Effects of addition of partially defatted groundnut paste on some Properties of kokoro (a popular snack made from maize paste).

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1 AGRICULTURE AND BIOLOGY JOURNAL OF NORTH AMERICA ISSN Print: , ISSN Online: , doi: /abjna , ScienceHuβ, Effects of addition of partially defatted groundnut paste on some Properties of kokoro (a popular snack made from maize paste). Otunola, E.T., Sunny-Roberts, E. O, Adejuyitan, J.A* and Famakinwa, A.O Department of Food Science and Engineering, Ladoke Akintola University, Ogbomoso, Nigeria ABSTRACT Kokoro a popular Nigerian snack obtained from maize has nutritional deficiencies, especially in terms of protein and amino acid contents. In this study therefore, it was enriched with partially defatted peanut paste by partially substituting the maize with the groundnut paste in varying proportions ranging from ten to fourty percent paste. The various mixtures obtained were separately processed into snacks following essentially the traditional method of production, involving thorough mixing, dough formation and deep frying in vegetable oil. The products obtained were analysed for proximate composition, some physico-chemical properties and pasting characteristics. The sensory attributes were also evaluated. Results obtained indicated substantial increases in the level of protein with increases in the level of substitution with peanut paste, ranging respectively from to 23.77% in the zero and 40% levels of substitution with peanut paste. This may be an indication of the potentials of the peanut paste in improving the nutritional status of the snack. While similar trends were observed with respect to the fat contents, the levels of ash, crude fibre and carbohydrate showed a reverse trend. The swelling capacity of the resulting flour mixtures before frying decreased in value with increases in the level of substitution, but increases, although only slightly in the values of water absorption capacity respectively. Slight increases were also recorded with respect to the generally low values of bulk density, an indication of a possible positive impact on the ease of packaging and transportation of products. There were no significant changes in the pasting properties of the resulting flour mixes regardless of the level of substitution. Sensory evaluation of the products obtained indicated that the greater the level of substitution with the defatted peanut paste in the mixture, the more acceptable the product is to consumers. Keywords: Maize, peanut, snacks, nutrition, Nigeria INTRODUCTION In recent times, it is becoming increasingly necessary to produce highly acceptable snack foods with high nutritional quality that are yet affordable by potential consumers. This is due to a number of factors; including the fact that many people now work in places relatively far from their homes and can ill afford to spare time to prepare regular meals and hence depend on ready to eat snacks. More over most school children depend, to a large extent on such foods as they can hardly wait for breakfast before leaving for schools early in the morning. Furthermore such foods, especially when appropriately enriched, could also be useful in nutritional programmes aimed at combating malnutrition and nutrient deficiencies (Rosa et al, 2003). Cereal grains are predominantly used for the production of different snack foods some of which may be eaten mainly to prevent hunger before main meals or just as relishes. Some of those traditionally used for such purposes at the moment include breakfast cereals such as corn flakes, breads, as well as alcoholic and non-alcoholic beverages. It is widely known that most of these snack foods do not provide nutrients in adequate quantities needed by the body (Omueti and Morton, 1996) because they are deficient in some essential amino acids especially lysine. Such deficiencies may be due to their composition, or in many instances due to losses during processing. What ever may be responsible for their poor nutritional status, the need arises to ensure that every food consumed by any individual contains appropriate nutrients in adequate amounts. Maize is predominantly starch ( 60-75%), in the form of amylase and amylopectin. The protein content of maize is very low constituting only about

2 9-12% when compared with other grains. They are however known to be rich in methionine, cystine and some sulphur containing amino acids (Bedolla et al, 1982). Such amino acids that are lacking can be supplied to the food by complimenting the maize with legumes such as peanuts, which are better sources of the sulphur amino acids (Okaka, 2005; Uzor- Peters et al, 2008). There is usually improved balance of amino acids in the products made from such combinations (Ameida-Dominguez et al., 1990). Several other studies have been carried out to improve the protein quality of maize products by fortification with plant proteins such as soy bean and groundnuts (Plahar and Leung, 1983; Adelakun et al, 2005; Uzor-Peters et al, 2008). Kokoro is a popular local snack made from maize flour. It is therefore a predominantly carbohydrate food lacking in some essential nutrients. The technology of kokro production is largely traditional, involving mixing maize flour with boiled water to form a paste and seasoning with salt and sugar. The dough is kneaded and cut into shapes. The pieces are then deep-fried in vegetable oil for 5 min to produce a golden-yellow, hard, textured, lowmoisture product (Adelakun et al, 2005). Kokoro is consumed during the day, alone or with roasted groundnuts, and washed down with soft drinks or just water by the people of South Western Nigeria. It is made as a product that is consumed on such a wide scale it would be important to enhance its nutritional value. Addition of vegetable protein such as textured vegetable protein could be one way of raising the nutritional value of the product by introducing more protein into it (Rosa et al, 2003; Uzor-Peters et al 2008). The possibility of producing acceptable Kokoro, with better nutritional content and sensory quality from maize flour mixed with defatted peanuts flour was therefore investigated. This was hoped, will increase the nutritional content of the snack as well as increase the use to which the defatted products (peanuts cakes) can be put to, in addition to their use as animal feed. MATERIALS AND METHOD Materials: The maize (Zea mays indeturata) grains, peanuts, vegetable oil, salt and sugar were purchased from a local market in Ogbomoso, Nigeria Methods Preparation of maize dough: Dried white maize was cleaned, winnowed, rinsed with water and then decorticated in a decorticating machine. The shaft was blown away and the decorticated maize milled in a milling machine to produce the maize four. This maize flour was then boiled and allowed to form a paste (Fig. 1). Production of partially defatted groundnut paste: This was done using a mechanical screw press. The groundnut was roasted in an oven at C for 1 hour. It was dehulled and allowed to cool. It was later crushed using mortal and pestle It was afterwards placed inside the cabinet drier at C. The crushed groundnut was placed inside a muslin cloth and attached to the screw press and the oil was squeezed out. The resulting pressed cakes was crushed again using mortal and pestle and then it was sieved using 750cm mesh screen. The flour was then packed into a polyethylene bag. Preparation of Kokoro : This was done essentially by a modification of the traditional method of kokoro preparation (Table 1). In each case the blends of the maize flour and defatted groundnut pastes were mixed. Salt and sugar were added to the mixture. 100ml of water was boiled and the mixtures were poured and mixed to form a dough in each case. The dough was then kneaded and cut out into pieces and the pieces were rolled into a ring shape on a chopping board. The rolled out pieces were then fried in a large quantity of hot refined vegetable oil, for 5 minutes using a deep fat metal colander for all round frying. The fried pieces were drained and left to cool and then transferred into a basket lined with paper. They were then packed in polyethylene bags and sealed. Determination of Proximate composition of kokoro: Determination of protein content, ash content, moisture content, fibre and fat content were carried out according to AOAC (1990) and carbohydrate content was determined by difference A.O.A.C (1990). 281

3 Maize (cleaned, winnowed) Rinse with water Decortication Milling Flour (Addition of defatted groundnut flour, sugar, salt) Boiling Dough Kneading Cutting and rolling Frying Drain Cooling Packaging Kokoro Fig 1: Flow diagram for the production of Kokoro Table 1: Formulation for kokoro samples. Sample code Ingredients Maize flour (g) Peanut paste (g) % peanut paste Vegetable oil (ml) Salt (g) Sugar (g) A B C D E Determination of Some Functional properties of supernatant decanted. The residue left was air the maize flour/peanut paste mixes: Water divided and weighed. absorption capacity was determined by modifying the Bulk density was determined using the method of method of Elkhalifa et al, (2005). 15g of the samples Akpapunam and Markakis, (1981). 20g of flour was was weighed accurately and water was added. It was poured into 100ml measuring cylinder and tapping then centrifuged at 3,250rpm for 25minuts and the 282

4 the flour stopped setting after 2 minutes. The volume of the flour was then measured. Swelling capacity was determined by using the method of Alfonso et al, (1998). This is difference between the volume before and after soaking the flour sample for 18 hour. The pasting viscosity was determined by using Rapid Visco-Analyzer, (model 3D (RVA) Newport Scientific pty. Ltd Narrabeen, Australia). A suspension of 3g (14% mb) sample in 25g of accurately weighted distilled water under well controlled heating and cooling cycle hinder constant shear where it was held at 50 0 C at 6 0 C/min and held at 50 0 C for 5minute. The pasting parameters of time from onset of pasting to peak-viscosity (Ptime); temperature at which viscosity (CPV); the setback ration and breakdown was all recorded Harold and Lilia, (1997). Microbiological Analysis of kokoro: The procedure described by Collins et al (1989) was used to evaluate the microbiological characteristics of the samples. Ten (10) grams of sample will be added to 100ml of distilled water and mixed thoroughly using Stuart Scientific auto vortex mixer. 1ml of the mixture was serially diluted for estimating the number of micro-organisms. Nutrient agar (NA) and potato dextrose agar (PDA) were used for bacteria yeast / mould counts respectively, while MacConkey agar was used in the estimation of the coliforms.. Sensory Evaluation of the Samples: The sensory attributes of the kokoro samples were evaluated by the multiple comparison difference test as described by Larmond (1991). This was done using a 16 member panel comprising of students and staff of the Department of Food Science and Engineering, LAUTECH., Ogbomoso, Nigeria, who were also familiar with the sensory properties of kokoro. Each panelist was asked to score each attribute on a seven- point hedonic scale where 1 and 7 represent dislike extremely and like extremely respectively. The attribute evaluated were colour, taste, flavour, texture, appearance, crispness and overall acceptability. Data obtained were subjected to appropriate statistical analysis using ANOVA to detect differences in the mean scores and Duncan Multiple range test (Duncan, 1955) to separate the differences in the means. RESULTS AND DISCUSSION Proximate Composition: The results of the proximate composition are as shown in Table 2. The crude protein content increased from 12.33% to 23.75% as the level of enrichment with defatted groundnut flour increased. The higher the protein content of the defatted groundnut flour accounted for greater increase in the protein content of maizedefatted groundnut flour blend. Protein content is one of the most important qualities of any food. F.A.O (1996) recommended a protein content of 20% for any food. However, it is expected that the groundnut flour blend will complement that of the maize flour limiting in lysine and tryptophan but has a fair amount of sulphur containing amino acids. Table 2. Proximate composition of kokoro Sample Code Moisture (%) Protein (%) Fat (%) Ash (%) Crude Fibre (%) Carbohydrate (%) A 5.79 ± ± ± ± ± ± B 5.06 ± ± ± ± ± ± C 4.91 ± ± ± ± ± ± 0.01 D 3.61 ± ± ± ± ± ± E 3.42 ± ± ± ± ± ± The carbohydrate content was also higher in the 100% maize then the enriched blends. This was due to the relatively low carbohydrate content of the defatted groundnut flour. The carbohydrate reduced from % in the 100% maize to 62.89% in the 30% enrichment with defatted groundnut flour and finally, to 58.17% in the 40% enrichment with defatted groundnut flour. The high carbohydrate yield makes it ideal since energy is required for rapid growth. The ash content would give an indication of the mineral content of the blends. The ash content of the blends ranged from to with maize having the highest and maize-groundnut blends lowest value, suggesting that maize may have more ash than groundnut. Moisture content, which is one of the outstanding qualities and widely used parameter in the processing and testing of food qualities was found to range from 5-790% to 3.420% with 100% maize has the highest moisture content of 5.740% while the blend with 40% groundnut has the 283

5 least of High moisture content may affect the storability and the quality of the product. The moisture content of any food is an index of its water activity (aw) as reported by Frazier and Westhoff (1978). This implies that the maize-groundnut blends may have a short shelf-life due to their high moisture content. Similarly, the crude fibre contents reduced as the level of substitution with defatted groundnut flour increased. The crude fibre content was 2.560%, 2.260%, 2.07%, 1.83% and 1.74% in the 100% maize, 10%, 20%, 30% and 40% enrichment with defatted groundnut flour respectively. The low fat content resulted to the low energy levels of the blends. The fat content in the maize was and increased with increased in enrichment with defatted groundnut flour. In the 40% enrichment with defatted groundnut flour was The storage life of the blend may be increased due to their low fat contents because all fats and fat containing foods contain some unsaturated fatty acids and hence are potentially susceptible to oxidative rancidity (Ihekoronye and Ngoddy, 1985) and when exposed to warm or hot air rancidity will not be encouraged. Functional Properties of Maize Groundnut Mixes: As shown in Table 3, the result of water absorption capacity of the maize-groundnut mixes indicated that samples absorbed water of higher weight then their original weight. This could be because the samples were pregelatinized. Sample A had the lowest water holding Adelakun et al reported the same trend in the addition of soy and maize flour mixes for kokoro production. The result of the bulk density showed that the values increased with increasing levels of defatted groundnut flour, ranging between to An increase in bulk density would be useful in the packaging of the flour and the space it would occupy in a container. Considering the result obtained sample A would require the least packaging material while sample E would require the most, owing to the effect of defatted groundnut addition. The results of the swelling capacity decreased with increasing proportion of defatted groundnut flour, with sample A having the highest swelling capacity and sample E the lowest (1.415 to 0.955) respectively. Table 3: Some Functional properties of peanut paste/maize mixes Samples Swelling Capacity (g/ml) Water absorption capacity (g/ml) Bulk Density (g/cm 2 ) A ± ± ± B ± ± ± C ± ± ± D ± ± ± E 0.955± ± ± is 3.10 (RVU) while sample A has the lowest breakdown 1.90 (RVU) as illustrated in table 4.3.The Pasting Characteristics of Maize-Groundnut set back value also decrease with an increase in Mixes: The peak viscosity data of the samples are as groundnut mixes of sample E 1.65 (RVU) and sample presented in Table 4. Peak viscosity was between C has the lowest set back of 0.29 (RVU). The pasting 6.70 to 7.90 (RVU) which increased with increases in time ranged between minutes. Sample E the level of groundnut in the mixes. This is a has the lowest pasting time of 7.20 minutes while reflection of the starch contents present in the sample A has the highest pasting time which is 9.40 samples. The amylograph peak viscosity has been to sample E has the highest pasting indicated to reflect the level of raw starch in maize. temperature ranges between sample E has the The trough or holding strength also increased with highest pasting temperature while sample A has the increase in the amount of groundnut in the mixes. It lowest pasting temperature. The final viscosity ranged between 4.80 and 5.12 (RVU) (Table 3). The ranged between (RVU). Sample E has breakdown in viscosity, sometimes called shearthinning. Sample B has the highest breakdown the highest value while sample A has the least value which 284

6 Table 4: Pasting properties of maize-peanut paste mixes Sample Peak viscosity (RVU) Trough (RVU) Breakdown (RVU) Final viscosity(rvu) Set back(rvu) Pasting time (min) A B C D E Sensory Evaluation: Table 5 shows the results of the sensory evaluation of all the Kokoro samples. In terms of colour, samples A, C and E were the most preferred and significantly different from sample B and D. With respect to the flavour, samples A, C, D and E are not significantly different from each other while sample B was the least preferred. The taste of sample C and E were the most preferred and significantly different from samples A, B and D. samples C and E were rated higher in terms of texture and samples A, B and C were the least preferred (Table 4). In terms of appearance C and E were equally accepted. Samples A and D were not significantly different from one another while sample B is significantly different from one another while sample B is significantly different from all other samples. The crispness of sample A and C were equally accepted. Samples B and C were significantly different from sample E which is the least preferred. In terms of overall acceptability, sample E is the most acceptable, while sample B is the least acceptable (Table 4). Table 5. The mean scores of sensory evaluation of kokoro Quality Attributes A B C D E Colour 5.94b 3.63d 6.13ab 5.44c 6.19a Flavour 5.56c 4.94d 5.81a 5.13ab 5.56c Taste 5.75c 5.13cd 6.19b 5.13c 6.56a Texture 5.50c 4.69d 5.94b 4.88d 6.31a Appearance 5.75cd 3.88e 6.13ab 5.31c 6.06a Crispness 5.94a 5.25c 5.69ab 4.44cd 4.25d Overall Acceptability 6.00c 4.56d 6.25ab 5.31abc 6.31a are members of the Enterobacteriacae family and Microbiological Analysis of Kokoro: The results of should not be found in food (Ihenkonye and Ngoddy, the total viable count are shown in Table 6 Sample A 1985) and hence could be regarded as been fit for had the highest count while sample E had the least consumption. Sample A and D had mould count while count. No coliform were detected in any of the samples B, C and E do not here any mould count. samples, an indication that the samples were Sample B and D had yeast count, while samples A, C completely free from feacal contamination. Coliform and E do not have any yeast count. Table 6:Microbiological analysis of kokoro Sample Code Total viable count Total Coliform count Mould count Yeast count A 2.5 NIL 0.1 NIL B 2.1 NIL NIL 0.2 C 2.3 NIL NIL 0.2 D 2.1 NIL E 1.4 NIL NIL NIL 285

7 CONCLUSION: The study indicated that it is possible to supplement maize flour with defatted groundnut flour that is rich in protein. The proximate analysis conducted on the mixes revealed an increase in the quality of nutrients REFERENCES Adelakun, O.E., Adejuyitan,J.A.,Olajide,J.O and Alabi,B.K (2005).Effect of soybean substitution on some physical,compositional and sensory properties of kokoro (a local maize snack).eur Food Res Techol.220:79-82 Alfonso, C., Sanchez-viogue, J., Bastiata,, J. and Millan, F Effect of processing on water absorption and softening kinetics of chickero pea seed. Journal of Science Food and Agriculture 18: Akpapunam, M.A. and P. Markakis, 1981.Physicochemical and nutritional aspects of cowpea flour. J. Food Sci., 46: Ameida-Dominguez N.G, Valencia M.E, Higuera-Capra I (1990). Formulation of Corn based Snack with high Nutritional and Biololgical and Sensory Evaluation. J. Food Sci AOAC (1990). Association of Official Analytical Chemist, Official method of analysis 14th Edition, Washington. Collins, C.H., Lyne M. Grage J.M (1989). Microbiological Methods (6 th Edn), Butter North and Co. Ltd., pp Duncan, D.B Multiple Range and MultipleF-test. Biometrics 11: 1-5 Elkhalifa, A.O,Schiffler B, and Bernhardt,R (2005). Effect of fermentation on the functional properties of sorghum flour. Food Chemistry (92) 1-5 FAO (1996). Grain legumes in Africa 3 rd edition Food and Agricultural Organization, Rome.Pp Frazier, W.C.; and Weshoff, D.C. (1978) Food Microbiology 3 rd edition. McGraw-Hill Inc. New York, Lond. Pp compared to unsubstituted maize flour. Sensory evaluation showed that the use of the mixes for the production of kokoro, a local snack, is also possible, although the result revealed that the 40% substitution of defatted groundnut flour was preferred. Ihekoronye, A.I., and Ngoddy, P.O. (1985). Integrated Food Science and Technology for the Tropics Macmillan publishers p. 65. Kirk R and.s, Sawyer R(1991). Pearson s Composition and Analysis of Foods. 9th edn. Longman Group. p 646. Larmond, E Laboratory Methods for Sensory Evaluation of Foods. Canadian Agricultural Publications. Series iv, Ottawa. Canada. Okaka, J.C (2005). Basic Processing of Grain Cereals and Legumes In: Handling, Storage and Processing of Plant Foods. OCJ Academic Publishers, Enugu, Nigeria. pp Omueti O,and Morton I.D (1996).Development by Extrusion of Soybean Snack sticks a Nutritionally Improved Soya-maize Products based on the Nigeria Snack (Kokoro). Inter. J.Food Sci. Nutri. 47: Onweluzo J.C, Morakinyo AO (1997). Effect of Predehulling treatments on the Composition of Seeds of the legume Afzelia africana and its potential use in pastries. J. Plant Foods for Human Nutri. Springer Netherlands. 50 (3): Pearson D (1976). Chemical Analysis of Foods.7th edition, Churchill Livingston, Edinburgh, United Kingdom. Plahar W.A and Leung H.K(1983). J. Sci Food Agric 34: Rosa N, Chávez-Jáuregui RAC, Maria EM, Pinto ES, Jose AGA (2003). Acceptability of Snacks Produced by the Extrusion of Amaranth and Blends of Chickpea and Bovine lung. International J. Food Sci.Technol. 38(7): Uzor-Peters P. I., Arisa, N. U Lawrence, C. O. Osondu N. S. and. Adelaja A (2008) Effect of partially defatted soybeans or groundnut cake flours on proximate and sensory characteristics of kokoro. Afr. J. Food Sci Vol (2) pp