Performance Evaluation of an Automated Combined Cassava Grater/Slicer

Transcription

1 International Invention Journal of Biochemistry and Bioinformatics (ISSN: X) Vol. 2(3) pp , June, 2014 Available online Copyright 2014 International Invention Journals Full Length Research Paper Performance Evaluation of an Automated Combined Cassava Grater/Slicer *Malomo, Olu., Bello, E.K., Adekoyeni, O.O. and Jimoh., M.O. College of Food Sciences, Bells University of Technology, P.M.B. 1015,Ota. Abstract Combined automated cassava grating/chipping machine was designed, tested and evaluated for its performance efficiencies, using two cassava species; TME 419 and TMS The cassava roots were classified into small, medium and large, the roots were used to evaluate the efficiency of the machine. The machine efficiency, mechanical loss and capacity (machine output, kg/h) for grating and chipping ranged between % and %, % and %, kg/h and kg/h respectively. The quality performance of the grater was between % while the chips size characteristics also revealed high efficiency. The performance of the machine was affected by the specie and size of the cassava tube. The medium size cassava revealed the highest efficiency in grating and chipping operation. Keywords: Machine performance efficiency, grating and chipping, quality performance efficiency. INTRODUCTION Cassava (Manihot esculenta crantz) is one of the most valuable staple food source for tens of millions of people in the West African sub-region (Adejumo et al., 2011). Grating and chipping are size reduction operation for processing cassava root. The transformation of cassava tubers into pulp form is called Grating while Chipping is slicing of cassava roots or agricultural material to obtain the length greater than other section of the cut (FAO, 2004). The traditional method of cassava grating is made of a perforated metal sheet of aluminum or galvanized sheet and the peeled cassava tuber is robbed on the rough surface, while the grated product is collected in a container (Jekayinfa et al., 2003). The traditional method apart from been laborious, have reported cases of the user having their fingers brushed off on the rough surfaces of the grater root vertically or horizontally along its length by free movement of a knife. It is also labour intensive and characterized with uneven sized products (chips). Currently (there exist individual motor powered grater and chipper that has been developed by Rural Agricultural Industrial Development Service (RAIDS) and International Institute of Tropical Agricultural (IITA). The length of the chips depends on the angle of contact of the cassava tuber with the blade; the size of the chips varies between 36mm thick, 6-10mm wide and mm long. The general consideration in designing a combined operational grating/chipping machine was another innovation aimed at reducing the capital involved in purchasing individually a power grater and chipper. This will also reduce the space interim of installation. Assessment of the performance of combined cassava grater/chipper in the production of pulp for the production of garri and the quality chip are essential to determine the level of efficiency and acceptability of the developed machine for usage. The objectives of this research work are to evaluate the performance of a combined cassava grater/chipper earlier designed by the Department of Food Science and Technology, Bells University of technology, Ota and to establish its operational suitability. MATERIALS AND METHODS Description and operation of the machine *Corresponding Author oludaremalomo1951@yahoo.com A combined cassava grater/slicer was developed by the

2 Malomo et al. 31 Department of Food Science and Technology, Bells University of Technology, Ota, Nigeria. It comprised both the grating and /chipping units; the power motor located midway between the two machines to be shared depending on the operation required. Grating Unit: The Grating drum is made of 2mm thick plate with perforated stainless wrappers for grating. Diameter of the Grating Rollers is 200mm diameter and 300mm long Chipping Unit: The Chipper is made up of Circular Rotational Disc punched zig zag for correct chipping. The hopper is made up of 2 mm plate; the frame of the machine is made with 50 x 50 x 4 mm angle iron. The pillow bearing that holds the roller is 30mm diameter and the shaft 300mm long and is made of 30mm shaft. The grater was designed to produce pulp for Garri or starch production while the chipper was meant for production of cassava chips that can be used for human consumption when further grounded or for animal feeds. Figure 1 Materials selection Two varieties of cassava were used for the evaluation. The Cassava (Manihot Utilisima) varieties: TMS and TME 419 were purchased from TREFAD (Teaching and Research Farms Directorate), Federal University of Agriculture, Abeokuta, Nigeria. Each of the varieties was grouped into small, medium and large sizes using length of the tuber as clustering parameter as follows: Large size (L) = 31-40cm Medium size (M) = 21-30cm Small size (S) = 1-20cm Performance Evaluation of the cassava grater/chipper Freshly harvested cassava were peeled manually and washed in clean water. Fairly regular size roots were randomly selected and introduced into the machine that has been on idle speed for about a minute. The machine was switched off when the roots are chipped/grated and the operation parameters recorded. The chips/pulp from the chute were collected and manually separated and categorized as well chipped/grated and non well chipped/grated; and their weight were noted. The parameters capacity, quality of grated and sliced cassava, mechanical losses, grating and slicing efficiencies were measured as described by (Jekayinfa et al., 2003; Adejumo et al., 2011) Determination of grater/chipper Efficiency The grating/chipping efficiency of the machines were calculated by the following procedures: Machine chipping Capacity = Wtc kg/hr...(1) Tc Machine grating Capacity = Wtg kg/hr...(2) Tg Chipping efficiency = Wwc 100%. (3) W i Grating Efficiency = Wwg 100%.....(4) Wi Grating Mechanical Loss = Wi - Wtg 100% (5) Wi Chipping Mechanical Loss = Wi - Wtc 100% Wi Quality performance efficiency = G 100%..(6) G+B Where: Wwc = mass of well chipped cassava Wwg = mass of well grated cassava Wtc = mass of total chipped cassava Wtg= mass of total grated cassava Wi = initial mass of cassava tuber Tc = chipping time Tg= Grating time G = Good quality B = Bad quality Estimation of Physical Characteristics of Cassava Chips The size characteristics were measured using Digital vernier caliper. 10 pieces of cassava chips were randomly selected and the length, breadth and thickness were measured using the vernier caliper. The means of the sizes were determined and compared. RESULTS AND DISCUSSION Evaluation result of grating unit The results of grating efficiency, grating mechanical damage, grating quality performance efficiency and grating capacity were shown in Tables 1-3 and 6. Evaluation result of chipping unit The results of chipping efficiency, chipping mechanical damage, chipping capacity and comparative analysis of

3 32 Int. Inv. J. Biochem. Bioinform GRATING UNIT = A,B,C,D A = HOPPER B = OUTLET C = GRATING ROLLER D = PRIME MOVER ELECTRIC MOTOR CHIPPING UNIT = D,E,F,G D = PRIME MOVER ELECTRIC MOTOR E = ROTATIONAL DISC F = INLET G = CHIPPING DISC Figure 1. Isometric representation of the machine Table 1. Grating efficiency of automated combined cassava grater / slicer Variety Tuber input (kg) Time Output (kg) Efficiency (%) (mins) TMS (L) TMS (M) TMS (S) TME 419 (L) TME 419 (M) TME 419 (S) Table 2. Mechanical damage of cassava grating Variety Mechanical loss (%) TMS (L) TMS (M) TMS (S) TME 419 (L) TME 419 (M) TME 419 (S) 11.50

4 Malomo et al. 33 Table 3. Quality performance of cassava grating Variety Good quality (kg) Bad quality) (kg) Quality performance (%) TMS (L) 1.47 kg 0.23 kg % TMS (M) 2.34 kg 0.31 kg % TMS (S) 1.48 kg 0.22 kg % TME 419 (L) 1.62 kg 0.17 kg % TME 419 (M) 2.48 kg 0.21 kg % TME 419 (S) 1.59 kg 0.18 kg % Table 4. Grating capacity of an automated combined cassava grater / slicer Variety Capacity(kg/hr) TMS (L) TMS (M) TMS (S) TME 419 (L) TME 419 (M) TME 419 (S) Table 5. Chipping efficiency of automated combined cassava grater/slicer Variety Tuber input Time Output Efficiency TMS (L) 2 kg 1 mins 1.65 kg % TMS (M) 3 kg 1 mins 2.77 kg % TMS (S) 2 kg 1 mins 1.60 kg % TME 419 (L) 2 kg 1 mins 1.80 kg % TME 419 (M) 3 kg 1 mins 2.80 kg % TME 419 (S) 2 kg 1 mins 1.78 kg % Table 6. Mechanical damage of cassava chipping Variety Mechanical loss (%) TMS (L) TMS (M) 7.60 TMS (S) TME 419 (L) TME 419 (M) 6.00 TME 419 (S) chips are shown in tables 5, 6, 7 and 9 DISCUSSION The percentage grating efficiency of the various size classifications are shown in Table 1. The Percentage efficiency ranged between %. The highest grating efficiency was recorded in the medium cassava root of the TME 419(M) (89.70%), followed by the large size of TME 419 (89.50%). The efficiency obtained was similar to the result recorded by Jefayinka (2003) in evaluation of a pedal-operated cassava grater which was recorded to be 75%. High grating efficiency was as a result of the construction which included provision of a hopper box with a base inclined at about 35 degrees, extended close to the top surface of the rotating drum in order to improve gripping to the working surface and minimizing splattering. The mechanical loss during grating is presented in Table 2. There exist direct correlation between grating efficiency and the mechanical damage during grating. The value obtained for mechanical damage during grating was low and ranged between %.

5 34 Int. Inv. J. Biochem. Bioinform Table 7. Chipping capacity of an automated combined cassava grater / slicer Variety Capacity(kg/hr) TMS (L) TMS (M) TMS (S) TME 419 (L) TME 419 (M) TME 419 (S) Table 8. Quality performance of cassava chips (TMS 30555) TMS (L) Height 6.02 Width 0.84 Thickness 0.50 TMS (M) Height 4.91 Width 0.77 Thickness 0.25 TMS (S) Height 5.89 Width 0.78 Thickness 0.46 Table 9. Quality performance of cassava chips (TME 419) TME 419 (L) Height 5.23 Width 0.63 Thickness 0.40 TME 419 (M) Height 5.19 Width 0.81 Thickness 0.53 TME 419 (S) Height 6.08 Width 0.91 Thickness 0.40 More losses were recorded in the large and small sizes of TMS The losses recorded were low compared to 35 % loss reported by Amoah et al The variation in the result might be as result of differences in the variety used for the experiment including other climatic and ecological factors. Table 3 showed the quality performance of the grating unit. The table revealed the highest quality performance with TME 419 (M) (92.19 %) followed by TME 419 (L) (90.50 %) while the lowest was the TMS 30555(L) (86.47 %). The result presented was an indication of high performance of the machine for grating and this per force is subject to the sizes of the cassava root. The low grating performance recorded for the large cassava root could be as a result age and high fibre content which might proof difficult to the grating operation. This is consonance with reports of Adtunji and Quadri (2011) and also Oriola and Raji (2013) According to a report by Adetunji and Quadri (2011) on design and fabrication of an improved cassava grater. The performance efficiency of cassava grater is dictated by various factors such as the belt design, power transmission efficiency (the ratio between the speed of the electric motor and the drum pulley, determination of centre distance (c), and shaft and hopper design including the bending moment at each point of loading. The result for the chipping efficiency of the machine is presented in Table 5. The value of the chipping

6 Malomo et al. 35 efficiency ranged between %. The highest output was recorded in the medium size of cassava TMS (M), TME 419 and decreased respectively with TMS (M), TME 419 (L), TME 419 (S), TMS (S). The chipping efficiency is higher compared to the value 80% reported by Akintunde and Akintunde (2001). Although, the variety of the cassava and the size can also dictate the efficiency of the chipping as revealed by the result. The mechanical damage during the chipping operation is shown in table 5. The mechanical loss is minimal (6.00% %). The small size of the cassava root of TMS was difficult to be position for slicing in the chipping unit. The losses could also be as a result of moisture drains during the operation. Some of the cassava particles may also be found in microscopic crevices in certain part of the machine. The Grating capacity is the amount of grated pulp that could be produced per unit time and the result is presented in Table 4. The highest grating capacity was recorded in the medium cassava root of the TME 419 (80.70 kg/hr) and TMS (79.50 kg/hr). The result obtained for the grating capacity is higher than the result recorded by Jefayinka (2003) who evaluated a pedal cassava grater, having an average grating capacity kg/hr. Also, this variation in the grating capacity can be as a result of the size and age of the tuber, feeding rate, speed, length of the roller and variety. The Chipping capacity is the amount of chips that can be produced per unit time. The highest chipping capacity was recorded in the medium cassava root of TME 419 ( kg/hr) and TMS ( kg/hr). The result obtained from the chipping capacity (Table 7) is similar to the result recorded by Silayo et al. (2007) in the evaluation of cassava processing machines having chipping capacity of 99.3kg/hr. The variation in the chipping capacity is a result of the size and the age of the tuber, the variety and rotating speed of the slicing blade. The quality chipping performance of the combined cassava grater/slicer were determined for the two varieties for the varieties of the cassava (TMS and TME 419) grouped into large, medium and small sizes. The result obtained is presented in table 8. The average result of the dimension of the cassava chips (height, width and thickness) of the TMS 30555(L) are 6.02, 0.84 and 0.50cm respectively, 4.91, 0.77, and 0.25cm for TMS 30555(M) and 5.89, 0.78 and 0.46cm for TMS 30555(S). The result of quality chipping performance of the TME 419 revealed 5.23, 0.63 and 0.40cm for height, width and thickness respectively for TME 419(L); 5.19, 0.81 and 0.59cm for the height, width and thickness of TME 419(M) respectively while 6.08, 0.91 and 0.40cm are recorded for TME 419(S) dimension height, width and thickness respectively. It is obvious that the chipping size characteristics were influenced by the size of the cassava root and also vary with variety. Adejumo et al. (2011) deduced that the length of the chips depends on the angle of contact of the roots with the blade. Generally, the result obtained in this experiment varied with the value reported when the performance of a prototype chipping machine developed by Post Harvest unit, International Institute of Tropical Agriculture (IITA)'s post harvest unit was accessed, they are 36mm thick, 6-10mm wide and mm long (Adejumo et al., 2011). The dimension of the chips is small and this will facilitate the increase in drying rate because of the large surface area. CONCLUSION The fabricated machine was a dual purpose and was tested for its performance efficiency in comparison with the existing single units of automated grating and chipping machines. The machine was found to be effective and efficient both in terms of grating and chipping. The grating efficiency of 85% and above and % for chipping with different sizes of cassava root revealed high performance. Though, there exist effect of cassava size but not obvious. Low insignificant levels of mechanical loss in the chipping and grating operation with good chipping size characteristics are indicators of the high performance required. It is hereby recommended that the machine can be used for grating and chipping operations in cassava processing REFERENCES Adebayo K (2005). Traditional institutions and information uptake in the conduct of cassava fufu market. In: Porter, G., Lyon, F. and the Nigerian Food Marketing Network (2005). Investigations on building a Food Marketing Policy Evidence Base in Nigeria. Briefing Report. Department for International Development, United Kingdom. pp Adejumo AOD, Oradugba OB, Ilori TA, Adenekan MO (2011). Development and Evaluation of a Cassava Chipping Machine. Journal of Raw Materials Research pg1-7 Adetunji OR, Quadri AO (2011). Design and fabrication of an improved cassava grater. Pacific Journal of Science and Technology. Vol. 12 (2); Akintunde BO, Akintunde TY (2001). Design and Construction of a motorized chipping Machine. Proceeding of the International Conference and Annual General meeting of the Nigeria Institute of Agricultural Engineers. 23:10-14 Food and Agriculture Organization of the United Nations, Agriculture and Consumer Protection Department (2006). CASSAVA STARCH. Food and Agriculture Organization of the United Nations. (2004). The global cassava development strategy and implementation plan. Proceedings of the validation forum on the global cassava

7 36 Int. Inv. J. Biochem. Bioinform development strategy, 1. Retrieved March 14, 2005, from 69e/y0169e00.htm Igbeka JC (1985). Mechanisation of Tuber in the Tropics. Food and Agriculture Cassava Peeling. Paper presented at International Organization of the United Nations, Rome, Italy, Symposium Organization by International pp: 3-4. Jefayinka SO, Olafimihan EO, Odewole GA (2003). Evaluation of a Pedal - Operated cassava grater. Lautech journal of engineering and technology: pp Oriola KO, Raji AO (2013). Trends at mechanizing cassava post harvest processing operations. International journal of Engineering and Technology. Vol. 3 (9); Silayo VCK, Laswai HS, Mpagalile JJ, Ballegu WR, Mtunda KJ, Chilosa DN, Nyborg ILP, Makungu PJ (2001). Development and Promotion of Improved Processing, Packaging and Storage of Sweetpotato and Cassava for Diversification of Use and Commercialization of the Value Added Products Under Smallholder Farmer Conditions. PRA Report for the participating villages of Songabatini (Muheza), Magindu (Kibaha) and Ihenje (Kilosa). How to cite this article: Malomo O, Bello EK, Adekoyeni OO, Jimoh MO (2014). Performance Evaluation of an Automated Combined Cassava Grater/Slicer. Int. Inv. J. Biochem. Bioinform. 2(3):30-36