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1. Effect of length of fermentation on the functional characteristics of fermented cassava 'fufu'
Oyewole, O.B. and Ogundele, S.L.
Department of Food Science and Technology,
University of Agriculture,
PMB 2240,Abeokuta. Ogun State, Nigeria.
Abstract
Cassava clones 30572 was fermented to 'fufu' for different period of time ranging from zero hour to 96 hours. The quality of the 'fufu' produced as a result of different duration of fermentation was assessed. The fermentation processes were characterized with acid production but the level of acidification increased with the duration of fermentation. The yield of 'fufu', the bulk density and the dispersibility increased with increasing period of fermentation. When subjected to sensory evaluation, the preference of the panelists for the characteristic 'fufu' texture and odour increased with increased length of fermentation. Except for the 'fufu' made without fermentation ( 0 h), there was no significant difference in the colour of the 'fufu' fermented for different length of time. For all the attributes rated ( texture, odour, colour, overall acceptability), there was no significant difference between the 'fufu' fermented for 72 hours and 96 hours. A fermentation period of 72 hours was recommended for the production of good quality 'fufu' when using the cassava clone TMS 30572.
2. The suitability of locally produced milk for human consumption: Investigations into quantity, composition and quality profiles of milk at Njoro, Kenya
P.G. Bille*, M. Ahamed, V. Othiambo and E.L. Keya
*University of Naminia, Faculty of Agriculture and Natural Resources,
Department of Food Science and Technology, P/Bag 13301, Windhoek Namibia.
Egerton University, Department of Dairy and Food Technology, P.O. Box 536, Njoro - Kenya
Abstract
The basic premise of this paper is that the supply of milk and milk products from the Guildford Dairy Institute (GDI) at Egerton University (EU) in Kenya decreased drastically over the recent past as a result of a nearly six-fold increase in the human population in the area. A drop of 40 % of milk production from the university farms also added more impetus to the study. These developments resulted in a significant shortfall of milk to the GDI factory for processing and for sale to the university and surrounding communities. The results of the study carried out at some randomly selected neighbouring farms as possible source of additional milk to GDI factory showed 3.8 ± 0.5 % BF, 12.6 ± 0.8 % TS, 0.16 ± 0.02 LA, 1.029 ± 0.003 Sp Gr; - 0.55 ± 0.02 Fr Pt; 0.03 ± 0.004 Fg Pb and 0.04 ± 0.003 ppm Hg and sensory results indicated 'Liked Moderately' for all samples, which were within the Kenya Bureau of Standards (KBS) guidelines. Milk was available but the logistics to collect and pay for the milk need to be put in place.
3. Examining the need for the use of calcium chloride in the processing of Gouda cheese made from pasteurised milk.
P.G. Bille, P. Hiwelepo and E.L.Keya
University of Namibia, Faculty of Agriculture and Natural Resources, Department of Food Science and Technology,
P/Bag 13301, Windhoek, Namibia.
Abstract
Two samples of Gouda cheese were made in triplicate; one without and the other with the addition of 5 grams of calcium chloride per 100 litres of pasteurised milk and compared in terms of their proximate composition (moisture, acid, ash, butter fat and protein contents) and sensory properties (appearance, texture, taste and smell). It was observed that the addition of calcium chloride to pasteurised milk in cheese making promoted greater curd firming and whey expulsion which produced a firmer textured cheese with a drier appearance, lower in moisture content and acidity , but higher in ash, butter fat and protein contents. Most of the sensory panellists, however, preferred the cheese without added calcium chloride as it had a better taste and smell and was softer, more pliable and tender to eat. It was shown that the addition of calcium chloride to pasteurised milk for cheese making was important for marketing, especially when it was desirable to make Gouda cheese with firm appearance and texture which was inevitably linked to higher nutrient content in the final cheese. The addition of calcium chloride however adversely affected the flavour of the cheese and reduced preference for it, especially when a softer textured, more tender Gouda cheese was desired. On storage, the cheese without added calcium chloride, developed greater acidity and harshness in taste giving it a shorter shelf life.
4. In vitro relative protein digestibility and lipoxygenase activity used as parameters to test and compare quality in five varieties of soybean meals.
Elizabeth Maforimbo
Department of Research and Specialist Services, Chemistry and Soil Research Institute,
P. O. Box CY 550 Causeway, Harare, Zimbabwe.
Abstract
Proximate composition, In Vitro Relative Protein Digestibility of 5 varieties of soybean (glycine max), was done. Meals from whole seeds and dehulled seeds were both investigated. Stability to photoxidation was also monitored on the oils over a period after sunlight exposure and finally the extent of oil oxidation was determined after 10 months of ambient storage.
There was an intervarietal similarity in proximate composition for the whole seeds as confirmed by the low coefficients of variation, i e, 4.73%; 2.23%; 5.09%; 3.87% and 11.76% for moisture, crude protein, ether extract, ash and fibre respectively. An intervarietal similarity was also shown in dehulled seeds with coefficients of variation at 11.9%, 3.49%, 2.3%, 4.0% for moisture, crude protein, ether extract and ash respectively, except for the fibre content which had a higher coefficient of variation of 31.62%.
Significant differences in relative protein digestibility were shown among varieties for both the whole and dehulled seeds. Dehulling significantly improved relative digestibility in all varieties as confirmed by the t-test at a 5% level. Nyala variety gave the highest relative protein digestibility both for the whole and dehulled seeds, at 78.03% and 87.02% respectively. The yield of oil after petroleum ether extraction was highest in the Roan and least in the Duiker seed variety at 20.70% and 17.8% respectively.
Stability to photoxidation (lipoxygenase activity) for the oils was least in the Duiker variety, giving an E1%1cm (UV absorbance at 232 nm) of 11.26 after 12 hours exposure to sunlight and 62,0 after 10 months of ambient storage. The most stable oil to photoxidation was from the Soma variety giving an E1%1cm of 6.23 after 12 hours of sunlight exposure and 15.63 after ambient storage of 10 months.
The t-test indicated that there was no significant difference (P <0.05) in the rate of oil oxidation between the Roan and the Soma varieties up to a period of 10 months at ambient storage. Ranking for the following quality parameters, protein, relative protein digestibility, oil content and its stability to oxidation were in the following order; Roan, Nyala, Soma, Nondo and Duiker.
Key words: relative digestibility, stability, photoxidation, lipoxygenase activity, soybean meals.
5. Microbiological quality of some groundnut products hawked in
Bauchi, a Nigerian City
1A. A. Adebesin, 1O. T. Saromi, 2N. A. Amusa and 3S. O. Fagade
1Department of Science Laboratory Technology, Federal Polytechnic, Ede. Osun State.
2 Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, PMB 5029 Ibadan, Nigeria.
3Department of Botany and Microbiology, University of Ibadan Nigeria
Abstract
The microbial quality of roasted groundnut , Kulikuli, Yaji and Dankwa hawked in three major areas in Bauchi, Northeastern Nigeria was determined. The microbial load of the product from from each location differs, while that of bacteria isolates ranges from 1.16±0.32x105 to 5.92±0.59 x105 colony forming units/gram (cfu/g), the fungal count ranges from 1.91±0.32 x104 to 8.60±0.22x104 cfu/g of the samples. Roasted groundnut had the highest count of micro-organisms followed by Kulikuli, then Yaji and Dankwa had the least. The dominant mold in these products was
Aspergillus niger, Rhizopus Stolonifer and A. flavus while the other associated fungi includes
Penicillum citrinum, Mucor spp. and Macrophomina phaseolina. The bacterial isolates found associated with these groundnut products include
Staphylococcus aureus, S. aureginosa, Micrococcus spp. and Bacillus cereus.
Key Words: Arachis hypogaea L, Kulikuli, Yaji and Dankwa, Bauchi, roasted groundnuts, microbial quality.
6. Cottage processing of cashew apple juice in Nigeria: physico-chemical and sensory evaluation of product.
T. O. Akinwale*, O. Olubamiwa, and E. A. Ajav**
Cocoa Research Institute of Nigeria,
P.M.B. 5244, Ibadan, Nigeria.
Abstract
Some manually operated equipment were employed for cottage processing of cashew apples into juice. These include an extractor, mixer pasteuriser and a bottling machine. The apples were preheated with steam for 10, 20 and 30 minutes before juice extraction. The average capacity and efficiency of the extractor were 31.82g/hr and 87.20% respectively. Treatment time affected the colour, acidity and vitamin C content of the juice. Apples treated for 30 minutes gave a brownish colour (which was not acceptable to consumers) with the least amount of vitamin C (120.60mg/100ml of juice). The 10 minute extracted juice was attractive in terms of colour and acceptability. Soluble solids, pH, and specific gravity values of the juice were not affected by heat treatment. From the sensory evaluation of the products, no significant differences were obtained for taste, mouthfeel and overall acceptability. It was concluded that 10-minute treatment time was ideal for the juice extraction.
7. Brine treatment, smoking and storage techniques: their effects on the microbial quality of smoked mackerel.
Eyabi Eyabi G. D
Research Station for Fisheries and Marine Science of the Institute
of Agriculture Research for Development (IRAD)
PMB 77 Limbe, Cameroon
Hanson S. W. and Barlow P. J.
University of Lincolnshire and Humberside, School
of Applied Sciences and Technology Grimsby, England.
Abstract
Sample of Atlantic Mackerel (Scomber scombrus) were treated with 800 brine for 2 hours with slight agitation while untreated fish served as control. Both treated and untreated fish were loaded in a Torry Afos Mini Kiln set at 50o C. The temperature was raised to 80o C after one hour and maintained at this temperature throughout the smoking process.
Samples of treated and untreated fish (U8 and B8) were removed after 8 hours of smoking and the last batch removed at the end of 16 hours smoking (U16 and B16). Analyses for growth, identification and coverage of fish surface with mould and for sensory attributes of discoloration, off odours, brittleness (texture) and personal preference were carried out for freshly smoked and stored samples. Samples for storage were packaged in clear polythene and stored in an environmental cabinet.
Bringing and smoking time retarded mould growth, controlled discoloration, off odour development, softening of the fish and positively affected personal preference.
Penicillium sp was identified as the incriminated species.
Keywords: Hot smoking, traditional smoking, water activity, brine strength, number of fish with mould growth and mean percentage coverage.
8. Simulation models for food separation by adsorption process
Ochieng Aoyi*, K Ofosu Asiedu** and Otieno Osembo**
Chemical Engineering Dept., University of Cape Town, Rondebosch 7701, Cape Town, South Africa
*Corresponding author
**Chemical and Process Engineering Dept., Moi University
P. O. Box 3900 Eldoret, Kenya
Abstract
Separation of simulated industrial food products, by method of adsorption, has been studied. A thermodynamic approach has been applied to study the liquid adsorption where benzene and cyclohexane have been used to simulate edible oils in a system that employs silica gel as the adsorbent. Different models suggested in the literature have been tested with experimental data in order to characterize properties of the system, such as the tendency to ideality, for both adsorbed and bulk liquid phases. The methods of determining thermodynamic properties such as free energy of adsorption, adsorption capacity and activity coefficients in the adsorbed phase have been studied.
It was observed that a model based on the assumption that adsorbed phase, but not liquid phase, is ideal gave a good for that may suffice for engineering design of liquid adsorption systems that may be applied in food processing, such as decolourising crude sugar syrup, recovery of polypeptides and extraction of flavouring.
Key Words: Separation, food, model, adsorption, simulation and surface excess.
9. Some aspect of the logical way of studying dinitrogen fixation in an
agroforestry context for improving food production
Elijah. M. Akunda
Crop physiologist, Department of Botany,
University of Nairobi,
P. O. Box 30197 Nairobi, Kenya.
Abstract
Dinitrogen fixation in an agroforestry context requires a careful approach which initially require derivation of the methods to be used and careful selection of the priorities of factors which influence the process. Nitrogen element is an important component of protein foods, hence its mechanisms of incorporation in biomass and grain through fixation is vital. The methods used to comprehend its incorporation are crucial to food production.
It is suggested that priority of the factors affecting the basic process of dinitrogen fixation, especially light and water, should be taken into consideration. Logically, a quick assessment of a nitrogen fixer versus a non-fixer should be grown near and far then their assessment done with respect to biomass response. Next phase should then involve how appropriate it would be to design spacing in dinitrogen fixation experiments.
Since dinitrogen fixation research is specific, there is need to clearly state the objectives. Observations should start on growth components and characters associated with yield and dinitrogen fixation. Growth, nodulation and dinitrogen fixation should involve looking at the dry matter of the tops of plants, nodule number, position, colour, size, shape and weight. In case some competition stress is observed in the initial stages of the study, then such simple parameters of total leaf area, leaf dry weight, specific leaf area and canopy structure should be studied in the second phase. Having accumulated some knowledge about the performance of the system in the early stages, then analysis of yield discerning processes in relation to canopy structure can then be assessed.
Key words: Dinitrogen fixation, agroforestry, biomass, nodulation, experimental methods.