Solomon Abera, Sudip Kumar Rakshit
Processing Technology Program, School of Environment, Resources and Development (SERD),
Asian Institute of Technology, Pathumthani, Thailand
Comparison of Physicochemical and Functional Properties of Cassava Starch Extracted from Fresh
Root and Dry Chips
Starch was extracted from dry chips of three varieties of cassava using wet milling and dry milling
methods. The physicochemical and functional properties were compared with those from fresh root.
The starch obtained exhibited lower peak viscosities, breakdowns and setbacks, and higher pasting
and peak temperatures than that from fresh root. Most thermal properties (onset and peak
temperatures of gelatinization and ret-rogradation; conclusion temperatures, enthalpies and peak
height indices of retrogra-dation; and degree of retrogradation) were found to be higher than those
of fresh-root starch. Moreover, swelling power, paste clarity and freeze-thaw stability of the former
were inferior to those of the latter. Both types of starches exhibited increased rate of syneresis with
increase in freeze-thaw cycles. Differences observed in properties of starches derived from dry
chips by wet and dry millings were very minimal. No indication of major change in granule
structure was noted for dry-chip starch that would alter the properties relative to fresh root starch.
Higher fiber content and annealing due to exposure to heat and moisture of the former accounted for
most of the variations of properties as compared to the latter. With the advanced technology used in
starch manufacturing industry today it would be possible to obtain starch from dry chips with
similar quality from fresh root. This would enable the industry to overcome the cycle of glut and
low season, and allow them to remain open for longer period of time in a year.
Keywords: Cassava starch; Cassava chips; Physicochemical properties; Functional properties
1 Introduction
In many tropical countries cassava (Manihot esculenta Crantz) is an economically important crop as
a source of starch and in form chip and pellet as important ingredient of animal feed.
Conventionally starch is extracted from fresh root and numerous studies had been done on extraction, properties, modification and other aspects of the starch.
Cassava, however, has one major drawback. The root starts to spoil after 48 h of harvest due to
physiological changes and microbial activity, unless kept under special storage condition [1, 2].
Some investigators reported an even shorter period before the tuber become unusable [2]. So far
there is no economically feasible technique of storing harvested cassava root for long period at a
large scale except in the form of dry chips. Compelled by this fact starch factories are usually
located close to the cultivation site to ensure supply of fresh root. As large-scale cultivation of
cassava is by and large climate dependent
Correspondence: Sudip Kumar Rakshit, Processing Technology Program, School of Environment,
Resources and Development (SERD), Asian Institute of Technology, Pathumthani, 12120,
Thailand. Fax: 662-02524-6200. e-mail: rakshit@ait.ac.th.
the supply of fresh root to starch factories fluctuates seasonally. During peak harvest supply
exceeds the production capacity of the factories resulting in low prices and consequent reduced
return to the growers. During slack harvest the supply dwindles forcing the factories to operate
under capacity and in some cases to temporary closure of the plant for three to four months in a
year.
The idea of extracting starch from dry cassava chips is an attempt to solve this problem. The surplus
root during peak harvest could be dried and stored. When supply of fresh root drops below demand
the dry chip from storage could be used to run the starch factories in full swing. Further, this can
also alleviate a problem of lack of market for dry chips caused mainly due to European Union quota
restrictions and trade barriers. This way all the parties involved in cassava business in countries like
Thailand would benefit considerably by managing the surplus root during peak harvest on the one
hand and the shortage of raw material for the starch factories during slack harvest on the other,
while at the same time ensuring a market for the chip factories.
An earlier study had been conducted to assess the possibility of extracting starch from dry chips and
pellets [3]. The starches obtained were of low quality suitable only for
limited applications. It was felt that the process followed in that work could easily be improved to
produce starch of acceptable quality.
This study aimed at finding a strategy for obtaining good quality starch from dry chips and
comparing its quality in terms of physicochemical and functional properties with that of starch
extracted from fresh roots.
2 Materials and Methods
2.1 Commercial starch and fresh root
Commercially processed native cassava starch was obtained from Siam Modified Starch Co. Ltd.
Thailand. Fresh cassava root of three varieties namely Kasetsart 50 (KU50), Rayong 5 (R5) and
CMR35-22-196 (CMR) was obtained from Rayong Field Crop Research Center in Thailand. The
varieties were planted in December 1999 and harvested in June 2001.
2.2 Dry chip production
The fresh root with a moisture content of around 61 % (wet basis, w. b.) was cleaned, washed and
peeled. It was then hand chopped into rectangular shape of dimensions 50 x 24 x 6 mm, placed on
drying trays and left in the sun for drying. The rate of chip loading on to the trays was 6.56 kg/m2
[4] and it was stirred every 2 h. After 24 h of drying the moisture content dropped to 12% (w. b.).
The chips were then placed in polyethylene bags of 0.1 mm thickness and stored at room
temperature until required for starch extraction.
2.3 Starch extraction
About 333 g of freshly chopped root was blended (Model Masterchef 65, Moulinex France) with
0.4 L water for 5 min and sifted through a 200 mesh screen. The residue was rinsed twice with 300
mL of water each time to remove remnants of starch. The slurry was left for 1 h before decanting
the liquor. The starch was suspended three times in 3 L water (the last suspension in distilled water)
and non-starch materials removed by decanting the supernatant. The starch was then dried in a hot
air oven at 45 °C for 18 h to attain 11-12% moisture content (w. b.), sifted with 200 mesh sieve,
placed in a polyethylene bag and stored at room temperature until required.
Extraction of starch from dry chip was conducted in two ways, wet-milling (blending) and drymilling. In wet-milling, the prepared dry chip was steeped in water at room temperature for 24 h,
changing the water every 6 h. Starch extraction from the re-hydrated chip was carried out the same
way as described for the fresh root.
In dry-milling the chips were first ground to powder by a steel roller rice mill and then washed with
water and sifted through a 200 mesh sieve. The slurry was left for 1 h to let the starch settle before
decanting the supernatant The starch was suspended three times to remove impurities and then
dried. The resulting dry cake was then crushed and stored.
2.4 Pasting property
A Rapid Visco Analyser (Model: RVA-4, Newport Scientific, Warriewood, Australia) was used for
the evaluation of the pasting properties of various samples of starch. Starch (2.50 g, dry basis, d. b.)
was suspended in 25.0 mL of distilled water. Test runs were conducted following standard profile 1
which included 1 min of mixing, stirring, and warming up to 50 °C, 3 min and 42 s of heating at 12
°C /min up to 95 °C, 2.5 min of holding at 95 °C, 3 min and 48 s of cooling down to 50 °C at same
the rate as the heating and 2 min holding at 50 °C.
2.5 Thermal properties
Differential scanning calorimetry (DSC) analysis was performed using a Perkin Elmer system
(Model DSC7; Nor-walk, CT, USA). Gelatinization properties were evaluated using 5 mg (d. b.)
starch suspended in distilled water at a starch-water ratio of 1:3 (w/w). Scanning was done from 40
to 110 °C at a rate of 10 °C/min. Distilled water was used in the reference pan. To evaluate
retrogradation properties pastes obtained from gelatinization test were cooled and stored at 4 °C for
7 days after which they were rescanned for the same range of temperature at same heating and
cooling rates as for gelatinization. Onset, peak and conclusion temperatures (T0, Tp and Tc, respectively) and enthalpy (AW) of gelatinization were determined automatically. Gelatinization range
(F?), peak height index (PHI) and retrogradation (R%) were computed as described by Yamin et al.
[5].
2.6 Swelling power, paste clarity and freeze-thaw stability
A sample of 0.5 g (d. b.) starch suspended in 15 mL of distilled water was heated in a hot water bath
at 85 °C for 30 min with vigorous shaking every 5 min. The cool paste was centrifuged at 2200 x g
for 15 min. The supernatant was decanted and the swelling power was determined as the ratio of
weight of sediment to dry weight of starch solidified by swelling (g/g) [6].
Paste clarity was determined following the procedure by Craig et al. [7], using a spectrophotometer
(Model Unicam 8675, Spectronic, Leeds, UK).
Freeze-thaw stability was evaluated using 5% starch pastes as described by Bello-Perez et al. [8].
Each sample was subjected to 1 - 5 cycles of 18 h freezing at -20 °C followed by 6 h thawing at
room temperature.
2.7 Amylose content and proximate composition
The apparent amylose contents were determined by a simplified blue amylose-iodine complex
procedure [9] using a spectrophotometer (Model Unicam 8675). Starch content was assayed as
glucose colorimetrically after enzymatic conversion and subsequent reaction with glucose oxidaseperoxidase [10]. Protein (N x 6.25) was determined with a semi-micro Kjeldahl unit following
AOAC standard method 2055 [11]. Lipids were analyzed using the Soxhlet method according to
AOAC official procedure [11]. Ash content was determined by weight of samples after incineration
in a muffle furnace at 550 °C for 3 h. Crude fiber was determined according to AOAC official
method [12].
2.8 Statistical analysis
Analytical determination of data was performed in triplicate. Analysis of variance and Duncan
multiple range test were done using SPSS (Version 9.0).
3 Results and Discussion 3.1 Starch isolation and yield
In fresh root processing the blended constituents of the cell easily passed through the sieve leaving
behind larger fiber materials. The starch in the slurry quickly settled at the bottom forming a tightly
packed layer while other cell contents and fine fiber materials remained dissolved and/or suspended
in the water. These were easily separated from the starch by decanting. Three rounds of washing the starch cake were needed to obtain a
clean and white starch sample.
During the process of starch extraction from dry chips by wet milling greater disintegration of cell
content occurred resulting in large proportion of fine fiber as compared to fresh root processing.
Some of the fine fiber, which managed to pass through the sieve with the starch, remained loose on
the surface of a tightly packed starch cake. This fine fiber was easily washed off with water.
Dry milling of the chips to 200 mesh size (80%) resulted in flour with highly varying particle size
comprising of very fine and coarse materials. Upon washing the flour to retrieve the starch the
apertures of the sieve were frequently clogged making it difficult for the starch slurry to pass
through. Use of excess water was necessary to force the material through the sieve. Large amount of
fine fiber thus managed to pass through the sieve with the starch slurry but remained isolated on the
top of the tightly packed starch cake. A minute fraction of the starch presumably of smaller particle
size remained trapped in the fiber forming small aggregates randomly spread throughout the same.
Decanting the water and subsequent washing of the cake surface with water enabled to remove the
mixture of fine starch and fiber. The starch yield per kilogram of net peeled root is presented in Tab.
1. The quantity of starch obtained from fresh root and that from dry chip by wet milling was almost
equal for all the three varieties. However, dry milling resulted in high loss of starch ranging from
13% to 20% of that obtained from fresh root. The loss is attributed to the small size starch particles
removed together with the fine fiber particles during cleaning of the starch cake and due mainly to
that lost in form of unreleased starch embodied in the large pieces of flour particles which were not
able to pass through the sieve during wet sifting.
Tab. 1. Yield and composition of cassava starches processed from fresh root and dry chip.
All data are averages of triplicates and expressed in dry basis.
Means of each component within a variety followed by same letter are not significantly different (p
< 0.05).
3.2 Pasting properties
The viscosity profiles of the starch produced from fresh roots, wet and dry milled chips are
presented in Fig. 1. They are typical of what has been reported previously of cassava native starch
[13, 14]; including a sharp rise in viscosity shortly after pasting temperature, reaching the peak
viscosity followed by a drop until it reached the trough viscosity (TV) before rising again gradually
to a moderately higher final viscosity (FV). The profiles of the two groups of starches are the same
except for the variations in values of main properties. Tab. 2 shows the values of the measured
pasting properties.
Peak viscosities (PV) of fresh-root starches were higher than those of dry-chip starches. Even
though the differences were statistically significant (p < 0.05) they were not appreciable. Besides,
the former had considerably higher breakdowns (BD). These were because granules of fresh root
starches had undergone a higher degree of swelling and subsequent disintegration than those of drychip starches, as evidenced by the higher swelling power of the former (Tab. 5). The relatively
higher fiber content in
Fig. 1. Pasting profiles of cassava starches: fresh root (——), wet-milled chip ( ) and dry-milled
chip (---) as determined by Rapid Visco Analyser.
Physicochemical and Functional Properties of Cassava Starches 291
dry-chip starches (Tab. 1) may have acted as a barrier to heat transmission to and expansion of the
starch granules resulting in delayed gelatinization, lower swelling and less disintegration. Moorthyet
al. [15] noted that fiber content plays an important role in determining the characteristics and
functional properties of cassava starches. Furthermore, the drying of the high moisture content
(61% w. b.) chips at elevated temperature is likely to anneal the starches. Annealing of granular
starches, which involves incubation in excess water, for a certain period of time, at a temperature
above the glass transition temperature but below the gelatinization temperature, changes the amorphous part of the starch granules structure [16]. According to Jacobs et al. [16] annealing of native
starches leads to higher pasting temperature and more stable viscosity in potato starches.
Atichokudomchai et al. [17] found that annealing resulted in a shift of gelatinization endotherms to a
higher temperature, a narrowing of the endotherms and an unchanged or higher gelatinization
enthalpy. They concluded that the changes resulted from the ordering of double helices in the
crystalline regions. Moreover, interaction between amylose and amylopectin [18], growth of
crystallites [19], and changes of the coupling forces between crystallites and the amorphous matrix
[20] were forwarded as possible explanations. No consistent trend has been noted as regards FV.
However, setbacks (SB) were consistently and significantly (p < 0.05) higher for fresh root starches
than for dry chip starches. Observation of the cooked starch obtained after the viscosity test showed
that pastes of dry-chip starches were less clear (translucent) and of shorter texture. On the other
hand PV, BD and SB of starches processed from dry chips by wet and dry millings showed
statistically not significant difference between them.
Pasting and peak temperatures of fresh root starches were more or less the same as those reported
elsewhere [21 ] taking into account minor differences that may prevail due to varietal differences
and environmental factors. Both pasting temperatures of the fresh root starches were found
significantly (p < 0.05) lower than those of dry-chip starches (Tab. 2). The differences varied
between 2 - 3 °C. The higher pasting and peak temperatures of the dry-chip starches indicated the
impact of the fiber [15] and of annealing of the starches [16] in delaying gelatinization of the
granules.
All aspects that have been discussed above on the pasting properties of starches processed from
fresh root and dry chips have also been observed in case of six other varieties considered under the
same study (data not presented).
3.3 Gelatinization
Gelatinization of starch in water is the collapse of the crystalline structure in the granules
accompanied by increase in volume, due to swelling, and leaching of soluble amylose and
amylopectin into the surrounding aqueous media as a result of heating [22]. The gelatinization properties of starches extracted from fresh root and dry chip are summarized in Tab. 3 and the
thermograms shown in Fig. 2. The temperatures agreed with those reported by Moorthy et al. [23].
Gelatinization temperatures are reflection of the crystallite perfection [24]. The high gelatinization
temperatures of the starches indicate that the granules have a high level of crystallinity as evidenced
by their high amylopectin content.
Tab. 3. Gelatinization properties of cassava starches extracted from fresh root and dry-chip as
obtained from DSC thermograms.
All values are averages of triplicates.
Means of each property within a variety followed by same letter are not significantly different (p <
0.05).
Fig. 2. DSC thermographs of gelatinization of starches from fresh root (•••-••), wet-milled chip ( —
—) and dry-milled chip (——). The thermograph of commercial starch is shown for comparison.
Cooke and Gidley [25] indicated that enthalpy of gelatinization was a result of both the level of
crystallinity and level of the double-helical order of amylopectin. Gelatinization of wet milled drychip starches exhibited smooth and relatively sharp endotherms similar to those of the fresh root
starches. Neither narrowing nor broadening of bases and peaks of endotherms were noted relative to
their counterparts. Melting enthalpies, gelatinization ranges and peak height indices of both group
of starches showed little difference except dry-chip starch of KU50 which exhibited a slight
increase in enthalpy value. However, the endotherms of dry-chip starches shifted to higher
temperatures by few degrees as can be seen from 70, Tp and Tc (Tab. 3). This is in line with the
result of RVA analysis that showed higher pasting and peak temperatures for dry chip starches
(Tab. 2). These changes are attributed to the same causes, brought forward earlier to explain the
changes in pasting property of dry-chip starches, namely high fiber content and annealing of the
starches. The maximum differential gelatinization temperature (in both T0 and TP) was about 3 °C
in the case of KU50, which was also found to have the highest difference of about 4 °C in pasting
temperatures. This can be explained by the fact that KU50 starches processed from dry chip had the
highest fiber content of all three varieties
Tab. 4. Retrogradation properties of cassava starches extracted from fresh root and dry-chip
obtained from DSC thermograms.
All values are averages of triplicates.
Means of each property within a variety followed by same letter are not significantly different (p <
0.05).
(Tab. 1) and also exhibited an increase in gelatinization enthalpy implying some change in the
granules structure as compared to the other starches.
Dry-chip starches processed by wet- and dry-milling methods showed little difference in almost all
gelatinization properties between themselves with nearly identical endotherms. However, the latter
exhibited relatively lower enthalpies that may be due to some degree of mechanical damage
inflicted to the granules during milling. The expected effect of lowering gelatinization temperatures
due to the starch damage was not observed probably because of low intensity of damage and/or
counter effects of the fiber and annealing.
3.4 Retrogradation
Retrogradation is a result of re-association of starch molecules in an ordered structure [22]. It is a
situation where the dissolved amylose chains associate to form helices and insoluble double helices
when starch paste cools. Further retrogradation involves formation of inter- and in-tra-molecular
double helices of amylopectin resulting in a gel. Tab. 4 presents the summary of retrogradation
properties of starches processed from fresh roots and dry chips. Onset, peak and conclusion
temperatures of the retrograded starch were very much lower than those of the native (fresh) starch.
This is understandable as the level of crystallinity restored by retrogradation was expected to have a
different kind of order than the original.
Little difference was found in T0 and in Tp between starches from fresh root and dry-chip for
varieties CMR and R5. However, KU50 showed 3 to 4 °C difference in Tp and Tc between the two
groups. Enthalpy, peak height indices and percentage of retrogradation of starches of all the three
varieties were higher for dry-chip starches than for their counterparts which is a reflection of the
higher degree of retrogradation of the former. This may seem in contradiction with the results of
RVA tests where the setback values of fresh-root starches were higher than those of dry-chip
starches. But this could be explained by the fact that the breakdown values of the fresh root starches
were so large that proportionally the setback would naturally be high despite having a relatively
lower percentage of retrogradation. Various starches retrograde differently depending on the ratio of
the amylose and amylopectin components of the starch, the molecular weight of amylose and the
chain length of amylopectin [26, 27]. Little difference was exhibited in the retrogradation rate of
starches from the three varieties as there is between their amylose contents (22.5% for R5, 22.9%
for CMR and 23.8% for KU50).
Fig. 3. DSC thermographs of retrogradation of starches from fresh root (••••••), wet-milled chip ( —
—) and dry-milled chip (——). The thermograph of commercial starch is shown for comparison.
DSC traces of retrograded starches are shown in Fig. 3. Both groups of starches had distinctly
noticeable but small endotherms for all the three varieties indicating low level of retrogradation.
Dry milled starches had lower enthalpies and retrogradation than wet milled ones for the same
reason mentioned earlier in Section 3.3.
3.5 Swelling power
Tab. 5 presents values of swelling power of starches. Tester and Morrison [24] had suggested that
swelling of starch was attributed to amylopectin. Furthermore, swelling has a high negative
correlation with amylose [28]. As the ratios of amylose/amylopectin fractions of the three varieties
were not much different from one another so were the swelling powers of the starches from fresh
roots. Swelling is inhibited by lipid content of starch [22]. The starches being of low lipid content
(Tab. 1) no appreciable influence was expected from lipid. However, as the amylose contents
(22.5% for R5, 22.9% for CMR and 23.8% for KU50) were slightly higher than that reported (17%)
elsewhere [14] the values of the swelling power were also less. Cassava varieties with amylose
contents exceeding 20% [29-31] are likely to have lower swelling power [28].
Tab. 5. Functional properties of cassava starches processed from fresh root and dry chip.
Fresh-root starches were found to have higher swelling power (p < 0.01) than dry-chip starches for
all the varieties. This goes in agreement with the result of the RVA where the peak viscosity values
of the former were greater than those of the latter. Values of swelling power of dry-chip-starches
processed by wet and dry milling methods have little difference between them except for KLJ50
where a profound difference was observed. However, this was not reflected by the RVA results.
In general the swelling power of the starches from both fresh root and dry chip was not as high as
reported in some references [14]. This may be explained by varietal differences and environmental
factors [13. 32].
3.6 Paste clarity
Tab. 5 shows summary of light transmittance values of pastes produced from fresh root and dry
chip starches. The values are in agreement with other findings on cassava starch [7]. Pastes of fresh
root starches were found to have a much higher light transmitting capacity than those of dry-chip
starches. The difference could be due to the presence of a higher level of fiber in pastes of dry-chip
starches that would have a double effect in reducing clarity. Firstly light would reflect on the
surface of the fiber particles resulting in diffused scattered light and also be absorbed by the
particles. Thus the intensity of light passing through the paste would be reduced [7]. Secondly interference of the fibers inhibiting the expansion of the granules [15] may have resulted in retarded
and distorted swelling of single and aggregates of granules causing non-uniform bending and
inhomogeneous reflection of light. Little difference in paste clarity was found between wet-milled
and dry-milled starches of dry chips for R5 and CMR varieties. However, a significant difference
was found for variety KU50 attributed to the large difference in fiber content between the two
differently milled starches.
3.7 Freeze-thaw stability
The results of the syneresis test of the starches are shown in Tab. 5. Gel of fresh root starch resulted
in very low syneresis value for the first two freeze-thaw cycles and increased abruptly and steadily
in the subsequent ones for all the three varieties. The gel did not show noticeable change in its
texture for the first two cycles. It remained as soft and loose as it initially was (before freezing) with
a tendency to flow when subjected to gravity force. The gel became more compact and relatively
firmer with increase in the number of cycles. But it still had a smooth surface. In general the extent
of syneresis increased with the number of freeze-thaw cycles.
Starches from dry chips showed a considerably higher rate of syneresis than those from fresh roots
in the first two cycles. This is related to the higher degree of ret-rogradation displayed by the former
group (Tab. 4). These starches must have retrograded faster than their counterpart in the first two
cycles such that more water separated from the gels. However, in the subsequent cycles the rate of
increase in syneresis value was not much different. As freezing and thawing continued the gels of
all the starches had enough time for more retrogradation hence increased syneresis. Furthermore,
rate of syneresis in both groups of starches was highest for variety KU50, particularly in the first
two cycles, followed by CMR and R5. This may be the influence of the amylose content on degree
of retrogradation hence on freeze-thaw stability of starches. The syneresis of starches processed
from dry chip showed little difference between those wet milled and dry milled ones for all the
three varieties.
The gel texture of dry-chip starches after thawing during the first cycle was relatively loose
although not as loose as that of the fresh root starch. Gels in the subsequent cycles were more
compact and firmer than their counterparts of the fresh root starches and capable of withstanding a
certain level of tensile force. When subjected to light pressure, even after centrifuging, a
considerable quantity (about 0.5 mL) of water oozed out, unlike in the fresh root starch gels,
indicating that greater separation of water had occurred in the system although was not fully retrieved due to re-adsorption. This showed that the gel had a porous texture. Rate of syneresis
consistently increased up to the fifth cycle for all the three types of starches and ail varieties.
In general the gels of starches extracted from fresh root were found to have a better freeze-thaw
stability than those of dry-chip starches at room temperature. Little difference was noted, as regards
syneresis, between dry-chip starches extracted by wet milling and those by dry milling. The
syneresis results of this work are in complete agreement with those of Varavinit et al. [33, 34].
4 Conclusion
Differences in functional properties existed between starches extracted from fresh cassava root and
those from dry chip. Nearly all the pasting properties of starches from dry chips significantly
differed from those of fresh roots. The starches from dry chips had lower peak viscosities,
breakdowns and setbacks and higher pasting and peak temperatures. Similarly the thermal
properties of dry chip starches, except a few related to gelatinization, were different from those of
fresh root starches. Dry-chip starches had higher onset and peak temperatures of gelatinization than
starches from fresh roots. Values of all
retrogradation properties including percentage of retrogradation were also higher for dry-chip
starches. However, the endotherms of the two groups of starches were almost identical except a
shift by few degrees to a higher temperature for those of dry-chip starches. This suggested
occurrence of no major structural changes in the granules of dry-chip starches due to chip drying
and starch extraction. Moreover, dry-chip starches showed lower swelling power, paste clarity, and
freeze-thaw stability than their counterpart. Percentage of syneresis increased with the number of
cycles for all the three types of starches and cassava varieties. These differences in properties may
have resulted largely from differences in the fiber content and also from annealing due to exposure
to excess heat and moisture during processing. The differences are without severe drawback for the
suitability of dry-chip starches in many applications. Furthermore, the high stability and resistance
against heat and shear could be beneficial in many respects. Processing of starch from dry cassava
chips resulted in more fine fiber particles in the starches and required a more efficient method of
separation than processing from fresh root. It is felt that the problems indicated by earlier workers
[3] in the preparation of good quality starch can easily be overcome taking into account that they
had started with pellets and chips prepared for animal feed containing sand, high fiber and other
impurities.
It is the opinion of the present authors that with little or no modification to the modern processing
equipment currently in use it may be possible to extract starch of higher purity and desirable
functional characteristics from dry cassava chips which have been appropriately prepared on a
commercial scale.
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(Received: November 11, 2002) (Revised: March 4, 2003) (Accepted: March 5, 2003)