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Abstract and Figures

The transfer kinetics of three labelled compounds (butanal, 2-phenyethanol, isoamyl acetate) was studied from a liquid medium into the coffee beans during simulated wet processing using four media (M) (M1: contained dehulled beans, M2: contained demucilaginated beans, M3: contained depulped beans, M4: contained depulped beans with yeast).Trials were carried out at 25°C, under agitation and for five time periods (0, 6, 12, 24 and 48 hours), and then the labelled volatiles were analyzed by SPME-GC-MS. The three labelled molecules were transferred into the coffee beans with different mass transfer rates; reaching at 12hrs in the M4, 0.2±0.03 ,11.2±0.66 and 1.3±0.04µg/g of coffee respectively for butanal, 2-phenyethanol and isoamyl acetate. The parchment resistance significantly affected the mass transfer of the 2-phenylethanol. Butanal and isoamyl acetate underwent metabolic reactions, which decreased their amount in the coffee beans. Furthermore, an interaction between molecules and the yeast was observed and decreased significantly the butanal’s transfer.
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UNCORRECTED PROOF
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1. Introduction
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2. Materials and methods
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G> E9FM9DDQ <=HMDH=< 9F< <=@MDD=< ;G>>== :=9FK 9F< L@AK E=<AME O9K
MK=< LG =KLAE9L= L@= H=JE=9:ADALQ G> L@= ;G>>== :=9FK LG L@= <A>>MKAGF G>
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H9J;@E=FL LG L@= LJ9FK>=J G> L@= ;GEHGMF<K
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G> J=@Q<J9L=< Q=9KL 9F<  E' G> <AKLADD=< O9L=J O=J= 9<<=< LG KM:
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O9L=J /@AK ;GF;=FLJ9LAGF O9K <=L=JEAF=< CFGOAF? L@= F9LMJ9D ;GF;=F
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9 ;GF;=FLJ9LAGF ?J9<A=FL AF L@= E=<AME AF >9NGJ G> ;GEHGMF< =FLJQ
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;@GK=F LG AFN=KLA?9L= L@= E9KK LJ9FK>=J CAF=LA;K DD LJA9DK O=J= AF<=H=F
<=FL 9F< H=J>GJE=< AF LJAHDA;9L=
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LAE=K OAL@ O9L=J LG KLGH L@= LJ9FK>=J J=9;LAGF 9F< LG J=EGN= D9:=D=<
EGD=;MD=K 9<@=JAF? LG L@= ?J9AF KMJ>9;= 9F< L@=F L@=Q O=J= ?JGMF< 9F<
>JGR=F 9L  Z MFLAD :=AF? 9F9DQR=<
 "*(43) *=5*7.2*39&1 &5574&(- &)).9.43&1 9*898
/G HJGH=JDQ AFL=JHJ=L GMJ J=KMDLK 9<<ALAGF9D L=KLK O=J= ;GF<M;L=< LG
AFN=KLA?9L= L@= AFL=J9;LAGF :=LO==F L@= D9:=DD=< NGD9LAD= EGD=;MD=K 9F<
L@= Q=9KL KLJ9AF '. MK=< >GJ L@AK KLM<Q
K >GJ L@= ^JKL =PH=JAE=FL9D 9HHJG9;@  E' G> 9 KGDMLAGF ;GFL9AFAF?
J=@Q<J9L=< Q=9KL 9L 9 ;GF;=FLJ9LAGF G>  E?E' 9F< 9 EAPLMJ= G> L@=
 D9:=DD=< EGD=;MD=K 9L 9 ;GF;=FLJ9LAGF G>  E?E' O9K HJ=H9J=< L@=
K9EHD=K O=J= NGJL=P=< >GJ  K LG @GEG?=FAR= L@= EAP 9F< L@=F L@=Q
O=J= 9F9DQR=< AEE=<A9L=DQ
UNCORRECTED PROOF
&)/"&1*2*9&1 44)-*2.897> === ==== ======
Fig. 1. .;@=E9LA; J=HJ=K=FL9LAGF G> L@= E=<A9 MK=< LG KLM<Q L@= LJ9FK>=J CAF=LA;K G> D9:=DD=< ;GEHGMF<K
 %41&9.1* (4254:3)8 &3&1>8*8
 =97&(9.43 '> "
G>>== :=9F K9EHD=K O=J= ?JGMF< LG 9 ^F= H9JLA;D= KAR=  ]E
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LJ9;L=< MKAF? L@= .+( 19J:GP=F+(.  ]E .MH=D;G
0. KGDA<H@9K=EA;JG=PLJ9;LAGF "JGMF< ;G>>==  \  ? O9K
O=A?@=< AF K;J=O;9HH=< ?D9KK NA9DK 9F< EAP=< OAL@  E' G> HMJ= O9
L=J .M:K=IM=FLDQ L@= NA9DK O=J= HD9;=< >GJ  EAF AF 9 L@=JEGKL9LA;9DDQ
J=?MD9L=< GN=F 9L  Z LG J=9;@ K9EHD= @=9<KH9;= =IMADA:JAME /@=F
L@=Q O=J= KM:B=;L=< LG .+( 9L  Z >GJ  EAF
 " &3&1>8.8
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F=KK ?AD=FL %2 " ;GDMEF 0. MF<=J KHDALD=KK EG<= OAL@ L@= AF
B=;LGJ L=EH=J9LMJ= K=L 9L  Z #Q<JG?=F O9K MK=< 9K L@= ?9K N=;LGJ
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KO==HAF? 9F AFL=JN9D 6 LG 7 2?AF .) EG<= /@= J=KMDLK K=L
O=J= HJG;=KK=< MKAF? (9KK#MFL=J ,M9DAL9LAN= F9DQK=K KG>LO9J= N=J
KAGF 
 "9&9.89.(&1 &3&1>8*8
(=9FK 9F< KL9F<9J< <=NA9LAGFK J=HGJL=< O=J= ;9D;MD9L=< >JGE LJAH
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;GEH9JAKGF G> E=9FK :Q /MC=QK L=KL H=J>GJE=< MKAF? L@= 3DKL9L N=J
KAGF  A>>=J=F;=K O=J= ;GFKA<=J=< KA?FA>A;9FL O@=F L@= HJG:9:AD
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 #7&38+*7 7&9* (&1(:1&9.43
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3. Results and discussion
 #7&38+*7 0.3*9.(8 89:)>
-=KMDLK G> L@= E9KK LJ9FK>=J CAF=LA;K G> L@= D9:=DD=< NGD9LAD=K 9J=
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;GEHGMF<K AFLG L@= ;G>>== :=9FK !A?  /@=K= J=KMDLK ;GF^JE HJ=
NAGMK OGJC :Q )=LG =L 9D  +=J=AJ9 =L 9D  N9F?=
DAKL9 =L 9D  .ADN9 =L 9D  O@G HGKLMD9L=< L@9L 9 LJ9FK
>=J HJG;=KK ;GMD< =PAKL G> NGD9LAD= E=L9:GDAL=K L@9L 9J= HJG<M;=< :Q L@=
Q=9KL <MJAF? L@= >=JE=FL9LAGF AFLG L@= ;G>>== :=9FK
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L@= ;G>>== >=JE=FL9LAGF MKAF? L@= ( E=<AME K== K=;LAGF  K@GO=< 9
KA?FA>A;9FL AF;J=9K= AFLG L@= ;G>>== :=9FK <MJAF? L@=  @JK !A?  9F<
HJ=K=FL=< L@J== LJ9FK>=J J=?AE=K MJAF? L@= ^JKL @GMJK L@= J=;GJ<=<
9EGMFL K@GO=< 9F =PHGF=FLA9D AF;J=9K= J=9;@AF? 9L  @ 9:GML  G>
L@= LGL9D LJ9FK>=JJ=< 9EGMFL G> H@=FQD=L@9FGD /@AK =PHGF=FLA9D H@9K=
O9K >GDDGO=< :Q 9 <=;=D=J9LAGF H@9K= FGLA;=< :Q L@= <=;J=9K= G> L@=
LJ9FK>=J KH==< O@A;@ :=;9E= ;GFKL9FL :=LO==F  @ 9F<  @ G> LJ9FK
>=J 9F< J=HJ=K=FL=< L@= ;GFKL9FL J9L= KL9L=/9:D= 
$F L@= E=9FLAE= L@= LJ9FK>=J HJG^D= G> L@= 9D<=@Q<= :ML9F9D 9F<
L@= =KL=J AKG9EQD 9;=L9L= J=HJ=K=FL=< 9 J=?AE= ?GAF? L@JGM?@ 9 E9P
AEME J=9;@=< 9L  @JK G> LJ9FK>=J !A?  (GJ=GN=J L@= LGL9D ;GF
L=FL G> :ML9F9D AF L@= ;G>>== :=9FK K@GO=< 9 KA?FA>A;9FL <=;J=9K= L@9L
O9K >9KL=J L@9F L@9L G:K=JN=< >GJ L@= AKG9EQD= 9;=L9L= HJG^D= /9:D=
 KK=FLA9DDQ 9 @A?@ ;GF;=FLJ9LAGF ?J9<A=FL O9K E9AFL9AF=< LG 9NGA<
UNCORRECTED PROOF
&)/"&1*2*9&1 44)-*2.897> === ==== ======
Fig. 2. (9KK LJ9FK>=J CAF=LA;K G> D9:=D=< ;GEHGMF<K AFLG <=HMDH=< ;G>>== :=9FK ( <MJ
AF? O=LHJG;=KK LJ=9LE=FL -A?@L N=JLA;9D 9PAK >GJ H@=FQD=L@9FGD 9F< D=>L N=JLA;9D 9PAK >GJ
:ML9F9D 9F< AKG9EQD 9;=L9L=
L@= DGKK G> EGD=;MD=K :Q L@= J=N=JK= LJ9FK>=J L@=J=:Q L@AK <=;J=9K= ;9F
:= =PHD9AF=< :Q 9 <=?J9<9LAGF E=;@9FAKE G> L@=K= ;GEHGMF<K AFKA<=
L@= :=9F '== @=GF? MJJ9F 4M 9F< 'AM  9DKG K@GO=<
<MJAF? L@= ?J==F ;G>>== >=JE=FL9LAGF L@9L KGE= NGD9LAD=K O=J= <=?J9<=<
9F< J=K=9J;@=JK ;GJJ=D9L=< L@AK >9;L LG L@= E=L9:GDAKE G> 9JGE9 HJ=;MJ
KGJK AF ?J==F ;G>>== :=9FK :Q !-.?45:8 41.,48547:8 (GJ=GN=J AF L@=AJ
KLM<Q .=DE9J =L 9D  E=9KMJ=< L@= =PHJ=KKAGF G> L@= ?=JEA
F9LAGFKH=;A^; =FRQE= AKG;ALJ9L= DQ9K= 9F< L@=Q A<=FLA^=< L@9L <MJAF?
L@= ^JKL LOG <9QK G> L@= ;G>>== O=LHJG;=KK L@= ?=JEAF9LAGFJ=D9L=< E=
L9:GDAKE J=;GJ<=< L@= @A?@=KL 9;LANALQ L@JGM?@GML L@= HGKL@9JN=KLAF?
HJG;=KK /@=J=>GJ= AL ;9F := 9KKME=< L@9L 9>L=J L@=AJ LJ9FK>=J AF L@=
;G>>== :=9FK :ML9F9D 9F< AKG9EQD= 9;=L9L= MF<=J?G 9F =FRQE9LA; J=9;
LAGF L@9L G;;MJK <MJAF? L@= ?=JEAF9LAGF #GO=N=J H@=FQD=L@9FGD
K==EK FGL LG := 9>>=;L=< :Q L@AK <=?J9<9LAGF HJG;=KK 9K ALK LJ9FK>=JJ=<
9EGMFL AFLG L@= ;G>>== :=9FK ;GFLAFM=< LG AF;J=9K= :Q 9;;MEMD9LAGF LG
J=9;@  \  ]?? 9>L=J  @JK
$F<==< L@= LJ9FK>=J G> NGD9LAD= ;GEHGMF<K AK ?GN=JF=< :Q L@=JEG<Q
F9EA; 9F< CAF=E9LA; H9J9E=L=JK J=D9L=< LG L@= ;GEHGKALAGF L@= H@QKA;9D
KL9L= G> L@= E9LJAP 9F< L@=AJ AFL=J9;LAGF OAL@ L@= H@QKA;G;@=EA;9D HJGH
=JLA=K G> L@= EGD=;MD=K 1GADD=Q =L 9D  $F GMJ ;9K= L@= EGD=
;MD=K O=J= LJ9FK>=JJ=< >JGE DAIMA< E=<AME LG GJ?9FA; E9LJAP L@= ;G>>==
:=9F :Q AEHGKAF? 9 LJ9FK>=J ?J9<A=FL ;;GJ<AF? LG L@= H@QKA;G;@=EA
;9D HJGH=JLA=K HJ=K=FL=< AF /9:D=  OAL@ 9 DGO=J EGD=;MD9J O=A?@L 9F<
9 DGO=J 'G?+ H@=FQD=L@9FGD OGMD< @9N= 9F =9KA=J LJ9FKHGJL L@9F L@=
AKG9EQD= 9;=L9L= 2@AD= :ML9F9D @9K L@= DGO=KL EGD=;MD9J O=A?@L 9F< 9
'G?+   :=LO==F L@= L@J== EGD=;MD=K MK=< 9F< ;GFLJ9JQ LG O@9L O9K
=PH=;L=< L@= H@=FQD=L@9FGD J=HJ=K=FL=< L@= @A?@=KL LJ9FK>=J J9L= OAL@
9 LJ9FK>=J KH==<  LAE=K >9KL=J L@9F L@9L G> :ML9F9D <MJAF? L@= ^JKL
 @ /9:D=  $F L@=AJ KLM<Q '== =L 9D  J=HGJL=< 9F AF;J=9K=
G>  G> H@=FQD=L@9FGD AF L@= >=JE=FL=< ;G>>== :=9FK ;GEH9J=< LG
L@= MF>=JE=FL=< ?J==F ;G>>== :=9FK /@MK AL KH=;MD9L=K L@9L L@= 9D;G@GD
MF<=J?G=K 9F AFL=FK= <A>>MKAGF HJG;=KK <MJAF? L@= >=JE=FL9LAGF O@A;@
AK J=IMAJ=< LG AF_M=F;= L@= GN=J9DD ;G>>== IM9DALQ +=J=AJ9 =L 9D 
9F< L@AK AFL=FK= LJ9FK>=J ;9FFGL := =PHD9AF=< =P;DMKAN=DQ :Q L@= H@QKA;
G;@=EA;9D HJGH=JLA=K G> L@= ;GEHGMF< :ML E9Q:= :Q L@= =PAKL=F;= G>
GL@=J H9L@O9QK KM;@ 9K 9;LAN= LJ9FKHGJL G:K=JN=< AF HD9FLK
+J=NAGMK KLM<A=K = 9KLJG  (9JJ9;;AFA  @9N= J=HGJL=<
L@= =PAKL=F;= G> E=L9:GDAL= =P;@9F?=K :=LO==F L@= H=JA;9JH HMDH 9F<
L@= =F<GKH=JE K==< =AL@=J :Q H9KKAN= LJ9FK>=J GJ :Q 9;LAN= LJ9FKHGJL
A= KM?9JK ;9>>=AF= ;;GJ<AF?DQ EGD=;MD=K ;9F := LJ9FK>=JJ=< AFLG
L@= ;G>>== :=9F :Q L@=K= LOG LJ9FKHGJL H9L@O9QK 9F< L@= 9KKMEHLAGF
G> L@= =PAKL=F;= G> 9 KH=;A^; 9;LAN= LJ9FKHGJL G> L@= @A?@=J 9D;G@GD
H@=FQ=L@9FGD ;9F =PHD9AF L@= J=HGJL=< @A?@ J9L= LJ9FK>=J G> L@AK ;GE
HGMF<
Table 1
/J9FK>=J KH==< G> D9:=D=< ;GEHGMF<K ;9D;MD9L=< >JGE L@= CAF=LA; KLM<Q
GEHGMF<LAE= /J9FK>=JJ9L=]??@
 @  @  @  @
ML9F9D  \  9 \  : \  ; \  ;
$KG9EQD9;=L9L=  \  9 \  :  \  : \  :
+@=FQD=L@9FGD  \  9 \  9:  \  : \  :
A>>=J=FL D9:=DK 9: AF<A;9L= L@9L E=9FK KA?FA>A;9FLDQ <A>>=J 9L H   :9K=< GF /MC=Q L=KL
Table 2
+@QKA;G;@=EA;9D HJGH=JLA=K G> L@= KLM<A=< EGD=;MD=K +M:@=E 
ML9F9D $KG9EQD9;=L9L= +@=FQD=L@9FGD
(GD=;MD9JO=A?@L?EGD   
/GHGDG?A;9D+GD9J.MJ>9;=J=9      
.GDM:ADALQAFO9L=JE?'9L Z   
=FKALQ?;E    
'G?+@Q<JGH@G:A;ALQ   
GF>GJE9LAGF
'G?+ H9JLALAGF ;G=>^;A=FL EGJ= L@= 'G?+   EGJ= L@= EGD=;MD= AK @Q<JGH@G:A;
UNCORRECTED PROOF
&)/"&1*2*9&1 44)-*2.897> === ==== ======
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'9:=DD=< ;GEHGMF< ;GFL=FLK ML9F9D $KG9EQD 9;=L9L= 9F<
+@=FQD=L@9FGD 9L  @JK G> LJ9FK>=J KLM<A=< AF >GMJ E=<A9 ( (
( 9F< ( 9J= NAKM9DAR=< AF !A? 
/@= LJ9FK>=JJ=< 9EGMFL G> H@=FQD=L@9FGD J=9;@=<  \  ]?
? AF L@= ?J==F ;G>>== :=9FK ( O@AD= L@AK 9EGMFL O9K KA?FA>A;9FLDQ
DGO=J AF L@= ?J==F ;G>>== :=9FK OAL@ H9J;@E=FL ( !A? ; ;
;GJ<AF?DQ 9F< 9K 9KKME=< :Q '== =L 9D  9F<
-9EXJ=R(9JLXF=R =L 9D  L@= H9J;@E=FL AF<M;=K 9 HGL=FLA9D
E9KK LJ9FK>=J J=KAKL9F;= #GO=N=J L@= IM9FLA^=< 9EGMFLK AF L@= L@J==
E=<A9 ( ( 9F< ( O=J= IMAL= ;DGK=  \   \  9F<
 \  ]?? J=KH=;LAN=DQ OAL@ FG KA?FA>A;9FL <A>>=J=F;= L@=J=:Q
HGAFLAF? GML L@9L L@= HJ=K=F;= G> EM;AD9?= 9F<GJ Q=9KL 9F< >=JE=FL9
LAGF E=;@9FAKEK <G FGL @9N= 9 KA?FA>A;9FL =>>=;L GF L@= LJ9FK>=J J9L= G>
H@=FQD=L@9FGD
!MJL@=JEGJ= L@= AKG9EQD 9;=L9L= ;GFL=FL AF 9DD ;GF<M;L=< LJA9DK
AF L@= ( ( ( 9F< L@= ( E=<A9 J9F?=< :=LO==F  \ 
9F<  \  ]?? !A? : 9K=< GF KL9LAKLA;9D L=KLK L@AK N9JA9LAGF
K@GO=< FG KA?FA>A;9FL <A>>=J=F;= !A? : /@MK AL ;9F := ;GF;DM<=<
L@9L L@= H9J;@E=FL 9F< L@= EM;AD9?= @9N= FG AF_M=F;= GF L@= LJ9FK>=J
J9L= G> L@AK EGD=;MD= /@= H@QKA;G;@=EA;9D ;@9F?=K G;;MJJAF? <MJAF? L@=
>=JE=FL9LAGF <G FGL 9>>=;L L@= E9KK LJ9FK>=J G> L@AK =KL=J =AL@=J
2AL@ J=?9J<K LG :ML9F9D FG KA?FA>A;9FL <A>>=J=F;=K AF L@= ;GF;=F
LJ9LAGF G> L@AK 9D<=@Q<= O=J= G:K=JN=< AF L@= E=<A9 ( ( 9F< (
!A? 9 O@A;@ O9K 9JGMF<  ]?? ?9AF L@= H9J;@E=FL <A< FGL
K@GO 9FQ J=KAKL9F;= LG L@= LJ9FK>=J G> L@AK EGD=;MD= #GO=N=J L@= :M
L9F9D ;GFL=FL IM9FLA^=< AF L@= ( E=<AME OAL@ Q=9KL O9K KA?FA>A
;9FLDQ DGO=J  \  ]?? !A? 9 $F ;GFLJ9KL LG L@= 9D;G@GD 9F<
L@= =KL=J L@= HJ=K=F;= G> "&((-&742>(*8 (*7*;.8.&* '. D=9<K LG 9 <=
;J=9K= G> L@= :ML9F9D LJ9FK>=JJ=< E9KK $F L@=AJ KLM<Q @9DA=J F
?GL =DL=AD G;G 9F< "MF9L9  K@GO=< L@9L 9F AFL=J9;LAGF
EA?@L =PAKL :=LO==F 9JGE9 ;GEHGMF<K 9F< E9FFGHJGL=AF AKGD9L=< >JGE
"&((-&742>(*8 (*7*;.8.&* KLJ9AFK O@A;@ J=<M;=K L@=AJ NGD9LADALQ L@= F9
LMJ= G> L@= G:K=JN=< AFL=J9;LAGF @9K FGL :==F ;@9J9;L=JAR=< >GJ L@= L9J
?=L=< EGD=;MD=K AF L@AK KLM<Q :ML L@=Q =PHD9AF AF L@=AJ KLM<Q L@9L L@AK
AFL=J9;LAGF AK DAFC=< LG L@= H@QKA;G;@=EA;9D HJGH=JLA=K G> L@= ;GEHGMF<
GF L@= GF= @9F< 9F< L@GK= G> L@= E9FFGHJGL=AFK ;GFKLALMLAF? L@= O9DDK
G> L@= Q=9KL ;=DDK GF L@= GL@=J @9F< #=F;= AL ;9F := 9KKME=< L@9L L@=
Q=9KL MK=< AF L@= ( E=<AME 9>>=;L=< L@= NGD9LADALQ G> :ML9F9D $F L@AK
;GFL=PL LJA9DK O=J= ;GF<M;L=< LG N=JA>Q L@= Q=9KL '. J=L=FLAGF =>>=;L
GF L@= L@J== EGD=;MD=K KLM<A=< .=;LAGF 
(=9KMJ=E=FLK G> AFL=J9;LAGF :=LO==F Q=9KLK 9F< L@= L@J== 9JGE9
;GEHGMF<K 9J= HJ=K=FL=< AF !A?  K =PH=;L=< L@= NGD9LADALQ G> :M
L9F9D O9K KA?FA>A;9FLDQ 9>>=;L=< :Q Q=9KL  <=;J=9K= G> MH LG  G> L@AK
9D<=@Q<= ;GFL=FL O9K G:K=JN=< O@=F ;GEH9J=< LG L@= E=<AME OAL@GML
Q=9KL )4 !A? 9 /@= =PHD9F9LAGF ;GMD< := 9F 9<KGJHLAGF G> L@=
EGD=;MD= GF L@= Q=9KL ;=DD O9DDK /@AK AFL=J9;LAGF :=LO==F Q=9KL 9F< :M
L9F9D ;GMD< AF<M;= 9 KDGO=J LJ9FK>=J G> L@AK ;GEHGMF< AFLG ;G>>== :=9FK
<MJAF? >=JE=FL9LAGF !A? 9
$F ;GFLJ9KL AKG9EQD 9;=L9L= <A< FGL KA?FA>A;9FLDQ AFL=J9;L OAL@ Q=9KL
!A? : @9DA=J =L 9D  J=HGJL=< L@9L L@= KLJ=F?L@ G> AFL=J
9;LAGFK :=LO==F 9JGE9 ;GEHGMF<K 9F< Q=9KL ;=DD O9DDK <=H=F<K GF L@=
H@QKA;G;@=EA;9D F9LMJ= G> L@= NGD9LAD= ;GEHGMF<
$F 9<<ALAGF L@= H@=FQD=L@9FGD NGD9LADALQ O9K KA?FA>A;9FLDQ 9>>=;L=<
:Q Q=9KL 9F< AF ;GFLJ9KL LG :ML9F9D L@= 9EGMFL AF;J=9K=< :Q 
;GEH9J=< LG L@= E=<AME OAL@GML Q=9KL $F L@=AJ KLM<Q GEMRRG =L
9D  G:K=JN=< L@9L H@=FQD=L@9FGD <A< FGL AFL=J9;L OAL@ "&((-&
742>(*8 (*7*;.8.&* ;=DD O9DDK #GO=N=J L@= Q=9KL KLJ9AF MK=< AF GMJ KLM<Q
O9K CFGOF LG HJG<M;= <A>>=J=FL 9JGE9 ;GEHGMF<K =KH=;A9DDQ @A?@=J 9D
;G@GDK /@=J=:Q L@= H@=FQD=L@9FGD ;GF;=FLJ9LAGF HJG:9:DQ AF;J=9K=<
AF L@= E=<AME AF;J=9KAF? L@= NGD9LAD= >J9;LAGF AF L@= @=9<KH9;=
/@MK NGD9LAD= ;GEHGMF< LJ9FK>=J ?GN=JF=< :Q 9 ;GF;=FLJ9LAGF ?J9
<A=FL MF<=J?G=K K=N=J9D <=NA9LAGFK AF<M;=< :Q ;GEHD=P H@QKA;G;@=E
A;9D AFL=J9;LAGFK :=LO==F L@= EGD=;MD= 9F< L@= <A>>=J=FL LJ9FK>=J E=
Fig. 3. '9:=D=< ;GEHGMF< ;GFL=FL AF ;G>>== :=9FK 9>L=J @ G> LJ9FK>=J ( ;G>>== :=9FK ( <=EM;AD9?AF9L=< ;G>>== :=9FK ( <=HMDH=< ;G>>== :=9FK ( >=JE=FL=< <=HMDH=< ;G>>==
:=9FK A>>=J=FL D9:=DK  AF<A;9L= L@9L E=9FK KA?FA>A;9FLDQ <A>>=J 9L H   :9K=< GF /MC=Q L=KL
UNCORRECTED PROOF
&)/"&1*2*9&1 44)-*2.897> === ==== ======
Fig. 4. >>=;L G> Q=9KL HJ=K=F;= GF 9JGE9 H=9C 9J=9 AF @=9<KH9;= :=LO==F 9 E=<AME OAL@ 4 9F< OAL@GML )4 Q=9KLK A>>=J=FL D9:=DK  AF<A;9L= L@9L E=9FK KA?FA>A;9FLDQ <A>>=J 9L
H   :9K=< GF /MC=Q L=KL
<A9 /@AK 9>>=;LK L@=AJ LJ9FK>=J >JGE EM;AD9?= LG L@= ;G>>== :=9FK <MJAF?
L@= >=JE=FL9LAGF
/@= H9J;@E=FL O@A;@ AK G> 9 ^:JGMK KLJM;LMJ= L@9L AK N=JQ ;DGK= LG
OGG< -9EXJ=R(9JLXF=R =L 9D  K@GOK 9 H@QKA;9D J=KAKL9F;=
9F< ;GFK=IM=FLDQ AL 9;LK 9K 9 EGD=;MD9J ^DL=J *FDQ H@=FQD=L@9FGD
O9K @=D< :9;C :Q L@AK :9JJA=J J=D9L=< LG ALK ;GF>GJE9LAGF L9:D= 
O@=J=9K L@= D9:=DD=< 9D<=@Q<= 9F< =KL=J K==E=< FGL LG := J=L9AF=< :Q
L@= H9J;@E=FL /@AK ^:JGMK D9Q=J AK 9 F9LMJ9D ;G>>== K==< HJGL=;LAGF
9?9AFKL <A?=KLAF? =FRQE=K >JGE L@= ?ML G> >JM?ANGJGMK 9FAE9DK 9F< C==H
L@= ;G>>== K==< 9N9AD9:D= LG ?=JEAF9LAGFJ=D9L=< E=L9:GDAKE 9>L=J @9J
N=KLAF? O@A;@ AK AFALA9L=< :Q L@= HMDH J=EGN9D = 9KLJG  (9JJ9;
;AFA  .=DE9J =L 9D  #=F;= <MJAF? L@= ;G>>== O=L LJ=9L
E=FL L@= :AG;@=EA;9D ;GEHGKALAGF G> L@= ;G>>== :=9FK MF<=J?G=K K=N
=J9D E=L9:GDA; J=9;LAGFK +9LMA =L 9D  .=DE9J =L 9D 
O@A;@ G;;MJ KAEMDL9F=GMKDQ LG EGD=;MD= LJ9FK>=JK /@=K= J=9;LAGFK ;9F
AF<M;= L@=AJ <AK9HH=9J9F;= :ML 9L L@= K9E= LAE= L@= 9HH=9J9F;= G>
GL@=J HJG<M;LK $F GMJ KLM<Q AL K==EK L@9L GFDQ H@=FQD=L@9FGD O9K FGL
9>>=;L=< :Q L@=K= J=9;LAGFK /@MK >JGE 9 :JG9< H=JKH=;LAN= AL OGMD< :=
AFL=J=KLAF? LG KLM<Q L@= E=;@9FAKE G> L@=K= J=9;LAGFK 9F< LJ9FK>=J AFLG
L@= ;G>>== :=9FK 9F< =N9DM9L= L@=AJ AEH9;L GF L@= 9JGE9LA; HJG^D= G> L@=
^F9D HJG<M;L (GJ=GN=J AL AK O=DD CFGOF = 9KLJG  (9JJ9;;AFA
 L@9L L@= =PAKL=F;= G> 9;LAN= LJ9FKHGJL E9Q 9;;=D=J9L= L@= LJ9FK>=J
J9L= G> KH=;A^; EGD=;MD=K AFLG ;G>>== :=9FK <MJAF? L@= O=L HJG;=KKAF?
$F GMJ ;9K= L@AK ;GMD< =PHD9AF L@= @A?@ LJ9FK>=J J9L= G> H@=FQD=L@9FGD
J=HGJL=< L@JGM?@GML L@= CAF=LA; KLM<Q
N=F A> L@= @A?@=J 9D;G@GDK 9J= CFGOF >GJ L@=AJ @A?@=J K=FKGJQ
L@J=K@GD< RA9DG +9JC .L==FK=DK 'A=N=FK  1=JKLJ=H=F 
H@=FQD=L@9FGD K==EK LG := 9F AFL=J=KLAF? 9JGE9 ;GEHGMF< :Q ALK @A?@
LJ9FK>=J J9L= AFLG L@= ;G>>== :=9FK <MJAF? >=JE=FL9LAGF /@=J=:Q AF L@=AJ
J=NA=O +=J=AJ9 =L 9D  HGKLMD9L= L@9L MKAF? Q=9KL KLJ9AFK OAL@
AEHGJL9FL @A?@=J 9D;G@GD HJG<M;LAGF ;9F =F@9F;= L@= K=FKGJQ IM9DALQ G>
L@= ;G>>== :=N=J9?= :Q HJGNA<AF? _GJ9D FGL=K +=J=AJ9 =L 9D 
#GO=N=J KGE= NGD9LAD= ;GEHGMF<K ;9F AFL=J9;L OAL@ Q=9KL AF<M;AF?
L@=J=:Q 9 KA?FA>A;9FL <=;J=9K= G> L@=AJ LJ9FK>=J J9L= MJAF? GMJ KLM<Q AL
K==EK L@9L :ML9F9D O9K @A?@DQ J=L9AF=< :Q L@= Q=9KLK "&((-&742>(*8 (*7*
;.8.&* '. O@AD= L@= H@=FQD=L@9FGD 9F< L@= AKG9EQD 9;=L9L= O=J=
FGL 9>>=;L=<
4. Conclusion
/@= NGD9LAD= LJ9FK>=J AFLG L@= ?J==F ;G>>== :=9FK <MJAF? >=JE=FL9LAGF
O9K @A?@DA?@L=< 9F< L@= CAF=LA; KLM<Q G> L@J== D9:=DD=< NGD9LAD=K O9K =K
L9:DAK@=< /@JGM?@GML L@=AJ LJ9FK>=J L@= 9JGE9 ;GEHGMF<K O=J= AF_M
=F;=< :Q K=N=J9D >9;LGJK KM;@ 9K L@= H9J;@E=FL J=KAKL9F;= L@= AFL=J
9;LAGF OAL@ L@= Q=9KL ;=DD O9DDK 9F< L@= <=?J9<9LAGF J=9;LAGFK AFLG L@=
;G>>== :=9FK /@= H@=FQD=L@9FGD K==E=< LG := 9F AFL=J=KLAF? 9JGE9
;GEHGMF< 9K AL @9< L@= @A?@=KL LJ9FK>=J J9L= ;GEH9J=< LG :ML9F9D 9F<
AKG9EQD 9;=L9L= AF KHAL= G> ALK J=L=FLAGF :Q L@= H9J;@E=FL
/@MK AL O9K HGKKA:D= LG ;GF;DM<= L@9L 9DD L@=K= NGD9LAD= ;GEHGMF<K
L@9L ;9F := HJG<M;=< :Q Q=9KL <MJAF? >=JE=FL9LAGF ;GMD< := LJ9FK
>=JJ=< AFLG L@= ;G>>== :=9FK OAL@ <A>>=J=FL J9L= 9F< ;GF;=FLJ9LAGF /@AK
UNCORRECTED PROOF
&)/"&1*2*9&1 44)-*2.897> === ==== ======
>9;L ;9F =F9:D= L@= ;G>>== AF<MKLJQ LG EG<MD9L= L@= ;G>>== 9JGE9LA; HJG
^D= :Q ;GFLJGDDAF? L@= >=JE=FL9LAGF KL=H $F L@= >MLMJ= AL OADD := F=;
=KK9JQ LG >GDDGO L@= >9L= G> L@=K= LJ9FK>=JJ=< EGD=;MD=K L@JGM?@GML L@=
HJG;=KKAF? KL=HK <JQAF? JG9KLAF? 9F< :J=OAF? AF GJ<=J LG =N9DM9L= L@=
AEH9;L G> L@= LJ9FK>=J G> NGD9LAD= ;GEHGMF<K GF L@= IM9DALQ G> L@= ^F9D
HJG<M;L MKAF? 9 K=FKGJA9D KLM<Q
CRediT authorship contribution statement
F. Hadj Salem: !GJE9D 9F9DQKAK $FN=KLA?9LAGF 2JALAF?  GJA?AF9D
<J9>L 1AKM9DAR9LAGF (=L@G<GDG?Q M. Lebrun: -=KGMJ;=K 9L9 ;MJ9LAGF
C. Mestres: (=L@G<GDG?Q 19DA<9LAGF N. Sieczkowski: 2JALAF?  J=NA=O
 =<ALAF? !MF<AF? 9;IMAKALAGF R. Boulanger: GF;=HLM9DAR9LAGF 19DA
<9LAGF 2JALAF?  J=NA=O  =<ALAF? !MF<AF? 9;IMAKALAGF A. Collignan:
(=L@G<GDG?Q .MH=JNAKAGF
Declaration of Competing Interest
/@= 9ML@GJK <=;D9J= L@9L L@=Q @9N= FG CFGOF ;GEH=LAF? ^F9F;A9D AF
L=J=KLK GJ H=JKGF9D J=D9LAGFK@AHK L@9L ;GMD< @9N= 9HH=9J=< LG AF_M=F;=
L@= OGJC J=HGJL=< AF L@AK H9H=J
Acknowledgements
/@= 9ML@GJK 9;CFGOD=<?= L@=AJ ^F9F;A9D KMHHGJL >JGE L@= '9DD=E9F<
.. GEH9FQ /GMDGMK= !J9F;= !MJL@=J L@= 9ML@GJK OGMD< DAC= LG
L@AFC (9JA=@JAKLAF= '9@GF >GJ @=DHAF? AF L@= HJ=H9J9LAGF G> L@= E9L=
JA9DK >GJ ^=D< =PH=JAE=FLK
Appendix A. Supplementary data
.MHHD=E=FL9JQ <9L9 LG L@AK 9JLA;D= ;9F := >GMF< GFDAF= 9L @LLHK<GA
GJ?B>GG<;@=E
References
J=KK9FA  + + (9JLAF=R . % N9F?=DAKL9 . - A9K -  .;@O9F - ! 
@9J9;L=JAKLA;K G> >=JE=FL=< ;G`== AFG;MD9L=< OAL@ Q=9KL KL9JL=J ;MDLMJ=K MKAF?
<A`=J=FL AFG;MD9LAGF E=L@G<K '2/   <GABDOL
QLG> " &FGHH . .;@A=:=JD= + /=MLK;@ $ .=DE9J  $F_M=F;= G> HJG;=KKAF?
GF L@= ?=F=J9LAGF G> γ9EAFG:MLQJA; 9;A< AF ?J==F ;G`== :=9FK MJGH=9F !GG<
-=K=9J;@ 9F< /=;@FGDG?Q  5=ALK;@JA>L !MJ '=:=FKEALL=D0FL=JKM;@MF? 0F<
!GJK;@MF?
@9DA=J + F?GL  =DL=AD  G;G /  "MF9L9 5  $FL=J9;LAGFK :=LO==F 9JGE9
;GEHGMF<K 9F< O@GD= E9FFGHJGL=AF AKGD9L=< >JGE .9;;@9JGEQ;=K ;=J=NAKA9= KLJ9AFK
!GG< @=EAKLJQ   <GAB>GG<;@=E
GEMRRG + /9L ' !=FRA  JGLLG ' 9LLAKLMLL9 !  5AJGFA -  $FL=J9;LAGFK
:=LO==F Q=9KL 9MLGDQK9L=K 9F< NGD9LAD= ;GEHGMF<K AF OAF= 9F< EG<=D KGDMLAGF !GG<
@=EAKLJQ   <GAB>GG<;@=E
= 9KLJG -   (9JJ9;;AFA +  QLGDG?Q :AG;@=EAKLJQ 9F< EGD=;MD9J ;@9F?=K
<MJAF? ;G`== >JMAL <=N=DGHE=FL J9RADA9F %GMJF9D G> +D9FL +@QKAGDG?Q 
 <GA.
M9JL= " . +=J=AJ9    !9J9@   @DGJG?=FA; 9;A<K 9F< GL@=J J=D=N9FL
;GEHGMF<K AF J9RADA9F ;G`==K HJG;=KK=< :Q K=EA<JQ 9F< O=L HGKL@9JN=KLAF?
E=L@G<K !GG< @=EAKLJQ  
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9F< AF<MKLJA9D 9HHDA;9LAGFK G> 9JGE9 >GJE9LAGF AF Q=9KL ! (. (A;JG:AGDG?Q -=NA=OK
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N9F?=DAKL9 . - .ADN9 ! (A?M=D ( " +<9  GJ<=AJG <=. +AF@=AJG ( M9JL=
2 !  .;@O9F - !  $EHJGN=E=FL G> ;G`== :=N=J9?= IM9DALQ :Q MKAF? K=D=;L=<
Q=9KLK KLJ9AFK <MJAF? L@= >=JE=FL9LAGF AF <JQ HJG;=KK !GG< -=K=9J;@ $FL=JF9LAGF9D 
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#9E==<  #MKK9AF .  $B9R ( 0 0DD9@ . +9K@9 $  .MD=JA9 #  - 
!9JE LG ;GFKME=J !9;LGJK 9`=;LAF? L@= GJ?9FGD=HLA; ;@9J9;L=JAKLA;K G> ;G`== $$
+GKL@9JN=KL HJG;=KKAF? >9;LGJK GEHJ=@=FKAN= -=NA=OK AF !GG< .;A=F;= 9F< !GG< .9>=LQ
  <GA
%GWL / '9`9J?M=  =K;JGAP ! GMD:=9M . =JLJ9F<  &G;@CG  <=  MKK=JL .
 $F_M=F;= G> =FNAJGFE=FL9D >9;LGJK O=L HJG;=KKAF? 9F< L@=AJ AFL=J9;LAGFK GF
L@= :AG;@=EA;9D ;GEHGKALAGF G> ?J==F J9:A;9 ;G`== :=9FK !GG< @=EAKLJQ 
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&FGHH . QLG> "  .=DE9J   $F_M=F;= G> HJG;=KKAF? GF L@= ;GFL=FL G> KM?9JK
AF ?J==F J9:A;9 ;G`== :=9FK MJGH=9F !GG< -=K=9J;@ 9F< /=;@FGDG?Q 
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'== ' 2 @=GF? ( 2 MJJ9F + 4M   'AM . ,  G`== >=JE=FL9LAGF 9F< _9NGJ
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B>GG<;@=E
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NA9 L@= >=JE=FL9LAGF G> ?J==F ;G`== :=9FK OAL@ -@ARGHMK GDA?GKHGJMK $ "J==F ;G`==
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"J==F ;G`== '2/   <GABDOL
(MKK9LLG . $ (9;@9<G ( . (9JLAFK .  /=AP=AJ9 %   +JG<M;LAGF
;GEHGKALAGF 9F< 9HHDA;9LAGF G> ;G`== 9F< ALK AF<MKLJA9D J=KA<M=K !GG< 9F< AGHJG;=KK
/=;@FGDG?Q   <GAKR
)=LG  + <=  +=J=AJ9 " 1 <= ( /9FG:= 1 /@GE9R .G;;GD 1 <9 .ADN9  % " -G
<JA?M=K   .G;;GD   4=9KL AN=JKALQ 9F< +@QKA;G;@=EA;9D @9J9;L=JAKLA;K
KKG;A9L=< OAL@ G>>== =9F !=JE=FL9LAGF >JGE L@= J9RADA9F =JJ9<G (AF=AJG -=?AGF
!=JE=FL9LAGF   *$>=JE=FL9LAGF
)=LG  + <=  +=J=AJ9 " 1 <= ( !AF;G  ( * '=LLA '  % <9 .ADN9  % "
19F<=F:=J?@= ' + .  .G;;GD  -  >^;A=FL ;G>>== :=9FK EM;AD9?= D9Q=J
J=EGN9D MKAF? D9;LA; 9;A< >=JE=FL9LAGF AF 9 KLAJJ=<L9FC :AGJ=9;LGJ &AF=LA; E=L9:GDA;
9F< K=FKGJA9D KLM<A=K !GG< AGK;A=F;=   *$B>:AG
+9LMA . DAF;GF ' +=J=KKGF  59F;9FA ( GFL= ' =D /=JJ9 ' J9A<GL 
'AH9K= 9;LANALQ 9F< 9FLAGPA<9FL ;9H9;ALQ AF ;G`== G`=9 9J9:A;9 ' K==<K <MJAF?
?=JEAF9LAGF +D9FL .;A=F;=   <GABHD9FLK;A
+=J=AJ9 " 1 <= ( )=LG  .G;;GD 1 / (=<=AJGK   + 2GA;A=;@GOKCA  ' .G;
;GD  -  GF<M;LAF? KL9JL=J ;MDLMJ=;GFLJGDD=< >=JE=FL9LAGFK G> ;G>>== :=9FK
<MJAF? GF>9JE O=L HJG;=KKAF? "JGOL@ E=L9:GDA; 9F9DQK=K 9F< K=FKGJA9D =>>=;LK !GG<
-=K=9J;@ $FL=JF9LAGF9D   *$B>GG<J=K
+=J=AJ9 " 1 <= ( .G;;GD 1 / J9J . & )=LG  .G;;GD  -  (A;JG:A9D
=;GDG?Q 9F< KL9JL=J ;MDLMJ= L=;@FGDG?Q AF ;G>>== HJG;=KKAF? JALA;9D -=NA=OK AF !GG<
.;A=F;= 9F< )MLJALAGF   *$
+=J=AJ9 " 1 <= ( )=LG  + <=  (9?9D@T=K %YFAGJ  $ 1SKIM=R 5 . (=<=AJGK 
 + 19F<=F:=J?@= ' + . .G;;GD  -  PHDGJAF? L@= AEH9;LK G> HGKL@9J
N=KL HJG;=KKAF? GF L@= 9JGE9 >GJE9LAGF G> ;G>>== :=9FK  J=NA=O !GG< @=EAKLJQ
  *$B>GG<;@=E
+GDLJGFA=JA +  -GKKA !  @9DD=F?=K AF KH=;A9DLQ ;G`== HJG;=KKAF? 9F< IM9DALQ
9KKMJ9F;= @9DD=F?=K   <GA;@9DD=
+M:@=E  @LLHKHM:;@=EF;:AFDEFA@?GN ;;=KK=<  !M:JM9JQ 
-9EXJ=R(9JLXF=R  .9D?9<G=JN9FL=K (  -G<JX?M=R%AE=F=K "  "9J;X9DN9J9<G
(  @=J:D9F; !  VF=L %   29L=J LJ9FKHGJL AF H9J;@E=FL 9F< =F<GKH=JE
G> ;G`== :=9F %GMJF9D G> !GG< F?AF==JAF?   <GA
BB>GG<=F?
-A:=AJG ' . (A?M=D ( " <9  + N9F?=DAKL9 . - (9JLAFK + ( ( N9F (MDD=E
% =DAR9JAG ( #  .;@O9F - !  =@9NAGJ G> Q=9KL AFG;MD9L=< <MJ
AF? K=EA<JQ ;G>>== >=JE=FL9LAGF 9F< L@= =>>=;L GF ;@=EA;9D 9F< K=FKGJA9D HJGH=J
LA=K G> L@= ^F9D :=N=J9?= !GG< -=K=9J;@ $FL=JF9LAGF9D   *$
B>GG<J=K
.=DE9J  QLG> " &FGHH .   J=AL=FKL=AF   "=JEAF9LAGF G> ;G`== K==<K
9F< ALK KA?FA^;9F;= >GJ ;G`== IM9DALQ +D9FL AGDG?Q   <GA
K
.ADN9  ! 1AD=D9  ( <= .GMR9 GJ<=AJG  M9JL= 2 ! A9K  -  .;@O9F - ! 
N9DM9LAGF G> 9 HGL=FLA9D KL9JL=J ;MDLMJ= >GJ =F@9F;= IM9DALQ G> ;G`== >=JE=FL9LAGF
2GJD< %GMJF9D G> (A;JG:AGDG?Q  AGL=;@FGDG?Q   <GA
K
.ADN9  ! ; (A;JG:A9D 9;LANALQ <MJAF? ;G>>== >=JE=FL9LAGF $F .;@O9F - !  !D==L
" # =<K G;G9 9F< ;G>>== >=JE=FL9LAGF )=O 4GJC )4- +J=KK 
1GADD=Q  .=MNJ= ( "GM?=GF - &9J:GOA9C / @9KK9?F=   =:=9M>GJL ! 
/J9FK>=J G> O9L=J 9F< 9;LAN= EGD=;MD=K 9L L@= AFL=J>9;=K AF ;GEHD=P >GG< KQKL=EK
/@=GJ=LA;9D 9F< HJ9;LA;9D 9KH=;LK +JG;=<A9 !GG< .;A=F;=   <GA
BHJG>GG
59;@D=<=J 1 1XLGNS ( #D9NGNS ( (GM<aXCGNS c (GBR=b + #=ME9FF # =;@=J
% -  AbGNS &  .L9:D= AKGLGH= ;GEHGMF<K+JG<M;LAGF <=L=;LAGF 9F<
9HHDA;9LAGF AGL=;@FGDG?Q <N9F;=K   *$
B:AGL=;@9<N
... The greatest diversification has occurred in the coffee bean fermentation process, in which the natural sugars in the coffee cherry are converted into alcohol, lactic acid, and a range of other secondary metabolites [6,10]. Although this process is often associated with coffee bean mucilage removal, several studies have shown that microbial metabolites diffuse into the beans and alter the quality of the final beverage [11][12][13][14]. Carvalho Neto et al. [15,16] recently proposed the use of a stirred-tank reactor (STR) and starter culture to standardize coffee fermentation, which is usually carried ...
... Although the exact function of this pathway is unclear, some results suggest that it may be associated with the maintenance of cell viability [39]. Furthermore, We speculate that this reduction may be associated with a diffusion process into the coffee beans or that these molecules were precursors for the formation of other volatile compounds [11,19]. Finally, the results showed that, in general, the consumption of sugars and the production of organic acids and volatile compounds showed significant differences among the bottom, middle, and top layers throughout the fermentation, suggesting that although the bacterial and fungal diversity did not show great variations, the metabolism of these microorganisms can change drastically among the layers. ...
... The increase in fermentation time resulted in the gradual decrease of some compounds belonging to the aldehydes, for instance: hexanal, nonanal, butanal, 3-methyl, and heptanal. A recent work by Salem et al. [11] evaluated the diffu- Esters also showed a relatively higher abundance when compared to other coffee fermentation studies [10,23,24,32]. At the beginning of fermentation, this chemical group was mainly represented by methyl acetate and ethyl acetate. ...
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In this study, an investigation of the microbial community structure and chemical changes in different layers of a static coffee beans fermentation tank (named self-induced anaerobic fermentation-SIAF) was conducted at different times (24, 48, and 72 h). The microbial taxonomic composition comprised a high prevalence of Enterobacteriaceae and Nectriaceae and low prevalence of lactic acid bacteria and yeast, which greatly differs from the traditional process performed in open tanks. No major variation in bacterial and fungal diversity was observed between the bottom, middle, and top layers of the fermentation tank. On the other hand, the metabolism of these microorganisms varied significantly, showing a higher consumption of pulp sugar and production of metabolites in the bottom and middle layers compared to the top part of the fermentation tank. Extended processes (48 and 72 h) allowed a higher production of key-metabolites during fermentation (e.g., 3-octanol, ethyl acetate, and amyl acetate), accumulation in roasted coffee beans (acetic acid, pyrazine, methyl, 2-propanone, 1-hydroxy), and diversification of sensory profiles of coffee beverages compared to 24 h of fermentation process. In summary, this study demonstrated that SIAF harbored radically different dominant microbial groups compared to traditional coffee processing, and diversification of fermentation time could be an important tool to provide coffee beverages with novel and desirable flavor profiles.
... During this step, the metabolism of yeast can lead to the hydrolysis of mucilage macromolecules and the generation of important metabolites such as flavor compounds like esters, alcohols, aldehydes, ketones, and terpenoids (Hameed et al., 2018;Lee et al., 2015;Martinez et al., 2019). Some of these metabolites can diffuse into coffee beans by crossing the parchment layer and therefore contribute to the aroma profile of coffee such as 2-phenylethanol, isoamyl acetate and butanal (Hadj Salem et al., 2020;Pereira et al., 2019). Parchment, a fibrous layer with a similar structure to wood (Ramírez-Martínez et al., 2013), is a natural means of protecting coffee seeds from digesting enzymes in the gut of frugivorous animals, keeps the coffee seed available to germination-related metabolism after harvesting (De Castro and Marraccini, 2006;Selmar et al., 2006) and acts like a transfer resistance layer (Hadj Salem et al., 2020). ...
... Some of these metabolites can diffuse into coffee beans by crossing the parchment layer and therefore contribute to the aroma profile of coffee such as 2-phenylethanol, isoamyl acetate and butanal (Hadj Salem et al., 2020;Pereira et al., 2019). Parchment, a fibrous layer with a similar structure to wood (Ramírez-Martínez et al., 2013), is a natural means of protecting coffee seeds from digesting enzymes in the gut of frugivorous animals, keeps the coffee seed available to germination-related metabolism after harvesting (De Castro and Marraccini, 2006;Selmar et al., 2006) and acts like a transfer resistance layer (Hadj Salem et al., 2020). Finally, the beans are sundried to 10-12% moisture content to facilitate storage and transport (Pereira et al., 2019). ...
... This work aims at building a dynamic model in order to better understand the evolution of the concentration of three aroma compounds in coffee beans during fermentation and to identify the mechanisms involved in this wet processing step which have a direct impact on the transfer of metabolites. The implementation of this model follows a progressive approach and uses data from the monitoring of transfer kinetics of labeled molecules obtained in our previous study (Hadj Salem et al., 2020). ...
Article
Models of increasing complexity were developed to identify and represent mechanisms affecting the evolution of the concentration of 3 aroma compounds (2-phenylethanol, isoamyl acetate and butanal) usually produced by yeasts and transferred to coffee beans during the fermentation. Model parameters were identified from simulated wet treatment performed with four media (M1: dehulled beans, M2: demucilaginated beans, M3: depulped beans, M4: depulped beans with yeast), at 25 °C using labeled aroma compounds. The transfer of 2-phenylethanol was well described by a model including evolving resistance over time (R² = 0.98) while the accumulation of isoamyl acetate and butanal was better described by a model including two first order reactions in parallel (r² = 0.87–0.66 and r² = 0.80–0.67, respectively). The model development contributed to understand several mechanisms involved during fermentation such as the evolutive parchment resistance and the complex degradation reactions that take place simultaneously and have a significant impact on the compounds transfer.
... During postharvest processing, fermentation occurs spontaneously by epiphytic microorganisms (bacteria, yeasts, and fungi), which process the coffee mucilage (Silva et al., 2013). The production of microbial metabolites can reach the interior of the seed, thus leading to beneficial (organic acids of interest, esters, alcohols, sugars) or harmful effects (undesirable organic acids and toxins) on the quality of coffee beans (Elhalis et al., 2021;Hadj Salem et al., 2020;Wang et al., 2019Wang et al., , 2022. In addition, during the postharvest period, physiological processes associated with germination begin inside the seed (respiration and cell division). ...
... Epiphytic microorganisms participate in coffee fermentation, competing for available nutrients (pectin, sugars, amino acids, polysaccharides) among themselves and with starter cultures (Silva et al., 2013). The microbial metabolites produced can migrate to the interior of the bean, altering the internal chemical composition of the bean and providing organic compounds (amino acids, sugars, volatile compounds) that modify the sensory profile of the coffee (Hadj Salem et al., 2020;Pereira et al., 2022;Wang et al., 2022). ...
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Microbial metabolites produced during fermentation migrate into the coffee and can influence the decrease in seed viability and coffee quality. This study evaluated the effects of physiological changes in seed viability on the sensory quality of the beverage using starter cultures through self-induced anaerobic fermentation (SIAF) in Coffea arabica L. for natural and pulped coffee. The yeasts were monitored by real-time polymerase chain reaction (qPCR). High-performance liquid chromatography (HPLC) detected citric, malic, and succinic acids in all fermented coffees. Furthermore, lactic acid was mainly identified in those coffees processed by the SIAF method. Volatile compounds (40) were detected by gas chromatography-mass spectrometry (GC-MS). Alterations in physiological quality were identified, with decreased embryonic viability and cell membrane damage by tetrazolium and electrical conductivity tests. All fermented coffees obtained scores above 80 points. The Torulospora delbrueckii yeast got the best score (86.50) in pulped coffee, and the Candida parapsilosis yeast received the highest score (85.90) in the natural coffee using the SIAF method. The coffees were characterized by aromas and flavors of citrus, caramel, honey, chocolate, and chestnut. The coffee fermentation process with yeast inoculation affected the coffee bean viability but not the beverage's sensory quality, indicating that the use of yeast starters by SIAF favors the production of specialty coffees with differentiated sensory characteristics.
... Synthetized codon-optimized enzymes were expressed in the yeast and the results showed that the engineered strain was able to significantly produce the phenylpropanoid in Chardonnay grape juice [76]. This same approach can be applied to cocoa and coffee fermentation which favor-active compounds (e.g., butanal, 2-phenyethanol, isoamyl acetate, acetaldehyde, 1-pentanol, ethyl acetate, and 2-phenylacetaldehyde) are used to select yeasts and bacteria capable of influencing the final product quality [59,77]. ...
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Rudimentary food fermentation can be defined as a spontaneous process of conversion of food components through enzymatic action. A great variety of fermented foods are produced using spontaneous approaches; however, cocoa and coffee represent the most important agricultural commodities on international markets. As a manner to increase the efficiency of these processes, starter cultures have been developed and applied under field conditions. The selection process begins with the recovery of microbial strains from spontaneous fermentation through phenotypic and metabolic traits. Next, mutation-based breeding is used to develop and improve well-adapted starter cultures. With advances in synthetic biology, especially in the last decade, the development of robust cellular fabrications with high fermentative capacity has become easier—largely due to the development of genomic approaches, such as next-generation sequencing techniques, CRISPR-Cas system and bioinformatics tools. This review brings prospects on the use of synthetic biology to design new robust strains for use in cocoa and coffee fermentations, but which can be extended to other rudimentary foods. In addition, metabolic traits and target genes (e.g., UvrA, RecA, GPD1, and GPP2) are proposed as a starting point for the improvement of cocoa and coffee starters. Finally, the regulatory and safety requirements for these food crops are addressed. This review aims to stimulate research on the process of fermentation and the associated synthetic biology tools to produce fermented food efficiently and sustainably.
... There were correlations between the genotypes: (4 and 10), (2 and 5), (6, 7 and 8). It can be observed in Figures 2 and 3 that the attribute aroma along the vertical axes tended to be more accentuated in the two pulping times, which can be explained by the fact that wet processing accentuates this attribute (Salem et al., 2020). ...
Article
In recent years, the Guatemalan coffee plantations have suffered a decline in its yield as a result of coffee rust. The use of cultivars resistant to this disease and with the potential to produce coffee with good drinking quality is essential for the sustainability of coffee cultivation in the country. The aim of this study was to analyze bean quality potential and the sensory profile of rust-resistant Arabica coffee genotypes as a function of different times of biological fermentation. The experiment was carried out in July 2014, at El Panorama farm, located in the municipality of San Rafael Pie de La Cuesta, Department of San Marcos, Guatemala. Eight rust resistant F5 progenies were tested and cultivars Marsellesa and Bourbon Amarelo were used as controls. Each genotype was subjected to two times of biological fermentation in water, after peeling (24 and 72 h). The experimental design was randomized complete blocks with three replications, in a 10 (genotypes) × 2 (times) factorial scheme, totaling 60 experimental units. The quality, sensory profile and granulometry of the treatments were evaluated. All the rust-resistant genotypes studied showed potential to produce specialty coffees in Guatemala and a superior granulometry in relation to Bourbon Amarelo. Marsellesa and Bourbon Amarelo obtained higher final scores and the attributes flavor, aftertaste, acidity, body, balance and overall were more accentuated. The time of biological fermentation did not influence the final score of the coffee (total score in the SCA protocol); however, there was a change in the sensory profile, with emphasis on cultivar Marsellesa, which increased the frequency of fruity notes and reduced caramel notes with longer fermentation time.
... L'étape de la fermentation est une étape clef car elle permet le développement d'un grand nombre de composés volatils aromatiques qui ne sont pas observés dans les fèves séchées non fermentées (Utrilla-Vázquez et al., 2020). Comme cela a été prouvé pour les grains de cafés, il est probable que les molécules produites lors de la fermentation à la surface de la pulpe des fèves de cacao pénètrent dans la fève et produisent des réactions chimiques et enzymatiques (Hadj Salem et al., 2020). ...
Thesis
Theobroma cacao est un arbre originaire des régions tropicales humides d’Amérique latine. Il est cultivé pour ses fèves qui permettent la production de chocolat. Le Nacional, originaire d’Equateur, est une variété de cacao fin connue pour ses arômes floraux et épicées, appelée saveur « Arriba ». Les mécanismes de la synthèse de ses arômes restent peu connus. Les travaux de cette thèse ont porté sur l’étude des déterminants génétiques et biochimiques des arômes des cacaos fins équatoriens afin d’initier de contribuer aux connaissances dans ce domaine.Une première partie de l’étude a été réalisée à partir d’une population de cacaoyer de type Nacional moderne, qui est la variété de Nacional actuellement cultivée. Des études d’associations ont été réalisées sur l’ensemble du génome (GWAS) et ont porté sur l’analyse des composés volatils relatifs aux arôme floraux et fruités (fruits frais et fruits secs) contenus dans les fèves, avant et après torréfaction, ainsi que, sur des résultats d’analyses sensorielles de liqueurs. Cette première étude a pu montrer que les arômes floraux du Nacional étaient principalement synthétisés grâce à deux voies de biosynthèse: celle des monoterpènes et la voie de dégradation du L-phénylalanine. Les résultats relatifs aux arômes fruités ont permis de mettre en lumière cinq voies métaboliques majeures: la voie de biosynthèse des monoterpènes, les voies de dégradations du L-phénylalanine, des sucres, des acides gras et des protéines. Des gènes candidats codant pour des enzymes impliqués dans ces voies métaboliques ont été identifiés dans les zones d’associations correspondantes.La variété Nacional moderne est issue de diverses générations de croisements entre des Trinitario (hybrides Amelonado/Criollo) et le Nacional ancestral, mettant ainsi en jeu 3 ancêtres contrastés. L’effet de cette étape de domestication récente sur les arômes de la variété Nacional moderne a été étudié. Grâce aux données de génotypage des trois ancêtres de référence et aux résultats des GWAS portant sur l’ensemble des caractères de qualité (composés volatils et non-volatils, analyses sensorielles), il a été possible de déterminer l’origine des allèles ayant un effet positif sur les arômes dans les différentes zones d’associations. Cette étude a montré que l’ensemble des ancêtres fondateurs ont apporté des allèles favorables à la synthèse d’arômes de qualité (floraux, fruités, …) mais aussi à la synthèse de défauts (amertume, astringence, …). Nous avons pu montrer que les zones d’associations en lien avec les arômes de qualité et celles avec les défauts n’étaient pas liées génétiquement. Il est donc possible de sélectionner les zones d’intérêts pour les arômes tout en contre-sélectionnant les zones apportant des défauts.La deuxième partie de cette étude a porté sur l’analyse des arômes d’une population de cacaoyers natifs d’Amazonie et issus de la zone d’origine de la variété Nacional ancestral. Dans cette étude, des analyses GWAS ont également été effectuées sur l’ensemble des caractères de qualité analysés précédemment. Quatre vingt dix sept gènes candidats sont communs aux deux populations analysées. De nouveaux composés volatils ainsi que de nouvelles zones d’associations ont également été détectées montrant ainsi une plus grande diversité et richesse aromatique de ces nouvelles ressources génétiques et leur intérêt pour la création de nouvelles variétés aromatiques adaptées à l’Amazonie.Enfin, une étude GWAS sur les composés non-volatils, les caractères sensoriels liés à l’amertume et à l’astringence, ainsi que la teneur en matière grasse et en protéines, a également été réalisée sur les deux populations. Des gènes candidats en lien avec la voie de biosynthèse de la caféine et celle des polyphénols, ou en lien avec la voie de biosynthèse des acides gras ont pu être observés dans les zones d’associations.
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