Chemical composition and organoleptic properties of Cocoyam starch-wheat flour blend noodles

Noodles are strips or strands cut from a sheet of dough made from fl our, water and either common salt or a mixture of alkaline salt. Noodles consumption represents about 40% of the total wheat fl our which are mainly consumed by school children. The use of composite fl our has been encouraged since it reduces the importation of wheat. Utilization of locally available, inexpensive materials like cocoyam that can substitute a part of wheat fl our without adversely affecting the acceptability of the product will be a product development. This study therefore studied the chemical composition and organoleptic properties of instant noodles from the blend of wheat and cocoyam starch. Cocoyam starch was substituted into wheat fl our at 20, 40, 60 & 80%. Analysis revealed higher carbohydrate (63.50-70.05)%, moisture (4.54-5.07)% and vitamin A (10.01-30.47) mg/100g, B1 (11.43-32.15) mg/100g but lower protein (4.56-8.79)%, phosphorus (0.34-0.52)%, calcium (1.83-0.98)%, iron (0.15-0.32) % and ash (1.19-3.20)%. The composite noodles revealed higher carbohydrate and mineral but lower protein than the commercial noodles. The sensory analysis revealed that 20% cocoyam compared favourably with the commercial noodles in terms of all the sensory attributes evaluated. This shows the possibility of producing noodles from cocoyam tubers which serves as novel food. This will further help to promote and improve utilization of cocoyam tuber. Research Article Chemical composition and organoleptic properties of Cocoyam starch-wheat fl our blend noodles Adedeji Temileye Omotayo* Department of Food Science and Technology, Osun State Polytechnic, Iree, Nigeria How to cite this article: Adedeji TO. Chemical composition and organoleptic properties of Cocoyam starch-wheat fl our blend noodles. Arch Food Nutr Sci. 2017; 1: 058-062. https://doi.org/10.29328/journal.afns.1001009 Introduction Wheat is a good source of vitamin B1 (thiamine), B2 (ribo lavin), niacin, B6 (tyrodixine), E (Tocopherol) as well as iron and zinc [1]. Most of these nutrients are concentrated in the outer layers of the wheat grains and a signi icant proportion is lost during the process of milling [2]. It is for this reason that some countries like Thailand have instituted the forti ication of noodles with essential micro-nutrients such as iron, iodine, vitamin A, etc. [3]. Wheat noodles can be forti ied with nutrients from cheap plant foods such as cocoyam (Colocosia esculenta). Cocoyam tubers (Colocasia esculenta ) are grown in the tropics and sub-tropical regions of the world particularly in Africa for human consumption, animal feed and cash income for both farmers and traders [4,5]. Cocoyam is vegetatively propagated using the corms and to a lesser extent the cormels. As food for human consumption, the nutritional value of the various parts of cocoyam is primarily caloric [6]. The underground cormel provide easily digested starch and the leaves are nutritious spinach-like vegetable, which give a lot of minerals, vitamins particularly thiamine [7]. In Nigeria, cocoyam is regarded as a major crop especially in female headed households. Nigeria is one of the largest producers of cocoyam in the world contributing about 40% of total annual production [8]. The annual production is estimated at 1.5 million tonnes valued at about 600,000,000 Naira [4,5]. Cocoyam grows in association with other food and tree crops, a system mostly practiced by subsistence farmers in Nigeria. The bulk of the production of cocoyam is in south east of Nigeria [9]. Nwabuzor also noted that, cocoyam can be consumed in various forms when boiled, fried, pounded or roasted [8]. It can also be processed into chips which have a long *Address for Correspondence: Adedeji Temileye Omotayo, Department of Food Science and Technology, Osun State Polytechnic, P.M.B. 301, Iree, Nigeria, Tel: 08066514332; Email: temileyeadedeji2@gmail.com Submitted: 23 October 2017 Approved: 10 November 2017 Published: 13 November 2017 Copyright: 2017 Adedeji TO. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Introduction
Wheat is a good source of vitamin B1 (thiamine), B2 (ribo lavin), niacin, B6 (tyrodixine), E (Tocopherol) as well as iron and zinc [1]. Most of these nutrients are concentrated in the outer layers of the wheat grains and a signi icant proportion is lost during the process of milling [2]. It is for this reason that some countries like Thailand have instituted the forti ication of noodles with essential micro-nutrients such as iron, iodine, vitamin A, etc. [3]. Wheat noodles can be forti ied with nutrients from cheap plant foods such as cocoyam (Colocosia esculenta). Cocoyam tubers (Colocasia esculenta ) are grown in the tropics and sub-tropical regions of the world particularly in Africa for human consumption, animal feed and cash income for both farmers and traders [4,5]. Cocoyam is vegetatively propagated using the corms and to a lesser extent the cormels. As food for human consumption, the nutritional value of the various parts of cocoyam is primarily caloric [6]. The underground cormel provide easily digested starch and the leaves are nutritious spinach-like vegetable, which give a lot of minerals, vitamins particularly thiamine [7].
In Nigeria, cocoyam is regarded as a major crop especially in female headed households. Nigeria is one of the largest producers of cocoyam in the world contributing about 40% of total annual production [8]. The annual production is estimated at 1.5 million tonnes valued at about 600,000,000 Naira [4,5]. Cocoyam grows in association with other food and tree crops, a system mostly practiced by subsistence farmers in Nigeria. The bulk of the production of cocoyam is in south east of Nigeria [9]. Nwabuzor also noted that, cocoyam can be consumed in various forms when boiled, fried, pounded or roasted [8]. It can also be processed into chips which have a long shelf life and provides food all year round especially during lean planting season [10]. Cocoyam leaves are also used as vegetable for preparing soup in various parts of the world. There has been a decline in the yields of cocoyam in the past few years and this has been attributed to factors such as climate variation, drought, poor cultural practices among cocoyam growers, pest and disease infestations [11].
Noodles are strips or strands cut from a sheet of dough made from lour, water and either common salt or a mixture of alkaline salt. Noodles consumption represents about 40% of the total wheat lour consumption in East and South East Asia [12]. Noodles are mainly consumed by school children. The use of composite lour has been encouraged since it reduces the importation of wheat. Utilization of locally available, inexpensive materials like cocoyam that can substitute a part of wheat lour without adversely affecting the acceptability of the product will be a product development. This will increase the overall nutrients, encourage agricultural sector, increase noodle variety, reduce dependence on wheat lour for the production of noodles at lower cost of production. The objective of this study was therefore to produce an acceptable instant noodle from a blend of cocoyam starch and wheat lour.

Materials
Cocoyam tubers, wheat lour and commercial noodles were procured from Igbona market in Osogbo, Osun State of Nigeria.

Extraction of cocoyam starch:
The cocoyam tubers were washed and diced into cubes into clean bucket of water prior to milling. Wet milling of the cubed tubers was carried out and a little amount of water was added to the slurry and sieved using a muslin cloth. It was then allowed to settle for 4 h. The supernatant water was decanted and the starch was placed in foiled aluminium trays and oven dried at 70 0 C for 6 h. The dried starch was them milled to a powdery form, sieved to pass through a 120μmm mesh and packaged in an airtight container (Table1).

Production of instant noodles:
The cocoyam starch at the rate of 20, 40, 60 & 80% was blended with the wheat lour on replacement basis in a food mixer, warm water (40 o C) and 5% CMC were added to form a stiff dough. The dough was allowed to rest for 20mins. Then kneaded with a rolling pin and manually sheeted to about 2 mm thickness. The sheets were extruded using a cold extruder (Eurosonic, Globe 150) model. This was subsequently cut with a pastry cutter into 10 cm strips, put in cleaned aluminium tray. The resulted noodles were dried at 60°C for 3 h and allowed to cool. The process lowchart is shown below in igure 1.

Analysis
Chemical analysis: The noodles from the wheat lour, cocoyam blends and the commercial instant noodles were subjected to proximate and mineral analysis using AOAC method [13]. Carbohydrates were calculated by difference. Minerals like calcium (Ca), magnesium (Mg), iron (Fe) and sodium (Na) contents were determined from their ashes by atomic bsorption spectrophotometry using a Perkin Elmer 300AA spectrophotometer (Perkin Elmet USA). Phosphorus (Ph) content was determined using Vanadomolybdate method [14]. All analyses were determined in triplicates.

Sensory evaluation
A panel of twenty tasters comprising of staff and students of the Department of Food Science and Technology, Osun State Polytechnic, Iree were used to evaluate the sensory properties of the cocoyam starch-wheat lour blends and commercial noodles. The panellists were selected based on their familiarity with sensory qualities of noodles and were served in Sensory Laboratory at room temperature (30±2°C). A nine-point hedonic scale was used to evaluate appearance, taste, crunchiness and overall acceptability of the noodles, where 1 and 9 represents dislike extremely and like extremely, respectively according to Iwe method [15]. Water was provided to rinse the mouth between evaluations.

Statistical analysis
All analysis was done in triplicate. Results were expressed in means±standard deviation.

Results and Discussion
The chemical composition of cocoyam starch-wheat fl our blend noodles Table 2 shows the result of the chemical composition of commercial noodles and those of the blends of wheat lour (wf) and cocoyam starch (cs). Analysis revealed higher carbohydrate (63.50-70.05)%, moisture (4.54-5.07)% and vitamin A (10.01-30.47) mg/100g, B1 (11.43-32.15) mg/100g but lower protein (4.56-8.79)%, phosphorus (0.34-0.52)%, calcium (1.83-0.98)%, iron (0.15-0.32) % and ash (1.19-3.20)%. The level of carbohydrates and vitamin A and B1 in the wf /cs noodles increased with the increase in proportion of cocoyam starch in the blend. This was in agreement with literature report on high contents of starch, beta-carotene and thiamine in cocoyam [16,17]. The control sample had highest sensory scores than all other samples. This may be due to the addition of other constituents of the commercial noodles like emulsi ier and stablilizers added to it. Sanni et al. [18], also reported similar results for noodles produced from cassava/wheat lour.

Sensory properties of cocoyam starch-wheat fl our blend noodles
The mean sensory scores of cocoyam starch-wheat lour blends and commercial noodles are presented in table 3, the mean sensory scores of the composite blends noodles for all the attributes decreased with an increase in the level of cocoyam lour in the blend with the commercial noodles (100% wheat lour) being the most preferred by the panelists. The blend containing 80% cocoyam starch was not acceptable at all to the panelist. However, the noodles containing 20% cocoyam starch compared favorably with the commercial noodles in terms of all the sensory attributes evaluated.

Conclusion
The combination of wheat lour and cocoyam starch in making noodles resulted in a product with improved nutrients composition and the wheat lour/ cocoyam starch blend at a ratio of 80:20 was the most acceptable among the blends. This implies that wheat lour could be supplemented with cocoyam starch. The production and the consumption of the cocoyam starch-wheat lour blend noodles should be encouraged to increase the calorie intake in the diet, noodles varieties, boost its nutritional content and improve the utilization of cocoyam tubers especially for children who are the major consumers of noodles.