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 American Journal of  
Food Science and Technology (AJFST)

Comparative Study on the Functional, Pasting and Physicochemical Properties of  Native 
and Pregelatinized Cocoyam Starch (Xanthosoma sagittifolium)

A. A. Amanyunose1*, B. F. Olanipekun1, O. E. Adelakun1

Volume 4 Issue 1, Year 2025
ISSN: 2834-0086 (Online)

DOI: https://doi.org/10.54536/ajfst.v4i1.3889
https://journals.e-palli.com/home/index.php/ajfst

Article Information ABSTRACT

Received: October 09, 2024

Accepted: November 12, 2024

Published: February 08, 2025

This study sought to extract and modify cocoyam starch for industrial use, as it is an un-
derutilized tuber in Nigeria. Pregelatinization was employed to change cocoyam starch, 
and the functional, physicochemical, and pasting properties and proximate composition 
were evaluated using standard methods. The results show that pregelatinization improved 
the starch’s water absorption capacity (164.333-249.333%), oil absorption capacity (97-
106.333%), bulk density (0732-0769g/ml), and solubility index (8.667-14.667%), but swell-
ing power dropped (9.553-7.147g.g-1). Native cocoyam starch had the lowest gelation capac-
ity (8%), while pregelatinized cocoyam starch had a gelation capacity of  6%. Native cocoyam 
starch outperformed pregelatinized cocoyam starch in terms of  peak viscosity (3724.5-944.5 
RVU), trough viscosity (3041-822 RVU), breakdown viscosity (683.5-162.5 RVU), and final 
viscosity (5516.5-1923 RVU). After pregelatinization, cocoyam starch had a higher pasting 
temperature (83.05-84.4oC) and peak time (5.03-7.0 min). The proximate composition indi-
cates a small increase in carbohydrate and protein concentrations while moisture levels fall.

Keywords

Cocoyam, Modification, 
Pregelatinization, Pasting, Starch

1 Department of  Food Science, Ladoke Akintola University of  Technology, Ogbomoso, Nigeria
* Corresponding author’s e-mail: ronkeamanyunose@gmail.com

INTRODUCTION
Cocoyam is an underutilized tropical crop in Nigeria 
that is abundant in carbohydrates and surpasses other 
root and tuber crops in terms of  protein and amino acid 
content (Obiegbuna et al., 2014). Despite this, farming has 
remained at subsistence level, with the tubers used only 
for boiling or frying and as a thickening agent in some 
traditional soup recipes. (Ejoh et al., 2013). Cocoyam 
consumption can be increased by using its high starch 
content for both food and non-food industries (Arinola, 
2019). According to Ashogbon and Akintayo (2014), 
starch is a naturally occurring, biodegradable substance 
that is widely available. In addition to its various industrial 
uses as a thickener, stabilizer, gelling agent, encapsulating 
agent, bulking agent, water retention agent, and adhesive, 
starch also influences the texture of  many meals (Singh 
et al., 2003). Water insolubility, retrogradation, heat 
sensitivity, shear stress, and pH limit the use of  native 
starch. By changing the shape of  the starch granules, 
these restrictions of  native starch can be lessened 
or abolished, leading to enhanced physicochemical 
qualities (Oladebeye et al., 2013). In order to improve 
its suitability for use in food and other applications, 
modified starch undergoes physical or chemical changes. 
Desired characteristics that are absent from native starch 
can be obtained through modification; many functional 
elements, including gelation, water absorption capacity, 
and thermal stability, can be brought to acceptable 
levels (Yousif  et al., 2012; Okunade & Arinola, 2021). 
One physical starch modification technique that is easy, 
affordable, and safe with no adverse health effects is 
pregelatinization (Ashogbon & Akintayo, 2014; Majzoobi 
et al., 2011). Because physical alteration doesn’t change the 

structure of  starch granules or generate hazardous waste, 
it is also chosen (Zavareze & Dias, 2011). According to 
Okunade and Arinola (2021), heat moisture treatment 
improved cocoyam starch’s pasting qualities. By oxidation, 
acetylation, and pregelatinization, Olatidoye et al., (2019) 
also enhanced the swelling and solubility of  cocoyam 
starch. In order to gather information for upcoming 
starch applications in the food sector, the goal of  this 
study is to extract cocoyam starch, pregelatinize it, and 
compare the physicochemical, pasting, and functional 
properties of  unmodified and modified starches.

MATERIALS AND METHODS
Materials 
Cocoyam (Xanthosoma sp) used for this research work 
was obtained from the International Institute of  Tropical 
Agriculture, Moniya, Ibadan

Cocoyam Starch Extraction
With minor adjustments, the technique outlined by 
Arawande and Ashogbon, (2019) was used to extract 
starch from cocoyam. Cocoyam was peeled. sliced and 
milled using a milling machine. Distilled water was added 
to the finished slurry (1:4). After passing the mixture 
through a muslin bag, the starch suspension was allowed 
to settle overnight at 4°C. After the supernatant had 
cleared, the white starch sediment was allowed to settle 
and then decanted after being cleaned three or four times 
with distilled water. A standard blender was used to blend 
the separated starch after it had been dried in an oven 
set to 40°C. Before being used, the product was sieved, 
sealed in ziplock bags, and stored at room temperature 
(26 ± 2 oC).



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Cocoyam Starch Pregelatinization
The pregelatinization procedure described by Okunade 
and Arinola, (2021) was used. 150 ml of  distilled water and 
a known weight (100g) of  starch sample were heated in a 
water bath at 80°C for 15 minutes while being manually 
stirred intermittently with a stirring rod. A stainless steel 
tray was coated with a thin layer of  pregelatinized starch, 
which was then dried for 24 hours at 40 degrees Celsius 
in the oven. After being processed, sieved, and packed 
in ziplock bags, this was kept at room temperature (26 ± 
2°C) until it was needed.

Determination of  Functional Properties 
Water Absorption Capacity
This was determined using Onwuka’s method (2005). 
One gram of  sample was placed in a clean conical 
graduated centrifuge tube and aggressively agitated with 
10 mL of  distilled water using a mixer for 30 seconds. 
After 30 minutes at room temperature (28 ± 2 °C), the 
sample was centrifuged at 5000 rpm for 30 minutes. 
After centrifugation, the volume of  supernatant water 
was measured directly from the graduated centrifuge 
tube. The absorbed water was then weighed (in grams) 
by multiplying it by the density of  water (1 g/mL). Water 
absorption capacity is expressed as grams of  water 
retained per gram of  sample used.

Oil Absorption Capacity
Onwuka, (2005)  technique was used to determine this. 
In a sterile conical graded centrifuge tube, one gram of  
the material was violently stirred for 30 seconds with 10 
milliliters of  oil. The sample was centrifuged at 5000 
rpm for 30 minutes after being allowed to sit at room 
temperature (28 ± 2 °C) for 30 minutes. Following 
centrifugation, the graduated centrifuge tube was used to 
measure the amount of  supernatant oil. The weight (in 
grams) of  the absorbed oil was calculated by multiplying 
it by its density (0.894 g/mL). The amount of  oil retained 
per gram of  sample used is the measure of  the oil 
absorption capacity.

Bulk Density
The method developed by Ashogbon and Akintayo, 
(2013) was used to ascertain this. A 10 ml graduated 
cylinder was filled with the sample until it reached the 
10 ml threshold. To remove air from between the flour 
mixtures, the cylinder was tapped (agitated) for five 
minutes. Mass per volume (mL) is used to calculate bulk 
density.

Solubility
The total solubility of  the starch samples at room 
temperature was ascertained using the methodology 
of  Gbadamosi and Oladeji, (2010). Ten milliliters of  
distilled water were added to a centrifuge tube containing 
one gram of  the material. After combining the mixture 
and letting it stand for an hour, it was centrifuged for 15 
minutes at 4,000 rpm. In a moisture container that had 

been cleaned and weighed beforehand, the supernatant 
evaporated. The weight increase of  the can over the 
weight of  the sample is used to calculate the solubility, 
which is then represented as a percentage. 

Swelling Power
A technique for figuring out the swelling power of  
modified cocoyam starch was presented by Arawande and 
Ashogbon, (2019). After weighing 1g of  starch, 50ml of  
distilled water was added and carefully stirred. The slurry 
was heated in a water bath at temperatures between 55 and 
95 degrees Celsius for 15 minutes. To prevent the starch 
from clumping, the slurry was gently churned. The tubes 
containing the paste were centrifuged for 10 minutes 
at 300 rpm after 15 minutes, and the supernatant was 
promptly decanted. The sediment’s weight was calculated 
and noted. The dry matter composition of  the gel was 
then ascertained by calculating its moisture content.
Swelling Power=Weight of  wet sediment/Weight of  dry 
matter in the gel                 (i)

pH 
This was computed by adding 20 milliliters of  filtered 
water to a beaker containing 5 grams of  starch. After 
five minutes of  agitation, the resultant suspension was 
allowed to settle for ten minutes. A calibrated pH meter 
was used to measure the water phase’s pH (AOAC, 2010).

Least Gelation Concentration
The method developed by Onwuka, (2005) was applied 
to find the lowest gelation concentration. Ten test tubes 
were filled with a 5 ml suspension of  starch (2-20% w/v), 
which was then cooked for an hour at 100 °C in a boiling 
water bath before being cooled in a cold water bath. Each 
test tube was inverted to determine the lowest gelation 
concentration after the samples had been cooled for two 
hours at 4°C. When the tube is inverted, the sample does 
not fall, indicating the lowest gelation concentration.

Determination of  the Amylose and Amylopectin Content
The Hoover and Ratnayake, (2001) method was used to 
ascertain this. It entailed weighing 0.1 g of  starch samples 
into a 100 mL volumetric flask and then progressively 
adding 9 mL of  a 1M sodium hydroxide solution and l 
mL of  99% ethanol. Before heating the sample solution 
in boiling water for ten minutes to gelatinize the starch, 
the ingredients were well combined. Following cooling, 
distilled water was added until the solution reached the 
desired level and then gently shaken. Next, 1 mL of  1M 
acetic acid and 2 mL of  99% iodine were added to 5 mL 
of  the starch solution in a 100 mL volumetric flask. Since 
the solution was opaque, 10 mL was made by mixing l 
mL of  the sample solution with 9 mL of  distilled water. 
A UV/Vis spectrophotometer set to 620 nm was used to 
measure absorbance. The absorbance of  the sample was 
deducted from the blank value. The following formulas 
are used to determine the contents of  amylose and 
amylopectin.



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Amylose Content (%)=3.06 x Absorbance  x 20          (ii)
Amylopectin Content (%)=100-% Amylose Content   (iii)

Pasting Properties
Pasting characteristics, such as peak viscosity, trough 
viscosity, breakthrough viscosity, final viscosity, setback 
viscosity, pasting temperature, and peak duration, were 
determined for both native and modified starch samples 
using the Rapid Visco Analyzer. A 12% (w/w; db) flour 
suspension was made by mixing a 3 g flour sample with 
25 ml of  water in the RVA canister. To guarantee proper 
mixing, a paddle was placed inside the canister and its 
blade was jogged through the suspension up and down 
roughly six times. The RVA machine was then filled with 
the paddle-containing canister. The sample was heated 
from 50 degrees Celsius to 95 degrees Celsius in 3 and 
a half  minutes, held at 95 degrees for two and a half  
minutes, and then cooled back to 50 degrees Celsius for 
three and a half  minutes. This was followed by a two-
minute phase in which the temperature was maintained at 
50 degrees Celsius. The 12-minute profile was employed.

Proximate Analysis 
AOAC (2006) procedures were used to determine the 
samples’ proximate components.

RESULTS AND DISCUSSION
Functional Properties of  Native and Pregelatinized 
Starch
The solubility index, bulk density, swelling capacity, 
water and oil absorption capacities, and other functional 
characteristics of  native and pregelatinized starch are 
contrasted in Table 1.

Water Absorption Capacity of  Native and 
Pregelatinized Starch
Compared to native starch (164.33%), pregelatinized 
starch exhibited a greater capacity to absorb water 
(249.333%). Arawande and Ashogbon’s, (2019) 162.51% 
water absorption capacity for cocoyam starch was 
comparable to the water absorption capacity observed 
for native cocoyam starch. However, it falls short of  the 
180.0% for cocoyam starch that Ariwaodo et al. (2017) 
were able to obtain. Arinola, (2019) findings for both 
pregelatinized and microwave-radiated cocoyam starch 
are in line with the observed increase in water absorption 
capacity for pregelatinized cocoyam starch. Additionally, 
cassava starch demonstrated a greater capacity to absorb 
water (Sarifudin et al., 2020). Following modification, starch 
granule disintegration and macromolecular rupture have 
been connected to the enhanced water absorption capacity 
of  modified cocoyam starches (Alcazar-Alay & Meireles, 
2015). The porosity of  starch granules has been determined 
using their water absorption capacity (Wang et al., 2016). 
Better starch digestion was suggested by an increased 
capacity for water absorption (Ariwaodo et al., 2017).

Oil Absorption Capacity of  Native and Pregelatinized 
Starch
Compared to native starch, pregelatinized starch was able to 
absorb more oil (106.333%). Okunade and Arinola, (2021) 
found that modified cocoyam starch has a higher potential 
to absorb oil. Following alteration, Sanyaolu et al. (2021) 
observed a comparable rise in cassava and red cocoyam 
starch. Both native and pregelatinized cocoyam starch 
have lower oil absorption capacities than those reported by 
Yussuf  et al. (2022), which are 164.0 and 173%, respectively.

Table 1: Functional Properties of  Native and Pregelatinized Starch
Sample Water Absorption 

Capacity %
Oil Absorption 
Capacity %

Swelling 
Power g.g-1

Solubility 
Index (%)

Bulk Density 
g/ml

pH

A 164.333±3.055 97.000±1.732 9.553±0.023 8.667±1.155 0.732±0.015 5.710±0.044
B 249.333±2.082 106.333±2.081 7.147±0.041 14.667±2.309 0.769±0.000 5.960±0.010

The values represent the means ± standard deviation of  the triplicate determination. The key B is pregelatinized starch, and A is native starch

One crucial functional characteristic that influences the 
choice of  starch in baked and extruded foods is the 
capacity to absorb oil (Arinola, 2019). One important 
determinant of  how well starches retain flavor is their 
ability to absorb oil (Aidoo et al., 2022). In certain dietary 
compositions that demand optimal oil absorption, starch’s 
ability to bind to oil is beneficial (Ariwaodo et al., 2017). 
Starch’s strong oil absorption capability indicates that it 
contains hydrophobic proteins, signifying increased lipid 
binding. This is significant because fat preserves flavor and 
improves the mouthfeel of  foods (Yussuf  et al., 2018).

Swelling Power and Solubility Index of  Native and 
Pregelatinized Starch
After pregelatinization, native starch’s swelling power 
reduced by 25%, from 9.553 to 7.14 g.g-1, while its 
solubility index increased by 41% (8.666 to 14.667 g.g-

1). This is consistent with Arinola’s (2019) findings 
about pregelatinized cocoyam starch. Olatunde et al. 
(2017) found a comparable decrease in swelling power 
after pregelatinization of  plantain starch. Compared to 
Ariwaodo et al. (2017), who discovered 0.105 g/mL for 
modified cassava starch and 0.505 g/mL for modified 
sweet potato starch, the swelling power values obtained 
are higher. Inadequate gelatinization of  the starch may 
be the cause of  the reduced swelling power seen for 
pregelatinized cocoyam starch. One method of  assessing 
the quality of  food is to look at its swelling power, 
which gauges a substance’s capacity to become hydrated 
(Adams et al., 2019). The degree of  interaction between 
starch chains in the crystalline and amorphous domains 
is referred to as solubility (Oladebeye, 2013). The granule 
size and amylose content of  cocoyam starch may be 
responsible for the rise in the solubility index.



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Bulk Density of  Native and Pregelatinized Starch
Pregelatinized starch had a bulk density of  0.769g/mL, 
whereas native starch had a bulk density of  0.732g/mL. 
Bulk density values for red and white cocoyam starch 
were determined by Yussuf  et al. (2022) to be 0.71 and 
0.70 g/mL, respectively. The findings, however, fall short 
of  the 0.88g/ml cocoyam starch content reported by 
Arawande and Asogbon, (2019). According to Ibikunle 
et al. (2019), bulk density is a measurement of  the weight 
of  solid samples that is used to guide material handling 
and application in food processing as well as the kind 
of  packing material required. Particle size and starch 
sample density dictate bulk density. The starch sample’s 
coarseness is also reflected in bulk density. The bulk 
density of  the material determines how much may be 
packed in a specific area (Adewumi et al., 2020).

pH of  Native and Pregelatinized Starch
Despite being both acidic, the pH of  the pregelatinized 
cocoyam starch samples is somewhat higher than that 
of  the native starch. The samples’ pH is lower than the 
7.84 reported by Ashogbon, (2017) but equivalent to the 
5.48–5.75 reported by Olatidoye et al. (2018) for native 
and pregelatinized cocoyam. The pH range of  native and 
pregelatinized starches, which are widely utilized in the 
domestic, culinary, and pharmaceutical sectors, is 3 to 9. 
Because it affects whether the liquid medium is acidic 
or alkaline, the starch’s pH is significant for applications 
(Awolu et al., 2020; Yusuf  et al., 2018). pH controls a 
number of  essential functional characteristics of  starch, 
including swelling and solubility, so understanding the pH 
is critical (Gbadamosi & Oladeji, 2013).

Least Gelation Capacity of  Native and Pregelatinized 
Starch
The findings of  the native and pregelatinized starch 
gelation at the lowest concentrations are shown in Table 2. 

by Okunade and Arinola (2021). The smallest quantity 
of  starch needed to create gel in a weighted volume of  
water is referred to as least gelation. Depending on their 
structural components—protein, carbs, and lipids—
starches have different gelation capacities (Ohizua et al., 
2016). One crucial measure of  starch’s gelling capacity 
is the lowest gelation concentration (Yadav et al., 2018). 
Better starch gelling capabilities are implied by the fact 
that lower concentrations are needed to form starch gel 
(Shrivastava et al., 2018).

Amylose and Amylopectin Content of  Native and 
Pregelatinized Starch
The amylose and amylopectin content results are shown 
in Table 3. Following pregelatinization, the amylose 
content of  native cocoyam starch decreased to 26.510 
percent, while the concentration of  amylopectin rose 
from 58.474% (native cocoyam starch) to 73.490% 
(pregelatinized starch). Amylose and amylopectin are 
the two main glucose polymers that make up starch. 
Amylose makes about 20–30% of  regular starches, 
whereas amylopectin makes up the remaining portion. 
Ishiwu et al. (2017) state that the percentage of  amylose 
in cocoyam starch varies by species and ranges from 3 
to 43%. Although it surpasses the values reported by 
Okunade and Arinola, (2021) for white (17.47%) and 
red (15.68%) cocoyam starch, the amylose level found 
in this study is within this range. Additionally, it is 
lower than the cocoyam starch value of  20.09 percent 
reported by Adewunmi et al. (2020). Species variations 
or the agricultural environment in which the plants were 
cultivated could be the cause of  the observed discrepancy. 
This study proved that amylopectin, a component 
of  starch, is heavier than amylose. Swelling happens 
when products have starch with a low amylose content. 
Because it affects pasting, gelatinization, retrogradation, 
swelling power, and enzymatic vulnerability, the amount 
of  amylose and amylopectin in starches is significant 
(Arawande & Ashogbon, 2019).

Pasting Properties of  Native and Pregelatinized 
Starch
Because they impact the functional and sensory aspects 
of  food formulation, affecting texture, digestibility, and 
starch consumption in food systems, pasting qualities 
are important when it comes to the usage of  starch. 
The pasting characteristics of  native and pregelatinized 
starches are contrasted in Table 4.

Peak Viscosity of  Native and Pregelatinized Starch
Compared to pregelatinized starch (984.5), native starch 
has a higher viscosity (3724.5 RVU). The maximum 
viscosity recorded during or right after the fast visco 
analyzer’s heating phase is known as the peak viscosity. 
It shows the amount of  viscosity that will be present 
during mixing. Because peak viscosity shows resistance to 
granule breakdown, it is also used to evaluate the stability 
of  starch (Adewunmi et al., 2015). 

Table 2: Least Gelation   of  Native and Pregelatinized 
Starch
Concentration% Sample A Sample B
2 Viscous Viscous
4 Viscous Viscous
6 Viscous Gel
8 Gel Gel
10 Gel Gel
12 Gel Gel
14 Gel Gel

Key: A = Native Starch, B =Pregelatinized  Starch

The concentration at which native cocoyam starch gelled 
was 8%, while the concentration at which pregelatinized 
cocoyam starch gelled was 6%. This implies that 
pregelatinization enhanced the starch’s capacity to gel. 
The lowest gelation concentration found for native starch 
is comparable to the native cocoyam starch reported 



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Pregelatinization decreased the peak viscosity of  cocoyam 
starch, which is in line with the pattern seen by Yussuf  et 
al. (2022) and Sanyaolu et al. (2021). A similar drop in 
peak viscosity was found by Obioma et al. (2022) after 
yam and sweet potato starch underwent chemical and 
physical modifications. This runs counter to the results 
of  Arinola, (2019), who found that the peak viscosities of  
pregelatinized red and white cocoyam starch were higher 
than those of  native starch. The obtained peak viscosity 
is lower than that reported by Lopulalan et al. (2020), who 
discovered that the native cocoyam starch had a peak 
viscosity range of  4601-5155RVU. Molecular weight, 
intermolecular conformation, amylose and amylopectin 
polymerization degree, amylopectin branching quantity, 
amylose/amylopectin quantities and ratios, and the 
presence of  minor components can all have an impact on 
viscosity (Subroto et al., 2019). Since peak viscosity and 
the degree of  starch damage have been related, higher 
peak viscosity will be the consequence of  more starch 
breakdown (Obioma, 2022). Poor molecular connections 
between starch granules are directly linked to high 
peak viscosity in starch, making them more prone to 
disintegration (Falade & Okafor, 2015).

Trough Viscosity of  Native and Pregelatinized Starch
Pregelatinized starch had a trough viscosity of  822 RVU, 
whereas native cocoyam starch had 3041 RVU. Following 
pregelatinization, the gelatinized cocoyam starch’s trough 
viscosity, also known as its minimum viscosity, decreased. 
The duration that samples are exposed to a constant 
temperature and mechanical shear stress is referred 
to as the hold time (trough), which is also called shear 
thinning, holding strength, or hot paste viscosity (Kiin-
Kabari, 2015; Addy et al., 2014). The results of  Obioma 
et al. (2022) for modified sweet potato, trifoliate yam, and 
white yam starches are in line with the reduction in trough 
viscosity observed with modified cocoyam starch. The 

trough viscosity value for native starch is greater than the 
2868 RVU found by Lopulalan et al. (2020) and the 2213 
RVU and 2519 RVU found by Arinola, (2019) for native 
white and red cocoyam starches, respectively.

Breakdown Viscosity of  Native and Pregelatinized 
Starch
Native and pregelatinized starches have respective 
breakdown viscosities of  683.5 and 162.5 RVU. The 
breakdown viscosity, which evaluates the degree of  
granule disintegration, paste stability, and the starch’s 
ability to withstand crumbling during cooling, is 
calculated by deducting the trough (hold) viscosity 
from the viscosity (Ojo et al., 2017; Kiin-Kabari, 2017). 
How well cooked starch may withstand shear-induced 
disintegration depends on its breakdown viscosity. The 
starch is very stable under heat and shear stress when the 
breakdown viscosity is low; however, high values suggest 
that the starch’s resistance to heat and shear stress during 
cooking is reduced (Ezeocha & Okafor, 2016). It is well 
known that breakdown viscosity is significantly impacted 
by amylose content. The decrease in breakdown viscosity 
values found in this investigation is in line with the results 
of  Aidoo, (2022) for cassava starch and Arinola, (2019) 
for modified red and white cocoyam starch.

Final Viscosity of  Native and Pregelatinized Starch
Pregelatinized starches have a final viscosity of  1923 
RVU, whereas native starches have 5516.5 RVU. The final 
viscosity is decreased by pregelatinization. The observed 
decrease aligns with the results of  Obioma et al. (2022) 
about the starches of  cocoyam, white yam, and sweet 
potatoes. The ability of  a starch material to solidify into 
a thick paste or gel upon heating or chilling is known as 
its ultimate viscosity. According to Awolu et al. (2017), 
it is a gauge of  starch quality. After boiling and cooling, 
the final viscosity is used to evaluate the starch’s capacity 
to gel. It explains how stable heated paste or gel is. Paste 
stability decreases as breakdown viscosity rises (Ikegwu 
et al., 2010). One important factor in determining and 
predicting the textural quality of  foods high in starch 
is final viscosity (Arinola et al., 2016). A realignment 
of  the amylose and amylopectin molecules may be 
the cause of  the decrease in final viscosity. This would 
strengthen the link between the amylose and amylopectin 
molecules in starch granules and reduce the likelihood of  
retrogradation (Subroto, 2019).

Table 3: Amylose and Amylopectin Content of  Native 
and Pregelatinized Starch
Sample Amylose  (Mg/100g) Amylopectin 

(Mg/100g)
A 41.526±0.520 58.475±0.520
B 26.511±0.633 73.490±0.633

The values represent the means ± standard deviation of  
the triplicate determination. Key: A = Native Starch, B = 
Pregelatinized Starch

Table 4: Pasting Properties of  Native and Pregelatinized Starch
Sample Peak viscosity 

(RVU)
Trough 
(RVU)

Break down 
(RVU)

Final viscosity 
(RVU)

Setback 
(RVU)

Peak time 
(min)

Pasting 
temp (℃)

A 3724.5±70.00 3041±4.24 683.5±74.25 5516.5±99.70 2475.5±95.46 5.03±0.14 83.05±0.00
B 984.5±36.06 822±21.21 162.5±14.84 1923±41.01 1101±19.79 7±0.00 84.4±0.57

Values are means of  triplicate determinations ± standard deviation. Key: A = Native Starch, B = Pregelatinized Starch



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Setback Viscosity of  Native and Pregelatinized 
Starch
Pregelatinized starch had a setback viscosity of  1101 
RVU, while natural starch had 2475 RVU. In line with the 
pattern noted by Awolu et al. (2020) for pregelatinized and 
acid-thinned maize starch, pregelatinization decreased 
setback viscosity. The starch molecules’ structural 
loosening and disruption may be the cause of  the low 
setback value; hence, the larger the setback value, the 
greater the retrogradation upon cooling. The likelihood 
of  the starch going stale increases (Awolu & Olofinlae, 
2016). The capacity to re-crystallize gelatinized starch 
after chilling can be evaluated using setback viscosity 
(Subroto, 2019). The texture of  different starch-based 
products is correlated with the retrogradation tendency 
of  cooked starch after cooling, which is indicated by 
setback viscosity (Ojo et al., 2017; Ezeocha & Okafor, 
2016). Lower vulnerability to retrogradation during 
cooling is indicated by a high setback number (Aidoo 
et al., 2022). This implies that a paste made from native 
cocoyam starch will be less likely to retrograde, which 
could be beneficial for nutritional bioavailability and food 
metabolism as retrograded starch is insensitive to human 
digestive enzymes.

Pasting Temperature and Peak Time of  Native and 
Pregelatinized Starch
The native starch pasting temperature was 83.05°C with 

a peak time of  5.03 minutes, whereas the pregelatinized 
starch pasting temperature was 84.4°C with a peak 
time of  7.00 minutes. Arawande and Ashogbon (2019) 
discovered a similar peak time of  5.03 oC for cocoyam 
starch. Shrivastava et al. (2018) found a slightly longer peak 
time of  5.23 minutes and a higher pasting temperature of  
89.63 oC for cocoyam starch. In line with Arinola’s (2019) 
finding that native red cocoyam starch rose from 80.70 
to 83.20 oC following pregelatinization, the pregelatinized 
starch had a little higher pasting temperature than the 
original starch. According to Rosa et al. (2017) and Kiin-
Kabari, (2015), the pasting temperature is the lowest 
temperature needed to cook a specific food sample or 
starch. It is the temperature at which viscosity increases 
noticeably for the first time and serves as a gauge for the 
first alteration brought on by starch swelling. Due to the 
closer connection between starch granules, a high pasting 
temperature usually signifies a high capacity for water 
absorption (Julanti et al., 2015; Tortoe et al., 2019). The 
amount of  time needed to boil starch is known as the 
pasting or peak time (Obioma, 2019). 

Proximate Composition of  Native and Pregelatinized 
Cocoyam Starch
The approximate proportions of  native and 
pregelatinized cocoyam starches are shown in Table 5. 
While pregelatinized starch had  8.67% moisture level, 
native starch had a 9.45% moisture content.

Table 5: Proximate Composition of  Native and Pregelatinized Cocoyam Starch
Sample Moisture (%) Ash (%) Crude fiber (%) Fat (%) Protein (%) Carbohydrate (%)
A 9.45±0.17 1.37±0.06 1.06±0.00 1.03±0.000 1.33±0.044 84.96±0.33
B 8.67±0.29 2.07±0.15 1.20±0.048 1.13±0.030 1.97±0.044  85.76±0.15

Values are means of  triplicate determinations ± standard deviation. Key: A = Native Starch, and B = Pregelatinized Starch

Despite the lower moisture content of  pregelatinized 
starch, both were within the commercially acceptable 
range of  less than 14.0% for stable shell life. Because it 
affects the product’s shelf  life, moisture content is a crucial 
food characteristic. The results of  Olatidoye et al. (2019), 
who found that the moisture content of  pregelatinized 
cocoyam starch increased from 7.52% to 11.34%, are 
in conflict with the decrease in moisture content values 
reported in this study. Native and pregelatinized starches 
had an ash percentage of  1.37% and 2.07%, respectively. 
This is higher than Okunade and Arinola’s (2021) white 
and red cocoyam starch concentrations of  1.28% and 
1.56%, respectively. The results also exceed the 0.21% 
reported by Ashogbon and Adeleke, (2019) for cocoyam 
starch. The ash content implies that the product contains 
inorganic nutrients. The crude fiber content of  native 
starch was 1.06%, whereas pregelatinized starch was 
1.20%. Olatidoye et al. (2019) and Ojo et al. (2023) have 
found that the crude fiber content of  native starch is 
higher than that of  cocoyam starch, at 0.05% and 0.10%, 
respectively. The figures, however, fall short of  the yam 
and cocoyam starch estimations of  3.22% and 2.01%, 
respectively, reported by Modu et al. (2015). The crude 

fiber indicates the starch’s cellulose, hemicelluloses, and 
lignin content (Ojo et al., 2023). Dietary fiber helps to 
prevent constipation, digestive issues, and piles, so it is 
essential to include it in the diet. 
Native and pregelatinized starch had respective protein 
and fat content of  1.33%, 1.97%, and 1.03%, 1.13%. 
The protein and fat content in this study is lower than 
that found in red and white cocoyam starch by Okunola 
and Arinola, (2021) and in white yam, trifoliate yam, and 
sweet potato starch by Obioma et al. (2022). Awolu and 
Olofinlae, (2016) stated that the protein content of  water 
yam starch was less than 1%, however Nadir et al. (2015) 
found that the protein content of  potato starch ranged 
from 0.17 to 0.40%. With values ranging from 0.07 to 
0.17%, Olatidoye et al. (2019) found a similar trend in 
the fat content of  native and modified cocoyam starches.  
Both native and modified starch are beneficial ingredients 
in the creation of  low-fat foods due to their low fat 
content. Since protein levels in starch below 5% have 
been shown to have no discernible impact on its thermal 
characteristics, the low protein and fat content suggests 
that there would be little interaction with the starch’s 
qualities (Okunola & Arinola, 2021). The carbohydrate 



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Am. J. Food. Sci. Technol. 4(1) 21-29, 2025

content of  native starch was 84.96%, while pregelatinized 
starch was 85.76%. Pregelatinization increased the 
starch’s carbohydrate content. Cocoyam starch is a good 
carbohydrate source that provides dietary energy for 
many organ functions in the body and can be a substantial 
energy source when consumed (Oko et al., 2015). Obioma 
et al. (2022) discovered a comparable carbohydrate gain 
after modifying white yam starch (85.36 to 87.17%), 
trifoliate yam starch (86.49 to 87.73%), and sweet potato 
starch (85.09 to 85.51%). Ojo et al. (2023) discovered that 
red native, white native, and Ghana native cocoyam starch 
all had the same carbohydrate content.

CONCLUSION
Pregelatinization of  cocoyam starch increased its 
solubility, bulk density, and capacity to absorb water and 
oil while decreasing its pasting ability. Both the food and 
non-food sectors employ pregelatinized cocoyam starch.

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