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European Journal of Applied Sciences – Vol. 11, No. 3
Publication Date: June 25, 2023
DOI:10.14738/aivp.113.15077
Olaleye, H. T., Oresanya, T. O., & Akinwande, F. F. (2023). Effect of Enzymatic Modification Period on Pasting Properties and
Functional of Two Varieties of Acha Starch (Digitaria Iburua and Digitaria Exilis). European Journal of Applied Sciences, Vol - 11(3).
805-811.
Services for Science and Education – United Kingdom
Effect of Enzymatic Modification Period on Pasting Properties
and Functional of Two Varieties of Acha Starch (Digitaria Iburua
and Digitaria Exilis)
Olaleye, H. T.
(ORCID: 0000-0002-7901-1129)
Department of Food Technology,
Yaba College of Technology, Yaba, Lagos, Nigeria
Oresanya, T. O.
(ORCID: 0000-0002-6133-7438)
Department of Food Technology,
Yaba College of Technology, Yaba, Lagos, Nigeria
Akinwande, F. F.
(ORCID: 0000-0003-4501-0731)
Department of Food Technology,
Yaba College of Technology, Yaba, Lagos, Nigeria
ABSTRACT
Native starches are starches in their pure original form and may not be suitable for
many food applications. The use of enzymes to modify starch results in
development of low molecular weight, linear short chains fractions of amylopectin,
increases the quantity of resistant starch content and promotes freeze thaw
stability because amylopectin branches prevent syneresis in the gel network. The
effects of enzymatic modification period on the pasting and functional properties of
the two Varieties of Acha (Digitaria exilis and Digitaria Iburua) starch were
investigated. Acha grains were modified with Enzymes for 30mins, 45mins and 60
mins and non-modified Acha grains served as control. The modified starches were
evaluated for pasting and functional properties using standard procedure. Results
obtained shows: Peak viscosity (2760.00-3752.00RVU), Trough viscosity (1717.00-
2888.00RVU), breakdown (713.00-1881.00RVU), final viscosity (2910.00- 4399.00
RVU), setback viscosity (1074.00-1652.50), peak time (4.77-6.10mins), pasting
temperature (78.28-80.70°c); water absorption capacity (2.03-2.28g/cm3), oil
absorption capacity (2.24-8.20g/cm3), bulk density (0.81-4653%), solubility index
(1.00-4.12%), swelling power (5.11- 11.50g/cm3) respectively. Enzymatic
modification of the two Varieties of Acha grains enhances its functional and pasting
properties of Acha based foods.
Keywords: Starch, Enzymatic Modification, Functional and Pasting Properties.
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European Journal of Applied Sciences (EJAS) Vol. 11, Issue 3, June-2023
INTRODUCTION
Acha (Digitaria exilis Spp), also called “Fonio” and Hungry rice, is a tiny seeded c classified
amongst the millet’s cereal, native to West Africa, especially Nigeria. It is mostly eaten whole,
but can be processed into flour to become a multifaceted raw material, which can be used in
the preparation of beverages, breakfast meals, gruels and porridges. Acha is a rich source of
cysteine and methionine, which are beneficial to the health of humans but not readily available
in common cereals. Acha varieties majorly cultivated in West African countries (Nigeria
inclusive) are Digitaria exilis or and Digitaria iburu and yearly production is estimated at about
250,000 tonnes (Ukim et al., 2018). Acha is an underutilized crop which is extensively
cultivated in commercial quantities in some states in Nigeria (Wilma et al., 2018). The black
Acha (Digitaria iburua) has a nutritional composition of protein (8.75%), fat (4%), crude fiber
(1.03%), carbohydrate 76.91% while the white Acha (Digitaria exilis) has a composition of
protein (7.11%), fat (3%), crude fiber (0.79% and 79.72% carbohydrate (0.79%) (Idris et al.,
2015).
Starch serves as one of the life-sustaining chemical energy that is continuously reproduced by
the process of photosynthesis. The major sources of starch are plants which are located in the
granules of crops such as cereals, stems, roots and tubers (Zubair and Osundahunsi, 2016).
Starch can be characterized by the constituent of its granules i.e., size of the granules, shape and
ratios of amylose (15-30%) to amylopectin (70-85%) (Yadav and Majumder, 2017). Currently
30% of the world’s enzymes production is made up of enzymes that convert or modify starch
into malto-dextrin, glucose and fructose syrups or modified starches. As a result, carbohydrate
enzymes are crucial for several processes in the baking and food industries. Their
responsibilities include the manufacture of food raw materials, the improvement of quality
product and the advancement of efficient food processing (Sung et al., 2017). Specifically, the
aim of this study is to evaluate the effect of Enzymatic modification period on functional and
pasting properties starches from Acha (Digitaria exilis and Digitaria iburua).
MATERIALS AND METHODS
Two varieties of Acha grains (Digitaria exilis and Digitaria iburua) were purchased from Lupe
market, FCT Abuja, Nigeria. The enzyme (alpha-amylase) for modification was purchased from
Ojota chemical market in Lagos, Nigeria.
Starch Preparation
The method applied by (Salcedo-Mendoza et al., 2018) was used to determine alpha-amylase
activity. To modify the Acha starch, 500g of dry milled Acha grains was dissolved in 120ml of
water, then dosages of alpha -amylase enzymes (30g/L) was added to the Acha slurry and
incubated at different times (30, 45 and 60 minutes). The slurry was poured into a muslin cloth
placed over a bowl while the starch was rinsed out with water, after which the starch was
allowed to sediments for the period of 8 hours. After sedimentation the water was decanted
and the starch dried at 700C for 3 hours.
Determination of Functional Properties of Starch Samples
Functional properties (bulk density, water absorption capacity (WAC), oil absorption capacity
(OAC), solubility index and swelling power) were determined using method describe by Oladele
and Aina (2007).
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Olaleye, H. T., Oresanya, T. O., & Akinwande, F. F. (2023). Effect of Enzymatic Modification Period on Pasting Properties and Functional of Two
Varieties of Acha Starch (Digitaria Iburua and Digitaria Exilis). European Journal of Applied Sciences, Vol - 11(3). 805-811.
URL: http://dx.doi.org/10.14738/aivp.113.15077
Determination of Pasting Properties of Starch Samples
Pasting properties (peak, Trough, breakdown, peak time, final viscosity, setback and pasting
temperature) were determined using method describe by Sanni et.al. (2004).
STATISTICAL ANALYSIS
Data obtained were subjected to analysis of variance (ANOVA) Using SPSS version 21.0 and
differences significant means value were evaluated at P<0.05 probability level using Duncan’s.
RESULTS AND DISCUSSION
Functional Properties
The results of functional properties of starch obtained by enzymatic modification method of
Acha are presented in Table 2. Water absorption capacity (WAC) ranged from 1.93g/cm3 to
2.28g/cm3. Sample OGU (30 minutes enzyme modification starch of white Acha) had the lowest
value and FDE (45 minutes enzyme modified starch of black Acha) had the highest value. WAC
is the ability of a product to associate with water under a condition where water is limited
(Adepeju et al., 2014). The result shows a low water absorption capacity of the modified starch
and this is an indication that the starches will have a good water absorption capacity and also
that the black Acha with 45 minutes enzyme modification was better than the sample modified
at 30minutes. Oil absorption capacity is an important property in food formulation because fat
improves the flavor and mouth feel of food. The Oil absorption capacity ranged from 2.24g/cm3
to 2.46g/cm3. Sample FDE (45 minutes enzyme modified starch of black Acha) had the least
value and sample SHO (30 minutes enzyme modified starch of black Acha). The result of oil
absorption capacity obtained is high which is probably due to low level of protein in Acha
starch. Bulk density ranged from 46.53% to 67.13%. Sample OND (45 minutes enzyme modified
starch of white Acha) had the lowest value and FDE (45 minutes enzyme modified starch of
black Acha) had the highest value. Bulk density is a measurement of heaviness of solid sample
which is important in determining the type of packaging material required, material handling
and application in wet processing in the food industry (Ibikunle et al., 2019). The high bulk
density in these modified starches may be due to the activity of the alpha-amylase in the starch
granules and this indicates their suitability and stability for use in various food products.
Solubility index ranged from 1.00% to 1.50% sample OND (45 minutes enzyme modified starch
of white Acha) had the lowest value and SHO (30 minutes enzyme modification starch of black
Acha) had the highest value. The low solubility index of the modified Acha starches indicates
the ability of these starches to dissolve in water or an aqueous solution. The swelling power
ranged from 5.11g/cm3 to 5.53g/cm3. Sample MST (60 minutes enzyme modified starch of
white Acha) had the lowest value and FDE (45 minutes enzyme modified starch of black Acha)
had the highest value. The swelling ability of starch is important in many food applications as
it measures it ability to imbibe water (Aidio et al., 2022). The high swelling power of the
modified starches maybe due to amylose content of the Acha starch.
Pasting Properties
Results of the pasting properties of Acha starches obtained from enzymatic modification are
shown in Table 3. The peak viscosity of the enzymatic modified starch ranged from 3555.00RVU
to 3752.50RVU. Sample OGU (30 minutes enzyme modified starch of white Acha) had the
lowest value of peak viscosity and sample MST (60 minutes enzyme modified starch of white
Acha) had the highest value. This result may be attributed to the modification time of alpha-