THE COLOR
OF
WINE:
A
HISTORICAL PERSPECTIVE.
11. TRICHROMATIC
METHODS
F.J.
HEREDIA
and
M.
GUZMAN-CHOZAS'
Depa men
o
Nu i ion and Food Science, Facul y
o
Pha macy
Uni e si y
o
Se illa,
41
01
2
Se illa, Spain.
Accep ed
o
Publica ion July
23, 1993
ABSTRACT
The ich oma ic heo y was applied o wines a he end
o
he
1930s.
T ich oma ic co-o dina es, dominan wa eleng h, pu i y and luminance we e
de e mined. The Munsell sys em and he Lo ibond me hod, which
had
indus ial
applicabili y, we e compa ed wi h he simpli ied me hods p oposed by he
L
'o lce In e na ionale de la Vigne e du Vin
(ON).
These me hods a e o lcial
in Spanish ood egula ions on wine analysis.
Re
CIE
ecommenda ions,
h ough he weigh ed o dina e me hod, se up he colo ime ic pa ame e s o
wines, such as hue, ligh ness, pu i y
o
sa u a ion, di e ences
o
colo ,
pe cep ibili y. La ely, a emp s ha e been made o co ela e he ch oma ic
p ope ies
o
wines wi h composi ion, o igin, aging and senso y e alua ion. Some
au ho s ha e s udied he eliabili y
o
he OIV me hods e sus he mo e igid
ecen
CIE
me hods. Imp o ed o mulae
o
he compu a ion
o
dominan
wa eleng h and ou s anding co ela ions among senso ial sco es, ch oma ic
pa ame e s and an hocyanins Cpolyphenols) con en
o
wines ha e been
es ablished.
INTRODUCTION
As
had been es ablished in
a
campaign a icle (He edia and Guzman-Chozas
1993)
ch oma ic me hods based on di ec spec al e alua ions, in spi e o being
use ul in he measu emen s
o
colo a ia ion in wine,
show
undoub ed
de iciencies wi h ega d o he de ini ion and cha ac e iza ion o colo .
Adequa e in eg a ion and isible abso p ion spec a ha e need o ich oma ic
me hods, ound in mechanisms o colo ision by luminous s imuli. I is
conside ed ha any colo may be ma ched by means o an app op ia e mix u e
o
h ee p ima y colo ed s imuli.
'Co espondence should be add essed
o:
P o .
D .
M.
Guzmin-Chozas
Jou nal
o
Food Quali y
16
(1993). 439-449.
All
Righ s Rese ed.
Topy igh
1994
by
Food
&
Nu i ion
P ess,
hc.,
T umbull,
Connec icu .
439
440
F.J.
HEREDIA
and
M.
GUZMAN-CHOZAS
The applica ion o ich oma ic heo y o he colo s udy o wines p o ides
a numbe o possibili ies in esea ch o hei op ical p ope ies and a mo e
accu a e ch oma ic cha ac e iza ion, h ough he se e al me hodologies suppo ed
by o ganiza ions, such as he
Commission In e na ionale de
1
'Eclai age,
(CIE
1986).
TRICHROMATIC STIMULI
Winkle and Ame ine (1938a,b) we e he pionee s in he applica ion o
ich oma ic heo y o wine colo . They conside ed he basic pa ame e s:
ich oma ic coe icien s (ch oma ici y coo dina es), dominan wa eleng h
(A,),
pu i y and luminance. Likewise, hey compa ed hei esul s wi h he
Wine-colo ime e o Salle on and hey ound:
(1)
a
lack o p ecision, o e all in s ongly colo ed wines, leading o e o s o
(2)
a co ec illumina ion seemed as no possible
(3) he colo ed specimens did no ha e an uni o m in ensi y
10-25
%
Mo eo e , hey s udied he e ec o di e se ac o s, as g ape a ie y, he
aging p ocess, e c., and concep s as "b illiance" and "b igh ness" we e
di e en ia ed. A e wa ds, a numbe o au ho s made clea he impo ance o
ich oma ic sys ems o e alua ing he colo o wines (Li le and MacKinney
1966; Joslyn and Li le 1967; F ancis 1969; Li le and Liaw 1974; Kapus ina
el
al.
1976; Roube 1976; Timbe lake 1981; Pi acci 1984).
"Colo
in wines is composed o ou basic colo s: blue, g een, yellow and
ed". This simple asse ion om Vill o h (1958) was he basis o his p oposal
o a colo index o indica ing he pe cen age
(%)
o ligh abso p ion
a
538 nm,
h ough
1
mm
pa hleng h. The echnique consis s o measu ing he ansmi anc-
es wi h se e al il e s:
(1)
420-490 nm, o blue
(2)
530-550 nm, o g een
(3) 570-620 nm, o yellow
(4) 665-750 nm, o ed
The Munsell sys em has been applied o ch oma ic e alua ion o wines and
o he oods ex ensi ely (Jacobs 1938; K ame and Twigg 1959; Na ional
Canne s Associa ion Resea ch Labo a o ies 1968; Ba da io 1970; Li le 1976).
Ame ine
e al.
(1959) ha e used he Munsell me hod o s udy he colo o whi e
and ed wines o compa e hei esul s wi h hose ob ained h ough he use o
di e en colo ime e s.
TRICHROMATIC PROPERTIES
OF
WINE COLOR
44
1
Sambuc and Naude (1965) emphasized he impo ance o colo in oods u s,
and hey s udied he use o he
XYZ
sys ems wi h illuminan
C
as a e e ence.
These au ho s p oposed eplacing he CIE me hods by simpli ied me hods, based
on he selec ion o he mos ep esen a i e wa eleng hs. Fu he mo e such
me hods would ha e an ins umen al ad an age, since only necessa y would be
a simple colo ime e equipped wi h ou colo il e s. They applied he s anda d
colo scales equen ly used, as he Ga dne o FAC scales. P e iously, hey had
de e mined he ich oma ic cha ac e is ics o he s anda d il e s by using he
Lo ibond me hod and by means based on ans o ma ion diag ams. Bu
(1)
in mos cases hese me hods ha e been es ablished om a se o gi en il e s
wi hou co ec ing o hei p obable inaccu acy
(2) ich oma ic de e mina ions we e only use ul o measu e ch oma ici ies
h ough il e combina ions, and mo eo e hey did no o e ligh ness
di e ences.
The Lo ibond me hod, ounded on he use o h ee se s o glass il e s ( ed,
blue and yellow) (Anonymous 1939), was de ised a i s o he con olling o
bee colo (Ingle 1962; Egan
e
al. 1981), and
i
has also been applied o a s
and oils (Pome anz and Meloan 1978). The me hod es ima es ligh ness
di e ences by using g ey il e s, bu
i
p esen ed some ins umen al di icul ies
and disabili y o ob ain he in e se ans o ma ion. Because o hem, Sambuc and
Naude (1965) ea ed he calcula ion o ich oma ic coo dina es o il e s and
hei combina ions.
The in e na ional me hods o wine colo analyses, p oposed by he "L'O ice
In e na ionale de la Vigne e du
Vin",
OIV, a e based on s udies o he colo o
edible oils (P esnell 1949; Sambuc and Naude 1956, 1965; Bigoni 1963; S ella
1966). These au ho s p oposed di e se exp essions (Table 1)
o
ob ain is imuli
alues
(X,Y,Z),
which a e alid in he p edominan colo egion, om he
simpli ied Selec ed O dina e Me hod
o
Ha dy (1936).
These o mulae ha e been included in na ional and in e na ional egula ions
on analysis o wines (P esidencia del Gobie no 1977; 1981; CEE 1990).
Some e o s ound in he ea lie equa ions (Table
1)
o calcula e is imuli
alues ha e been demons a ed ecen ly by He edia and Guzmh (1991).
Negue uela and Echa a i (1988; 1989) and Negue uela
e
al.
(1988; 1990) ha e
p oposed a modi ica ion
o
he OIV me hod o ed wines and hei mix u es,
by using he S anda d Illuminan
D,,
and he CIE S anda d Obse e 1964 (x,,,
y,,), de ined o ision angles g ea e han 4". They ha e ob ained equa ions
dependen on abso bances a 420, 520 and 620 n n, conside ed by Glo ies (1984)
as he mos signi ican in wines.
442
F.J.
HEREDIA
and
M.
GUZMAN-CHOZAS
TABLE
1.
EQUATIONS
TO
OBTAIN TRISTIMULI VALUES
(X,
Y,
Z)
P esnell
(1949)
:
X
3
0.20
Tyu
+
0.15
TN
+
0.65
Tm
Y
0.10
T,
+
0.10
TN
+
0.20
Ta
2
3
1.20
Tyu
+
0.06
Ts
Sambuc and Naude
(ISSS),
o
he illu ninan
A:
X
a
0.46
T-
+
0.33
TSiS
+
0.19
T-
Y
0-20
T-
+
0.63
TSIS
+
0.17
T,,
2
0.24
T-2
+
0.94
T,
Bigoni
(1963),
o
he illuminan
A:
X
0.04
T,
+
0.40
T,
+
0.37
T,
+
0.19
T,
Y
=
0.19
Tby.
+
0.64
T,
+
0.17
T-
2
I
0.18
Ta
+
0.82
T,
S ella
(1966),
o
he illu ninan
C:
X
0.04
T-
+
0.39
TslJ
+
0.36
Tm
+
0.18
TW
Y
0.19
Ta
+
0.64
T,
+
0.17
T-
2
0.21
T,
+
0.97
TM
(5)
OIV
(1969) equa ions:
X
=
0.42
Tby
+
0.35
T,
+
0.21
Tyu
Y
=
0.20
T,
+
0.63
T,
+
0.17
T-
2
0-24
T,
+
0.94
TM
TRICHROMATIC PROPERTIES
OF
WINE COLOR
443
Li le (1976) de ined hue as he a ibu e by which a colo is iden i ied as
ed,
yellow,
g een,
e c.,
so
i
is closely ela ed wi h dominan wa eleng h
(A,,).
Dominan wa eleng h
(A,),
as
a ep esen a i e pa ame e o he hue
o
in
o colo , is e y impo an in he ch oma ic s udy o ed wines. Se e al au ho s
(Winkle and Ame ine 1938a; Ough
e
al.
1962) ha e demons a ed he in e es
o
A,
o he colo cha ac e iza ion.
Fo
ose wines, dominan wa eleng h akes
alues lowe han o ed wines (up o 40 nm o di e ence);
so,
we can hink
his could be a use ul disc iminan pa ame e (Ame ine and Winkle 1941).
Ame ine
e
al.
(1959) s udied dominan wa eleng hs in whi e and ose wines
om Cali o nia. Sud aud (1958) poin ed ou ha he a io A3?O/A520 could be
used as a measu e
o
hue changes ela ed o dominan wa eleng h. Ough
e
al.
(1962), by using a simpli ied me hod, ound a linea ela ion be ween log l/%X,
log 1/%Y, log
l/%Z
and colo in ensi y. Beginning om h ee samples (pu ple,
A,
=
505
nm; o ange,
A,
=
592 nm; ed,
Ad
=
611.2 nm) he au ho s p epa ed
di e en mix u es.
Beginning om h ee s anda d wines (Cabe ne , da k pu ple- ed; Bu gundy,
da k ed; and ose, ligh o ange- ed) and hei blends, Be g
e
al.
(
1964) ound
an ag eemen be ween
Ad
alues and he esponse o hue o he panelis s, ha
was di ec ly ela ed wi h he squa e oo o he inc ease o dominan wa eleng h
By means o a g aphic p ocedu e, he dis ance be ween Po
(A,,:
700-770 nm)
and
P
(Ad
o he sample) was measu ed by Pi acci and Spe a (1986). F om his
dis ance hey p oposed o apply a i e-g ade polynomic equa ion o calcula e he
dominan wa eleng h
(Ad)
o a ed wine.
A
no el polynomic quo ien o mula
o calcula e dominan wa eleng h o colo o ed wines has been ecen ly
p oposed (He edia and Guzman, 1992).
LIGHTNESS
Acco ding o Li le (1976) he ligh ness could be conside ed as he appa en
p opo ion o inciden ligh e lec ed
o
ansmi ed by he objec
on
a scale ha
goes om he whi e
o
colo less o black. Ligh ness da a o 33 a he di e en
whi e wines and
18
ed wines ha e been o e ed (Ame ine
e
al.
1959). I was
p o ed ha ose wines had g ea e ligh ness alues han ed wines (Ame ine and
Winkle 194
1).
App oxima ions o pe cen b igh ness and dominan wa eleng h
and some blending applica ions wi h ed wines ha e been ca ied ou (Ough
e
al.
1962).
When he colo poin s each alues which co espond o luminosi y
(Y)
alues o
Y
=
2, he ends o he colo poin s o mo e in pa allel wi h he
spec um locus, as well as he hue o shi om pu ple owa ds o ange- ed

444
F.J.
HEREDIA
and
M.
GUZMAN-CHOZAS
s opped (Kampis and As any 1985); ha is, he spec al colo s o he monome
and polyme pigmen s o ed wines whose luminosi y
(Y)
su pass he alue
Y
=
2
may no di e signi ican ly. Bu in da k ed wines, whose luminosi y
(Y)
was below
2,
he end o he shi o colo poin s du ing s o age would esul
in
an
alignmen o hese poin s away om he ach oma ic poin . As a conse-
quence o his beha io , he colo poin s mo e o highe dominan wa eleng h
(Ad), and hey we e placed in he come o he "colo iangle". This e en is
owing o he polyme iza ion
o
pigmen s du ing he s o age pe iod.
PURITY
Li le (1
976)
de ines pu i y o sa u a ion
as
he p opo ion o ch oma ic
con en in he o al pe cep ion; i is also he le el o di e ence om he neu al
o g ey poin o he same ligh ness alue. The Munsell ch oma scale is ounded
on he second de ini ion. In he pape published by Ame ine
el al.
(1959), da a
o pe cen age o pu i y o di e se ed and whi e wines (Sau e ne, Musca el,
She y, Bu gundy) a e gi en. Rose wines ha e pu i y alues lowe han ed
wines (Ame ine and Winkle 1941).
COLOR DIFFERENCES
Be g
e
al.
(1964) p oposed a spec opho ome ical me hod based on isual
compa isons o a i icial blends o p edic pe cep ibili y o he di e ence
be ween ansmi ance and dominan wa eleng h among ed wines. In he
CIELAB colo space, he dis ance be ween wo dis inguishable s imuli by a well
ained eye is
0.1
uni s
o
di e ence
o
colo (AE) (when op imal condi ions a e
applied). Bu o he human eye in o dina y ci cums ances, a dis ance o
1
be ween he s imuli o be dis inguishable is mo e app op ia e. Negue uela and
Echa a i (1983) ha e calcula ed in Rioja wines AE o check he eliabili y o
he simpli ied me hods p oposed by
OIV
(1969). They obse ed high alues o
AE, be ween
7
and 15 uni s, when young ed wines we e es ed. In wines aged
mo e han wo yea s, he colo di e ences (AE) oscilla ed a ound
1-2
uni s, e y
nea he pe cep ibili y limi .
SENSORY
EVALUATION
The human eye is ex ao dina ily sensi i e o small di e ences in colo s, and
he de elopmen o a a ional colo nomencla u e would be desi able (Ame ine
and Roessle 1983). O he wise, e ms such as
sca Le , b illian sca le , lashing
sca le , b igh
uby
sca le ,
limpid
sca le ,
uby
sca le
and
sca le - oned
seem
impossible o be dis inguishable (Peynaud
1984).
TRICHROMATIC PROPERTIES
OF
WINE
COLOR
445
Un il now, no many s udies abou senso y e alua ion o wines and
i s
ela ion wi h he ch oma ic pa ame e s ha e been ca ied ou (C aw o d
e
al.
1958; Single on and Ough 1962; Pangbo n
e
al.
1963; Li le 1973; Ame ine and
Roessle 1983; De Rosa 1985; Cas ino
e
al.
1990). Ough and Be g (1959)
published a pionee s udy
on
wines ega ding he possibili y
o
a co ela ion
be ween ch oma ici y quali ies and he sco es gi en by expe ienced panelis s
unde a ious ligh sou ces. S udies in ol ing ose wine colo p e e ences, by
compa ing he sco es gi en by expe ienced and inexpe ienced panels (consume s
panel), ha e been ca ied ou oo (Ough and Ame ine 1967). Bo h g oups
showed simila pa e ns, bu he e was signi ican ly mo e consis en p e e ences
wi h he expe ienced panel.
Co ela ions be ween he cha ac e is ics o he objec i e (ins umen al)
measu emen s and isual sensa ion ha e been es ablished. By means o
iangula and anking es s he ag eemen be ween he human eye and
ins umen al sensi i i ies ha e been s udied. Sco es om
0
o
30
we e hen
compa ed wi h an hocyanin con en , colo in ensi y, hue and is imuli alues
(Ke enyi and Kampis 1984). Casp and Be nabeu (1987a,b) de elop senso y
cha ac e iza ion a emp s using ose, whi e and ed wines; bu hey did no
co ela e senso y sco es wi h objec i e (ins umen al) me hods.
The e a e a numbe o gene al s udies abou isual pe cep ion ha mus be
conside ed when a p og am on senso y e alua ion o colo is de eloped. S udies
on isual e iciency (MacAdam 1935a,b) and subjec i e abili y o colo
ma ching (Newhall
el
a .
1957); he in luence o he me ame ism and usion o
p ima ies on colo di e en ial h eshold (Hi a e
a .
1976; Lozano 1979) ha e
been made. E en conside a ions abou he in luence o he ime in e al be ween
s imuli pe cep ion disc imina ion expe imen s, ha e been aken in o accoun
(Rome o
e
a .
1986)
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