PROF. MICHAEL WANDAYI OKOTH

The objective of this work was to develop an artificial neural network model to predict milk temperature of a locally fabricated solar milk pasteuriser, based on measures of error deviation from experimental data. A three-layer feed-forward neural network model based on back propagation algorithm was developed using the Neural Network Toolbox for MATLAB®. The inputs of the model were ambient air temperature, solar radiation, wind speed, temperature of hot water, and water flow rate through the collector, whereas the output was temperature of milk being pasteurised. The optimal neural network model had a 4-4-1 structure with sigmoid transfer function. The neural network predictions agreed well with experimental values with mean squared error, mean relative error and correlation coefficient of determination (R2) of 5.22°C, 3.71% and 0.89, respectively. These results indicate that artificial neural network can successfully be used for the prediction of the performance of a locally fabricated solar milk pasteuriser.

A total of 138 households were interviewed on various aspects of camel milk and camel milk products using a single-visit multiple-subject diagnostic survey in Garisa, Wajir and Eastleigh the main urban centres with high camel milk consumption. 75% of the respondents generally take camel milk or milk products every day. Raw and sour milk are the most popular products. The most important purchasing criterion for raw camel milk was taste (19 and18%) while packaging was more important for pasteurized milk (18, 18 and 16%) for Wajir, Garisa and Eastleigh respectively. For Yoghurt, the most important purchasing criteria were taste (18%) and aroma (19%). The taste of sour milk is the most important attribute in both Garisa (30%) and Eastleigh (24%). To enhance marketing of camel milk, the appropriate attributes demanded by customers needs to be seriously addressed. Promotion of camel milk and products to non conventional consumers should be done in order to increase their consumption.

Objective: To determine the consumption pattern and characteristics of potato crisps in Nairobi City, Kenya. Methodology and results: Potato crisps consumption pattern was studied using studied structured questionnaires to collect data from 215 crisps consumers. A total of 80 shops were surveyed to establish the brands and characteristics of potato crisps sold within Nairobi City. The available brands were then sampled and evaluated at the University of Nairobi. Of the sampled 215 consumers were males while 67.4 % were females. A majority, 73.9 % consumed potato crisps on average once a week. A part from gender, the frequency of purchasing crisps was also influenced by factors such as occasions, seasons and availability of money. Most consumers (22.3 %) preferred Tropical heat brand, 10.82 % preferred Krackles while the least (0.57 %) preferred Pringles, Delice and Highlands crisps. The most preferred flavor was onion and slightly salted crisps. The most purchased packaging units (51.7 %) ranged from 30-50 g due to affordability, retailing at Kshs. 30-40 (about 0.5 USD) compared to units of 150 g and above that were least purchased (1.7 %) due to their high costs, retailing at Kshs. 100 (about 1.5 USD) and above. A total of 28 % of the consumers bought crisps for self-consumption while 72 % purchased both for self and family members. All the outlets surveyed (100 %) sold potato crisps. Only 15 % of the outlets stocked potato crisps and other potato products such as chevda and potato sticks. A total of 24 brands of crisps were sold in Nairobi city. The most stocked brands in the outlets were Tropical heat and Krackles that were available in 46 and 45 % of the outlets surveyed, respectively. All the shops surveyed stocked brands of crisps made in Kenya while only 15.3 % of the outlets also had imported brands. The units of packaging ranged from less than 10 g to 1 kg. The most popular unit packages (40 %) varied from 10 to 100 g as they were cheap and affordable to most customers selling between Kshs. 10 to Kshs. 60. The study indicates that potato crisps are highly consumed by young children and youths in their teen ages while parents were moderate buyers of the products. Laboratory characteristics of the brands evaluated included colour, size, thickness, moisture, salt and oil contents that significantly (PB0.05) differed among the brands. The oil content ranged from 24.37 to 40.22 % while the moisture and salt contents varied from 1.09 to 5.45 %, and 1.10 to 2.96 %, respectively. Conclusions and application of results: Consumption of crisps in Nairobi city depends on gender, occasions, and seasons of the year and availability of disposable income. Except in the sizes, most brands had characteristics that conformed to the standards set for crisps. This study provides a view of the current scenario in the crisp market and is useful information to consumers, processors and policy makers in the potato sub sector.

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