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Agriculture and Food Sciences Research 
Vol. 12, No. 1, 19-24, 2025 

ISSN(E) 2411-6653/ ISSN(P) 2518-0193 
DOI: 10.20448/aesr.v12i1.6555 

© 2025 by the author; licensee Asian Online Journal Publishing Group 

 
 

 

 
 
 
Effect of extrusion process parameters on the overall acceptability of snacks 
produced from aerial yam and soybean flour mixture 

 
Umoh, Enobong Okon   

 

  
Department of Agricultural Engineering, Akwa Ibom State University, Ikot Akpaden, P.M.B., 1167, Uyo, 
Nigeria. 
Email: enoumoh40@gmail.com  

 
Abstract 

This study was conducted to evaluate the effect of extrusion cooking parameters on the overall 
acceptability of the snacks produced from aerial yam and soybean flour mixture. Design Expert 
(version 11.0.1) was used in the experimental design, with a three-factor experimental setup at five 
levels each. The aerial yam and soybean flour mixture was formulated in the ratio of 1:3 and 
extruded using a laboratory-scale single-screw extruder. Response Surface Methodology was 
adopted in analyzing the effect of the independent variables on the dependent variable. Results 
showed that the overall acceptability scores ranged from 4.20 to 7.10. Response surface analysis 
revealed that an increase in barrel temperature, screw speed, and feed moisture resulted in an 
increase in overall acceptability. The overall acceptability of the snacks was significantly (p < 0.05) 
affected by barrel temperature and feed moisture, while the screw speed had no significant (p > 0.05) 
effect on overall acceptability. The interaction of the extrusion cooking parameters had a significant 
(p < 0.05) effect on the overall acceptability of the snacks. The high range of scores recorded for the 
snacks indicates that the aerial yam and soybean composite flour extruded snacks were generally 
well accepted by the panelists. 

 
Keywords: Aerial yam flour, Extrusion cooking, Overall acceptability, Response surface, Single-screw extruder, Soybean flour, Snacks. 

 
Citation | Okon, U. E. (2025). Effect of extrusion process parameters 
on the overall acceptability of snacks produced from aerial yam and 
soybean flour mixture. Agriculture and Food Sciences Research, 12(1), 
19–24. 10.20448/aesr.v12i1.6555 
History:  
Received: 21 February 2025 
Revised: 24 March 2025 
Accepted: 28 March 2025 
Published: 4 April 2025 
Licensed: This work is licensed under a Creative Commons 

Attribution 4.0 License  
Publisher: Asian Online Journal Publishing Group 

Funding:  This study received no specific financial support.    
Institutional Review Board Statement: Not applicable. 
Transparency: The author confirms that the manuscript is an honest, accurate, 
and transparent account of the study; that no vital features of the study have 
been omitted; and that any discrepancies from the study as planned have been 
explained. This study followed all ethical practices during writing. 
Competing Interests: The author declares that there are no conflicts of 
interests regarding the publication of this paper. 

 

 

Contents 
1. Introduction ...................................................................................................................................................................................... 20 
2. Materials and Methods ................................................................................................................................................................... 20 
3. Results and Discussions .................................................................................................................................................................. 21 
4. Conclusion ......................................................................................................................................................................................... 23 
References .............................................................................................................................................................................................. 23 
 

 

 

 

 

 

 

 

mailto:enoumoh40@gmail.com
https://creativecommons.org/licenses/by/4.0/
https://creativecommons.org/licenses/by/4.0/
https://www.doi.org/10.20448/aesr.v12i1.6555
https://orcid.org/0000-0003-0970-3493


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Contribution of this paper to the literature 
This paper presents an empirical study on the effect of extrusion process parameters (barrel 
temperature, screw speed, feed moisture) on the acceptability of snacks derived from aerial yam 
and soybean flour mixtures. The study is relevant to food science and agricultural processing, 
particularly in formulating/developing new extruded food products. 

 
1. Introduction 

Mixing, shearing, heating, pumping, shaping, and sizing are just a few of the unit operations that are uniquely 
combined in the efficient, continuous extrusion process. A high-temperature-short-time (HTST) process called 
extrusion cooking technology is being used more and more in the food industry to create new cereal-based snacks, 
such as breakfast cereals, baby foods, high-dietary-fiber foods, and modified starch from cereals [1-5]. 

Extrusion cooking, like other methods of heating food, can affect nutritional content in both positive and negative 
ways. Benefits include minimizing lipid oxidation and contaminating microbes, increasing soluble dietary fibers, 
gelatinizing starch, destroying anti-nutritional elements, and preserving the food's natural colors and flavors. 
Notwithstanding these benefits, the process's drawbacks include the loss of heat-labile vitamins and the occurrence 
of the Maillard reaction, which lowers the protein's nutritional value. For an extruded product to be nutritionally 
balanced, production factors must be controlled [5, 6]. 

Establishing a trustworthy dataset that can tell processors, vendors, and customers about their preferences 
depends heavily on the sensory qualities of food [7]. According to Umoh et al. [8], sensory qualities that are 
perceptible to the human senses, such as appearance, flavor, texture, scent, taste, and general acceptability of foods, 
are commonly used to evaluate the quality of food. 

Kothakota et al. [9] investigated how the extrusion procedure affected the extrudates' overall acceptability. The 
extruded product, comprising broken rice flour, dehydrated pineapple waste pulp powder, and red grain powder, has 
an overall acceptance rating of 5.2 to 7.5, according to the investigations. The total acceptability value of the 
extrudates made from rice flour, red grain powder, and pineapple waste pulp powder was also found to rise 
quadratically as screw speed and barrel temperature increased, before falling linearly as these parameters decreased. 
As the feed moisture content rose, so did the total acceptance value, according to Kothakota et al. [9]. Upadhyay et 
al. [10] also observed similar findings. The barrel temperature and their interactions, screw speed, and feed moisture 
have been reported to have a significant effect on the overall acceptability of the extrudates [11]. 

A perennial, semi-wild food crop, the aerial yam (Dioscorea bulbifera) is a member of the Dioscoreaceae family of 
yams and grows on vines that ascend to poles and trees. After cooking, the hard back of the bulb is peeled off and 
consumed. Among its many common names are bitter yam, aerial yam, potato yam, air yam, and air potato. 
Originating in West Africa, Dioscorea bulbifera is a hardy climbing plant that is grown for its bulbils, which are eaten 
after being cooked like potatoes in oily water or roasted with a local sauce made of palm oil and additional spices 
[12]. 

Aerial tubers or bulbils are harvested by manual plucking from the vine. They are included in the roots and 
tubers, which are widely distributed throughout the tropics, with only a few in the temperate regions of the world 
[13]. 

There are roughly 50–60 species of yams (Dioscorea spp.) in Nigeria, but only 5–6 of them are significant food 
crops. Regrettably, some of these food crops, like Dioscorea bulbifera, have been underutilized for their nutritional 
value [12, 14, 15]. 
     Soybeans are cultivated mainly for their seeds, which are used to produce oil and as food for humans and animals. 
In the food industry, soy food sources are probably the ones that are developing the fastest. Products range from 
traditional soy food assortments to protein trimmings, dairy and meat substitutes, and various Western and 
traditional food assortments that have advanced with soybean flour and its components [16, 17] 

Soybeans are nutrient-dense and have a distinct chemical makeup on an average dry matter basis; they have the 
highest protein concentration of any legume, with roughly 40% protein and 20% oil [16]. Soybeans have high levels 
of both quantity and quality in their protein and oil components. Because soy oil has a high percentage of unsaturated 
fatty acids, including linolenic and linoleic acids, it is considered a healthy oil. Furthermore, soybeans contain a 
variety of trace chemicals called phytochemicals that have been demonstrated to have special health advantages. The 
greatest amount of protein obtained comes from soy meals because of their high protein content and high protein 
utilization [15, 16]. 

Additionally, the use of aerial yam (Dioscorea bulbifera) in conjunction with known food processing techniques, 
such as extrusion cooking, would introduce new food processing technology and food products, providing consumers 
with variety [15]. The potential application of aerial yam and soybean blending and/or extrusion cooking of the 
blend in food product formulation has not been sufficiently studied [18]. 

This study aims to evaluate the impact of extrusion cooking on the overall acceptability of snacks produced from 
aerial yam and soybean composite flour, using response surface analysis. 
 

2. Materials and Methods 
2.1. Procurement of Soybean Seeds and Aerial Yam Bulbs 
The aerial yam bulbs and soybean seeds were acquired from the Uyo Urban Market in the Uyo Local Government 
Area of Akwa Ibom State, Nigeria. 
 

2.2. Sample Preparation 
In this study, flour samples were made at the Department of Agricultural Engineering's Crop Processing 

Laboratory at Akwa Ibom State University, Ikot Akpaden, Akwa Ibom State, Nigeria. 
 
 
 



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2.3. Preparation of Aerial Yam Flour  
In accordance with the procedure outlined by Umoh et al. [12], aerial yam flour was made by cleaning and 

sorting the bulbs to remove any unwanted materials, then peeling them with a knife, washing them with clean water, 
and cutting them into chips that were 10 mm thick. The chips were then dried in a laboratory oven set at 60°C for 
12 hours, after which they were milled using an Italian-made MF120 Hammer mill and sieved through a laboratory 
sieve with an aperture size of 600 µm. The flour that was produced was then sealed in a polyethylene bag for later 
use. 
 

2.4. Preparation of Soybean Flour  
The process outlined by Umoh and Ekanem [5] was used to prepare the soybean flour. After screening the seeds 

to remove splits, foreign materials, and damaged beans, they were cleaned and roll-boiled at 100°C for 30 minutes, 
oven-dried at 70°C for 12 hours, and then ground in a disc attrition mill. The milled full-fat soybean was then sieved 
using a 100-mesh standard sieve, and the flour was sealed in an airtight polyethylene bag at room temperature for 
later use. 
 

2.5. Preparation of Flour Mixture Sample  
Aerial yam and soybean flour mixture was made in a 1:3 ratio, which consists of 25% aerial yam flour and 75% 

soybean flour. 
 

2.6. Preparation of the Extruded Snacks  
A laboratory-scale single-screw extruder was used for this purpose. Two hundred grams (200 g) of the composite 

flour sample were precisely measured, preconditioned to the appropriate moisture levels, and left for approximately 
two minutes (2 min) to ensure uniform hydration of the raw material. The extruder was turned on, and the barrel 
temperatures and screw speeds were adjusted accordingly. The raw material was fed into the extruder through the 
hopper, and the extruded snacks were collected as they came out of the die, oven-dried, and then placed in airtight 
zip-lock polyethylene bags for further laboratory analysis [5]. 
 

2.7. Determination of Overall Acceptability  
The overall acceptability (sensory quality attribute) of the aerial yam and soybean composite flour extruded 

snacks was determined using a 9-point Hedonic scale ranging from 1 (extremely dislike), 5 (neither like nor dislike), 
to 9 (extremely liked) [15]. A ten-member semi-trained panel evaluated the samples and accordingly scored the 
overall acceptability of the snacks. 
 

2.8. Experimental Design/Statistical Analysis  
The experimental design was created using Design Expert (version 11.0.1). Barrel temperature (BT), screw speed 

(SS), and feed moisture levels (FM) were chosen as the independent factors in a three-factor experiment that had five 
levels each. The impact of the independent variables or factors on the dependent variable (the response) was examined 
using Response Surface Methodology (RSM). 
 

3. Results and Discussions 
The results of the overall acceptability of snacks produced from aerial yam and soybean flour mixture are 

presented in Table 1. 
 
Table 1. Overall acceptability of aerial yam and soybean composite flour snacks. 

S/N BT (OC) SS (rpm) FM (%) Overall acceptability 

1 105 115 31 5.51 ± 0.011 
2 105 115 35 6.43 ± 0.031 
3 105 115 35 6.39 ± 0.031 
4 105 85 35 5.76 ± 0.111 
5 100 130 33 6.42 ± 0.008 
6 110 100 37 7.10 ± 0.006 
7 100 100 37 6.00 ± 0.021 
8 110 130 33 5.45 ± 0.008 
9 105 115 35 6.45 ± 0.031 
10 115 115 35 5.60 ± 0.001 
11 95 115 35 4.89 ± 0.021 
12 105 115 39 6.17 ± 0.043 
13 105 115 35 6.47 ± 0.031 
14 100 100 33 4.20 ± 0.002 
15 110 130 37 5.13 ± 0.002 
16 110 100 33 5.98 ± 0.021 
17 105 145 35 4.99 ± 0.006 
18 100 130 37 6.11 ± 0.011 
19 105 115 35 6.41 ± 0.031 
20 105 115 35 6.44 ± 0.031 

Note: Values are mean ± standard deviation of triplicate determination. BT = Barrel temperature, SS = Screw speed, FM = Feed moisture. 

 
Table 1 depicts the overall acceptability results of the snacks made with a composite flour of aerial yam and 

soybean. According to the recorded ratings, the snacks' overall acceptability ranged from 4.20 to 7.10. This range of 
values is lower than 7.22 to 8.33 for pulse-based snacks [11] but higher than 4.00 to 6.44 previously reported for 
sorghum-based extrudates supplemented with defatted soy meal flour by Tadesse et al. [19]. 



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However, the range of values for overall acceptability for the extruded snacks made from aerial yam and soybean 
composite flour falls between 5.2 and 7.5 for rice flour-pineapple waste pulp powder-red grain powder extrudates 
those previously reported by Kothakota et al. [9] and those reported to be 5.94 to 7.02 for selected aerial yam 
cultivars and African breadfruit extruded snacks by Olatoye and Arueya [20].  

The snacks produced at 100°C barrel temperature, 100 rpm screw speed, and 33% feed moisture had the lowest 
overall acceptability score of 4.20, while the snacks made at 110°C barrel temperature, 100 rpm screw speed, and 
37% feed moisture yielded the highest score (7.10). The wide range of scores recorded for the snacks indicates that 
the extruded aerial yam and soybean composite flour was generally well accepted by the panelists. 
 

3.1. Effect of Extrusion Process on Overall Acceptability 
The response surface plot displayed in Figures 1 through 3 illustrates how the extrusion process factors (barrel 
temperature, screw speed, and feed moisture) affect the overall acceptability of the aerial yam and soybean composite 
flour extruded snacks. 

 

 
Figure 1. Response surface plot showing the impact of barrel 
temperature and screw speed on overall acceptability. 

 

 
Figure 2. Response surface plot showing the impact of barrel 
temperature and feed moisture on overall acceptability. 

 



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Figure 3. Response surface plot showing the impact of screw speed and feed 
moisture on overall acceptability. 

 
The overall acceptance score of the snacks increased when both the barrel temperature and the extruder's screw 

speed increased, according to the response surface plot for the effects of both variables on the extrudates' overall 
acceptability in Figure1. The findings of Kothakota et al. [9] are comparable to this discovery. 

The response surface plot for the impact of feed moisture and barrel temperature on the snacks' overall 
acceptability score is displayed in Figure 2. The overall acceptability increased when the extruder's barrel 
temperature was raised. In the meantime, the overall acceptability of the snacks increased in tandem with an increase 
in feed moisture. This claim supports the earlier report of Kothakota et al. [9]. 

Consistent with the findings of Kothakota et al. [9] the response surface plot on the effect of screw speed and 
feed moisture on overall acceptability in Figure 3 showed that an increase in both factors led to a corresponding 
increase in the overall acceptability of the snacks. 
 
Table 2. Analysis of variance for overall acceptability at a 5% significance level. 

Source Sum of squares df Mean square F-value p-value 

Barrel temp 2.472 3 0.824 1.609 0.0255 
Screw speed 1.975 3 0.658 1.285 0.338 
Feed moisture 1.398 3 0.466 0.910 0.0474 
Error 4.611 9 0.512   
Total 704.359 20    
Corrected total 9.339 19    

 

Barrel temperature, screw speed, and feed moisture all had p-values of 0.0255, 0.338, and 0.0474, respectively, 
according to an analysis of variance (ANOVA) at the 5% significance level (Table 2). This suggests that screw speed 
had an insignificant (p > 0.05) impact on the snacks' overall acceptability, whereas barrel temperature and feed 
moisture had a significant (p < 0.05) impact. The overall acceptability of the snacks was shown to be significantly (p 
< 0.05) impacted by the extrusion process parameters and their interactions, according to the "test of between-
subjects effects" of the parameters. 

 
4. Conclusion 

This study has demonstrated that the extrusion process parameters—barrel temperature, screw speed, and feed 
moisture—as well as how they interact, affect the snacks' quality features in both positive and negative ways. The 
overall acceptability of the aerial yam and soybean composite flour extruded snacks increased as a result of increases 
in barrel temperature, screw speed, and feed moisture. While screw speed had no discernible impact on overall 
acceptance, barrel temperature and feed moisture had a considerable impact on the snacks' overall appeal. The overall 
acceptance of the snacks was significantly impacted by the interactions of the extrusion parameters. 
 

References 
[1] L. Sebio and Y. Chang, "Effects of selected process parameters in extrusion of yam flour (Dioscorea rotundata) on physicochemical 

properties of the extrudates," Food/Nahrung, vol. 44, no. 2, pp. 96-101, 2000.  https://doi.org/10.1002/(sici)1521-
3803(20000301)44:2<96::aid-food96>3.0.co;2-9 

[2] I. Pardeshi and P. Chattopadhyay, "Whirling bed hot air puffing kinetics of rice-soy ready-to-eat (RTE) snacks," Journal of Ready to 
Eat Food, vol. 1, no. 1, pp. 01-10, 2014.  

[3] S. Pawar, I. Pardeshi, P. Borkar, and M. Rajput, "Optimization of process parameters of microwave puffed sorghum based ready-to-
eat (RTE) food," Journal of Ready to Eat Foods, vol. 1, no. 2, pp. 59-68, 2014.  

[4] S. Navale, S. B. Swami, and N. Thakor, "Extrusion cooking technology for foods: A review," Journal of Ready to Eat Food, vol. 2, no. 
3, pp. 66-80, 2015.  

https://doi.org/10.1002/(sici)1521-3803(20000301)44:2
https://doi.org/10.1002/(sici)1521-3803(20000301)44:2


Agriculture and Food Sciences Research, 2025, 12(1): 19-24 

24 
© 2025 by the author; licensee Asian Online Journal Publishing Group 

 

 

[5] E. O. Umoh and M. C. Ekanem, "Effects of barrel temperature, screw speed and moisture content on the organoleptic properties of 
aerial yam and soybean flour extruded snacks," African Journal of Agricultural Science and Food Research, vol. 16, no. 1, pp. 51-67, 2024.  
https://doi.org/10.62154/ajasfr.2024.016.010409 

[6] N. Nikmaram, M. H. Kamani, and R. Ghalavand, "The effects of extrusion cooking on antinutritional factors, chemical propertiesand 
contaminating microorganisms of food," International Journal of Farming and Allied Sciences, vol. 4, no. 4, pp. 352-354, 2015.  

[7] B. E. Edet, P. J. Etim, A. U. Udo, I. E. Ekop, and E. O. Umoh, "Sensory evaluation of croaker fish exposed to solar and traditional 
drying methods," AKSU Journal of Agriculture and Food Sciences, vol. 8, no. 3, pp. 63-70, 2024.  
https://doi.org/10.22392/actaquatr.1560683 

[8] E. O. Umoh, M. O. Iwe, and P. C. Ojimelukwe, "Optimization and validation of extrusion process parameters for the sensory 
characteristics of extruded aerial Yam and Soybean flour blends," Asian Journal of Science and Applied Technology, vol. 13, no. 2, pp. 
14-24, 2024.  https://doi.org/10.70112/ajsat-2024.13.2.4246 

[9] A. Kothakota, N. Jindal, and B. Thimmaiah, "A study on evaluation and characterization of extruded product by using various by-
products," African Journal of Food Science, vol. 7, no. 12, pp. 485-497, 2013.  https://doi.org/10.5897/ajfs2013.1065 

[10] A. Upadhyay, H. K. Sharma, and B. C. Sarkar, "Characterization of dehydration kinetics of carrot pomace," Agricultural Engineering 
International: CIGR Journal, 2008.  

[11] H. Alemayehu, S. A. Emire, and C. Henry, "Effects of extrusion process parameters on the quality properties of ready-to-eat pulse-
based snacks," Cogent Food & Agriculture, vol. 5, no. 1, p. 1641903, 2019.  https://doi.org/10.1080/23311932.2019.1641903 

[12] E. O. Umoh, M. O. Iwe, and P. Ojimelukwe, "Optimization of Extrusion process parameters for the Anti-nutritional composition of 
Aerial Yam (Dioscorea bulbifera)-Soybean (Glycine max) flour Blends using Response surface Methodology," International Journal 
of Food Science and Nutrition, vol. 6, no. 6, pp. 62-69, 2021.   

[13] E. Umoh, "Evaluation of proximate composition, functional properties and Antinutritional factors of aerial yam-soybean flour," 
Evaluation, vol. 5, no. 1, pp. 70-74, 2020.  

[14] M. Ogbuagu, "Nutritive and antinutritive composition of the wild (in-edible) species of Dioscorea bulbifera (Potato Yam) and 
Dioscorea dumentorum (Bitter Yam)," Journal of Food Technology, vol. 6, no. 5, pp. 224-226, 2008.  

[15] E. O. Umoh and K. S. Abasiekong, "Production and quality evaluation of pasta from aerial yam and soybean flours blend using single-
screw extruder," Research Journal of Food Science and Quality Control, vol. 2756, p. 5483, 2024.  
https://doi.org/10.56201/rjfsqc.v10.no4.2024.pg24.41 

[16] M. O. Iwe, The science and technology of soybean: Chemistry, nutrition, processing, utilization. Enugu, Nigeria: Rojoint Communication 
Services Ltd, 2003. 

[17] E. O. Umoh and M. O. Iwe, "Influence of extrusion process conditions on bulk density, water absorption capacity and oil absorption 
capacity of extruded Aerial yam-Soybean flour mixture," African Journal of Food Science, vol. 17, no. 6, pp. 111-121, 2023.  

[18] E. O. Umoh and M. O. Iwe, "Effects of extrusion processing on the proximate composition of aerial yam (Dioscorea bulbifera)-
soybean (Glycine max) flour blends using response surface methodology," Journal of Food Research, vol. 1, no. 1, pp. 38-52, 2022.  
https://doi.org/10.5539/jfr.v11n1p38 

[19] S. A. Tadesse, G. Bultosa, and S. Abera, "Functional and physical properties of sorghum-based extruded product supplemented with 
soy meal flour," Cogent Food & Agriculture, vol. 5, no. 1, p. 1707608, 2019.  https://doi.org/10.1080/23311932.2019.1653617 

[20] K. Olatoye and G. Arueya, "Chemical and sensory characteristics of extruded snack from selected Aerial Yam (D ioscorea Bulbifera) 
Cultivar and African Breadfruit (Treculia Africana) seed," Journal of Culinary Science & Technology, vol. 21, no. 3, pp. 449-465, 2023.  
https://doi.org/10.1080/15428052.2021.1955795 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  

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https://doi.org/10.62154/ajasfr.2024.016.010409
https://doi.org/10.22392/actaquatr.1560683
https://doi.org/10.70112/ajsat-2024.13.2.4246
https://doi.org/10.5897/ajfs2013.1065
https://doi.org/10.1080/23311932.2019.1641903
https://doi.org/10.56201/rjfsqc.v10.no4.2024.pg24.41
https://doi.org/10.5539/jfr.v11n1p38
https://doi.org/10.1080/23311932.2019.1653617
https://doi.org/10.1080/15428052.2021.1955795

