HIT Motto
School of Industrial Sciences & Technology - Student Projects

Industrial Sciences & Technology

Selected Final Year Student Projects – Capstone Design Project (HIT400)

 

Development of Carboxymethyl cellulose from sugarcane bagasse (a local resource) for use in the in the Dairy industry

NOBAKHE NYONI(H1210766C), nobakhenyon@gmail.com and C.NYAMBI, cnyambi@ hit.ac.zw

Abstract

The objective of the study was to develop a functional stabilizer CMC from sugarcane bagasse which can be used in the dairy industry. The extraction of cellulose was carried out in a 1000ml beaker, equipped with stirrer and temperature controller. A 38% of cellulose was successfully extracted from sugarcane bagasse through 4% nitric acid hydrolyzed process followed by alkali treatment. Cellulose obtained was not purer cellulose. The crude cellulose was then converted to carboxymethyl cellulose (CMC) by treatment with 1 mol sodium hydroxide (NaOH) concentration and successfully etherified with 6g of monochloroacetic acid. Viscosity measurements on 2% CMC concentration showed a decrease in viscosity with increase in temperature. Functionality of the CMC was further tested by preparing a yoghurt against gelatin at different concentrations thus 0.5g/L, 1.0g/L, 1,5g/L. After the viscosity and sensory evaluation measures it was concluded that the CMC at 1.0g/L was best suitable for drinking yoghurt or stirred yoghurt.

 

Designing unshelled groundnuts (Arachis hypogaea) residual soil cleaning machine from a food safety perspective

JOYLINE CHIPINDURO (H1111750Y); jchipinduro@gmail.com and R. KWIRI, rkwiri@hit.ac.zw

Abstract

The objective of this research was to design a machine that can improve the quality of the groundnuts after harvest by removing residual soil from the surfaces of the groundnuts that have been grown on clayey soils. Residual soil carries fungal spores that can lead to the production of aflatoxin in groundnuts. Aflatoxins are mycotoxin that renders food unsafe for human and animal consumption. Soil also carries eggs of pests which when hatched can proliferate the groundnut shell degrading the intactness of groundnut shell thereby making the kernel susceptible to aflatoxin infection. Small scale famers that relocated in different agricultural zones due to the Agrarian land reform of 2000 continue with their faming of traditional crops, groundnuts included. However some of the farmers relocated to regions with clayey soils. From the researchers point of view, these farmers to do not have adequate technologies to remove clinging clay soils from the surfaces of the groundnuts leading to the infection of groundnuts by aflatoxin thus post-harvest losses due to loss of quality by groundnuts

The design project aimed at developing a cleaning mechanism of removing residual soil from the surfaces of the groundnuts without causing significant gain in moisture content and bruising or damaging the groundnut shells. Groundnut samples from Goromonzi, Mutare and Murehwa were used for experiments in the design .The design project aimed at controlling the gain in moisture content of the groundnuts by deducing a residence of the groundnuts in the washing chamber in relation to their hydration capacity, the water pressure required to remove residual soil and abrasive action that can help scour away residual soil. The design also aimed at controlling the bruising or damaging of the groundnuts by controlling the speed of rotation of shaft during cleaning. The design includes a washing chamber, brushes lined on blades mounted on the shaft to. Blades provide agitation while brushes scour away residual soil from the surfaces of groundnuts while the shaft rotates. The shaft is driven by a 2 horsepower electric motor. The design also consists of a drainage facility to drain away used water from the washing chamber and thus no accumulation of water which could lead to possible absorption by the groundnuts. Water is introduced in the design by spraying nozzles at a flow rate of 5.64lms-2.

To ascertain effectiveness of design machine, pre and post cleaning moisture content was measured. The fungal spores present in the wash water during start of cleaning duration and after where enumerated. The bruised or damaged groundnuts after cleaning where also calculated together with the cleaning efficiency of design.

 

Development of an analytical model for butterfat determination, in bovine milk, based on electrical conductivity principle. The Milklipidometric model.

SHADRECK MUYAMB(H1212505Z), shadiemyambo@hotmail.com and M. MUDYIWA, mmudyiwa@hit.ac.zw

Abstract

Methods used for butterfat determination are considered expensive and time consuming. Therefore, it was then indispensable to develop an analytical model which is inherently flexible for easiness of use and considerably cheap for accurate and precise determination of butterfat in bovine milk. Hence, the development of analytical model based on conductivity principle – Milklipidometric model. The model was developed through sampling and preparation of raw milk sample with varying butterfat concentration (n=39 for modelling; n=12 for validation) in dairy companies around Harare, Zimbabwe. The samples were analysed for compositional profile and total dissolving solids (TDS). Electrical conductivity and viscosity were analysed at constant temperature (25±0.5°C) and varying temperatures (5-60°C). Models were developed using linear regression, by considering established mathematical relationships of milk conductivity and using robust linear regression modelling. The best fit model was obtained using robust linear regression modelling (Bisquare), and the parameters include electrical conductivity (), volume fraction of whole milk (mL), calibration ratio (), temperature () and temperature dependent power constant (). The predicted butterfat shows no significant difference with observed butterfat at 95% confidence interval, and also shows a correlation of 96.0%. Considering the general model assumption a conclusion was made that there was a relationship between butterfat concentration and conductivity of milk.  The model can be used for prediction of whole milk and whole milk-skimmed milk dilution. A calculator was also programmed using visual basic studio for easy calculation of butterfat concentration.

 

 THE PRODUCTION OF FOOD GRADE ALGINATES FROM LOCAL EDIBLE ALGAE SPECIES.

MUKAMBA VAINAH MAZVITA (H1112230K) and A. Musengi, amusengi@hit.ac.zw

Abstract

Laminaria digitata was found in Kariba dam, Chinhoyi river and Mazowe dam while Laminaria hyperboria was found in Mazowe dam only. These two species were cultivated for 53 days and 48 days (Laminaria hyperboria and Laminaria digitata respectively) and they were harvested. Laminaria hyperboria yielded a biomass of 1.653 grams while Laminaria digitata yielded 0.976 kilograms. Laminaria hyperboria was harvested by filtering on filter paper and oven drying at 50ᵒ C. Laminaria digitata was dried using two methods which were compared and these were oven drying and air drying. The air drying method gave a better quality dry algae but it took 8 to 9 days compared to the oven drying method which took 5 to 6 hours. The Laminaria digitata was used for the extraction process as it had a higher biomass and the extraction was done using two methods denoted method A which was as per patent number US3396158 (US Patent office, 1959) and method B as described by Columpong et al, (1999). The alginates obtained were analyzed physically and chemical to ascertain if fulfilled their functional properties. The results obtained showed the following quality attributes; yield of 6.908% and 15.8958% for method A and method B respectively, purity of 69.83% and 96.2% for method A and method B respectively as well as color which was 75.236% and 72.6785% respectively. The alginates were analyzed microbiologically and the results were as follows; E. coli 3CFU/g, Micrococcus leutus 2 CFU/g, fungi 1 CFU/g and yeast 13CFU/g and these were within the recommended specification range. The alginates were used to stabilize yoghurt and this was done by measuring its viscosity over 21 days and synerisis was observed on the on the 14th day while for the control it was observed on the 9th day. The gelling properties were investigated by production of a gelly powder which was then made into a gel whose viscosity was measured and was 7.42 centipoise at 1.5 ᵒC compared to that of the control which was 1.54 centipoise at 4.9ᵒC. It was concluded that Laminaria digitata can be used at industrial level to produce food grade alginates based on its yields and the fact that it met international specifications.


Design of a mixer for reconstitution of milk powder for use by micro, small and medium Dairy companies in Zimbabwe.

MACHINGAUTA BLESSING S.F. (H1212010Y) faraisibongile@gmail.com and F. Mujuru, fmujuru@hit.ac.zw

Abstract

Currently the Zimbabwean dairy sector is in short supply of fresh milk, thus, the milk being produced fail to sustain the demand for milk by dairy companies. This has led to many companies (new and existing) resort to supplementation by reconstitution of milk powders. The cost of mixing equipment used for reconstitution is prohibitive therefore in this project a cheaper design was made. From the concepts formulated one was chosen which could effectively reconstitute milk and lower temperature of the product at an affordable price. The chosen concept was affordable and easy to make for micro, small and medium Zimbabwean Dairy companies. The chosen design parameters were calculated and defined. After making of the prototype the machine was validated and verified for functionality. Mixing efficiency, removal of impurities and temperature control was measured on the prototype. Decrease of impurities by 9% from 10% was obtained due to the sieve that was on the prototype hopper. The number of lumps formed at a temperature of 47ᵒC at 3000 revmin-1 was 0, therefore a reconstitution temperature of between 45ᵒC - 50ᵒC was recommended. The average variance of the mixture was 80.5 which is a high value and showed that mixing efficiency was fairly high. Temperature decrease was also calculated and the mean was 84.1 %. A t-tailed test was also used to support this observation and H0 which was μ1=μ2 was rejected showing that there was significant difference in temperature of the raw materials and the product. Mixer unit for particular industrial field is not very common, unlike other ordinary mixer solutions, therefore special care was taken to first study the milk powder properties to be mixed before the machine for reconstitution was designed.

An investigation on the causes of escherichia coli and coliform contamination of cheddar cheese and how to reduce the problem (a case study)

AMANDA KWENDA (H1010987H) ammaragie@gmail.com and A. Musengi, amusengi@hit.ac.zw

Abstract

During the past year (2013) at a cheese processing company, pathogenic microorganisms, Escherichia coli (E.coli) in particular have been increasingly included in various types of cheeses including Cheddar cheese. E.coli outbreaks associated with consumption of different varieties of dairy products have been reported in several countries. The aim of this study was to investigate on the causes of E.coli contamination on Cheddar cheese through the application of some Hazard Analysis Critical Control Points (HACCP) principles. Cheese samples were analyzed for E.coli and coliform bacteria after production during the validation stage as well as at the verification stage and the average E.coli and coliform counts were statistically analyzed using the T-test. Results showed that after the implementation of the corrective measures there was a decrease in E.coli and coliform count which was compared at 5% significance level. Results presented in this study also showed that the manufacturing of Cheddar cheese at high hygienic standards improves the reduction of E.coli and other coliform related bacterial contamination of the product though the problem is not entirely eliminated.

 

Selected Third Year Student Projects – Design and Innovation Project (HIT 300)

 Automation of the sugar mixing process in a soft drink manufacturing plant.

1S.T Gwala; 2C.Winini; 3P.Muredzi
1Department of Food Processing Technology, Harare Institute of Technology, Box Be 277, Belvedere, Harare
2Department of Food Processing Technology, Harare Institute of Technology, Box Be 277, Belvedere, Harare; cwinini@hit.ac.zw
3Dean – School of Industrial Sciences & Technology, Harare Institute of Technology, Box Be 277, Belvedere, Harare; pmuredzi@hit.ac.zw

Abstract

The design aims to improve an existing sugar mixing process by automating it. The existing system is manual and is carried out in batches which are repeated as required by an order, hence the process is slow and quality consistency is also low. Since a lot of manual materials handling is involved, the system requires of a lot of labour. The system to be designed consists of a continuous process of dissolving sugar with water in a tank to a pre-determined concentration level. The automation design of the system comprised of basically three goals. These were (1) concentration control (2) flow rate control (3) fluid level control. The design comprises of a fluid level sensor connected in cascade with an inline refractometer to a throttling control valve in order to maintain the sugar concentration at the desired set point. The mass flow rate of the sugar and the volumetric flow rate of the inlet water are predetermined by calculations and set at that rate in a Programmable Logic Controller (PLC). The concentration of the sugar level is measured by an inline refractometer. The sugar mixture at the desired Brix level is released through an output line and pumped to the desired location. The design procedure was done in five stages which were: defining or establishing goals, preparation of information, formulation of models, and determination of the solution and finally a description of the controller system. Components of the control system were chosen in such a way that they were in sync with the holistic control design.

 

Production of a biodegradable plastic from chicken feathers.

1N.Tamirepi; 2A.Musengi; 3P.Muredzi
1Department of Food Processing Technology, Harare Institute of Technology, Box Be 277, Belvedere, Harare
2 Department of Food Processing Technology, Harare Institute of Technology, Box Be 277, Belvedere, Harare; amusengi@hit.ac.zw
3Dean – School of Industrial Sciences & Technology, Harare Institute of Technology, Box Be 277, Belvedere, Harare; pmuredzi@hit.ac.zw

Abstract

Poultry feathers were utilized in an attempt to produce a plastic from chicken feathers. This was done in an effort to reduce land pollution from waste plastics due to their non-biodegradability nature. Chicken feathers were pulverized and mixed with glycerol which was used as the plasticizer. Different combinations of feather and glycerol were applied. Sodium sulphate was also added in some of the samples to increase viscosity. All the samples were heated to 60◦C then left to air dry. One sample had pressure and heat applied simultaneously and another, just pressure. Some of the samples did not solidify, while others became hard brittle substances and one turned into gel like substance.

 

Design of a Whey Treatment Process at DairibordKadoma Manufacturing Plant

1F.Shawarira; 2D.N.Moyo
1Department of Food Processing Technology, Harare Institute of Technology, Box Be 277, Belvedere, Harare
2Department of Food Processing Technology, Harare Institute of Technology, Box Be 277, Belvedere, Harare; dmoyo@hit.ac.zw

Abstract

The study project involved the design of a whey treatment process designed to utilize the whey volumes produced from the manufacturer of hard chesses at Kadoma Dairy. The design was aimed at reducing the biological oxygen demand (BOD) of whey (=60g oxygen/litre), whilst recovering some nutrients from the whey. The study involved research into whey processing applied in foreign dairy industries and process and equipment design.
Based on material balances on one batch production of Cheddar cheese at the aforementioned dairy (employing 12,000L of whole milk), the raw whey quantities expected were determined to be 10,961.20 L. From these volumes, mass balances for whey process unit operations were calculated. The final product is expected to be a whey protein and lactose concentrate (60% solids). This product could be of benefit to Dairibord Zimbabwe Pvt Ltd since, (i) it helps avoid any legal law suits concerned with the pollution of the environment due to the reduced BOD of the resulting effluent stream and (ii0 it can be added to other products such as ice cream and yoghurt to increase total solids.

 

Selected Second Year Student Project – Team Food Product Development Project (HIT200)

 

Development of cocoyam breakfast flakes

Oak Munyaki, Gerald C. Gumbo, Thelma Mudhara, Fortunate Shenje, Rumbidzai Sauti, Cara Mugadziwa, John Ndikudze

Abstract

A project was done on the development of breakfast flakes from cocoyams. The idea was to formulate the steps and procedures in the flake production and adopt the most suitable on one in the development of the gluten free breakfast flakes from cocoyam. The group members found a gap in production pertaining to the underutilisation of the cocoyams and sought to diversify and at the same time introduce a gluten free product into the market. Cocoyams are aroid crops grown in marshy areas and are root tubers. They are high in digestible starch and other minerals with relatively high sodium to potassium ratio. Five trials were done, grits were used in the first trial and paste in the second trial. In the 3rd ,4th and 5th trials a combination of paste and grits was used. The product quality kept improving until the final trial when a moisture content of 3.005 was achieved from 1%, 5.2%, 2.8% and 3.012% in the 1st ,2nd, 3rd and 4th trials respectively. The sweetness of the final product was reduced and the hydration properties improved from bad to good to very good. The most acceptable trial was the 5th trial in which the moisture content was 3.005%, the hydration properties were very good and sweetness was good. The cocoyam breakfast flakes were also not too sweet and the colour was golden brown.

 

Production of a cow pea sausage 

Kudzai Makaza, Nozithelo Manyumwa, Audrey Chimeri, Grace Rundora, Bothwell Marumbwa, Amos Musengi

Abstract

The study was carried out based on the aim of producing a dried cowpea sausage as a source of concentrated protein. Cowpeas are leguminous plants that belong to the Vigna Unguiculata taxonomy. The extraction process was done using an alkaline (NaOH) as the solvent for carbohydrate isolation. Several trials were carried out while varying the steeping time. To neutralize the extract acetic acid was used. A paste was then made of a solution containing protein, lipids, minerals, and the remaining carbohydrates. Additives for flavoring were added to the paste which was then dried partially using a microwave oven. The dried paste was stuffed into cellulose casings and the cooked in a force draft oven. The best viscosity resulted from the solution that was steeped in sodium hydroxide for the least hours. It was concluded that domestic processing techniques like soaking and cooking have a significant effect on the carbohydrate and mineral content of cow pea. Processing of cowpeas reduce post-harvest grain losses caused by insects and pests which are constraints to the wide utilization of the produce.

 

Production of pumpkin bar

Raymond Chinaka, Kuzivakwashe Chasi, Vincent Kahari, Takudzwa Nzombe, Ratidzai Bvitira, W. Gwala  

 Abstract                                    
After taking into consideration that in the Zimbabwean markets most of the snack bars were being imported from other countries this stimulated this project which aims to come up with a   pumpkin bar that would increase variety in the market. The production of the bar utilized the locally available   vegetable, pumpkin. During the course of the product development, product testing analysis tests were carried out to get the views of the consumers, so that the pumpkin bar would bring about the attributes that consumers liked most. The pumpkin bar was  prepared by first peeling the pumpkin and drying the pumpkin to produce the pumpkin powder which was then mixed with other ingredients which include  honey , oats,  peanuts , milk and milk the flux seed was used as a binder and then moulded into desired shapes. After coming with the product we carried out a sensory evaluation test among the students by use of questionnaires and from the results it showed that 48% of the consumers liked the product while the others were not very fond of the idea of the pumpkin could be cooperated in the production of a bar.

 

Development of cookies from colocasia esculenta

Mark Jonathan, Elton M. Chikosha, Ruvimbo Chihwai, Vanessa Chawafambira, 
Elizabeth V. Mungwari, F. Mujuru,  C. Nyambi

Abstract

After realizing that in the Zimbabwean market the dominating cookies are from wheat and that the madhumbe crops are being underutilized, the main aim of this project was therefore to come up with a product which diversifies products on the market, hence the production of madhumbe cookies. During the course of the product development, concept development testing and prototype development analysis tests were carried out to get the views of the consumers, so that the madhumbe cookies would bring about the attributes that consumers liked most in wheat cookies. Madhumbe were peeled, washed, sliced, dried and milled to obtain flour. The madhumbe flour was then blended with wheat flour. Other baking ingredients were then added to attain a non-sticky dough which was cut into shapes then baked. Varying proportions of ingredients and different temperature-time profiles were used during baking while noting the colour, texture and appearance until a desirable product was obtained with the attributes expected by the consumers. Sensory evaluation was carried on the product by use of questionnaires. From the results obtained 68% of the consumers liked the product, 18% did not like the product and 14% neither liked nor disliked the product.

 

Formulation and development of bread from blending wheat (triticum sativum)   and sorghum (sorghum bicolor) flour

Edward Makumire, Munyaradzi Mutero, Evelyn Gumunyu, Dephine Gwezere, Tariro Chikanga, Ruvimbo Mukombero, Rapheal Kwiri  


Abstract

After realizing that sorghum, a small cereal grain produced in Zimbabwe, was being underutilized yet it has high fiber, an idea of making bread from a blend of white sorghum and wheat flour. The aim of the project was to produce a healthy bread, with the objectives of formulating the wheat to sorghum ratio, designing a production process and determining the major nutritional value of the wheaghum bread. The bread was made by blending sorghum and wheat flour, yeast, salt, sugar, baking fat, and water to form a dough. The dough was kneaded and fermented primarily for one hour at 35 degrees Celsius then secondarily for 30 minutes at 35degrees Celsius. The bread was baked at 220 degrees Celsius for 15 minutes then the temperature was reduced to 180 degrees Celsius for 30 minutes to complete the baking process. During the course of the product development, product testing analysis tests were carried out to get the views of the consumers, so that the wheaghum bread would bring about the attributes that consumers liked most in bread. Many samples of the bread were prepared while varying the sorghum contents until complete rising of the bread dough had been achieved. Temperature was maintained whilst noting the texture, taste, color, springiness and the proximate analysis of the bread until a desirable product was produced with all the expected attributes. After coming up with the product sensory evaluation tests were carried out among the students by use of questionnaires and from the results it showed that 80% of the consumers liked the product while the 10% where not very interested about the idea of the sorghum containing bread  and the other 10% rejected the bread.