 gmiddotLminus1 thiophene) to5 g durian homogenate prior to taking SPME [11]

Volatile content ng thiophene gminus 1FW1113872 1113873 peak area of volatilepeak area of internal standard

g durian aril homogenate (1)









10 cm

(a)

10 cm

(b)

10 cm

(c)

10 cm

(d)











Total 979 0 361 166Acid









values (ppb)



Ester




























0025 mdash mdash 84329 2694 I














Table 2 Continued


values (ppb)





33 Ethyl nonanoate








Phenolic




Aldehyde











2

18


Seco

nd C

ompo

nent

ndash4

ndash3

ndash2

ndash1

0

1

2

3

4

83310

Chanee

Kanyao


Monthong

Chanthaburi 1

21

2820

3022

17

11

251647 6233

932

9429

26511

(a)

Figure 3 Continued

4231

000

3333

6667

10000

Observations

Sim

ilarit

y





First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthburi 1

Monthong

Chanee Kanyao

(b)


First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthaburi 1





Methyl octanoate







Ethyl decanoate


Chanee

Ethyl nanonoate






Kanyao

(c)




4 Conclusions



Data Availability




Acknowledgments




Ethyl octanoate


Ethyl acetate

100


895579096864

0 2100 4300






Ethyl dodecanoate



References






















































10 cm

(a)

10 cm

(b)

10 cm

(c)

10 cm

(d)











Total 979 0 361 166Acid









values (ppb)



Ester




























0025 mdash mdash 84329 2694 I














Table 2 Continued


values (ppb)





33 Ethyl nonanoate








Phenolic




Aldehyde











2

18


Seco

nd C

ompo

nent

ndash4

ndash3

ndash2

ndash1

0

1

2

3

4

83310

Chanee

Kanyao


Monthong

Chanthaburi 1

21

2820

3022

17

11

251647 6233

932

9429

26511

(a)

Figure 3 Continued

4231

000

3333

6667

10000

Observations

Sim

ilarit

y





First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthburi 1

Monthong

Chanee Kanyao

(b)


First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthaburi 1





Methyl octanoate







Ethyl decanoate


Chanee

Ethyl nanonoate






Kanyao

(c)




4 Conclusions



Data Availability




Acknowledgments




Ethyl octanoate


Ethyl acetate

100


895579096864

0 2100 4300






Ethyl dodecanoate



References























































Total 979 0 361 166Acid









values (ppb)



Ester




























0025 mdash mdash 84329 2694 I














Table 2 Continued


values (ppb)





33 Ethyl nonanoate








Phenolic




Aldehyde











2

18


Seco

nd C

ompo

nent

ndash4

ndash3

ndash2

ndash1

0

1

2

3

4

83310

Chanee

Kanyao


Monthong

Chanthaburi 1

21

2820

3022

17

11

251647 6233

932

9429

26511

(a)

Figure 3 Continued

4231

000

3333

6667

10000

Observations

Sim

ilarit

y





First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthburi 1

Monthong

Chanee Kanyao

(b)


First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthaburi 1





Methyl octanoate







Ethyl decanoate


Chanee

Ethyl nanonoate






Kanyao

(c)




4 Conclusions



Data Availability




Acknowledgments




Ethyl octanoate


Ethyl acetate

100


895579096864

0 2100 4300






Ethyl dodecanoate



References

















































values (ppb)



Ester




























0025 mdash mdash 84329 2694 I














Table 2 Continued


values (ppb)





33 Ethyl nonanoate








Phenolic




Aldehyde











2

18


Seco

nd C

ompo

nent

ndash4

ndash3

ndash2

ndash1

0

1

2

3

4

83310

Chanee

Kanyao


Monthong

Chanthaburi 1

21

2820

3022

17

11

251647 6233

932

9429

26511

(a)

Figure 3 Continued

4231

000

3333

6667

10000

Observations

Sim

ilarit

y





First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthburi 1

Monthong

Chanee Kanyao

(b)


First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthaburi 1





Methyl octanoate







Ethyl decanoate


Chanee

Ethyl nanonoate






Kanyao

(c)




4 Conclusions



Data Availability




Acknowledgments




Ethyl octanoate


Ethyl acetate

100


895579096864

0 2100 4300






Ethyl dodecanoate



References



















































Table 2 Continued


values (ppb)





33 Ethyl nonanoate








Phenolic




Aldehyde











2

18


Seco

nd C

ompo

nent

ndash4

ndash3

ndash2

ndash1

0

1

2

3

4

83310

Chanee

Kanyao


Monthong

Chanthaburi 1

21

2820

3022

17

11

251647 6233

932

9429

26511

(a)

Figure 3 Continued

4231

000

3333

6667

10000

Observations

Sim

ilarit

y





First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthburi 1

Monthong

Chanee Kanyao

(b)


First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthaburi 1





Methyl octanoate







Ethyl decanoate


Chanee

Ethyl nanonoate






Kanyao

(c)




4 Conclusions



Data Availability




Acknowledgments




Ethyl octanoate


Ethyl acetate

100


895579096864

0 2100 4300






Ethyl dodecanoate



References





















































2

18


Seco

nd C

ompo

nent

ndash4

ndash3

ndash2

ndash1

0

1

2

3

4

83310

Chanee

Kanyao


Monthong

Chanthaburi 1

21

2820

3022

17

11

251647 6233

932

9429

26511

(a)

Figure 3 Continued

4231

000

3333

6667

10000

Observations

Sim

ilarit

y





First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthburi 1

Monthong

Chanee Kanyao

(b)


First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthaburi 1





Methyl octanoate







Ethyl decanoate


Chanee

Ethyl nanonoate






Kanyao

(c)




4 Conclusions



Data Availability




Acknowledgments




Ethyl octanoate


Ethyl acetate

100


895579096864

0 2100 4300






Ethyl dodecanoate



References
















































First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthburi 1

Monthong

Chanee Kanyao

(b)


First Component


Seco

nd C

ompo

nent

ndash3

ndash2

ndash1

0

1

2

3

4

Chanthaburi 1





Methyl octanoate







Ethyl decanoate


Chanee

Ethyl nanonoate






Kanyao

(c)




4 Conclusions



Data Availability




Acknowledgments




Ethyl octanoate


Ethyl acetate

100


895579096864

0 2100 4300






Ethyl dodecanoate



References
















































4 Conclusions



Data Availability




Acknowledgments




Ethyl octanoate


Ethyl acetate

100


895579096864

0 2100 4300






Ethyl dodecanoate



References















































References















































fruit volatile fingerprints characterized among four

Documents