PHYSICO-CHEMICAL AND STRUCTURAL
CHARACTERISTICS OF PIANTAIN (MU6a. paJr.a.cLL6A.ac.a. )
FLOUR WITH A SPECIAL REFERENCE TO "FUTU" PREPARATION
A Thesis
Presented to
the Faculty of the School of Graduate Study
Alabama Agricultural and Mechanical University
In Partial Fulfillment
of the Requirements for the Degree
Master of Science in Food Science
by
Agbo N'zi Georges
April 1979
D t ~ ~~/d 1.
. r \\
.
Major ~arat .~~
1

VITA
Agbo N'zi Georges
Candidate for the Degree of
Master of Science
Thesis:
Physico-Chemical and Structural Characteristics
of Plantain (Mu~a pa~adi~iaea) Flour with a
Special Reference to "Futu" Preparation
Major Field:
Food Science
Biographical Information:
Personal Data:
Born in Dimbokro, Ivory-Coast, April 23,
1948; Son of Brou Agbo and Konan Akissij
Married to DiomanseB. Albertinej two
daughters, Adjoua Maryse, Aya Celia and
one son. Kouadio Serges.
Education:
College of Fisheries. Navigation,
Mechanical Engineering and Electronics.
St. John's Newfoundland. Canada
Diploma of Food Technology. 1974
Alabama A&M University. Normal. Alabama
B.S. Food Science and Technology. 1976
Alabama A&M University, Normal. Alabama
M.S. Food Science. 1979
Experience:
Aid'chemist. SAPROCSY-Blohorn. Abidjan
Ivory-Coast, December 9. 1968 to April 29.
1969..
Lab assistant. Federal Fishery Inspection
Laboratory. Montreal P.Q. Canada. ·Summer
1972 and St. John's Newfoundland Canada.
1973.
Lab assistant. Institut de Transformation
et d'Industrialisation des Produits Agri-
coles Tropicaux (I.T.I.P.A.T.). Abidjan
Ivory-Coast, l1arch to June. 1975
i

Lab assistant, Department of Food Science
and Technology, Alabama A&M University,
Normal, Alabama, September 1975 to March
1976.
Research assistant, Department of Food
Science and Technology, Alabama A&M
University, Normal, Alabama, February 1979.
ii

ACKNOWLEDGEMENTS
l wish to express my deep sense of gratitude to Dr. Bharat
Singh, my major advisor, for his guidance during the present
investigation and review of this study.
l am also grateful to my committee members, Dr. G.R. Sunki,
Dr. G. C. Sharma, Dr. J. Savage for their suggestions and
review of this study.
l express my deep sense of appreciation and love to my
dear mother and late father Mrs. and Mr. Agbo, for their wise
advises and encouragement in many ways.
l am thankful to my counsin, Mrs. Suzanne Laffite, for
her moral understanding and support.
l further thank both my
wife, Bodjebie Albertine, and a graduate student, P. Anthony,
for their experimental assistance in sorne parts of this study.
This research was supported by the RIAS-RSCS, the
National Science Foundation, Grant No. SER 76-1825.
Agbo N'zi Georges
iii
1

TABLE OF CONTENTS
Page
VITA. . . . . . .
i
ACKNOWLEDGEMENTS.
. iii
TABLE OF CONTENTS
iv
LIST OF TABLES.
v
LIST OF FIGURES
.
.
.
.
.
.
vi
ABSTRACT
.
.viii
INTRODUCTION
.
1
REVIEW OF LITERATURE.
5
EXPERIMENTAL METHODS . . .
16
RESULTS AND DISCUSSIONS .
28
SUMMARY. . . .
54
REFERENCES
55
iv

LIST OF TABLES
TABLE
PAGE
1.
Properties of starches
.
23
2.
A comparison of proximate content of plantain
with other starchy food materials . . . .
. .
29
3.
Simple correlation coefficient between crude
fat, crude fiber, protein and ash in plantain
30
4.
A comparison of pulp moisture, starch, total
sugars, reducing sugars, and amylose contents
of plantain with other starchy food materials
31
5., Simple correlation coefficient between moisture,
starch, total sugars'lreducing sugars, and
amylose of plantain pulp.
. . . . . . . . . . . . .
33
6.
Proximate content of "futu" prepared from the
flours obtained from the various stages of
ripening of plantain. .
. .
. . . . . . . .
.
34
7.
Simple correlation coefficient between moisture,
protein, crude fat, crude fiber and ash of
"futu" from flours obtained from the various
stages of ripening of plantain.
. . . . . • • . . .
36
8.
Pasting characteristics of plantain flours at
47
pH 4.50.
.
.
.
.
.
.
.
.
.
.
..
.
.
.
.
.
.
.
9.
Pasting characteristics of plantain flours
compared to other starch foods at pH 5.35 .
49
10.
Functional properties of plantain flours
compared to other starchy food materials.
52
Il.
Panel evaluation of "futu" prepared from
plantain flours • .
. . . . . • . .
• • .
53
v

LIST OF FIGURES
FIGURES
PAGE
l.
Four stages of ripening of plantains
.
17
2.
Flow diagram for production of plantain
flour used-for "futu" . . . .
18
3 .
Plantain flours·-
19
4.
Flow diagram of "futu" preparation.
.
25
a.
For plantain flour
.
25
b.
For conventional procedure
.
25
5.
"Futu" prepared from plantain flours
.
26
6.
Scanning electron micrograph of pulp from hard
green plantain (400X)
. . . . . . . .
37
7 .
Scanning electron micrographs of pulp from half
green plantain (400X)
. . .
. . . .
. . . . . . .
37
B.
Scanning electron micrographs of pulp from light
yellow plantain (400X)
.
38
9.
Scanning electron rnicrograph of inner surface of
peel from hard green plantain (400X) . . . . .
40
la.
Scanning electron micrograph of inner surface of
peel from half green plantain (400X) . . . . .
40
Il.
Scanning electron micrograph of inner surface of
peel from light yellow plantain (BOOX)..
. . . .
40
12.
Scanning electron micrograph of peel from hard
green plantain (BOOX)
. . . . . . . . . . . . .
41
13.
Scanning electron micrograph of peel from half
green plantain (BOOX)
. . . . . . . . . . . . .
41
14.
Scanning electron micrograph of pulp from
blanched hard green plantain (400X)
. . .
42
15.
Scanning electron micrograph of traditional
"futu" (400X). . . .
. . . . . . .
. . . .
42
16.
Scanning electron rnicrograph of flour from hard
green plantain (400X).
. . . . . .. .
. . . . .
44
17.
Scanning electron micrograph of flour from half
green plantain (400X).
. . . . . .
.
44
18.
Scanning electron micrograph of flour from light
yellow plantain (400X)
. .
. . . .
.
44
vi

FIGURES
PAGE
19.
Scanning electron micrograph of the outer surface
of "futu".
A) From hard green plantain flour.
b) From blanched hard green plantain flour (400X) . . 45
20.
Scanning electron micrograph of the outer surface
of "futu" from half green plantain flour (400X).
. . 45
21.
Scanning electron micrograph of the outer
surface of "futu" from light yellow plantain
flour (400X).
. .
. . . . . . . . . . . .
. . ..
. . 45
22.
Brabender curves of plantain flour from three
stages of ripening at pH 4.50 . . . . . . . . .
46
23.
A comparison of Brabender curves of plantai,n
flour from three stages of ripening at pH 5.35
with other starchy foods..
. . . . .
. .
. . . . . . 48
vii

PHYSICO-CHEMICAL AND STRUCTURAL
CHARACTERISTICS OF PLANTAIN (Mu~a pa~ad~~~aQaJ
FLOUR WITH A SPECIAL REFERENCE TO "FUTU" PREPARATION
by
Agbo N'zi Georges
Alabama A & M University
Major Professor:
Dr. Bharat Singh
Department:
Food Science and Technology
ABSTRACT
"Futu
or Fufu" is the traditional African name given to
a softly pounded
uniformly compact cooked yam
plantain pulp,
J
J
cassava or cocoyam made in baIl form.
Plantain fruits obtained
from Colombia, Central America, were used in this study.
Proxi-
mate compositions of plantain flour and "futu" prepared from
different plantain stages of ripening were determined.
The
starch granules changes occuring during the ripening of plantain
fruit, and the structure of "futu" from plantain flours were
observed with a scanning electron microscope (SEM).
The
starch gelatinization characteristics of the flours were deter-
mined using Brabender Amylograph.
Starch and crude fiber contents decreased during the
ripening of plantain while total sugars, reducing sugars, crude
fat
protein and ash increased.
The plantain pulp showed
J
significantly higher amounts of moisture, total sugars
reducing
J
viii
1

sugars, protein, and crude fat at the light-yellow stage of
ripening than at other stages.
The amounts of crude fiber and
amylose were significantly higher at the half-green stage than
at other stages.
No significant variations were found in the
ash content due to ripening stages.
There was a positive
significant correlation between crude fat and ash contents, and
total sugars with reducing sugars at 0.05 level.
The crude
fiber and ash contents of "futu" prepared from plantain flours
and that of "futu" made in a traditional manner did not differ
significantly.
A significantly higher amount of protein was
found in the traditional "futu" than in the "futu" prepared
from the plantain flours.
SEM study revealed that plantain starch granules have
spherical, kidney-shaped, elongated and irregular forms and
sizes at different stages of ripening.
It indicated also that
starch granules increase in size during ripening of plantain
pulp ; and they are larger at the outer side of the pulp than
at the inner side.
vfuen green, the peel of the fruit had an
intact rough structure of cellulose cell wall, air space, and
vessel elements; but it showed a collapsed structure when it
,
became half green.
The pulp, when cooked or blanched, had a
compact amorphous structure of smashed and damaged starch
1
granules in combination with a protein matrix.
"Futu" made in
the traditional manner had an outer surface entirely covered
1
with a smooth protein matrix, ymile that made from plantain
1
flours showed an outer surface with visible starch granules
l
[
ix
1
!

embedded in and covered with an amorphous protein film.
This
could be due to the fact that the product was not pounded as
in the traditional "futu".
In spite of these differences,
the products prepared from plantain flours were rated to be good
and acceptable as the traditional "futu".
The amylograph viscosity measurement of the flour indicated
that plantain starch viscosity decreases during ripening.
Scanning electron microscograph of unblanched plantain flours
showed undamaged starch granules while in the case of blanched
plantain flour starch granules were completely damaged.
This
blanched flour was found to be unsuitable for good quality
"futu" preparation because it had a very low viscosity.
x
1

INTRODUCTION
The name "Plantain" is used to specify any banana that is
eaten in the cooked state assuming that all such banana must be
starchy.
There are two main varieties, Mu~a pa~ad~~~aQa or
French bananas and Mu~a Qo~n~Qula~a or Horn bananas (Von
Loesecke, 1950).
These varieties are known by different names
in various banana-producing regions.
After harvest, fully mature plantains tend to ripen
quite rapidly with an accelerated rate of change of starch inta
sugars (Von Loesecke, 1950; StmIDonds, 1966; Sanchez, ~968).
The difficulty of maintaining plantain in the green stage poses
a problem to both the farmer and the housewife.
The farmer
must market his product immediately after harvesting ta avoid
fast: ripening, and the latter is completely dependent en the
daily fresh market supply for her cooking.
In the processing of foods derived from green plantains
(normally used for cooking a variety of dishes, not as fresh
fruit) it is of prime importance that the plantains are at the
proper stage of development; fully mature but completely green.
No changes in starch. total sugars, acidity and pH take place
as the bunch matures on the plant.
There seems to be a s1ight
tendency for reducing sugars values to increase with maturity
(Sanchez, et al., 1968; Palmer, 1971).
Starch granules from several food sources such as
cereals, tubers or roots have been extensively stuàied but
l
1

those of banana have been investigated by only few scientists.
Banana starch grains vary in length from 20 to 90 micron (u)
and from 12 to 45 u in width (Collins, 1915).
Carson (1972)
gave an approximation of 22±7 u for the smaller grains and
39±10 u for the larger grains.
Banana flour (dried and finely
ground) of green plantain pulp contains 70% starch and has
functional properties remarkably similar to the isolated banana
starch (Carson, 1972).
Palmer (1971) reported that plantains
differ from sweet banana in having a higher starch content in
the pulp (33% at harvest and 5-10% when ripe).
Many products have been produced commercially from
plantain such as fried plantain chips (Sarna, 1971),flour
(Rahman, et al, 1968; Hapitan, 1969) beer, (Dupaigne, 1974),
drink (Casimir, et al., 1971) and others.
Sanchez and Hernan-
dez (1968) developed methods for the preparation of syrup
from frozen ripe plantain.
Banana plantains are used to prepare a staple food in
most of the West African countries.
The staple food is called
"futu" in Ivory-Coas t and "fufu" in Ghana and Nigeria.
This
product is a softly pcunded, uniformly compact cooked yam,
plantain pulp, cassava, or cocoyam traditionally made in a baIl
forme
The preparation of the product follows a traditional
process using unripe plantain pulpe
Occasionally, cooked
slightly ripe plantain pulp or cassava is added to improve the
softness of the product.
The product must be eaten within a
few hours after preparation, usually with a stew (made of
2
1

vegetables mixed with either meat or fish. and very often
both) because it may become very firm when left for a period
of time at room temperature or even in a warm place.
The
cooking tools have changed from firewood to the electrical
stove. but the preparation process is till the same.
For
centuries. West African housewives have depended on visual
observation only to determine when the plantain is ready for
good quality "futu" preparation.
Cereal starches are commonly used in food industries
at the present time.
Sorne tubers or roots of plants such as
cassava and potatoes are also used.
The products derived from
these food sources are processed adequately for preparing foods
in the Western ways.
Most of those products such as pizza.
ravioli, tacos, jellies and others are not accepted by a large
number of people in Africa because Africans have their own ways
to prepare their foods from the starchy food crops.
As far as "futu" is concerned, no literature is
available on the method of preparation.
The product from
plantains could be prepared commercially as a dehydrated
product which could save time for the housewife. and reduce
losses of raw materials and money associated with home prepara-
tion and the marketing period of the fruit.
If it is economical.
these products could help to increase the food supply in West
Africa.
In this study. plantain Mu~a pa~ad~~~aea was used.
The objectives of the present study were; 1) To
determine the chemical changes in starch. sugars. amylose,
3
1

protein, fat, crude fiber, and ash during ripening of plantain;
2) To determine changes in starch granules during ripening
of plantain, and the
structure of "futu" products from plantain
flours by scanning electron microscope; 3) and finally to
determine the physical characteristics of plantain flour and
correlate with "futu" preparation.
4
1

REVIEW OF LITERATURE
Banana plantains belong to the section Eumu~a, the
edible banana species of the genus Mu~a.
The genus derives
frorn the MU~ac.eCle farnily of the order Z-ing-ibeftClte/5 ~
The plan-
tain varieties, MU~Cl pClltCld-i~-iClc.Cl or French bananas and Mu~a.
c.oltn-ic.ulClta or Horn bananas are widely spread in the tropical
and subtropical areas of the world.
Those varieties are kno~vn
by different narnes in various banana-producing regions (Von
Loesecke, 1950).
The terrn "plantain" has an arnbiguous nom-
enclature (Simmonds, 1966) and is used ta specify any banana
that is eaten in the cooked state assuming that aIl such banana
must be starchy.
Plantains are also known as starchy banana.
In general, plantains are moderately vigorous bananas
that are resistant to both Panama Disease and leaf spot.
They
are important sources of food in India, East, Central, and West
Africa (Tackholm and Drar, 1954), and tropical America.
The
so-called French plantains are knOTNn only in Africa, India, and
Tropical America (Sanchez,
et Cli., 1974).
Horn plantains occur
in the same areas but ex tend farther East inco Indonesia, the
Philippines, and the Pacifie where there is no record of the
occurence of variability.
Variability in Africa and Tropical
America is weIl recognized (Sanchez,
et Cli., 1974).
In Puerto
Rico, the two commonly cultivated plantains are Maricongo and
Guayamero.
Maricongo gives higher yields of fruit in terms of
weight and fruit number.
In addition, the fruits from this
5
1

cultivar are uniform in weight.
The fruits from both cultivars
are similar in pulp composition and texture (Sanchez, ~t af.,
1968).
In fact, the vast majority of them are sweet at rnaturity
and cooking is a matter of custom rather than necessity.
After
harvest, fully mature plantains tend to ripen quite fast with
an accelerated change of starch into sugars (Von Loesecke, 1950;
Simmonds, 1966; Sanchez, ~t at., 1968; Palmer, 1971).
In the
processing of food products derived from green plantains
(normally used for cooking a variety of dishes, not as fresh
fruit) it is of prime importance that they are at an adequate
stage of development: fully mature but completely green.
No
1
changes in starch, total sugars, acidity and pH take place as
the bunch matures on the plant (Sanchez, et a{.. 1968).
Starch is one of the most abundant naturally occuring
organic compounds.
It is found in almost all plant tissues,
where it functions as a source of reserve energy, which can be
utilized gradually through enzyme actions.
Starch accumulates
to high concentrations (20-70%) in the roots, tubers, fruits
and seeds of many plants.
Chemically, starches from all sources
are carbohydrates, polymers of a-D-glucopyranose units linked
prirnarily by 1,4 and 1,6 glucosidic bonds.
Each glucose unit
contains one prirnary and two secondary hydroxyl groups which
are responsible for the hydrophilic properties of the starch.
Starch is made up of two types of polymer chains, amylose, the
linear fraction (1,4 bonds) and amylopectin, the branched
chain fraction (1,4 bonds and 1,6 bonds).
The ratio of amylose
6
1

and amylopectin in starches also provides sorne indication of
their origine
The exact structural relationship between the two
components in the starch grain is not known, but the molecules
are linked together to form starch granule by hydrogen bonds
(Hahn, 1969; Wurzburg, 1968).
Starch granules are insoluble in cold water.
In a humid.
environment, starches will take up moisture, but the swelling
which occurs is reversible.
When starch granules in water are
heated past a critical temperature, in the range 60-70 0 C
(gelatinization temperature, characteristic of a specifie starch),
the hydrogen bonds which hold the granules together begin to
weaken, allowing the granules to swell.
Since the gelatiniza-
tion begin at the hilum, the first indication of swelling is the
loss of birefringerce.
Then, as the amylose fraction is dis-
solved and leached out, the granules begin to take in water and
then clarity and the viscosity of the slurry begin to increase.
Eventually, the granules, having became completely hydrated,
may collapse and break down.
The resulting starch "paste" is
composed of granule fragments and molecules in solution.
The
viscosity of the paste decreases as a result of this granule
breakdown.
On cooling the paste usually increases in viscosity
and decreases in clarity.
This results from retrogradation of
the linear (amylose) molecules a process whereby the amylose
molecules tend to forro rigid gels by hydrogen bonding.
The
degree of retrogradation is dependent on amylose content and
the degree to which the amylose has been solubilized during the
7

heating cycles.
Cross-bonded starches have their granule
structures reinforced by covalent bonds and the granule shows
less tendency to swell and retrogradation.
(Wurzburg, 1969;
Leach, 1965; Smith, 1964b; Collison, 1968; Mazurs,
~t al., 1957;
Hoseney, et al., 1978).
The suitability of starch, natural or modi~ied, for a
specifie use depends on the functional properties.
The functional
properties would include, for example, ease of cooking (temper-
ature, and stirring energy to cook through the swelling region),
thickening power (final viscosity of the paste after cooking
and cooling, as a function of concentration), and stability
(resistance to thinning resulting from stirring, pH or tempera-
ture change).
Because of the variety of changes which may occur in
starch paste during processing, many different methods have
been developed for following these changes in the paste and
estimating the functional properties of the starch from them.
These methods fall into two categories, those involving direct
microscopie observation such as monitoring granule swe11ing,
10ss of birefringence or staining reactions (Collison, 1968;
Mas ter , 1964), and those involving measurement of physical
properties such as swelling power, solubilization, sedimentation
rate or viscosity (Collison, 1968; Schoch, 1964; Smith, 1964).
The most usefu1 methods measure the viscosity of the paste
continuously during the standardized cooking and cooling cycle
which stimu1ates a wide variety of processing conditions (Smith,
8

964b).
The most common instrument used for this purpose is the
Brabender Amylograph.
This machine continuously measures the
viscosity of starch pastes and flours while they are
stirred and
·heated at a constant rate, held at 95 0 C for 30 minutes and held
at 30 0 C for 30 to 60 minutes (these methods have also been
developed for relating the viscosity data to the functional
properties of the starch)
(Mazurs,
et at, 1957).
These kinds
of data are available for most food starches (Mazurs, et a~.,
1957; Kite, e~ a~., 1957; Hahn, 1971) , but not for plantain
starch.
Banana "flour" (dried and finely ground) of green
banana pulp contains 70% starch and has functional properties
remarkably similar to the isolated banana starch (Carson, 1972).
Plantains differ from sweet banana in having a higher
starch content in the pulpe
The sugar content of plantains is
similar to that of sweet bananas (Palmer, J.K. personal
communication).
Bates (1943) reported that banana starch con-
tains 20.5% amylose.
Yang and Ho (1958) proposed that starch breakdown in
banana during ripening was catalyzed by phosphorylase, but
presented little evidence to support their theory.
Simmonds
(1966) makes no mention of any work of relevance concerning
banana amylases.
Triton X-100 and PVP (polyvinylpyrrolidone)
were equally effective at the 1% level in complexing tannins
during isolation and characterization of banana enzymes
(Baij al,
e~ al., 1972).
The concentration of cysteine and EDTA
(Ethylenediaminetetraacetic acid) chosen favored optimum
9
1

tannin inhibition.
Young (1975) however, could not show amylase
activity in the fresh extracts of banana, but obtained hydrolysis
of starch upon acrylamide gel electrophoresis of the fresh
extract.
The gels were prepared to contain 0.2% soluble starch.
After incubation, the gels showed clear zones when stained with
iodine.
This indicated that the amylolytic action was the
result of the separation inhibitors by electrophoresis.
Recently. Martin Segundo (1977) suggested that starch
hydrolases in bananas could be partially characterized, and
five components could be separated by electrophoresis in starch
polyacrylamide gels.
He stated that their pH optimums were
between 5 and 6, and their temperature optimums were aro~~d
28 0 C for aIl components.
Sanchez, e.t ai.
(1968) suggested that plantains should
be harvested for processing when pulp content is over 60%. which
corresponds to a pulp: peel ratio over 1.5.
This is considered
by judging the stage of maturity from angularity, and the
general appearance of the fruit.
Freshly harvested green plan-
tains start to ripen in about seven days. reaching a full
ripeness in two days later. when kept under room conditions at
temperature of about 85 0 F.
When stored in refrigerated chambers,
plantains remain green for 12 days, at which time signs of
chilling damage begin to appear (Hernandez, 1973).
Now, shelf
life of green plantains can be prolonged for 25 days at room
temperature (85 0 F) and for 55 days under refrigeration (55 0 F)
by applying Hernandez techniques (1973), using 200g of purafil
10
1

(an ethylene absorbant), and 200ppm of thiobendazole (to control
mold growth) sealed in polyethylene bags with the fruits.
During ripening of bananas, peel color changes from
green to yellow due to a complete degradation of chlorophyll
while yellow pi~ent remains relatively constant (Von Loesecke,
1950).
Changes in peel color is an index of the stage of
ripening; a chart giving peel color and stage of ripening was
published by Von Loesecke (1950).
The starch structural changes
occuring during ripening of banana plantain fruit have not been
yet studied.
Protopectin content decreases with concomitant
increase in soluble pectin during ripening.
A large increase in
the quantity and diversity of the volatiles present also occurs
1
(Palmer, 1971).
It has b~en reported that dopamine, a phenolic
compound found in banana skin, accumula tes as ripening
1
progresses (Buckley, 1965).
Dopamine has been related to
enzymatic
brovming (Palmer, 1963), and associated with tyro&ine
in its synthesis (Buckley, 1965).
~1
In preparing the banana for drying, Hapitan (1969)
!
suggested that peeling the banana fruit must be done using a
f1
stainless steel knife in order to minimize discoloration of
~
the slices.
When peeling, contaminating the pulp with the
1
latex that oozes from the banana skin should be avoided because
f
this latex, when allowed to dry on the pulp or flesh, will give
1
the finished product a brownish color.
To prevent contamination,
blanching of the fruit before peeling (by dipping in boiling
1
,
water until the color of the skin changes) is necessary.
11

Haendler (1966) revealed that sweet banana treated with
a mixture solution of sulfur dioxide (S02)
(8 g/liter) and citric
acid (3 g/liter), or a solution of sodium metabisulfite (4 g/
liter) gives a very good light yellow color of the product.
But
in France, only gas sulfur dioxide is allowed to be used on
products and the final product must not contain more than 100
mg. (Annonymous, 1934).
Haendler (1966) suggested that the
best procedure and the most cornmonly used one for drying is the
hot air drying method where the heat is transmitted to the
product by the dry air which flows around and through it.
Rahman (1971) developed in Puerto Rico an economic method
for the production of flour from green plantains.
Plantain
and banana flours are produced in significant quantities in many
countries of the world, especially Brazil, Philippines, Puerto
Rico and others.
These flours have been known and used for
centuries in the tropical banana-producing areas of the world
(Rahman, 1963).
Hapitan (1969) suggested that the flour placed
tightly in closed plastic bags will preserve its physical
qualities for about six months.
A major concern in flour is the
particle-size reduction and the degree of starch damage (Fan,
and HSU,
1976).
For baking, damaged starch is known to affect
dough rheology and gas retention ability (Farrand, 1972); on
the other hand, if the flour is to be used for fermentation, a
degree of starch damage might be àesirable, because damage
starch is more susceptible ta enzyme attack than unda~aged
starch (Fan and HSU,
1976).
12

The starch granule size, shape and structure have been
the object of study by a number of microscopie observations.
Microscopie studies of the wheat kernel with the scanning
electron microscope showed that starch granules of different
shapes and sizes are embedded in a protein matrix (Aranyi, et
a~, 1969).
Dronzek, e~ al., (1972) by using electron micro-
scopy and light microscopy to study the changes that occur in
starch granules during sprouting of wheat, found two sizes of
starch granules (large and small).
The large granules were
eroded differently than the small, spherical granules.
Scanning
electron micrograph of normal opaque-2, and hard and soft
portion of modified opaque-2 endosperms have shown that the
hard endosperms had tightly packed, polygonal starch granules
[
associated with a continuous protein matrix, and no intergra-
nular air space (Robutti, e~ ai., 19732.
Similar study by
Palmer (1972) on sorghum endosperm revealed that starch
granules
of soft endosperm are loosely associated with papery sheets
of protein materials and that of hard endosperrn is tightly
packed in a rigid protein matrix.
Hill and Dronzek (1973)
r1
studied wheat, corn and potato starches during early gelatinizR-
tion,
and found an exudate coming from the granules at low
1
temperatures, and associated this with the loss of polaTization
crosses.
At higher temperatures, they found total disruption
of the granules.
Crozet (1977) investigated the structural
changes in wheat flour proteins produced by the fixation,
dehydration, and embedding processes, and found that proteins
were modified to form lamellar and fibrillar matrix by those
13

processes.
Scanning electron microscopy studies have been used
to investigate the ultrastructure of several other food sources
such as soybeans, rice, millet, potatoes, and peas, but its
application to the study of banana has not yet been done.
Collins (1915) studied banana starch granules using a
simple light microscope with iodine as starch staining agent,
and suggested that starch grains were of 20 to 90~
in length
and 12 to 45~ in width.
Another microscopie investigation
showed that green banana starch granules were not uniform in
size (Von Loesecke, 1950).
Rahman (1963) indicated that
plantain starch grains from different plantain flours seen
under a microscope (magnification x 80; A) were observed clearly
throughout the entire slide.
However, the flour prepared from
steam-peeled plantains showed only clusters, which is a good
indication of the coagulation of starch grains as weIl as of
the protein caused by the application of heat.
Carson (1972)
pointed out that banana starch has two major grain sizes under
Spencer microscope at magnification 150 X.
The irregular
shapes of grains of banana starch make it difficult to specify
their size.
She gave an approximation of 22±7~ for the smaller
grains and 39±lO~ for the larger grains.
More recently, it
has been observed that banana starch exists as multi-size
particle which can be of two major size categories depending on
their localization in the fruit tissues (Palmer, J.K., personal
communication) but that of plantain is not weIl studied and
~o~.
14
1

Although considerable research is now being conducted
on the plantain because of its potential for industrial purposes,
nothing is known. of its physical and chemical properties in
relation to preparation of "futu".
Plantain pulp flour has
never been utilized in the preparation of "futu".
15
1

EXPERIMENTAL METHODS
The banana plantains (Mu~a pa~adi~iaea) used in this study
were obtained from Colombia's Turbo area, delivered under refri-
gerated conditions through a grocery store in Huntsville,
Alabama.
Fruits were classified as hard green, half green, and
light yellow according to the prepared chart by Von Loesecke
(1950).
(Figure 1)
PREPARATION OF PLANTAIN FLOUR
Plantain flour was prepared froQ the hard green, half green,
and light yellow plantains.
The fruits were peeled by hands
and were then cut in thin slices of about 1-2.5 cm of thickness
each with a stainless steel knife.
The slices were kept in a
tank containing tap water to prevent enzymatic browning, and
later dipped for three minutes in a 1.5% sodium metabisulfite
solution.
The treated thin slices were laid on aluminlli~ foil
(
sheets and dried in an air-oven at lOO±2°C for two hours.
The
dried slices were cooled at room temperature and then milled in
1
Fitz-mill Homoloid Machine (Model J-T) using 60 mm size screen.
(Fif,ures 1 and 3).
1
f
In another experiment a set of hard green plantain pulp
was cut into thin slices, blanched for five minutes in boiling
1
water, dried and milled as above.
The plantain flours obtained
from the three categories of pulps were stored in polyethylene
o
containers at l4 C.
16

Fig. l
Four stages of ripening of plantain
1
r
t
!
1
1
1
J
l
17
1

SELECTION OF
APPROPRIATE
PEELING
PEEL
-
PLA'ITAIN FRUITS
il
WATER BATIi
PULP
J-----~(Room Tempera-
ture)
SODIlJH METABISUL-I
CUITING
SPREADI1\\G
1 i l E - - - - - - - l FITE SOLillION~
L
_ _--j(in thin slices)
OF SLICES '1
DIPPING
1
HLLING
DRYING
ai lOO:t2oC)I--------~-(60nnn
screen)
FLOUR
....
STORAGE
Fig.
2
Flow diagram for production of Plantain Flour used for
"Futu".
18

Fig. 3: Plantain flours from (1) Hard green plantain
(2) Ralf-green ~lantain
(3) Light yellow plantain
19
1

MOISTURE CONTENT DETEm1INATION
Moisture contents of raw plantain pulp, plantain flours,
and "futu" have been determined by drying samples in an air-oven
at l30 0 C for two hours.
DETERMINATION OF STARCH, SUGARS AND AMYLOSE:
For the determination of starch, total sugars, reducing
sugars and amylose, dried and milled plantain pulp was used.
Total sugars and starch were extracted and determined by sügar-
anthrone sulfuric acid method, and amylose by the Iodine-
potassium iodide procedure (McCready, et al., 1950).
Reducing
sugars were determined by the arsenomolybdate-reagent method of
Nelson (1944).
DETERMINATION OF PROTEIN, CRUD~ FAT, CRunE FIBER AND ASH:
The standard Kjeldhal procedure was used for the deter-
mination of protein (N x 6.25)
(A.O.A.C., 1975).
The crude fat, crude ficer and ash were determined by
the A.O.A.C. methods (1975).
SCANNING ELECTRON HICROSCOPY OF PLAJ.'TTAIN AND ITS PRODUCTS:
A piece of dried thin slice of each category of pulp
and peel, and drieci. "futu" T..;rere attached to stubs using silver
conducting paint and were coated with 150 A gold-palladium
layer.
The plantain flours were simply sprinkled ante double-
backed scotch tape (Lineback and Ke, 1975).
The specimens
were viewed and photographed individually using the ISI Super
II Scanning Electron Microscope (SEM).
20
1

GELATINIZATION CHARACTERISTICS OF PLANTAIN FLOUR:
The functional properties of flours were determined by
the A.A.C.C. methods using Brabender Amylograph (1969).
A sample
containing 40 g of plantain flour (adjusted to 14% moisture)
from each stage of ripening of banana plantain was used with
420 ml of Phosphate buffer, pH 4.50 or 5.35 to make the slurry
ready for heating.
METHOD OF GRAPHIC ANALYSIS FOR FUNCTIONAL PROPERTIES:
The charts of the various starch sample from the Braben-
der Amylograph were redrawn to make analysis and comparison
easier (The chart paper on the amylograph has a curved ordinate).
Several sample of same weight of each plantain flour were run
to produce a family of curves.
Although the characteristic
shape for each flour is different, they had in common five
significant points or regions (Maz~rs, ~t ai , 1957; Kite et
1
al , 1957) (Figure 19 and 20).
A. --The Peak Viscosity or Pasting Peak - This is the
highest viscosity which is reached during the geltinization of
the starch.
The temperature where the viscosity begins to
increase, and the rate of increase are also considered.
Together
these three factors indicate the ease of cooking and the pasting
peak provides an estimation of the power requirements for
f
stirring the starch paste during gelatinization.
1
Some starches do not have a distinct peak.
The vis-
f
cosity simply increases during heating and tend to remain
relatively constant during the holding cycle at 95 0 C.
1
21

B. - The Viscosity at the Ehd of the Heating Cycle as
the Sample
Reaches 9S oC.
This gives an indication of stability during cooking
when related to peak viscosity.
A sharp drop in viscosity from
the viscosity peak indicates granules fragility and solubiliza-
tion.
C. - The Viscosity at the End of the 9S oC Holding Cycle:
This indicates the degree of fragility or stability of
the hot paste.
A drop suggests additional breakdown of granules
or solubilization due to stirring.
D. - The Viscositv at the End of the Cooling Cycle. When
the Paste Reaches again saoc:
This is a measure of the thickening or "set-back of
the paste with cooling.
It arises from retrogradation of the
linear molecules and be a serious obstacle during processing.
E. - The Viscosity at the End of the saoc Holding Cycle:
This indicates the stability of the paste to stirring
in the form in which it will most likely be used by the industry.
It is a good indication of granule rigidity and resistance to
shear.
The actual viscosity at this point may also be considered
as a measure of thickening power or thickening efficiency of
a starch.
Table l summarizes the relationships between the Bra-
bender viscosity curves and the functional properties.
These
functional properties are the basis for determining the use-
fulness of a food starch.
Table l also indicates the molecular
22
1

~~~Rf~
\\1'")1
'#"'.h;,,j~h+
7tI
~'''';',*".'
" ' ' ' ' ' i
" " ' i l ;
! M e
","'M'ffi'
·'TW.oe\\'ft
TABLE 1
a
Properties of Starches
Paste Properties
(Experimen~ally Determined)
Functional Properties
Molecular Properties
Rate of Increase bn Viscosity
1;vhen heated to 95 C
Ease of cooking
Rate of granules swelling
(Region prior to point a)
Viscosity Peak (Point A)
Haximum thickness on
Extent of granule swelling
cooking
Viscosity changes (after
Stability during
Granule fragility and
reaching maximum viscosity)
cooking
degree of solubilization
during heating and 95 0 C holding
cycles (region of Points A to C)
C":
C'.:
Increase in Viscosity during
Set-back on cooling
Retrogradation of linear
cooling (Region of Points C to D)
molecules
Changes in Viscosity during
Resistance to shear
Granule rigidity
holding at 50 0 C (region of
Points D to E)
Final viscosity after holding
Thickening power or
Granule rigidity extent of
at SOoC (Point E)
Thickening efficiency
maintained swelling
a
Data from Mazurs,
et al., 1957

events which are believed to be responsible for the observed
changes (Mazurs, 1957; Carson, 1972).
PREPARATION OF "FUTU":
After several primary experiments in the department
kitchen, definite amounts of flour and water were determined
for "futu" preparation.
Thirty-five grams of flour from hard green or half
green banana plantain (Mu-6a paltad,t-6.-tac.a) were poured into a pan
containing about 100 ml of warm water (temperature 6SoC - 80 oC) .
The product was mixed in the pan with a wooden spoon, while
sprinkling drops of water onto it until a possible "futu" like
consistency is obtained (which is characterized by a compact,
uniform but still soft baIl).
It takes 60 g of light yellow
plantain flour to get the right consistency.
During mixing
period, the temperature was set low in order to avoid gel
formation and burning up of the product (Figures 4 and 5).
The end product was made in baIl in a traditional manner
and served in a plate ready for eating with a stew.
The product
was kept in a wet warm environment to avoid hardness.
ORGANOLEPTIC TESTS:
A panel of tasters, consistinE mainly of at least nine
1
African students, was used to judge the differences in general
color, texture and taste of plantain."futu" made from the
different flours obtained from the different stages of ripening
of plantains.
The tasters were presented aIl samples including
"futu" prepared in conventional manner, marked with code only.
The tasters evaluated each sample on a scale of 25 points. where
24

(A)
PLANTAIN
FLOUR
MIXING OF FLOUR
~
WAffi:I WATER
WIlli WARM WATER
FUTU
(50 - 700 C)
(B)
SELE0'ION OF
....
.....
APPROPRIATE
PEELING
PEEL
PL~.I\\'TA.IN FRUITS
PULP
BOl LING
7'1
OF PULP
iCcookedJ
~
POUNDING OF
COOKED
WARt>1 PULP
il
FUTU
Fig. 4
Flow diagram of "futu" preparation
(A)
From plantain flour
CF)
Conventional procedure
25
1

1
f
t!
Fig. 5:
"Futu" prepared from plantain flours
(1) Hard green plantain;
(2) Half-green plantain
(3) Light yellow plantain;
26
1

25, indicated very agreeab1e; 20, agreeab1e; 15, slight1y
agreeab1e; la, rnoderate1y agreeab1e; 5, not agreeab1e (Rahman,
1963).
STATISTICAL ANALYSIS:
An ana1ysis of variance was performed and the rneans were
cornpared according ta the student Newman Keu1's (SNK) procedure.
Standard deviation of rneans was used ta compare the data for
"futu" score (SakaI and Rolf, 1969).
!
t
f
t
!
27

tl
RESULTS AND DISCUSSIONS
Data on crude fat, crude fiber, protein and ash of
banana plantain at three stages of ripening are presented in
Table 2.
The crude fat, protein and ash contents increased
while crude fiber decreased during the ripening process.
The
amounts of crude fat, crude fiber, protein and ash varied from
0.52 to 0.90%, 0.78 to 0.87%, 2.25 to 2.49%, and 2.34 to 2.42%
respectively.
The plantain at the light yellow stage containeà
significantly large amount of crude fat than at other stages
1
of ripening.
There were no significant variations in ash
content during the ripening of plantain.
Simple correlation coefficients between crude fat, crude
fiber, protein and ash in ripening of plantain are shown in
Table 3.
Significant positive correlations were found between
crude fat and ash at 0.05 level.
On a wet weight basis,
the starch, total sugars, reducing
sugars and amylose contents of plantain fruits (pulp) at the
turning stage of ripening from hard green to light yellow peel
are presented in Table 4.
The results indicated a progressive
decrease in starch content and an increase in reducing sugars
and total sugars during the ripening process.
The half green
fruit had a significantly higher amount of amylose than either
hard green or light yellow fruit.
Similar results have been
found in other varieties of plantains (Sanchez, ~t ai., 1968;
28
1

TABLE 2
A comparison of proximate content of plantain with other
starchy food sa
Crude fat
Crude Fiber
Protein
Ash
pH
Source of foods
0"1
,0
(,
%
i.
Banana plantain
Hard green
o.52d1':
0.87a
2.2.5h
2.34a.
5.41
lIard green
blanched
o.L~ 7c
0.88a
2.31b
2.33a
5.53
Half green
O. 6L~b
0.78a
2.44a
2.36a
5.15
Light yellow
0.90a
0.83a
2.49a
2.42a
4.88
0'
b
N
Svleet banana
Hard green
1.15
- -
3.78
3.23
Half green
1.11
-
3 . 8L~
3.28
Light yellow
1.02
-
3.81
3.17
c
Cassava
(Manihot
utilissima)
fJ.67
4.66
1. 20
0.75
c
Yam
1.30
2.10
7.80
3.18
d
Wheat durum
1.75
-
17.50
0.73
T . .
l d
r1t1ca e
1.80
-
12 .L~O
0.61
a
Data express on dry basis.
Each value is the mean of three samp1es.
b
Data from Haend1er, 1966.
c
Data from Ciacco and D'Appo10nia, 1978.
d
Data from Berry et al"
1971.
*Means not fo110wed by the sallIe 1etters are not signi.ficant1y different from each
other by SNK procedure at the 0.05 1eve1 of probabi1ity.

TABLE 3
Simple Correlation Coefficient between Crude Fat,
Crude Fiber Protein, and Ash in Plantain Flours
X
X
X
CHARACTERS
2
3
4
X1Crude Fat
-.496
.870
.998~';-
X2 Crude Fiber
-.750
-.437
X Protein
.844
3
X4 Ash
Degree of freedom associated with cornparison = 1·
*Significant at 0.05 level of probability.
30
1

~
TABLE 4
A comparison of pulp moisture, starch, total sugars, reducing sugars, and
amyloâ e contents of plantain at various star,es of ripening with other starchy
foods
b
Hoisture
Starch
Total Sugar
Reducing
Amylose
Source of Food
%
10
"'/
Sugars %
10
'0
Banana Plantainh
Hard green
58.3lc;'~
27.61a
3.95b
0.79c
33.63b
Half green
GO.65h
25.82b
L~. 52b
1.15b
37.69a
Light - yellmv
62.l5a
22.l4c
l5.66a
10.44a
26.96c
Sweet Bananac
Hard green
75.00
21. 50
0.10
5.68
20.82
Half green
18.00
3.50
31. 80
Light'yellow
78.00
15.00
6.00
41.50
-
....-l
d
C'1
Cassava
Pana
57.93
22.95
2.03
0.69
13.00
Zenon
68.08
22.19
3.82
0.53
21.00
e
f
Yam
IV. ae.ata)
79.00
23.00
5.23
/..55
34.00
po
Wheat durumo
70.20
-
-
27.00
Triticaleg
7/~. 70
-
-
23.00
a
Data expressed on wet weight basis except wheat and triticale starch contents.
b
Amylose was determined on plantain using hydrolyzed starch assuming that aIl the
hydrolyzed starch was amylose.
c Data from Haendler, 1966; dData from Rodriguez -Sosa e,t. rie. .,1975;
e
f
Data from rUvera
C!.taf.,
1974;
DatafromCruzCayetaf., 1974
f,Data from Berry et al., 1971; hThe statistical analysis was done only on banana plantain
;'~Heans not followed by the sarne letters are significantly different from each
nl-hpr
hv
~NK nrnrpilllrp ."1 t- t-hp (). () '1 1 pup 1 nf nrnh."lhi 1 i ru.

1
Hernandez, 1973), and sweet bananas (Von Leosecke, 1950;
Simmonds, 1966; Palmer, 1971).
The amounts of moisture, starch,
total sugars, reducing sugars and amylose varied from 58.31 to
62.15%, 22.14 to 27.61%, 3.95 to 15.66%, 0.79 to 10.44% and
26.96 to 33.63% respectively.
The plantain contained a signi-
ficantly higher amount of starch at the hard green stage than
at other stages of ripening.
The light yellow plantain
contained significantly higher amounts of moisture, total sugars,
and reducing sugars than other stages of ripening.
Simple
correlation coefficients between the above compounds revealed
that a significantly positive correlation was noted between
total sugars and reducing sugars at 0.05 probability level
(Table 5).
According to âata available on other starchy foods~
plantains have higher content of starch, total sugars, reducing
sugars and amylose than sweet banana, cassava, yam, \\vhea t and
triticale.
However sweet banana, yam, wheat, and triticale aIl
have higher crude fat and protein contents than plantain.
But
the ash content in plantain is higher than that in cassava,
wheat and triticale.
The proximate composition of "futu" prepared from. the
various flours is presented in Table 6.
Crude fiber and ash
were not different in "futu" prepared either in a traditional
manner or from the flours.
Protein and crude fiber contents
were lower in "futu" than in flour.
The "futu" from hard
green plantain flour and the traditional "futu" contained
32
1

TABLE 5
Simple Correlation Coefficient between moisture, starch
total sugars, reducing sugars, and amylose of plantain pulp
X
X
2
X
3
4
X4
Characters
Xl Moisture
-.948
.823
.816
-.512
X
Starch
-.961
-.958
.759
2
X
Total Sugar
.999";'(
-.909
3
v
Reducing Sugar
-.914
•...4
X Amylose
5
Degree of freedorn associated with comparison = 1
*Significant at 0.05 level of probability.
33


-l<'ik'**'';''''
- ~ _...w....
t1.:'
Ail
frlUW*'W'wX\\
b " \\ _ V
l
',"-~'lIa
lt'~
TABLE 6
Proximate content of "futu" prepared from. the flours ohtained
from the various stages of ripening of planta~n
Source of
a
b
b
Moisture
P
. b
1>
Crude Fiber
Ash
plIe
roteln
Crude Fat
the product
"/
.0
%
%
%
"/.,
-
-
-
Futu from hard green
75. 78a~'~
2.l0b
0.19a
O.SOa
2.0la
5.75
plantain flour
Futu from half green
75.79a
2.251>
0.07b
0.7la
2.03a
5.62
plantain flour
Futu from light
57.50c
2.l6b
O.Oi'b
0.72a
1.95a
5.35
yellm" plantain
flour
e
Traditional futu
69.65b
2.65a
0.17a
0.8la
1.89a
5.57
~
("l
a
Expressed on wet weight basis.
b
Expressed on dry weight basis.
c
The pH was not used in the statistical analysis.
e
Traditional "futu" was prepared from mixed boiled hard green and ripe plantain pulpe
*~1eans not followed by the same letters are not significantly different from each
other by SNK procedure at the 0.05 level of probability.

similar amounts of crude fats.
The traditional "futu" showed
a significantly higher amount of protein than "futu" prepared
from any of the plantain flours.
This problem could be solved
by mixing an appropriate arnount of hard green and ripe plantain
flours.
The moisture content of the "futu" ranged from 57.50
to 75.79% with the extreme being recorded from "futu" of light
yellow plantain flour "futu" of half green plantain flour
respectively.
Significant positive correlation was found only
between crude fat and fiber (Table 7).
The scanning electron microscopie observations revealed
that the starch granules from each pulp and peel (inner face)
of plantain have similar spherical, kidney-like, elongated and
irregular forms and sizes at the various stages of ripening
(Figure 6 to Figure 8) .
In the pulp they are small ranging from
7.5 to l7.4~ in diameter (or length) at the inner side (Figure
6A, 7A, 8A, 9),and a little bit bigger of 12.5 to 47.6~ at the
outer side (Figure 6B, 7B, 3D).
Starch granules are tightly
embedded in a thin protein matrix.
The peel from the hard
green plantain fruit showed an inner face full of a tightly
embedded starch granules layer (Figure 9).
The longitudinal
side of the same peel had a rough structure of cellulose, cell
wall, air space, xylem and phloem vessel elernents and other
vascular elements (Figure 12). ~fuen the plantain is
half green and light yellow, the starch granules seem to be
increased in sizeat the outer side of the pulp (Figuré 7B, 8C,
8D).
The granules in the half green stage pulp are packed
35

TABLE 7
Simple Correlation Coefficient bet1;'leen Hoisture, Protein,
Crude fat, Crude fiber and Ash of "futu" from flours
obtained from the various stages of ripening of plantain
X
X
2
X4
X
CH.I\\RACTERS
3
5
Xl
Moisture
.026
.440
. 31L~
.526
X
Protein
.277
.453
-.609
2
X
Crude Fat
.976~':
.562
3
X
Crude Fiber
.373
4
X
Ash
5
Degree of freedom associated with cornparison = 2
*Significant at 0.05 level of probability.
36
1

Fig. 6.
Scanning electron micrographs of hard green plantain
pulp cross-section slice.
A) view of 1/5 of the slice from
the inner side (40aX) with packed starch granules (s), B) view
of 1/5 of the same slice from the outer side (40aX) showing
round starch granules (rs), elongated starch granules (es) and
protein matrix (pm).
Fig. 7.
Scanning electron rnicrographs of half green plantain
pulp cross-section slice.
A) view of 1/5 of the slice from
the inner side (400X) with starch granules(s) arranged in a
protein matrix following aregular pattern. B) view of 1/5 of
the sarne slice from the outer side (400X) ~Jith starch granules(s)
enveloped in a protein matrix.
37
1

Fig.
8.
Scanning electron micrographs of light yellow plantain
pulp cross-section (400X).
A) view of 1/5 of the slice from
the inner side, showing honeycornb cell walls (cw). encloseà
starch granules(s). B) view of 1/2 of the same slice sho~]ing
breaking cell walls(cw) and protein matrix(pm) with starch
granules(s).
C) viewof 1/3 of the sa~e slice from the inner
side showing free starch granules(fs).
D) view of 1/5 of
the same slice from the outer side presenting round starch
granules(rs) and elongated starch granules(es).
38
1

regularly arranged in a protein matrix network (Figure 7A).
The inner face of the peel at that stage of ripening showed
releasing starch granules from the protein matrix and presented
a honeycomb structure (Figure 10). At the light yellow stage
of ripening the protein matrix ruptures and releases the
starch granules which move free in the pulp before their breaking
down into sugars (Figure RB, BC).
The inner side of that
pulp presented a honeycomb structure which could be due to the
rupture of the protein matrix surrounding the packed starch
granules (Figure BB).
The inner face of ~he peel at this stage
showed an almost complete release of the starch granules and
partial disruption of the protein matrix (Figure 11). This may
be one of the factor in the softening of the plantain peel.
The
longitudinal side view of the last two stages of ripening
presented a collapsed carpellar element structure (Figure 13).
This is a sign of loss of rigidity in the peel.
A close observation of the milled (60 mm screen) flour
particles of hard green plantain pulp revealed that, although
their size had been greatly reduced, the integrity of the
protein-starch matrix remained intact (Figure l6B).
This
integrity of the protein-starch matrix was less in half and
light yellow stages plantain flours.
Figures 15,
16 and 17
indicated that the plantain flour particles obtained from
Fitz-Mill Homoloid Machine of 60 mm mesh-size contained no
damaged starch.
This showed that plantain pulp flour might be
suitable for the preparation of good dough.
The peculiarity
39
1

Fig. 9.
Scanning electron micrograph of hard green plantain
peel inner face (400X) showing starch granules(s) in clusters
(sc).
Fig. 10.
Scanning electron micrograph of half green plantain
peel inner face (400X) showing liberated starch granules(ls)
leaving homeycomb cell walls(cw) structure.
Fig. 11.
Scanning electron micrograph of light yellow plantain
peel inner face (800X) presenting a complete rupture of the
protein matrix(pm) and exposing free starch granules (fs) .
40
1

Fig. 12.
Scanning electron ~icrograph of hard green plantain
peel l011gitudinal view (800X) showing air space (as)
vessel elements(ve) of xylem and phloem in perfect
rigidity.
Fig.13.
Scanning electron micrograph of half green plantain
peel longitudinal vie~y (800X) showing collapsed
tissues.
41
1

Fig. 14.
Scanning electron micrographs of hard green blanched
plantain pulp slice (400X). A) surface showing
complete loss of forrn of the starch granules
presenting an amorphous structure with air space(as).
TI) flour showing a compact smashed starch form.
Fig. 15.
Scanning electron micrograph of A) the outer surface
of traditional "futu" from plantain (400X) and B)
flour from traditional fu.tu made sho~·J'ing a compact
srnashed starch granules.
42
1

with plantain starch granules is that they mostly arranged in
clusters.
Hard green blanched plantain pulp had a tightly
compact amorphous starch structure in a combinat ion with the
protein matrix (Figure l4A, l4B).
The starch granules seemed
to have lost their form during the blanching process.
"Futu"
prepared in a traditional manner exhibited similar amorphous
structure (Figure l5A. l5B, l6A).
The hard green blanched
plantain pulp was palatable but the unblanched one was not.
Although the hard green blanched and dried plantain pulp had
a palatable taste, the flour from it did not give the
traditional "futu" like consistency.
This could be due to the
fact that the starch granules had already ruptured and combined
with the protein matrix or other constituents during the
blanching or cooking process.
The traditional "futu" presented
an outer surface entirely coated with a smooth protein film
(Figure l5A) similar to a spaghetti outer surface (Matsuo et.
al., 1978).
The "futu" prepared from flours at the various
stages of ripening presented an outer surface with sorne visible
starch embedded in and covered with an amorphous protein film
(Figure 19A, 19B, 20, 21).
This could be due to the fact that
the product was not pOl..mded as the traditional "futu".
Amylograph gelatinization curves at pH 4.50 and 5.35
are shown in Figure 22 and 23.
The data on pasting character-
istics of the flours are presented in Tables 8 and 9.
The
data indicated that hard green blanched flour had the lowest
43
1

Fig. 19.
Scanning electron micrograph of the outer surface of
"futu" (400X). A). From hard g!;'een treated (1.5% NaZ
S 0
for 3 min.) plantain flour show~ng embedded
sta~ch granules(~s). B). From hard green blanched
plantain flour with embedded starchgranules(es)
Fig. ZO.
Scanning electron micrograph of the outer surface of
"futu" (400X) from half green treated (1.5% Na S 0
Z Z 5
for 3 min.) plantain flour ..
Fig. 21.
Scanning electron micrographof the outer surface of
"futu" (400X) from light yello'Y7 treated (1.5% Na2S2
05 for 3 min.) plantain flour.
45

TEMPERATURE (0 C)
50
65
00
95
-
-
~
95
80
65
50-.--
~ 50
1000 1
i
i
1
i
i
i
i
1
A
B
c
o
E
- 800
en
-.- 1
..-..1
c:
:>
..Q)
1:J
600
c:
Q)
.a
..caID
\\.CI
400 L
1
1
~
~
-
..j-
~
-ën0uen:; 200
o ...
' ------
o
15
30
45
60
75
90
105
120
TIME (minutes)
Fig. 22
Brabender, Amylogra~h curves of plantain flour at ~H 4.50
1.
Hard ~rccn plantain; 2.
liard green blanched
3.
Half green pl:mtain; 4.
Li8ht yelloH

~ ~
TABLE 8
Pasting Characteristics of plantain flours at pH 4.50
I
VIS COS l T Y
in
BU
Initial
After
After
Initial
pasting
At
Peal-: on
30 min.
Peak on
30 min.
Stage of
pasting
ternperature
95°
Heating
at 95°C
50°C
cooling
at 50 0 e
Haturity
time (min.)
(oC)
Hard green
18
75
700
740
710
890
920
900
lIard green
12
65
98
120
120
170
170
160
blanched
Half-green
14
74
570
570
510
740
760
740
1"-
-j"
Light yellow
16
76
250
370
360
520
530
520
1
Brabender Unit.

TEMPERATURE (OC)
----TAPiOCA
.............. coRN·:":":":·':":":":":'·:· SWEET
----PLANTAIN
BANANA
65
80
95 ....
---95
80
65
A
B
c
800
-en
"
1 \\
-.-
\\
1
c
1
:J
, \\
..
\\
CIJ
1
C01'T~··
.....
. .
:=:1
"'C
\\
600
C
1
........
/
..

\\

CIJ


1

oC



1

l!
ID
,


Tapioca
- 400
~---...--._-
co
>.
1
...-
-j"
=
1
en
...........
Plantain
o
1
u
en
.·-Y--.
1
----------:.....
.
............
.
:;
200
1
4
1
1
o l
' 4 ' /, 1
1
l
,
,
1
l
,
o
15
30
45
60
75
90
105
120
TIME (minutes)
Fig. 23
Brabender Amylograph curves of plantain flours; corn and tapioca
(mazurs and !<ite. 1957). and s~veet banana (Carson. 1972)
1.
Hard green plantain; 2.
Hard creen blanched plantain
3.
Half green plantain; 4.
Li3ht yello~ plantain

~
TABLE 9
Pasting characteristics of plantain f10urs compared to
other starchy foods (pH 5.35)
VIS COS l T Y
in
BU1
Initial
Intia1
H. Peak After
M. Peak
After
Stage of
pasting
pasting
At
on
30 min.
At
on
30 min.
Maturity
time (min.) temperature (oC) 95 C
heating at 95 C
50 C coo1ing
at 50 C
Hard green
17
75
698
740
710
890
940
930
Hard green
12
65
175
200
180
240
250
240
b1anched
Ha1f green
18
75
600
620
540
760
790
750
C\\
...:t
Light ye110w
19
76
370
410
380
500
540
520
Durum wheata
-
79
-
920
900
990
T . .
1 a
r1t1ca e
-
68
-
110
0
0
b
Cassava
Pana
-
63
415
507
202
440
435
Zenon
-
63
296
298
137
348
320
1
Brabender unit
a
Data from Berry et ai., 1971; amy10grams at pH 5.35 buffer.
b
Data from Rodriguez-Sosa et ai., 1975; amy10gram at pH 6.57 and 6.10 for Pana and
Zenon respective1y.

initial pasting temperature (65 0 C) and light yellow flour the
highest (76°C) while hard green and half green flours had
initial pasting temperature of 75 0 C and 74 0 C respectively at
both pH.
These initial pasting temperatures are higher than
those of other starchy foods such as Durum wheat flour (64 oC)
o
and triticale (58 C)
(Berry and D'Appolonia, 1971) or cassava
(63 0 C) (Rodriguez, et al., 1975).
The peak height ranged from
118 to 718 BU at pH 4.50 and 200 to 738 BU at pH 5.35 for the
different flours with the extreme being recorded by hard green
blanched flour and hard green flour respectively.
The low
viscosity of the hard green blanched flour further confirmed
its inability for preparation of traditional "futu"-like product.
The gelatinization curves revealed a decrease in the
flour viscosity during ripening of the banana plantain fruit,
however, it had been observed under the scanning electron
microscope that the starch granules increased in size in the
pulp during ripening process.
The decrease in viscosity coulà
be explained in a way that the starch granules increasing in
size might have reached a maximum swelling point where in
presence of water they showed a reduced swelling ability.
It
might also be due to substantial levels of sucrose, glucos~ or
other water-soluble hydroxyl-containing substances which could
exert an inhibiting action on the swelling of starch granules.
Such materials be:ing water-soluble and containing hydroxyl
groups have a strong affinity for water and interfere with the
hydration and swelling of granules (Wurzburg, 1968).
50
1

The functional properties of the flour at various stages
of ripening of plantain are presented in Table 10.
These
properties revealed that plantain flour had a slow pasting
process similar to that of sweet banana flour (Carson, 1972)
and other starchy foods (Mazurs and Kite, 1957).
The set-back
ability of plantain flour is low as that of tapioca, sweet
banana, durum wheat
triticale and cassava except corn which
J
has a high set-back (Mazurs,
e.:t al., 1957).
In addition, the
thickening power which is high when the fruit is green, gets
low when the fruit is light yellow or when the pulp is blanched.
Compared to the other starchy foods, only green banana has a
high thickening power.
The panel evaluation scores p;;iven to "futu" prepared
from plantain flours of hard green, half green and light yellow
stages are presenzed in Table 11.
The results showed that
"futu" from half green and light yellow plantain flours scored
better in overall appearance than "futu" from hard green
plantain flour.
The test panel in general, indicated that the
"futu" from flours were good and acceptable as the "futu"
prepared in the traditional manner.
Since the flour from the
hard green blanched or cooked pulp did not produce a desirable
"futu"-like consistency, it was not used in the "futu" prepara-
tion for the taste panel.
51
1

~
TABLE 10
Functional Properties of Plantain Flours Compared to
Other Food Materials
Haro
green
c
d
Functional
Hard
blan-
Half
Light
Sweetb
lfueat C Triti-
Cassava
a
a
Properties
green
ched
green
yellow
Corn
Tal?ioca
banana
durum
cale
Pana
Zenon
Ease of coo-
slow
very
slow
slow
slow
fast
slow
slow
slow
slow
slow
king (rate)
slow
Maximum thic- almost
none
almost none
modera- high
none
high
very
high
mode-
keness on
none
none
te
low
rate
cooking
(viscosity
peak)
Stability
good
good
good
good
good
poor
good
good
poor
poor
poor
C'.f
during cook-
ln
ing
Set-back
low
very
low
low
verh'
very
lO~l
very
none
very
very
on cooling
low
hig
low
low
low
low
Thickening
high
very
mode-
low
mode-
low
high
-
-
low
low
power
low
rate
rate
a
Data from Mazurs and Kite, 1957.
b
Data from Carson, 1972.
c
Data from Berry
e.t a.e., 1971.
d
Data from Rodriguez-Sosa e.t al . , 1975 .

~
TABLE Il
Panel evaluation of "futu" prepared from plantain flours
Color
Odor
Texture
Taste
Total Score
Stage of ripening
(25 )
(25 )
(25)
(25)
(100)
Hard green
l8.8±6.9
l3.l±6.6
19.1~±5.2
22.5±3.5
73.8±3.4
Half green
23.l±2.4
l7.5±/~.3
20.0±fi.l
21.9±4.3
82.5±2.l
Light yellow
22.5±5.0
l8.l±4.9
l7.5±7.9
23.l±3.5
81.2±2.5
C1')
lJ")

SUHMARY
The plantain [Mu~~ p~~adi~i~Q~l pulp was cut into thin
slices, dipped in a solution of sodium metabisulfite (to prevent
browning), dried in an air-oven, and milled into flour using
Fitz-mill Homoloid Machine (Model J-T) with 60 mm screen.
The
flour was used in preparing "futu" of acceptable quality.
Proximate composition of "futu" prepared from flours did not
differ significantly from that of traditional "futu".
The changes in starch granules during ripening showed
larger granule size at the outer side of the pulp than at the
inner side.
When milled (60 mm mesh) , the starch granules
did not indicate any sign of damage.
Flour showed considerable decrease in viscosity during
ripening of plantain.
The flour from the hard green and
blanched plantain had lower viscosity compared to the flour from
the unblanched plantain slices.
The organoleptic evaluation indicated that flour from
half-green plantain pulp could be recommended for a good quality
"futu" preparation.
1

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Hethods ~n
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1972.
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1966.
Bananas.
Tropical Agricultural Series.
Second edition.
Longmans, Green and Co., Ltd., London.
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1968.
Foam-mat drying of
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1964a.
Determination of moisture.
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Smith, R. J.
1964b.
Viscosity of starch paste.
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60
1

~. '.~
At"lERISTiQUES PHYSICO-CHIMIqUES ET STRUCTURALES
DE LA FARINE DE PLANTAIN (MUSA PARADISIACA) AVEC UNE
REFERENCE SPECIALE A LA PF~EPARATION DU IIFOUTOU II
"j
RESUME EN FRANCAIS
IIFoutou ll ou IIfoufou ll est le nom traditionnel africain donné à l'igname,
à la pulpe de banane plantain, au manioc et au taro cuit et pilé uniformementi,,)yt;
en pâte et modelé sous forme ovale. Le~ fruit~ rlantains obtenus de la colombie,,':\\;;~:
Amérique Centrale, sont utilisés dans cette étude. Les compositions approximativ~~~
de la farine de plantain et du "foutou" pr'éparés à différents stades de maris-\\$'1f
sement en farine de plantain furent déterminés. Les modifications physiques des'?',;:,:,
grains d'amidon pendant le mOrissement du fruit plantain, et la structure des
~~~
"foutou ll préparés à partir des farines obtenues des différents stadf's de mûris- :~{,
sement furent examinés au microscope à bdlayage. Les caractéristiques de gélati-
~
nisation de l'amidon des farines furent déterminées en utilisant l'amylographe
Brabender.
Les teneurs en amidon et fibre diminuent pendant le mûrissement du
1
plantain alors que celles en sucres tota~x, sucres réducteurs, lipides, protéine'
et cendre augmentent. La pulpe du plantain présenta de~ valeurs significatives
~,
1
d'humidité, sucres totaux, sucres r€ducteurs,
protéine et lipides au stade jaune
,
complet de mQrissement qu'aux autres stades. Les teneurs en fibre brute et amylose,U
étaient en quantités significatives au stade moitié mûr qu'aux autres stades de
1
mûrissement. Aucune variation significative fut trouvée dans la teneur en cendre
dû aux différents stades de mûrissement. Il y avait deux corrélations positives
significatives entre les tenfurs en lipides et cendre, puis entrE les sucres totaux
et les sucres réducteurs à l'échelle de 0,05. Les teneurs en fibre et cendre des
"foutou" préparés des farines de plantair et celles dl! "foutou ll préparé de la
manière traditionnelle n'ont indiqué aucune diffÉrence significative. Une plus
grande valeur en protéine fut observée dans le "foutou'l préparé de la manière
traditionnelle que ceux préparés des farines de plantains. Cela est dû au fait
que pour la préparation du foutou de 1a mdnière traditionnelle, la ménagère
mélanç;e du fruit mûr et du fruit vert. Donc, pour le IIfoutou" à partir des fari-
nes, le problème peut être résolu par un mélange de farine de fruit mûr et de
farine de fruit vert dans des proportions à déterminer.
L'étude à l'électron microscope à balayage révela que les grains d'amidon
de plantain ont des formes sphéri~ues, de type de haricot, allongées et irrégu-
lières ft des dimensions variées à différents stades de mûrissement. L'étude indiqu
auss i que les grains d;':ami don augmentent en di mens i on lors du mûri ssement de la
pulpe du plantain. Ces grains sont plus gros à la partie extérieure de la pulpe
qu'à la partie intérieure. Lorsque le fruit est vert, la peau a une structure
rigide intacte de membranE: cE"llulosique (C'llulaire, de~ p(lche:~ d'air et des vais-
saux; mais cette structure perd sa forme lorsque le fruit devient à moitié mûr. ,
La pulpe, lorsqu'elle est cuite, montre une structure amorphe compacte de grains
d'amidon aplatis et de formes d~truites pn combinaison avec la matrice de protéine.

)$ :
t
.
la:;;::;:; f. .
\\ ; 4jAb Ji '9
lb
.. ..
-~_
Le "foutou" préparé de l a man i ère tradit i onne 11 e montra un@. sur'face ent ière··
ment (ouverte par lN: couche uniforme de protéi net alors que ceux pr'éparés à
partir des farines de plantain indiquèrent des surfaces rugueuses de grains
d'amidon enfouis et couver·ts d'un film amor'phE: dE:' protéineo Ceci peut être
dû au fait que le proGuit n'avait pas été pilé comme on le fait dans la prépa
ration traditionnelle du "foutou".
Les mesures de viscosité des farines à l'amylographe révélèrent que
la viscosité de l'amidon du plantain décro't pendant le mûrissement. Le
rnicroscographe dE:'~ farine~ de plantairl non blanchi montrÈrent des grains non
endommagés alors que celui des farine~ de plantain blanchi présenta. des
grains d'amidon complètement détruits. La farine de plantain blanchi ne fut
donc: pas souhaitable PCtL\\t' la préparatiol1 d'une bonne qualité de "foutou"
parce qu'il a une très basse viscosité.
L'évaluation organoleptiqwe (ies foutou préparés à partir ~e farines
de plantain à difffrents stades de m~rfSsfment indiquèr~nt les foutou obtenLs
du plantain moitié vert et jaune pâle comme ayant les mêmes caractéristiques
d'acceptabilité que le foutou traditionnel
Alors. des travaux futurs ~~éci­
0
fiques à l'amélioration de la t(~ture du produit pourraient rendre cette
étude définitive.
,
,j
i
~