Nondairy Fermented Foods and Products
189
and Congo coffee cherries,
83 although Pederson and Breed
59 indicated that the fermentation of coffee
berries from Mexico and Colombia was carried out by typical lactic acid bacteria (leuconostocs and
lactobacilli). Agate and Bhat
3 in their study of coffee cherries from the Mysore state of India found
that the following pectinolytic yeasts predominated and played important roles in the loosening and
removal of the mucilaginous layers: Saccharomyces marxianus, S. bayanus, S. “ellipsoideus,” and
Schizosaccharomyces spp. Molds are common on green coffee beans, and in one study, 99.1% of
products from 31 countries contained these organisms, generally on the surface.
45 Seven species of
aspergilli dominated the biota, with A. ochraceus being the most frequently recovered from beans
before surface disinfection, followed by A. niger and species of the A. glaucus group. The toxigenic
molds, A. flavus and A. versicolor, were found, as were P. cyclopium, P. citrinum, and P. expansum,
but the penicillia were less frequently found than the aspergilli.
45 Microorganisms do not contribute
to the development of flavor and aroma in coffee beans as they do in cocoa beans.
Cocoa beans (actually cacao beans–cocoa is the powder and chocolate is the manufactured product),
from which chocolate is derived, are obtained from the fruits or pods of the cacao plant in parts of
Africa, Asia, and South America. The beans are extracted from the fruits and fermented in piles,
boxes, or tanks for 2–12 days, depending on the type and size of beans. During the fermentation, high
temperatures (45–50
◦ C) and large quantities of liquid develop. Following sun or air drying, during
which the water content is reduced to less than 7.5%, the beans are roasted to develop the characteristic
flavor and aroma of chocolate. The fermentation occurs in two phases. In the first, sugars from the
acidic pulp (about pH 3.6) are converted to alcohol. The second phase consists of the alcohol being
oxidized to acetic acid. In a study of Brazilian cocoa beans by Camargo et al.,
16 the biota on the
first day of fermentation at 21
◦ C consisted of yeasts. On the third day, the temperature had risen to
49
◦ C, and the yeast count had decreased to no more than 10% of the total biota. Over the seven-day
fermentation, the pH increased from 3.9 to 7.1. The cessation of yeast and bacterial activity around
the third day is due in part to the unfavorable temperature, lack of fermentable sugars, and increase
in alcohol. Although some decrease in acetic acid bacteria occurs because of high temperature, not
all of these organisms are destroyed. The importance of lactic acid in the overall process was shown
earlier.
54,66
In one study, the cocoa fermentation was carried out with a defined microbial cocktail consisting
of only five organisms rather than the 50 or so that have been isolated from natural fermentations.
74
The five consisted of Saccharomyces cerevisiae var. chevalieri, Lactobacillus plantarum, L. lactis,
Acetobacter aceti, and Gluconobacter oxydans subsp. suboxydans. The defined inoculum led to a
product highly similar to that produced by natural fermentation. The key roles for the yeasts involved
elevating pH from about 3.5 to 4.2, breaking down citric acid in pulp, producing ethanol, producing
organic acids (oxalic, succinic, malic, etc.) that destroy bean cotyledons, producing volatile substances
that may play a role in chocolate flavor, and reducing viscosity of pulp. S. cerevisiae was the most
important organism in the above activities.
Although yeasts play important roles in producing alcohol in cocoa bean fermentation, their presence
appears even more essential to the development of the final, desirable, chocolate flavor of roasted beans.
Levanon and Rossetini
42 found that the endoenzymes released by autolyzing yeasts are responsible
for the development of chocolate precursor compounds. The acetic acid apparently makes the bean
tegument permeable to the yeast enzymes. It has been shown that chocolate aroma occurs only after
cocoa beans are roasted and that the roasting of unfermented beans does not produce the characteristic
aroma. Reducing sugars and free amino acids are in some way involved in the final chocolate aroma
development.
67 For an extensive review, see reference 81.
Soy sauce or shoyu is produced in a two-stage manner. The first stage, the koji (analogous to malting
in the brewing industry), consists of inoculating either soybeans or a mixture of beans and wheat flour
189
and Congo coffee cherries,
83 although Pederson and Breed
59 indicated that the fermentation of coffee
berries from Mexico and Colombia was carried out by typical lactic acid bacteria (leuconostocs and
lactobacilli). Agate and Bhat
3 in their study of coffee cherries from the Mysore state of India found
that the following pectinolytic yeasts predominated and played important roles in the loosening and
removal of the mucilaginous layers: Saccharomyces marxianus, S. bayanus, S. “ellipsoideus,” and
Schizosaccharomyces spp. Molds are common on green coffee beans, and in one study, 99.1% of
products from 31 countries contained these organisms, generally on the surface.
45 Seven species of
aspergilli dominated the biota, with A. ochraceus being the most frequently recovered from beans
before surface disinfection, followed by A. niger and species of the A. glaucus group. The toxigenic
molds, A. flavus and A. versicolor, were found, as were P. cyclopium, P. citrinum, and P. expansum,
but the penicillia were less frequently found than the aspergilli.
45 Microorganisms do not contribute
to the development of flavor and aroma in coffee beans as they do in cocoa beans.
Cocoa beans (actually cacao beans–cocoa is the powder and chocolate is the manufactured product),
from which chocolate is derived, are obtained from the fruits or pods of the cacao plant in parts of
Africa, Asia, and South America. The beans are extracted from the fruits and fermented in piles,
boxes, or tanks for 2–12 days, depending on the type and size of beans. During the fermentation, high
temperatures (45–50
◦ C) and large quantities of liquid develop. Following sun or air drying, during
which the water content is reduced to less than 7.5%, the beans are roasted to develop the characteristic
flavor and aroma of chocolate. The fermentation occurs in two phases. In the first, sugars from the
acidic pulp (about pH 3.6) are converted to alcohol. The second phase consists of the alcohol being
oxidized to acetic acid. In a study of Brazilian cocoa beans by Camargo et al.,
16 the biota on the
first day of fermentation at 21
◦ C consisted of yeasts. On the third day, the temperature had risen to
49
◦ C, and the yeast count had decreased to no more than 10% of the total biota. Over the seven-day
fermentation, the pH increased from 3.9 to 7.1. The cessation of yeast and bacterial activity around
the third day is due in part to the unfavorable temperature, lack of fermentable sugars, and increase
in alcohol. Although some decrease in acetic acid bacteria occurs because of high temperature, not
all of these organisms are destroyed. The importance of lactic acid in the overall process was shown
earlier.
54,66
In one study, the cocoa fermentation was carried out with a defined microbial cocktail consisting
of only five organisms rather than the 50 or so that have been isolated from natural fermentations.
74
The five consisted of Saccharomyces cerevisiae var. chevalieri, Lactobacillus plantarum, L. lactis,
Acetobacter aceti, and Gluconobacter oxydans subsp. suboxydans. The defined inoculum led to a
product highly similar to that produced by natural fermentation. The key roles for the yeasts involved
elevating pH from about 3.5 to 4.2, breaking down citric acid in pulp, producing ethanol, producing
organic acids (oxalic, succinic, malic, etc.) that destroy bean cotyledons, producing volatile substances
that may play a role in chocolate flavor, and reducing viscosity of pulp. S. cerevisiae was the most
important organism in the above activities.
Although yeasts play important roles in producing alcohol in cocoa bean fermentation, their presence
appears even more essential to the development of the final, desirable, chocolate flavor of roasted beans.
Levanon and Rossetini
42 found that the endoenzymes released by autolyzing yeasts are responsible
for the development of chocolate precursor compounds. The acetic acid apparently makes the bean
tegument permeable to the yeast enzymes. It has been shown that chocolate aroma occurs only after
cocoa beans are roasted and that the roasting of unfermented beans does not produce the characteristic
aroma. Reducing sugars and free amino acids are in some way involved in the final chocolate aroma
development.
67 For an extensive review, see reference 81.
Soy sauce or shoyu is produced in a two-stage manner. The first stage, the koji (analogous to malting
in the brewing industry), consists of inoculating either soybeans or a mixture of beans and wheat flour