See discussions, stats, and author profiles for this publication at:
Article · January 2016
6 authors, including:
25 PUBLICATIONS 296 CITATIONS
99 PUBLICATIONS 1,052 CITATIONS
325 PUBLICATIONS 5,230 CITATIONS
318 PUBLICATIONS 4,389 CITATIONS
Al in-text references underlined in blue are linked to publications on ResearchGate,
Available from: Davy Van de Wal e
letting you access and read them immediately.
Retrieved on: 12 May 2016
Food Research International 82 (2016) 44–52
Contents lists available at ScienceDirect
Food Research International
Factors inﬂuencing quality variation in cocoa (Theobroma cacao) bean
ﬂavour proﬁle — A review
John Edem Kongor ,, Michael Hinneh , Davy Van de Walle , Emmanuel Ohene Afoakwa ,Pascal Boeckx , Koen Dewettinck
a Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgiumb Department of Nutrition & Food Science, University of Ghana, P. O. Box LG 134, Legon-Accra, Ghanac Isotope Bioscience Laboratory (ISOFYS), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgium
This review examined the factors that inﬂuence ﬂavour volatiles of cocoa beans and the volume of work that
Received 30 November 2015
needs to be done on these factors and their impact on the ﬂavour volatiles of commercial cocoa beans. Cocoa
Received in revised form 8 January 2016
bean ﬂavour is one of the most important quality attributes as ﬂavour is central to acceptability of cocoa beans
Accepted 15 January 2016
and cocoa products such as chocolate. The complex composition of cocoa bean ﬂavour depends on bean geno-
Available online 18 January 2016
type, postharvest treatments such as pulp pre-conditioning, fermentation and drying, industrial processes suchas roasting as well as the type of soil and age of cocoa tree. The bean genotype determines the chemical compo-
sition of the bean, speci
ﬁcally the contents of bean storage proteins, polysaccharides, and polyphenols. This de-
termines the quantities and type of precursors formed during fermentation and drying processes leading to
ﬂavour formation, hence, inﬂuencing both ﬂavour type and intensity. Cocoa bean fermentation and drying result
in the breakdown of the storage proteins by endogenous proteases into amino acids and short chainoligopeptides while the polysaccharides are also degraded by invertase to glucose and fructose. The aminoacids, oligopeptides, glucose and fructose react with each other during the roasting process to produce the typicalcocoa ﬂavour volatiles. Polyphenols are also oxidized by polyphenol oxidase during fermentation and dryingwhich reduce the astringency and bitterness of the beans, thus, enhancing the ﬂavour of cocoa beans. However,the extent to which other factors such as age of the cocoa tree and soil chemical compositions inﬂuence the for-mation of ﬂavour precursors and their relationships with ﬁnal ﬂavour quality remains unclear. With increasingdemand for sustainable production of high quality cocoa beans, greater understanding of factors contributingto the variations in ﬂavour character would have signiﬁcant commercial implications.
2016 Elsevier Ltd. All rights reserved.
Factors affecting ﬂavour quality of cocoa beans. . . . . . . . . . . . . . . . . . . . . . . . 452.1.
Effect of genotype and origin of cocoa tree on cocoa bean ﬂavour quality. . . . . . . . . . . . . . . . . 45
Effect of postharvest treatment of cocoa on bean ﬂavour quality. . . . . . . . . . . . . . . . . . . 472.2.1.
Effect of industrial processing of cocoa on bean ﬂavour quality . . . . . . . . . . . . . . . . . . . 492.3.1.
Soil chemical composition and cocoa bean ﬂavour quality . . . . . . . . . . . . . . . . . . . . 49
⁎ Corresponding author at: Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgium.
E-mail addresses: [email protected], (J.E. Kongor).
0963-9969/ 2016 Elsevier Ltd. All rights reserved.
J.E. Kongor et al. / Food Research International 82 (2016) 44–52
practices, planting low-yield varieties, pests and diseases, ageing cocoatrees and loss of soil fertility due to inadequate or no use of fertilizers
Cocoa (Theobroma cacao L.) is a cash crop of huge economic signiﬁ-
cance in the world and the key raw material for chocolate manufactur-
The economic and health beneﬁts
ing It forms the major
of cocoa depend on the sustainable production and intensiﬁcation of
agricultural export commodity for several producing countries in
high quality cocoa beans. Also, sustaining the production of high quality
West and Central Africa, such as Cote d'Ivoire, Ghana, Nigeria and
cocoa beans in West Africa is crucial for the millions of smallholder fam-
Cameroon (). Cocoa be-
ily farmers that depend on cocoa for their livelihoods and the millions of
longs to the family of Sterculiaceae and the genus Theobroma
people who enjoy chocolate and other cocoa products around the
). The genus has twenty-two species of which
world. In promoting sustainability, the cocoa industry wants to see
T. cacao L. is commercially the most important due to the value of its
growth and improvement in the quantity and quality of the cocoa
seeds (). The seeds, commonly known
beans produced as well as the standard of living enjoyed by growers.
as cocoa beans, are obtained from the pods. These pods are oval in
Sustainable cocoa production also involves the production of high
shape, measure between 12 and 30 cm long, and contain 30 to 40
quality cocoa beans. Cocoa bean quality is made up of several compo-
beans embedded in a mucilaginous pulp, which comprises approxi-
nents such as ﬂavour volatiles, nutritional composition, polyphenolic
mately 40% of the bean fresh weight (
content and fermentative quality. The most important components are
The pulp is reported to be
the ﬂavour volatiles of the beans as these affect cocoa bean acceptability
rich in fermentable sugars of about 9 to 13% w/w ()
such as glucose, fructose and sucrose (
These compounds which constitute the ﬂavour quality of the beans
), high acidity (pH 3.0–3.5) conferred by the presence of di-
are, however, inﬂuenced by several factors. This review discussed the
verse organic acids, but mainly citric acid
factors that inﬂuence cocoa bean ﬂavour quality. The current state of
, and a protein content in the range of 0.4 to 0.6% w/w
knowledge in terms of research ﬁndings of these factors on the ﬂavour
volatiles of cocoa beans is presented. Research gaps in terms of the vol-
Cocoa is cultivated on lands covering over 70,000 km2 worldwide
ume of work that needs to be done on these factors and their impact on
between 20° north and south of the equator,
the ﬂavour volatiles of commercial cocoa beans are also exposed.
in areas with suitable environment for cocoa (). About70% of the world's cocoa production takes place in the equatorial region
2. Factors affecting ﬂavour quality of cocoa beans
of West Africa, and the rest in the equatorial regions of Central andSouth America, the West Indies, and tropical areas of Asia
Several indicators are used to measure the quality of cocoa beans.
. The cocoa tree is a perennial tree, 8 to 15 m in height
These include the bean size and count, bean colour and acidity of the
and requires hot, moist conditions to grow and will
beans. However, the most important quality indicator of cocoa beans
not withstand prolonged drought conditions without seriously depress-
is the amount and type of volatile ﬂavour compounds
ing the tree's vegetative and reproductive functions (
). Flavour is central to acceptability of cocoa
The fruit varies among varieties in size, shape, external colour, and ap-
beans and cocoa products such as chocolate (
pearance. These characters have often been used in classifying cocoa.
) and, consequently, contributes to determining
According to the World Cocoa Foundation (WCF), there are 5–6 mil-
the quality The characteristic ﬂavours of cocoa beans
lion farmers in developing countries across tropical Africa, Asia and
are due to a very rich volatile fraction composed of a mixture of
Latin America who produce around 90% of cocoa worldwide, and the
hundreds of compounds (). Currently, more than 600
number of people who depend upon cocoa for their livelihoods world-
ﬂavour compounds have been identiﬁed from cocoa beans and cocoa
wide is 40–50 million ). In West and
products ). These compounds comprise of nitrogen
Central Africa, cocoa continues to be an important source of export
and oxygen heterocyclic compounds, aldehydes and ketones, esters, al-
earnings contributing signiﬁcantly to the Gross Domestic Product
cohols, hydrocarbons, nitriles and sulphides, pyrazines, ethers, furans,
(GDP) of these producing countries. Cocoa exports generate over $8 bil-
thiazoles, pyrones, acids, phenols, imines, amines, oxazoles, and pyr-
lion for the region's national economies and support about
two million smallholder farm households in West and Central Africa. In
Ghana, the industry employs about 70% of the national agricultural
labour force in the country ). For these farmers,
cocoa contributes about 70–100% of their annual household incomes
Most of these compounds possess particular ﬂavour characteristics.
Apart from the economic importance of cocoa, consumption of
Thus, while most esters confer a fruity/ﬂowery attribute to ﬂavour,
chocolate and other cocoa products is reported to contribute positively
pyrazines usually give earthy/roasted ﬂavour Flavour
compounds in cocoa beans are formed during roasting from ﬂavour
). Polyphenols in cocoa beans have been reported
precursors generated during the fermentation and drying process. Fla-
to exhibit anti-carcinogenic (
vour compounds in cocoa beans are thus inﬂuenced by factors such as
type of cocoa (genotype), bean composition, soil type, age of cocoa
and vasodilatory (
tree, postharvest treatments such as pulp pre-conditioning, fermenta-
) effects and they exert them mainly as antioxidants
tion and drying, industrial processes such as roasting as well as storage
and transportation (
Annual global cocoa production is reported to be more than
4 million tons per season (4.4 million tons in 2013/2014 crop season)
2.1. Effect of genotype and origin of cocoa tree on cocoa bean ﬂavour quality
However, while global demand for sustainable cocoa isgrowing annually by 2 to 3%, and West Africa still contributes about
Flavour quality of cocoa beans depends on the genotype and origin
70% of the global supply, this region is confronted with a 2% annual de-
of the cocoa tree that has produced the beans. Cocoa beans from differ-
cline in production There is low
ent genotypes and origin of cocoa tree have distinct ﬂavour characteris-
cocoa productivity in West Africa due to poor farm management
tics (). Currently, three broad cultivars of cocoa are commonly
J.E. Kongor et al. / Food Research International 82 (2016) 44–52
Table 1Flavour proﬁle of different cocoa beans from different origins.
Source: Adopted from
Good cocoa impact, low bitterness, low acid, fruity, nutty
Strong chocolate ﬂavour
Medium cacao, occasional off-notes
São Tomé & Principe
Good cocoa ﬂavour, bitter, spicy, fruity, earthy
Winey, putrid, citrus
Mild chocolate, slightly bitter, distinct fruity notes (plum and cherry)
Cocoa impact, bitter, acid, astringent (sometimes rubber, hammy, smoky),some fruitiness, no nutty notes
Trinitario and Criollo
Fruity, bitter, cacao
Slightly bitter and fruity
Ecuador (home of Arriba)
Balanced proﬁle, low chocolate, ﬂoral, fruity, grass, earthy notes
Low chocolate, strong acid, low fruitiness
Moderate chocolate, acidic, fruit and nut notes
Dominican Republic (Sanchez)
Low cacao, ﬂavourless, bitter
Dominican Republic (Hispaniola)
Winey, earthy, can have tobacco notes
Fruity, balanced cocoa ﬂavour
Trinidad & Tobago
High cacao, nutty and winey notes, aromatic
Chocolate, fruity, ﬂoral, grassy, woody
Low chocolate, acidic, fruity
High bitter, low sour, low cacao, astringent
Mild, bland proﬁle, acid, low cacao, light colour
Hybrids/pure Criollo and Forastero
Variable strong acid, ﬂoral, mild, nutty
Low to medium cacao, medium to high acidity, astringent (due to fermentation level) phenolic
recognized: Forastero, Criollo, Trinitario and a fourth variety grown in
considered to be moderately resistant to pests and diseases
Ecuador, called Nacional
The cultivars exhibit differences
Forastero beans have a higher pH after fermentation and drying when
in the appearance of pods, yields of beans, ﬂavour characteristics and
compared with Criollo beans. Thus, chocolate produced from the
in resistance to pests and diseases (
Forastero beans are less bitter, less astringent and less acidic than choc-
olate produced from either Criollo beans or Trinitario beans
cocoa type has a unique potential ﬂavour character (
). These differences in ﬂavour can be attributed to inherent genetic
Criollo is the original cultivated cocoa, indigenous to Northern,
composition of the bean, botanical origin, location of growth but grow-
South, and Central America. The beans are white to ivory or have a
ing conditions such as climate, the amount and time of sunshine and
very pale purple colour, due to an anthocyanin inhibitor gene (
rainfall, soil conditions, ripening, time of harvesting, and the time be-
). Their low yields and susceptibility to many dis-
tween harvesting and bean fermentation all contribute to variations in
eases make them rare to cultivate. Nowadays, its cultivation is limited
the ﬁnal ﬂavour formation. (See .)
to Central America and a few regions in Asia (
Forastero, native to the Amazon basin ), comprises
Criollo cocoa is reported to
of 95% of the world production of cocoa
contain high amount of pyrazines
and is commonly referred to as "bulk cocoa" in trade. Forastero
and exhibit low pH which easily affect the ﬂavour proﬁle (
cocoa is predominantly cultivated in West Africa particularly Côte
d'Ivoire, Ghana, Nigeria and Cameroon. The seeds are ﬂat, astringent,
The Trinitario type originated in Trinidad and covers all the products
and purple in colour (more rarely ivory or pale) due to the presence
of natural hybridization and recombination of the Criollo and Forastero
of anthocyanins. Forastero cocoa trees are very productive and are
populations ). The beans are variable in
Table 2Summary of factors and their impact on cocoa bean ﬂavour.
Impact on cocoa bean ﬂavour
Inﬂuences the type and quantity of bean storage proteins, carbohydrates and polyphenols which are degraded duringfermentation and drying to form ﬂavour precursors
Removes portion of the pulp prior to fermentation hence, reduces fermentable sugars during fermentation leading tothe production of less acids
Reduces pulp volume per seed due to water evaporation and inversion of sucrose; reduces total sugar content and increasesmicro-aeration within the pulp and eventually reduces alcohol fermentation and acetic acid formation
Generates ﬂavour precursors, namely free amino acids, peptides and reducing sugars from which ﬂavour volatiles are formed.
Polyphenols are oxidized and polymerized to insoluble high molecular-weight compounds (tannins) leading to a signiﬁcantreduction of its concentration and, thus, reducing the bitterness and astringency of the beans
Physical loss of acidity through outward migration of volatile acids as well as biochemical oxidation of acetic acid from thebeans leading to less acids in the beans. Oxidization and polymerization of polyphenols resulting in reduction of its concentration.
Non-enzymatic reactions, that is the Maillard reactions to form volatile fractions like pyrazines
Evaporation of volatile acids from the beans causing a reduction in acidity, hence, reducing sourness. Flavour precursors namelyfree amino acids, short-chain peptides, and reducing sugars undergo the Maillard reaction and Strecker degradation to producethe desirable ﬂavour compounds
NB: impact of other factors such as soil chemical composition and age of cocoa tree on cocoa bean ﬂavour quality is not yet known. A research gap which needs to be ﬁlled.
J.E. Kongor et al. / Food Research International 82 (2016) 44–52
colour, although rarely white, and the trees show a susceptibility to
). Three groups of polyphenols can be
pests and diseases intermediate to Forastero and Criollo populations
distinguished in cocoa beans and these are: catechins or ﬂavan-3-ols
The Trinitario cultivar is
(ca. 37%), anthocyanins (ca. 4%) and proanthocyanidins (ca. 58%)
known to have strong basic chocolate characters and some typical win-
). The main catechin in
ery type of aroma that are not found in other varieties
the cocoa bean is (−)-epicatechin with up to 35% of polyphenol con-
). Both Trinitario and Criollo varieties produce the "ﬁne" cocoas,
tent. Other catechins found in smaller amounts are (+)-catechin
whose share in the total world production is below 5% ().
as well as traces of (+)-gallocatechin and (−)-epigallocatechin
These cocoas are used to make high quality dark chocolate (
The anthocyanin fraction
). Nacional cacao is viewed as a ﬁne variety producing the well-
consists mainly of cyanidin-3-α-L-arabinoside and cyanidin-3-β-D-
known Arriba beans with distinctive ﬂoral and spicy ﬂavour notes
galactoside ), while proanthocyanidins are
mostly ﬂavan-3,4-diols, that are 4 → 8 or 4 → 6 bound to condensed
dimers, trimers or oligomers with epicatechin as the main extension
Work by noted consistent differences in
overall cocoa ﬂavour intensity, acidity, sourness, bitterness and astrin-
Other polyphenols found in cocoa beans are the ﬂavonol glycosides
gency among West African Amelonado variety (AML), four Upper Ama-
such as quercetin-3-O-α-D-arabinoside and quercetin-3-O-β-D-
zon clones [Iquitos Mixed Calabacillo 67 (IMC67), Nanay 33 (NA33),
glucopyranoside ). Again, up to 17 phe-
Parinari 7 (PA7), and Scavina 12 (SCA12)], and unidentiﬁed Trinitario
nolic acids and esters have also been reported and the total amount
(UIT1) grown in Sabah, Malaysia. Work by also sug-
of seven of them comprises not more than 23 ppm of the seed
gested that monoterpenes such as linalool are part of the components
dry weight (phloroglucinol, protocatechuic acid, vanillic acid, o-
or molecules responsible for ﬁne ﬂavour in cocoa and concluded that
hydroxyphenylacetic acid, p-coumaric acid, caffeic acid, ferulic acid)
ﬁne ﬂavour cocoas contain higher amounts of linalool than bulk cocoa.
). reported that epicatechin
Cocoa bean genotype inﬂuences the type and quantity of bean stor-
and the smaller procyanidins up to three subunits are soluble and,
age proteins, carbohydrates and polyphenols ().
therefore, cause the astringent taste sensation of cocoa but molecules
This determines the quantities and type of precursors formed during
built up of more than three subunits are insoluble and cause no
fermentation and drying processes leading to ﬂavour formation thus in-
ﬂuences both type of ﬂavour of the beans and intensity
found four predominant fractions of
protein in cocoa beans representing 95% (w/w) of total seed proteins,
bean is made up of two main parts namely, the testa (seed coat or the
and these are albumins (water-soluble), globulins (salt-soluble), prola-
shell) and the embryo ). Attached to
mins (alcohol-soluble) and glutelins (soluble in dilute acids and alkali).
the testa is the sugary, white mucilaginous pulp that surrounds it,
Albumin is a major polypeptide accounting for about 52% of total bean
while the embryo is contained within the seed coat or testa. The main
protein and has a molecular weight of 21 kDa (
parts of the embryo are two folded cotyledons connected by a small em-
bryonic axis (The dry weight of cocoa bean
varies considerably, but is approximately 1.0–1.2 g (
min is not degraded during fermentation ().
The chemical composition of cocoa beans has been studied ex-
Work done by showed that incubating the puri-
ﬁed cocoa albumin with cocoa proteases did not produce any speciﬁc
cocoa aroma upon roasting. The globulin fraction accounts for 43% of
cocoa bean has an approximate composition of 32–39% water, 30–32%
total protein in cocoa beans and it consists of three polypeptide subunits
fat, 10–15% proteins, 5–6% polyphenols, 4–6% starch, 4–6% pentosans,
with apparent molecular weights of 47, 31 and 16 kDa (
2–3% cellulose, 2–3% sucrose, 1–2% theobromine, 1% acids and 1% caf-
) and it is almost insol-
feine The predominant
uble at pH b 5.0 (). These are subunits of the
sugars in cocoa beans are sucrose, fructose and glucose (
vicilin-type (7S) globulin (VCG), a glycoprotein, each of them consisting
) with sucrose being the major component (about 90% of
of multiple pI-forms
total sugars), followed by fructose and glucose (about 6%) (
The vicilin-class globulins are quantitatively de-
graded during fermentation (88–90% of the initial content) into ﬂavour
Cocoa fat contains about 95% triacylglycerols, 2% diacylglycerols, b1%
precursors such as peptides and amino acids, which are important pre-
monoacylglycerols, 1% polar lipids, and 1% free fatty acids (as percent-
cursors for the formation of cocoa ﬂavour through Maillard reactions
ages of lipids) (). The predominant fatty acids
during drying and roasting
in cocoa butter are saturated (stearic; 18:0, 35% and palmitic; 16:0,
25%) and monounsaturated (oleic; 18:1, 35%), with the remaining fatbeing primarily polyunsaturated linoleic (3%) The coty-
2.2. Effect of postharvest treatment of cocoa on bean ﬂavour quality
ledon is composed of two types of parenchyma storage cells The ﬁrst storage cell is the polyphenolic cells (14–20% dry bean
Postharvest treatment of cocoa involves all the primary process har-
weight) which contain a single large vacuole ﬁlled with polyphenols
vested cocoa pods goes through before the ﬁnal dried beans is obtained.
and alkaloids including caffeine, theobromine and theophylline
These processes include pulp pre-conditioning, fermentation, and dry-
). argued that the
ing. These processes are usually carried out in the country of origin
pigmented polyphenols, when undisturbed, confer deep purple colour
and they play a critical role in the ﬂavour proﬁle of the dried cocoa
to fresh Forastero cotyledons. The other storage cells, the lipid–protein
beans ). While the complex composition of cocoa
cells, on the other hand, have cytoplasms tightly packed with multiple
bean ﬂavour depends on the bean genotype, speciﬁcally on contents
small protein and lipid vacuoles and other components such as starch
of bean storage proteins, polysaccharides and polyphenols, it is possible
granules — all of which play roles in deﬁning cocoa ﬂavour and aroma
and easier to produce cocoa beans with poor ﬂavour proﬁle with bad
Polyphenols in cocoa beans are stored in the pigment cells of the cot-
2.2.1. Pulp pre-conditioning
yledons and depending on the amount of anthocyanins, those pigment
Pulp pre-conditioning involves changing the properties of the
cells, also called polyphenol-storage cells, are white to deep purple
pulp prior to the development of microorganisms in fermentation
J.E. Kongor et al. / Food Research International 82 (2016) 44–52
(). The pulp is the
reported that pulp preconditioning by post-harvest storage of
substrate metabolized by a sequence of microorganisms during fermen-
Malaysian cocoa pods led to the reduction of nib acidiﬁcation during
tation and since the properties of the sub-
subsequent fermentation, reduction of acid note and an increase in
strate determine microbial development and metabolism, changes in
cocoa ﬂavour in the resulting cocoa beans. also
the pulp may affect the production of alcohols by yeasts and subsequent
noted that increasing pod storage (PS) consistently decreased the
production of acids by lactic acid bacteria and acetic acid bacteria. These
non-volatile acidity with concomitant increase in pH during fermenta-
changes may be in the form of altering the moisture content of the pulp,
tion of Ghanaian cocoa beans. reported that
sugar content, and volume of pulp per seed as well as pH and acidity of
pulp pre-conditioning of cocoa prior to fermentation was signiﬁcant in
the pulp. Removing portions of cocoa bean pulp or reducing the fer-
affecting the changes in acidity, causing a signiﬁcant reduction in the
mentable sugar content has been shown to contribute to less acid pro-
content of polyphenol compounds especially (−)-epicatechin and
duction during fermentation, leading to less acid beans
(+)-catechin during fermentation, hereby reducing the astringency
). Studies have shown that pre-
and bitterness in cocoa and cocoa products (
fermentation treatments have signiﬁcant effects in changing the acidityand polyphenol content of the cocoa beans and thus, ﬂavour of the
Fermentation of cocoa beans is very crucial as it promotes dramatic
Pulp pre-conditioning can
biochemical changes in the type and concentration of ﬂavour precursors
be done in three basic ways prior to fermentation and these are pod
storage, depulping (mechanical or enzymatic depulping) and bean
beans have an astringent and unpleasant taste and have to be fermented
. Cocoa pulp can be pre-
and dried to obtain the characteristic cocoa taste and ﬂavour. The cor-
conditioned either inside the pods (pod storage) before the bean–pulp
rect fermentation and drying of cocoa beans, which are carried out in
mass is brought out for fermentation or outside the pods (mechanical
the countries of origin are essential to the development of suitable ﬂa-
or enzymatic depulping and bean spreading).
vour and/or ﬂavour precursors (). During fermentation, microbial successions occur as the
22.214.171.124. Depulping of cocoa beans. Excessive pulp on the cocoa beans leads
micro-environment (temperature, pH, oxygen availability) changes
to high acid production during fermentation which is detrimental to
bean ﬂavour quality as it makes it excessively sour (
). The ﬂavour quality of cocoa beans depends
By removing a portion of the pulp, or reducing the fer-
on complex chemical and biochemical changes which occur in the
mentable sugar content of the beans, it has been shown that less acid is
beans during fermentation and drying. Fermentation generates ﬂavour
produced during fermentation, leading to less acid beans
precursors, namely free amino acids and peptides from enzymatic deg-
radation of cocoa proteins and reducing sugars from enzymatic degra-
Removal of up to 20% of the cocoa pulp
dation of sucrose
from fresh Brazilian cocoa beans signiﬁcantly improved the ﬂavour
quality of the beans produced (). Depulping
which the typical cocoa aroma is generated during the subsequent
can be done in two ways, namely mechanically and enzymatically
roasting process ). Besides the forma-
tion of the ﬂavour precursors, there is also a signiﬁcant increase in vol-
Methods for mechanical depulping of fresh cocoa beans include
atile compounds, such as alcohols, organic acids, esters and aldehydes
presses (), centrifuges
after fermentation (
or simply spreading beans onto a ﬂat surface for several hours
). Again, phenolic compounds are oxidized and polymerized to in-
prior to fermentation, causing a signiﬁcant increase in the sweating pro-
soluble high molecular-weight compounds (tannins) leading to a signif-
duced in the ﬁrst 24 h of fermentation. Mechanical depulping is done to
icant reduction of its concentration and, thus, reducing the bitterness
remove some of the pulp of the fresh cocoa beans so as to reduce sub-
and astringency of the ﬁnal product to acceptable levels (
strates and therefore acids produced during fermentation with a subse-
quent decrease in sourness. The process causes bruising of the beans
Cotyledon protein degradation into peptides and free amino acids
and its cell structures leading to the activation of enzyme, which
appears central to ﬂavour formation and reported
might inﬂuence various biochemical processes during fermentation. In
that the combined action of aspartic endopeptidase and serine
addition to reducing acidity, beneﬁts of de-pulping include shorter fer-
carboxy-(exo) peptidase on vicilin (7S)-class globulin (VCG) storage
mentations and increased efﬁciency and the ability to use the excess
polypeptide yields cocoa-speciﬁc precursors. Proteolysis in the seeds
pulp in the manufacture of jams, marmalades, pulp juices, wines or
mainly takes place within 24 h after destruction of the cells and acidiﬁ-
cocoa soft drinks (
cation by acetic acid (The aspartic endopeptidase hy-
). By using a mechanical depulper,
drolyses peptide bonds in VCG at hydrophobic amino acid residues,
the pulp is removed substantially uniformly from the beans and the
forming hydrophobic oligopeptides which then become substrates for
amount of pulp removed from the fresh cocoa beans in the depulper
the serine carboxy-(exo) peptidase which removes carboxyl terminal
may be from 10 to 30%, preferably from 20 to 25% by weight based on
hydrophobic amino acid residues
the original total combined weight of the beans and pulp.
). Carboxypeptidase plays an impor-
Enzymatic depulping involves the addition of pectin degrading en-
tant role in converting hydrophobic oligopeptides to cocoa speciﬁc
zymes to the cocoa bean–pulp mass prior to the fermentation process
aroma precursors, namely hydrophilic oligopeptides and hydrophobic
to breakdown the pectin in the pulp. The breakdown of the pectin in
free amino acids (especially leucine, valine, alanine, isoleucine, phenyl-
the pulp leads to a reduction in pulp volume which in turn increases
alanine), which are required for the formation of the typical cocoa
the aeration of the fermenting mass during fermentation.
aroma components in the presence of reducing sugar upon roasting(
126.96.36.199. Pod storage. Pod storage is basically storing harvested cocoa pods
The duration and method of fermentation are crucial to the forma-
for a period of time before opening the pods and fermenting the beans.
tion of ﬂavour compounds and ﬂavour precursors.
Pod storage as observed by appears to have
noted an increased level of organic acids such as propanoic acid, 2-
highly beneﬁcial effect on the chemical composition of cocoa beans
methylpropanoic acid, 3-methylbutanoic acid and acetic acid after
and subsequent development of chocolate ﬂavour.
72 h of cocoa fermentation. The increased levels of organic acids are a
J.E. Kongor et al. / Food Research International 82 (2016) 44–52
result of the breakdown of sugars from the pulp surrounding the cocoa
beans ). Propanoic acid, 2-methylpropanoic acid, 3-
). The less volatile acids, such as oxalic,
methylbutanoic acid and acetic acid are all reported to be important
citric, tartaric, succinic and lactic acids remain largely unchanged by
odour-active compounds in cocoa
the roasting process ).
). Unfermented cocoa beans are reported to develop little
Again, ﬂavour precursors namely free amino acids, short-chain pep-
cocoa and chocolate ﬂavour when roasted while over-fermented beans
tides, and reducing sugars produced during fermentation and drying
produce unwanted hammy and putrid ﬂavours (
process undergo the Maillard reaction and Strecker degradation during
Important ﬂavour-active components produced during
roasting to produce the desirable ﬂavour compounds such as pyrazines,
fermentation include ethyl-2-methylbutanoate, tetramethylpyrazine
alcohols, esters, aldehydes, ketones, furans, thiazoles, pyrones, acids,
and certain other pyrazines ).
imines, amines, oxazoles, pyrroles and ethers (
Bitter notes are evoked by theobromine and caffeine, together with
diketopiperazines formed from roasting through thermal decompositions
). The ideal conditions for the Maillard re-
of proteins (). Other ﬂavour precursor compounds
action to occur are high temperatures and low moisture content and
derived from amino acids released during fermentations include 3-
these conditions can be found in roasting . The carbon-
yl derivative from the Maillard reaction reacts with free amino acids
2-ethyl-3,5-dimethyl- and 2,3-diethyl-5-methylpyrazine (
during Strecker degradation. This causes degradation of amino acids to
aldehydes which contribute to the aroma. Strecker degradation ofeach speciﬁc amino acid produces a unique aldehyde with a unique
After fermentation, the beans are dried to reduce the moisture con-
The choice of roasting parameters determines the character of the
tent from about 60% to between 6 and 8% ) to
chemical and physical processes that occur inside the beans, and thus
prevent mould infestation during storage and also allow some of the
the quality of the end products
chemical changes which occurred during fermentation to continue
Several studies revealed that the tem-
and improve ﬂavour development (). The drying process
perature and duration of roasting substantially affect the chemical and
of fermented cocoa beans initiates major polyphenol oxidizing reactions
physical changes occurring in cocoa beans
catalysed by polyphenol oxidase, giving rise to new ﬂavour components
). Cocoa bean roasting conditions generally range from
and loss of membrane integrity, inducing brown colour formation. This
15 to 45 min with temperatures from 130 to 150 °C
helps to reduce bitterness and astringency and also the development of
the chocolate brown colour of well fermented cocoa beans. The bio-
). Time and temperature of the roasting process depend on several
chemical oxidation of acetic acid from the beans continues during dry-
factors, such as cocoa material (beans, nibs or liquor roasting), ﬁnal
cocoa product (dark or milk chocolates) and type of cocoa (Criollo or
and have both suggested that during
the drying of fermented cocoa beans, reducing sugars participate
reported that "ﬁne" cocoa varieties
in the thermal treatment of non-enzymatic browning reactions, that
such as Criollo require lower temperatures than the "bulk" ones, while
is the Maillard reactions to form volatile fractions of pyrazines.
indicated that low temperature roasts are
have conﬁrmed earlier ﬁndings by
employed for milk and some dark chocolates.
and by identify-ing Amadori compounds, the ﬁrst intermediates of Maillard reaction in
2.4. Soil chemical composition and cocoa bean ﬂavour quality
dried, unroasted cocoa beans. These Amadori compounds are the ﬁrstintermediates of the reaction of free amino acid and glucose.
Cocoa trees are extremely selective about where they grow, includ-
Drying rate during the drying process is of crucial importance for the
ing the type of soil they prefer. Cocoa tree needs a soil containing coarse
ﬁnal quality of the cocoa beans. The drying process must not be too
particles and with a reasonable quantity of nutrients, to a depth of 1.5 m
rapid otherwise the beans tend to retain an excessive amount of acetic
to allow the development of a good root system ). Cocoa
acid, and this is deleterious to ﬂavour
trees are more sensitive to moisture stress than other tropical crops.
The cocoa tree is sensitive to a lack of water, so the soil must have
). Rapid drying of the beans results in case hard-
both water retention properties and good drainage. The chemical prop-
ening which prevents outward migration of acetic acid from the beans,
erties of the topsoil are most important, as the plant has a large number
thus, leading to a build-up of acidity in the beans (
of roots for absorbing nutrients. Cocoa can grow in soils with a pH in the
). On the other hand, too slow drying rate would
range of 5.0–7.5. It can therefore cope with both acid and alkaline soil,
result in low acidity, poorer colour and high presence of moulds
but excessive acidity (pH 4.0 and below) or alkalinity (pH 8.0 and
above) must be avoided (). The inﬂuence of soil pH is critical
on the solubility of minerals and nutrients and it is thus regarded as auseful indicator of other soil parameters
2.3. Effect of industrial processing of cocoa on bean ﬂavour quality
Soil pH provides useful information about the availabilities of ex-
changeable cations (e.g. Ca2+, Mg2+ and K+) in soils (
Roasting is one of the important steps which affects the quality char-
). The soil should also have a high content of organic matter of
acteristic of cocoa beans during industrial processing
about 3.5% in the top 15 cm of soil. The organic matter of soils includes
Roasting determines the character of
the remains of plants, animals and microorganisms in all stages of de-
the chemical and physical processes that occur inside the beans, as
composition. The level of organic matters in soils inﬂuences a number
well as the quality of the ﬁnal products (
of soil chemical and physical properties (). Soils for
). During roasting, there is evaporation of volatile acids from the
cocoa must have certain anionic and cationic balances. Exchangeable
beans causing a reduction in acidity, hence, reducing sourness and bit-
bases in the soil should amount to at least 35% of the total cation
terness of the cocoa beans (). The high roasting tem-
exchange capacity (CEC) otherwise nutritional problems are likely
perature reduces the acidity, speciﬁcally the volatile acids with low
). The CEC is a measure of the soil's ability to adsorb (and
boiling point such as acetic acid, making the cocoa beans less acidic
release) cations (It is highly needed for the
J.E. Kongor et al. / Food Research International 82 (2016) 44–52
estimation of contaminant transport potential and sorption capacity for
Sustainable cocoa production, however, depends largely on the quantity
any soil location, i.e., the total number of cations it can retain on its
cocoa beans produced annually as well as the quality of the beans.
adsorbent complex at a given pH. The optimum total nitrogen/total
Cocoa bean ﬂavour is an important quality attribute which determines ac-
phosphorus ratio should be around 1.5
ceptability of cocoa beans and cocoa products such as chocolate. The com-
Several works have been done on soil type, soil chemical composition
plex composition of cocoa bean ﬂavour depends on the bean genotype
and nutrient requirements for cocoa production (
speciﬁcally on contents of bean storage proteins, polysaccharides and
polyphenols. Pulp pre-conditioning, fermentation and drying enhance
However, all research works
the formation of the ﬂavour precursors which undergo the Maillard reac-
on soil effects on cocoa are focused on yield with little or no work on
tion during roasting to produce the typical cocoa ﬂavours. Research works
the effect of soil on the ﬂavour quality of cocoa beans. There is, therefore,
on age of cocoa tree and the soil chemical compositions are focused on
a big gap in terms of research work on the effect of soil chemical compo-
yield with little or no work on ﬂavour quality. More works need to be
sition on the ﬂavour quality of cocoa beans.
done on the impact of age of cocoa tree and soil chemical compositionson the development of ﬂavour precursors during fermentation and drying
2.5. Age of cocoa tree and ﬂavour quality
and their subsequent formation of ﬂavour volatile compounds duringcocoa bean roasting.
Like any living organism, the cocoa tree goes through different
stages in its entire life cycle. According to
production life cycle of cocoa occurs in four stages whichincludes: (1) an early period of no yield which normally occurs in the
This review was conducted as part of a project funded by the
ﬁrst 3 years, (2) a period of increasing yield at an increasing rate, (3) a
Belgium Government (ZEIN2013PR394) under the VLIR TEAM Cocoa
period of increasing yield at a decreasing rate, and (4) a period of de-
Project. The sponsor is gratefully acknowledged for the Research
creasing yields. The last stage is associated with trees that are past
their yield prime. also reportedthat after four years from the time of planting, the cocoa tree becomesproductive and the yield rate increases annually until approximately
18 years of age. Then, the yields begin to decline due to exhaustion of
Abekoe, M. K., Obeng-Ofori, D., & Egyir, I. S. (2002). Technography of cocoa in the forest
soil nutrients, erosion, and increasing occurrence of pests and plant dis-
zone of Ghana. Unpublished technical report, Convergence of Sciences Project.
University of Ghana, Legon, Pp. 51.
Age is therefore an important factor in the life of cocoa trees due to
biological lags inherent to the crop (). Several studies
have reported on the impact of ageing cocoa farms or trees in Ghana
Adewole, E., Ogunmodede, O. T., Talabi, J., Ajayi, O. O., Oso, O. A., & Lajide, L. (2011).
and other West African cocoa producing countries on yield (
little or no work on ﬂavour quality. There is therefore a big research
gap that needs to be ﬁlled. The inﬂuence of cocoa tree age on the forma-
tion of ﬂavour precursors during cocoa bean fermentation as well as the
formation of ﬂavour volatiles needs to be studied.
Afoakwa, E. O. (2015).
Afoakwa, E. O., & Paterson, A. (2010).
2.6. Research gaps
Cocoa is a crop of huge economic signiﬁcance especially in develop-
ing countries. The crop is also enjoyed by millions of people around the
world in the form of chocolate and other cocoa related products. As a
result, several researchers have taken keen interest in developing and
improving on the quality characteristics of cocoa beans as well as the
wellbeing of cocoa farmers so as to ensure a sustainable production. Ex-
tensive works have been done on cocoa fermentation, drying and
roasting and their impact on the polyphenolic and ﬂavour characteris-
Afoakwa, E. O., Quao, J., Takrama, J., Budu, A. S., & Saalia, F. K. (2011b).
tics of cocoa beans. Other factors such as pod storage and mechanical
depulping which inﬂuence the ﬂavour proﬁle of cocoa beans during fer-
mentation, drying and subsequent roasting have also received fair at-
Afoakwa, E. O., Quao, J., Takrama, J., Budu, A. S., & Saalia, F. K. (2012).
tention by some researchers.
However, works done on age of cocoa tree and soil characteristics
have concentrated on the impact on yield with little or no work on the ﬂa-
vour quality characteristics of the beans. Therefore, works need to be
done on the inﬂuence of age of cocoa tree on the formation of ﬂavour pre-
cursors during cocoa bean fermentation, drying as well as the ﬂavour vol-
atiles produced during subsequent roasting. The nutrients and chemical
composition of soils need to be studied and ascertain their inﬂuence on
Amusan, O. A., Amusan, F. O., Braimoh, A., & Oguntunde, P. (2005).
the ﬂavour quality of cocoa beans.
Sustainable production of cocoa is crucial to both the small holder
Andújar, I., Recio, M. C., Giner, R. M., & Ríos, J. L. (2012). Cocoa polyphenols and their
farmers and their families that depend on cocoa for income and also the
potential beneﬁts for human health — Review article. Oxidative Medicine and
millions of people who enjoy chocolate and other cocoa related products.
Cellular Longevity, 906252. http://dx.doi.or(23 pp.).
J.E. Kongor et al. / Food Research International 82 (2016) 44–52
Fennema, O. R. (1996).
Awua, P. K. (2002).
Ferrão, J. E. M. (2002).
Foundation, W. C. (2010).
Beckett, S. T. (2000).
Bharath, S., & Bowen-O′Connor, C. (2008).
Biehl, B., & Voigt, J. (1999).
Biehl, B., & Ziegleder, G. (2003).
Biehl, B., Heinrichs, J., Voigt, G., Bytof, G., & Serrano, P. (1996).
Hainmueller, J., Hiscoxb, K., & Tampec, M. (2011).
Hashim, P., Selamat, J., Muhammad, K., & Ali, A. (1999).
Hoskin, J., & Dimick, P. (1984).
ICCO (2015b). Fine or ﬂavour cocoa. Retrieved from
(Assessed on 13–11-15)
ICCO (2015c). Growing cocoa.
(Assessed on 13–11-2015)
IDH Sustainable Trade Initiative (2015). Cocoa.
(Assessed on 02–08-2015)
De Zaan Cocoa Manual (2009).
Despreaux, D. (1998).
Kim, J., Lee, K. W., & Lee, H. J. (2011).
Dodo, H. W., & Furtek, D. B. (1994).
Duncan, R. J. E., Godfrey, G., Yap, T. N., Pettiphar, G. L., & Tharumarajah, T. (1989).
J.E. Kongor et al. / Food Research International 82 (2016) 44–52
Reed, S. (2010). Sensory analysis of chocolate liquor. Retrieved from
(Assessed on 16–11-2015)
Rodríguez-Ramiro, I., Ramos, S., López-Oliva, E., et al. (2011).
Romanczyk, L. J., Hammerstone, J. F., Buck, M. M., Post, L. S., Cipolla, G. G., Micceland, C. A.,
Mundt, J. A., & Schmitz, H. H. (1997). Cocoa extract compounds and methods for making
and using the same. Patent Cooperation Treaty (PCT) WO 97/36497, Mars incorporated,
Lopez, A. S., & Dimick, P. S. (1995).
Luna, F., Crouzillat, D., Cirou, L., & Bucheli, P. (2002).
Schinella, G., Mosca, S., Cienfuegos-Jovellanos, E., et al. (2010).
Martorell, P., Forment, J. V., de Llanos, R., et al. (2011).
Schwan, R. F., Rose, A. H., & Board, R. G. (1995).
Misnawi, S., & Teguh, W. (2010).
Motamayor, C. J., Lachenaud, P., Loor, R., Kuhn, N. D., Brown, J. S., & Schnell, R. J. (2008). Geo-
graphic and genetic population differentiation of the amazonian chocolate tree
(Theobroma cacao L). PLoS One, 3(10), e3311. http://dx.doi.or
Taylor, A. J., & Roberts, D. D. (2004).
de Muijnck, L. (2005).
Thompson, S. S., Miller, K. B., & Lopez, A. S. (2001).
Thompson, S. S., Miller, K. B., & Lopez, A. S. (2007).
Vekua, K. (2013).
Owusu, M. (2010).
Ziegleder, G. (1990).
This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party
Actividad docente y riesgo de estrés. Acerca de la relación entre el trabajo en escuelas de los niveles educativos obligatorios y su impacto sobre la salud física y psicológica de los docentes. Olga Cristina Colatarci. El presente trabajo se propone analizar como afecta a los docentes, a cargo de un grupo de alumnos, realizar la totalidad de la tarea que su rol implica. ¿Cuáles son los límites o