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OCR for page 163
VII.
COMMERCIALIZATION
OCR for page 164
OCR for page 165
24
Commercialization of Fermented
Foods in Sub-Saharan Africa
Nduka Okafor
Fermented foods form an important part of the diets of people
throughout the world, and the people of sub-Saharan Africa are no
exception. In many parts of the world, as urbanization increases, the
preparation of fermented foods moves from the small-scale household
level to large-scale operations. Under these new conditions the foods
are prepared with better scientific knowledge. For this reason large-
scale factory procedures may differ from traditional approaches. For
example, cheese that used to be produced with protease present in
rennet may now be produced with protease produced by fungi.
With this in mind, a review was carried out in 1981 (1) to learn the
extent to which some important fermented foods of sub-Saharan Africa
had progressed toward commercialization. The stage that each food
had attained was measured on a scale of 8, as shown in Table 1.
The purpose of this paper is to indicate to what extent various sub-
Saharan fermented foods have progressed in the past decade toward
being industrialized and to examine the role, if any, that modern
techniques of biotechnology, particularly genetic engineering, have
played in commercialization.
INDUSTRIALIZATION OF FERMENTED FOODS
Table 1 lists the fermented foods about which information is available,
including those reviewed earlier (11. A review of the extent of progress
toward industrialization of alcoholic beverages of sub-Saharan Africa
was recently published (2) and is incorporated here into Table 1.
The following conclusions can be drawn:
· In 1981 the following foods had been produced on an industrial or
165
OCR for page 166
166
FERMENTED FOODS
TABLE 1 Fermented Foods of Africa South of the Sahara
Food Region Processing Level of Advance Microorganisms
CASSAVA-BASED
1981 and 1991
Garri West Africa; Pulp fermented 1,4,6,7 8
Zaire
Foo-foO (4) Nigeria Whole roots 0 1 Cornebacterium
fermented Bacillus
Lactic acid bacteria
Chikwangue Zaire Whole roots 0
fermented
Lafun Nigeria Flour from chips 0
Kokonte Ghana Flour from chips 0
Cingwada East, Central & Flourfrom chips 0
South Africa
CEREAL-BASED
NON-ALCOHOLIC
Ogi Nigeria, Benin
Republic
Koko (aflate) (5) Ghana
Fermented ground 1,2,4,6 8
cereal
Fermented ground 1
cereal
7,(8?)
1 Lactic acid bacteria
Mahewu (Mogow) South Africa Fermented ground 1,2,4,5,
cereal 6,7,8
Injera (10) Ethiopia Fermented ground 1,2 1.2 Entero bacteria ceae,
cereal Lactic acid bacteria
MILK-BASED
Ayib (16) Ethiopia Cheese-like — 1,2 Lactic acid
bacteria and yeasts
Nono Nigeria Fermented milk — 1 Lactobacillus bulgaricus
L. plantarum,
L. helvebcus
Streptococcus cremoris
Fermented milk (3) Zimbabwe
``Lacto" (3) Zimbabwe
ALCOHOLIC
BurukutulPito West Africa
Fermented milk
Fermented milk — 8
Fermentation of 1,2
malted sorghum
Sorghum (Kaffir) South Africa Fermentation of 1,2,4,5,
beer malted sorghum 6, 7, 8
Merissa (2) Sudan Fermentation of 0
malted sorghum
Bussa (2) Kenya Fermentation of 1,2
malted sorghum
PALM-BASED
Palm wines East, West,
Central and
South Africa
1,2 Lactococcus spp.
Lactococcus spp.
Spontaneous
fermentation of
palm sap
OCR for page 167
COMMERCIALIZATION OF FERMENTED FOODS
MISCELLANEOUS
Iru (dawadawa) (10) Nigeria Fermented seeds 0 8 Lactic acid bacteria
of Parkia
Ogili (17) Nigeria Fermented seeds 0 1,2 Lactic acid bacteria
of castor oil
Ugha (Ukraka) (6) Nigeria Fermented seeds 0 1,2 Bacillus
of oil-bean
Fura (Ghussab) Mali Millet and cheese O
Asami
East, Central Fermented milk O
South Africa
167
Key: 1 = Organisms isolated
2 = Role(s) of organism(s) determined
3 = Selection and genetic improvement
of organisms
5 = Improvement in raw material used
6 = Laboratory simulation of fermented food production
7 = Pilot plant production
8 = Industrial plant production
semiindustrial scale: ogi, garri, palm wine, mahewu, and sorghum
(kaffir) beer.
Two new products are now being produced on an industrial or
semiindustrial scale. The first is a Nigerian condiment known as dawa-
dawa. It is being produced under the trade name of Dadwa by the
firm of Cadburys in Nigeria from Parkia seeds as in the traditional
fermentation. The second is a Zimbabwean fermented milk product
known as Lacto. It is similar to the traditional fermented milk of
Zimbabwe (31.
· The organisms involved in the fermentation of several foods that
were unknown in 1981 have now been identified. They are foo-foo (4),
kokonte (5), ugba (ukpaka) (6), and ogili (7,81.
The case of dawa-dawa is interesting. In 1981 the organisms involved
were unknown; in 1991 not only are they known (9), but the food itself
has been commercialized.
· Some foods not previously recorded have been added: tej
from Ethiopia (10~; nono, a milk-based product from Nigeria; and
Zimbabwean fermented milk (31.
DISCUSSION AND CONCLUSIONS
As can be seen, very little has changed in the progress of the
fermented foods of Africa toward industrial production. The 1990s are
the era of biotechnology, especially genetic engineering. Fermented
foods are brought about by microorganisms, and one would expect
that these organisms would be subjected to the technology of gene
cloning to improve their activity in the fermentation of foods.
OCR for page 168
168
FERMENTED FOODS
For example, the fermentation of most carbohydrate foods such as
cassava or maize is brought about by lactic acid bacteria. One would
therefore have expected that these organisms would be targeted for
improvement by gene cloning. Only one example of the advantage of
the use of this technique will be given.
In garri fermentation lactic acid bacteria play an important part in
producing the flavor of the food (111. Yet these organisms cannot split
starch. If the amylase gene can be cloned into a lactic acid bacterium
involved in garri fermentation, it is conceivable that fermentation will
occur faster. If the gene for linamarase production can also be
simultaneously cloned, then not only will the fermentation be faster
but detoxification also will occur (12~.
The only work having any relationship to gene cloning in organisms
involved in fermentation was the isolation of plasmids from cassava
fermenting organisms by Nwankwo et al. (131. They found that they
could not transfer the plasmids to E. cold and there the work ended.
The lack of ability to exploit this new technique in an area of vital
importance to Africa south of the Sahara is a clear example of (an
almost?) missed opportunity in an age when seemingly everyone is
cloning a gene from one source or another. Nevertheless, there have
been some developments in other directions. For example, Ofuya and
Nnajiofor (14) have developed a starter culture for garri that should
prove useful in the commercialization of the food. Also, Ofuya and
Fiito (15) have developed a rapid method for assessing the quality of
garri based on an iodine reaction.
REFERENCES
1. Okafor, N. 1981. A scheme for the improvement of fermented
foods of Africa, south of the Sahara. Pp. 61-69. In: Global Impacts of
Applied Microbiology. S. O. Emejuaiwe, O. Ogunbi, and S. O. Sanni
(Edgy. London: Academic Press.
2. Okafor, N. 1990. Traditional alcoholic beverages of tropical
Africa: Strategies for scale-up. Process Biochemistry International
25:213-220.
3. Feresu, S. B., and M. I. Muzondo. 1990. Identification of some
lactic acid bacteria from two Zimbabwean fermented milk products.
World Journal of Microbial Biotechnology 6:178-186.
4. Okafor, N., C. O. Oyolu, and B. C. Ijioma. 1984. Microbiology
and biochemistry offoo-foo production. Journal of Applied Microbiol-
ogy 55:1-13.
5. Mensah, P., A. M. Tomkins, B.S. Drasar, and T. J. Harrison.
OCR for page 169
COMMERCIALIZATION OF FERMENTED FOODS
169
1991. Antimicrobial effects of fermented Ghanaian maize dough.
Journal of Applied Bacteriology 70:203-210.
6. Obeta, J. A. N. 1983. A note on the microorganisms associated
with the fermentation of the seeds of the African oil bean tree. Journal
of Applied Bacteriology 54:433~35.
7. Ogundana, S. K. 1980. The production of ogiri: Nigerian soup
condiment. Lebensmittel Wissenschaff und Technologia 13:33~336.
8. Onunkwo, A. U. 1982. Some edible fermentation products of
Nigeria. M.Sc. thesis, University of Strathclyde, Glasgow.
9. Odunfa, S. A. 1981. Microorganisms associated with the fermen-
tation of the African locust bean, Parkia:filicoidea, during iru prepara-
tion. Journal of Plant Foods 3:245-250.
10. Girma, M., B. A. Gashe, and B. Lakew. 1989. The effect of
fermentation on the growth and survival of Salmonella typhimurium,
Staphylococcus aureus, Bacillus cereus, and Pseudomonas aeroginosa
in fermenting tef (Eragrostis tefJ. Mircen Journal of Applied Microbiol-
ogy 5:61-66.
11. Okafor, N., and J. Uzuegbu. 1987. Studies on the contributions
of microorganisms on the organoleptic properties of garri, a fermented
food derived from cassava (Manihot esculenta Crantz). Journal of
Food Agriculture 2:99-105.
12. Okafor, N., and A. O. Ejiofor. 1990. Rapid detoxification of
cassava mash fermenting for garri production following inoculation by
a yeast simultaneously producing linamarase and amylase. Process
Biochemistry International 25:82-86.
13. Nwankwo, D., E. Anadu, and R. Usoro. 1989. Cassava fer-
menting organisms. Mircen Journal of Applied Microbiology 5:169-
179.
14. Ofuya, C. O., and C. Nnajiofor. 1989. Development and evalua-
tion of a starter culture for the industrial production of garri. Journal
of Applied Microbiology 66:37~2.
15. Ofuya, C. O., and J. Fiito. 1989. A rapid method for determining
the quality of garri based on iodine reduction test. Letters in Applied
Microbiology 9:153-155.
16. Ashenafi, M. 1990. Effect of curd cooking temperatures on the
microbiological qualities of ayib, a traditional cottage cheese. World
Journal of Microbial Biotechnology 6: 159-162.
17. Odibo, F. J. C., and A. I. Umeh. 1989. Microbiology of the
fermentation of Telfaria seeds for ogiri production. Mircen Journal of
Applied Microbiology and Biotechnology 5:217-222.
OCR for page 170
25
Biotechnology for Production of
Fruits, Wines, and Alcohol
J. Maud Kordylas
Fermentation is biotechnology in which desirable microorganisms
are used in the production of value-added products of commercial
importance. Fermentation occurs in nature in any sugar-containing
mash from fruit, berries, honey, or sap tapped from palms. If left
exposed in a warm atmosphere, airborne yeasts act on the sugar to
convert it into alcohol and carbon dioxide. The making of wines and
beers uses this biotechnology under controlled conditions. Alcoholic
beverages have been produced for centuries in various societies. They
are often central to the most valued personal and social ceremonies of
both modern and less literate societies. In such traditional ceremonies
as childnaming, marriage feasts, and funerals, alcoholic beverages are
often present. In Africa, maize, millet, bananas, honey, palm and
bamboo saps, and many fruits are used to ferment nutrient beers and
wines. The best known being kaffir beer and palm wines.
Industrial fermentation processes are conducted with selected micro-
organisms under specified conditions with carefully adjusted nutrient
concentrations. The products of fermentation are many: alcohol,
glycerol, and carbon dioxide are obtained from yeast fermentation
of various sugars. Butyl alcohol, acetone, lactic acid, monosodium
glutamate, and acetic acid are products of bacteria action; citric acid,
gluconic acid, antibiotics, vitamin Be, and riboflavin are some of the
products obtained from mold fermentation.
YEASTS
Yeasts, the main microorganisms involved in alcoholic fermentation,
are found throughout the world. More than 8,000 strains of this
vegetative microorganism have been classified. About 9 to 10 pure
170
OCR for page 171
BIOTECHNOLOGY
171
strains, with their subclassifications, are used for the fermentation of
grain mashes. These belong to the type Saccharomyces cerevisiae.
Each strain has its own characteristics and imparts its special properties
to a distillate when used in fermentation. A limited number of
yeasts in the classification Saccharomyces ellipsoides are used in the
fermentation of wines from which brandy is distilled. The strains used
in the fermentation of grain mashes are also used in the fermentation
of rum from sugarcane extracts and in beer production. Since yeasts
function best in slightly acid medium, the mash, juice, sap, or extract
prepared for fermentation must be checked for adequate acidity. If
acidity is insufficient, acid or acid-bearing material are added. For
distilled liquors, fermentation is carried out at 24° to 29°C for 48 to 96
hours, when the mash or must is ready for distillation. The alcohol
content of the fermented must is about 7 to 9 percent.
RAW MATERIALS
Cereals and Starchy Roots
For most distilled liquors, the raw material used is a natural sugar
as found in honey, ripe fruit, sugarcane juice, palm sap, beet root,
milk, or a substance of amylaceous (starchy) nature that can be easily
converted into simple sugars using enzymes present in cereals or
through the addition of suitable malted cereal. Maize or corn is the
most important grain used as fermentable starchy cereal. Starchy roots
and tubers are also used. Industrial production of alcohol from cassava
in Brazil has been described by De Menezee (11. The alcohol produced
is concentrated in a second distillation column to 97.2 percent and is
further dried to 99.9 percent and blended with gasoline for energy
purposes.
Malt is important in distilled liquor. In addition to converting starches
from other carbohydrates to sugars, malt contains soluble proteins that
contribute flavor to the distillate obtained from the fermentation of
grain malt mixtures.
Sugarcane
Grown throughout the tropics and semitropics, sugarcane and its
products, including cane juices, molasses, and sugar are used to make
rum and an alcohol derived from rum. Pressed juice from sugarcane
can be used as the base raw material for fermentation, or the juice can
be concentrated for sugar production with the molasses residue from
sugar crystallization used as a base for alcohol fermentation. Molasses
OCR for page 172
172
FERMENTED FOODS
contains about 35 percent sucrose and 15 percent reducing sugars. This
gives molasses its principal value as an industrial raw material for
fermentation to produce rum. Two or 3 liters of molasses produces 1
liter of rum. Acetone and butanol also are produced from molasses by
fermentation with Clostridium bacteria. Food yeast Torulopsis utilis,
is prepared from molasses, as are baker's and brewer's yeasts (21.
Coconut Palm
The coconut palm finds many uses on the tropical islands of the
Pacific. Toddy is produced by tapping the unopened flower spathe of
the coconut palm. The spathe is bruised slightly by gentle tapping with
a small mallet and is tied tightly with fiber to prevent it from opening.
It is bent over gradually to allow the toddy to flow into a receptacle.
About 5 centimeters is cut from the tip of the spathe after about 3
weeks. Thereafter, a thin slice is shaved off once or twice a day and
the exuding sap is collected. Palms are tapped for 8 months of the year
and rested for 4 months. The average daily yield per palm is about 2
liters. The yield per spathe varies from 15 to 80 liters, and an average
palm can yield 270 liters during 8 months of tapping. The fresh sweet
toddy contains 15 to 20 percent total solids, of which 12 to 17.5 percent
Is sucrose.
Toddy ferments rapidly due to naturally occurring yeasts. Fermented
toddy contains about 6 percent alcohol. After 24 hours the toddy
contains 4 to 5 percent acetic acid and is unpalatable as a beverage. It
can be used for the production of vinegar. Fermented toddy can be
distilled to produce arrack. Freshly fermented toddy is used instead
of yeast in bread making. Constant tapping of coconut palms for toddy
eliminates the nut crop. In 1952 in wine distilleries in Sri Lanka, over
49 million liters of toddy was fermented to give 4.5 million proof liters
of arrack (21.
Oil Palm
By tapping the male inflorescence of the oil palm, a sweet sap is
obtained. The leaf subtending the immature male inflorescence is
removed to provide access, the inflorescence is excised, and thin slices
are cut once or twice daily. The exuding sap is funneled into a calabash
or a bottle. The fresh sap contains 15 percent sugar. Tapping is done
daily for 2 to 3 months, yielding about 3.5 liters of sap per day. The
sap ferments by the action of bacteria and natural yeast to produce a
beverage with a milky flocculent appearance and a slight sulfurous
odor known as palm wine. Palm wine is produced and marketed in
considerable quantities in Nigeria.
OCR for page 173
BIOTECHNOLOGY
173
The sap may be boiled to produce dark-colored sticky sugar or
jaggery, which does not keep well. About 9 liters of juice produces 1
kilogram of jaggery. The fermented sap also yields yeasts and vinegar.
A mean annual yield of 4,000 liters of sap per hectare of 150 palms has
been recorded in eastern Nigeria. This was estimated to have a value
more than double that of oil and kernels from similar palms. Tapping,
however, reduces the fruit yield. Sap can also be obtained by tapping
the crown of the tree laterally or by felling the palm and drilling a hole
through the growing point. Both these methods are very wasteful since
they kill the plant. The Palmyra palm yields about 2 liters of palm sap
per day. Large palms with several tapped inDorescences give as much
as 20 liters per day. A single palm of this type is estimated to produce
12,000 liters of sap during its tapping life.
Fruits
Grapes are the most common fruit used as raw material for alcoholic
fermentation. They are used in distilled liquor to make brandy.
Historically, wine is the product of fermentation of grape species Vitis
vinifera. The high sugar content of most V. vinifera varieties at maturity
is the major factor in their selection for use in much of the world's
wine production. Their natural sugar content provides the necessary
material for fermentation. It is sufficient to produce a wine with an
alcohol content of 10 percent or higher. Wines containing less alcohol
are unstable because of their sensitivity to bacterial spoilage. The
grape's moderate acidity when ripe is also favorable to wine making.
The fruit has an acidity of less than 1 percent, calculated as tartaric
acid, the main acid in grapes, with a pH of 3.1 to 3.7. The flavor of
grapes varies from neutral to strongly aromatic, and the pigment pattern
of the skin varies from light greenish-yellow to russet, pink, red,
reddish violet, or blue-black. Grapes also contain tannins needed to
give bite and taste in the flavor of wines and to protect them from
bacteria and possible ill effects if overexposed to the air.
Other fruits can be used to produce wine. When fruits other than
grapes are used, the name of the fruit is included, as in papaya or
pineapple wine. Apples and citrus fruits with sufficient fermentable
sugars- are crushed, and the fermentable juices are either pressed out
for fermentation or the entire mass is fermented. Tropical fruits such
as guava, mangos, pineapple, pawpaw, ripe banana, ripe plantain,
tangerine, and cashew fruit also contain fermentable sugars with levels
varying from 10 to 20 percent. Overripe plantain pulp was reported to
contain 16 to 17 percent fermentable sugar, with the skin containing
as much as 30 percent (3~.
The tropical climate prevailing in Africa is ideal for the growth and
OCR for page 178
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OCR for page 179
BIOTECHNOLOGY
179
carambola somehow continued to flower and set fruit during the rainy
season as long as there was periodic sunlight.
Quality was high in guavas and soursop harvested at the beginning
of the rains. The fruits were large and well formed and had good flavor.
Most of the fruits harvested at the ends of the dry and rainy seasons
were smaller, malformed, or diseased. This may be due to the effects
of too little or too much water on the health of the plants. Too little
water may have affected the activities of microorganisms in the soil,
and too much water may have reduced air supply to microorganisms
in the soil and leaching of nutrients from the soil. Diminished microbial
activity may have affected the well-being of the plants. These assump-
tions might, however, need to be confirmed through controlled experi-
ments.
The 180-square meter backyard plot yielded sufficient quantities of
fruits guava, soursop, and carambola to provide raw materials for
processing to make jams available on the local market throughout 1989
and thereafter. Carambola yields were also sufficient for wine making.
The amount of pawpaw harvested from the backyard was not sufficient,
however, for both jam production and wine making. More pawpaw
was therefore purchased from the local market to supplement the
amount harvested. The quantity of mango obtained from the one mango
tree was also not sufficient to keep up with the demand for mango jam
on the market. More was obtained from the local market.
Table 2 shows total yields for guava, soursop, carambola, and
pawpaw harvested from 1986 to 1990. Although two of the four pawpaw
trees died, total yields of fruits from the backyard continued to increase
over the years. Yields from crops interplanted among the fruit trees,
including pepper, cocoyam, plantain, and winged beans, and from the
one avocado tree that started bearing fruit in 1990, when added to
those obtained from trees in Table 2, provided an overall yield of over
1 ton from the backyard plot in 1989 and again in 1990.
Wine Production
Wine of acceptable quality were produced from pawpaw, pineapple,
and carambola. The wines made were either dry, semidry, or sweet.
TABLE 2 Fruit Yields (kilograms), 1986-1990
Fruit 1986 1987 1988
1989 1 990
Guava 49.0 131.2 217.5 208.3 295.0
Soursop — 173.0 151.5 397.0 286.3
Carambola — 0.4 63.6 221.5 279.0
Pawpaw — 28.3 100.9 72.6 40.0
Total 49.0 332.9
533.5 899.4 900.3
OCR for page 180
180
FERMENTED FOODS
Although no controlled organoleptic assessment was organized to
evaluate the acceptability of the wines, reactions from random individu-
als who tasted the wines were favorable. Marketing trials will be
conducted.
Alcohol Production
Juice extracted from the crushed pineapple core and the inner seeded
cover contained sufficient sugar to produce 6.5 to 7 percent alcohol
after fermentation. With the addition of extra sugar, however, the
alcohol content was increased to 10 percent. A total of 25 liters of over
90 percent concentration alcohol was distilled from 200 liters of
discarded wines and 100 liters of fermented pineapple waste extract.
Portions of the alcohol were used to carry out experiments to produce
aperitif drinks with guava, pineapple, passion fruit, carambola, and
ginger. The experiments are still in progress.
BIOTECHNOLOGY PRODUCTION SYSTEM
The integrated bioechnology research and development system is
shown in Figure 1. The broken-line arrows indicate units not yet
included but for which information has been collected to enable their
future integration into the system. The chickens are needed to produce
manure for the composting process, with meat and eggs as additional
marketable products. Wastewater from fruit processing would be
recycled to provide water for irrigation and for comporting to econo-
mize on the use of potable water for those processes.
From the data collected and from experience gained through the
project, the integrated biotechnology production system has many
advantages:
· It is environmentally sound: Wastes generated from fruit pro-
cessing and from the backyard plot are recycled through the composting
process to produce organic fertilizer.
· Labor requirements have not been excessive: Once the necessary
conditions are met and controls applied for microorganisms to grow
and multiply, the productive processes for wine and alcohol production,
for comporting, and for nutrient release for plant nourishment are
carried out with little or no supervision.
· Energy requirements are low: Apart from the energy needed for
production of jams and for pasteurization and to run the small-scale
equipment used in processing, the integrated production system needs
limited amounts of energy input to function. The microbial processes
generate their own energy. The need for air conditioning to maintain
OCR for page 181
BIOTECHNOLOGY
Meat Eggs
Chlickens
1
1
Manure
i: _ _
Composting ~ ~
Peels and other
Waste Products
Fermentation ^~
/
/
Distillation
1
_ Wastewater
-
-
/
/
/
Pineapple Core Plus
Inner Cur
Fer~at~on
Wines
/1
Carambola Wine,
Rejected Papaya Wine,
Wines Pineapple Wine,
/ (sold on order)
Alcohol Research and Development
Vodka ~ for Aperitif Wines and Liquors
Promising Products
Guava Aperitif
Ginger Aperitif
Passion Fruit Aperitif
Not yet added onto the system
181
''~Fruit Trees
\
1/
_ Processing
/
Juices
Jellies
Guava Jelly,
Soursop Jelly
(on the market)
\* Research
/ and Development
\
\
\
Pulp
Ja s
Guava Butter
Pineapple Jam
Pawpaw-Ginger Jam
Pineapple-Ginger Jam
Mango Jam
Carambola Jam
(on the market)
FIGURE 1 An integrated research and development system using biotechnology in the production of fruits,
wines, and alcohol.
OCR for page 182
182
FERMENTED FOODS
constant environmental temperatures will likely add to the energy
costs.
· The system is sustainable: The interdependency of the microbial
subprocesses provides sustainable support to each other with limited
input required from outside. Funds generated from the sale of products
(jams, wines, apertif drinks) are used to support needed research and
to purchase equipment and supplementary produce required to sustain
the production of marketable products.
· Only practical research is undertaken: Experiments carried out
are those needed to solve immediate problems arising from the
production system. These are carried out either to improve the quality
of a product, to formulate new products from raw materials or by-
products generated within the system, or to enhance marketability of
a product.
· Realistic data is collected for feasibility reports. Production and
trial marketing of products from the system have enabled real data to
be collected. These are being used to evaluate the system economically
and to produce a feasibility report based on actual figures to make
decisions on establishing an industry based on the prototype research
and development unit.
· Valuable experience has been gained: The project has provided
valuable experience in the management of a small enterprise.
CONCLUSIONS AND RECOMMENDATIONS
A good number of efficient microbial processes are available.
Sufficient knowledge has been accumulated and information provided
on their management and control. If properly selected, synchronized,
and integrated, the activities of microorganisms from such processes
may be harnessed and used. Their exploitation may be a more promising
alternative to large-scale industrial technologies imported from devel-
oped countries, which developing countries in Africa cannot afford,
sustain, or manage.
The priority for research is, therefore, on selecting the right types
of microbial processes that can be put together to form sustainable
productive systems, with research trials carried out on prototypes to
determine the most economically viable combinations to be adopted
for commercial exploitation.
REFERENCES
1. De Menezee, I. J. B. 1978. Alcohol Production from Cassava.
Pp. 41~5 in: Cassava Harvesting and Processing. International Devel-
opment Research Center, Ottawa, Canada.
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2. Purseglove, J. W. 1985. Tropical Crops. In: Monocotyledons.
England: Longman.
3. Kuboye, A. O., A. B. Oniwinde, and 1. A. Akinrele. 1978.
Production of Alcoholic Beverages from Ripe Pineapples, Plantain,
and Bananas, Vol. 2, Pp. 78-80. Nigerian Institute of Food Science
and Technology. Lagos, Nigeria.
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26
Future Directions
Leslie Fook-Min Yong
The preparation of fermented foods predates the recorded history
of Man. Early humans used observation of the apparent effects of
microbial alteration of food characteristics to develop processes for
food fermentation. The resultant fermented products normally have a
different texture and flavor compared to the unfermented starting
materials, thus making them more palatable and digestible and pro-
longing their shelf life. Technical progress was initially slow, as
reflected in the long fermentation periods required; it was incremental
to the technical know-how and basic scientific information then
available. It is probably fair to say that in the very early days
brew-masters were more artisans than technologists. With the rapid
advancement in understanding of the basic sciences of microbiology
and biochemistry, coupled with the introduction of new equipment,
the developed nations have forged ahead in improving the safety and
efficiency of the bioprocesses used to manufacture traditional fermented
foods, such as cheese fermentation.
"OLD" AND "NEW" BIOTECHNOLOGY
With the rapid progress in the biological sciences, both basic and
applied aspects, it has been possible to gain a better understanding of
the mystery that has surrounded fermentation processes. The types of
microorganisms involved has been isolated and identified, and the
physiology and metabolism of these organisms have been studied.
Hence, traditional fermented foods can now be made better, faster,
and more economically. The application of available knowledge to
In this paper I draw on my experience working with soy sauce fermentation and then
proceed to discuss the production of flavor and fragrance materials by microbial
fermentation. Experience gained from this traditional fermented condiment has enabled
me to develop novel bioprocesses for the production of aroma chemicals.
184
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improve traditional food fermentations in developed countries has far
outpaced that in developing countries.
The terms "old biotechnology" and "new biotechnology" have been
used "old" to mean the undirected manipulation of microorganisms
and plants, such as by mutagenesis and selection of the better strains.
In this old biotechnology I would like, for convenience, to include
directed control of the physical and chemical environments of the
fermentation process, which could result in better performance of the
useful microbes.
Though mutation
increases the ability to select better strains, there
can, of course, be little directed alteration of genetic material. The
new biotechnology, such as recombinant DNA techniques, overcomes
this problem. The new biotechnology can, of course, be of tremendous
help in producing superstrains of microbes that could enable accelera-
tion of fermentation processes, provide more efficient utilization of
raw materials, and produce better-quality products. How best can
developing nations apply these biotechnologies to traditional fermented
foods? Should it be application of the `'old" before the "new," "new"
without the "old," or "old" and "new" simultaneously?
In their enthusiasm to promote the new biotechnology for traditional
fermented food applications, scientists from developed countries should
not forget the different environments that exist in developed and
developing countries. In developed countries the old biotechnology is
already well understood and practiced efficiently in fermented food
industries. Developing countries may need to acquire a better under-
standing of the old biotechnology before efficiently absorbing and
implementing the new biotechnology to its fullest.
APPLICATION OF BIOTECHNOLOGY
Preparation of traditional fermented foods is more complex and time
consuming than that involved in the production of single chemical
substances. For example, in soy sauce fermentation more than one
type of microorganism is involved, whereas in citric acid fermentation
only one species of fungus is normally used. How can developing
countries apply new knowledge in the old and new biotechnologies to
their own complex traditional food fermentations?
Take soy sauce fermentation as an example of a traditional fermenta-
tion process conducted in a developed country, such as Japan compared
with that in a country like Malaysia. The technology in use in Japan
is sophisticated, very advanced, and highly productive and mechanized.
The microbes used have been selected over the years for their
performance in producing a better-quality product. The cottage industry
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FERMENTED FOODS
soy sauce fermentation in Malaysia is highly labor intensive and usually
relies on "natural" inoculation of raw materials using unwashed trays
for previous fermentations rather than using a separately prepared
inoculum of Aspergillus oryzoe.
The equipment used in Japan to conduct the fermentation is state-
of-the-art machinery with microprocessor or computer control to
provide the optimum conditions for microbial growth and activity. The
microorganisms used have been manipulated by mutagenesis to give
better performance, such as better enzymatic activity to give better
hydrolysis of proteinaceous matter in defatted soybean meal as well
as better flavor production. In comparison, the average process used
in Malaysia could be considered primitive.
This disparity is attributable to a better understanding of the
theoretical and practical bases of soy sauce fermentation by scientists
and technicians in Japan's soy sauce factories. The old biotechnology
involved in this type of traditional fermentation is well understood in
Japan, and the Japanese are now able to make better use of the new
biotechnology such as the directed alteration of genetic material of
the mold (Aspergillus oryzoe), yeast (Saccharomyces rouxii), and
bacteria (Pediococci) used in soy sauce fermentation so as to improve
their fermentative qualities.
Necessary Prerequisites
For developing countries to make full use of the available biotechnol-
ogies in their traditional food fermentations, an understanding and
acquisition of expertise in the following areas are essential.
Art of fermentation
A clear understanding by the master brewer of every step used in
the fermentation is needed. This is the art of fermentation. Although
the master brewers might not have scientific backgrounds, they could
normally ensure a proper fermentation as a result of years of experience.
Without a knowledge of the art of traditional food fermentation, a
scientist cannot provide a scientific explanation for the process and
proceed to provide assistance in improvement of the process.
Microbiology
It is essential to know which microorganisms involved in food
fermentations are useful and how the physiology and metabolism of
these microbes are affected by the physical and chemical environments
of fermentations, as well as how their microbial activities in turn affect
the fermentation processes. Microorganisms normally break down
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carbohydrates, proteins, and lipids present in the raw materials to be
fermented by releasing enzymes into the medium. As the raw materials
are hydrolyzed, the environment is changed, as sometimes reflected
by a drop in pH value. Moreover, the breakdown products such as
peptides and amino acids can be further converted into smaller
volatile molecules that are odoriferous and hence improve the flavor
characteristics of the fermented foods.
Upstream and downstream processing
Normally raw materials are pretreated before fermentation. It is
important to comprehend how such pretreatment could affect the
fermentation process. In soy sauce fermentation, whole soybeans are
steamed to make the soy protein more easily hydrolyzable by the
proteases of Aspergillus oryzoe. In so doing, too much moisture is
introduced and-wheat flour must be added to lower the moisture
content to a level that does not favor early bacterial growth and hence
prevents spoilage of the fermentation.
Downstream processing does not affect the bioprocess involved.
However, it could alter the normal organoleptic properties of the
product, especially when downstream processing involves heating,
such as in the pasteurization of soy sauce. Heating causes a change in
the flavor of soy sauce due to nonenzymic browning reactions, which
could result in the production of pyrazine compounds.
Biochemistry
An understanding of the biochemical activities of the microbes
actively participating in the fermentation could help to explain the
change In the texture of the raw material as well as the origin of
flavoring substances often present in fermented foods. Flavor and
texture are important properties of fermented foods. Elucidation of
flavor production in such fermentations could result in the development
of processes for producing of flavoring materials by fermentation, as
in the production of cheese flavors by Penicillium roquefortii.
Fermentation equipment and techniques
Practical experience in the use of both solid-state and submerged
culture fermentation equipment is very useful. Normal training includes
submerged culture bioreactors but not solid-state fermenters. It is
useful to know both types of fermentations because traditional food
fermentations often involve solid state fermentation. In soy sauce
fermentation an initial solid-state fermentation is followed by a sub-
merged fermentation step. Systems that measure and control pH,
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FERMENTED FOODS
dissolved oxygen, temperature, and moisture help to make these
bioprocesses more efficient and reduce the time required for production
of a quality product.
CONCLUSIONS
For developing countries, future directions in applying biotechnology
to traditional fermented foods should be: (1) training of a pool of
technicians in the art and science of traditional food fermentations
and (2) investigations by local scientists into the scientific basis of
indigenous food fermentations.
Theoretical basic science education, such as the microbiology and
biochemistry of food fermentations, could be taught in schools; so
could the use of modern bioreactor systems. However, the application
of such biotechnological knowledge to actual commercial fermentations
can come about only after a practical experience in a fermented food
factory for a period of time. The approach to be taken in applying
biotechnology to traditional food fermentations should be that of finding
solutions to existing bioprocessing problems and not trying to find
problems with newly acquired biotechniques.
Only after the old biotechniques of fermentation have been success-
fully used can industries in developing countries look forward to using
the new biotechniques of recombinant DNA to improve the genetic
constitution of the microorganisms involved.
Representative terms from entire chapter:
lactic acid
