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In the present investigation, African arowana ( Heterotis niloticus ) fish samples were subjected to drying and smoking separately in order to evaluate the effect of low and elevated temperatures on the chemical and microbiological qualities of resulting product. The different temperatures used during drying included 50°C (SampDried50), 60°C (SampDried60), 80°C (SampDried80) and 100°C (SampDried100) and 120°C (SampDried120). Cold smoking (smoking at 45-50oC) and hot smoking (smoking at 75-80oC) were also used in producing smoked Heterotis niloticus . Analysis of the dried and smoked Heterotis niloticus samples indicated that the SampDried120 had the highest protein content of 37.98% while 4.12% was recorded for the SampSmoked75-80 sample as the highest ash content. Free fatty acid (FFA) was lowest (0.31 KOH/g lipid)) in the SampSmoked75-80 sample while 0.31 (mg MDA/kg) was recorded as Thiobarbituric acid (TBA) value for SampDried120. The SampDried120 sample recorded the highest potassium, calcium, phosphorus, magnesium and sodium contents (mg/100g), having respective values of 76.38, 43.04, 64.37, 21.20 and 134.24. Similar results were recorded for the essential amino acids of the Heterotis niloticus samples, with the SampDried120 sample having highest values. Evaluation of microbiological quality showed that Pseudomonas , coliforms and Staphylococcus were lower in the smoked samples than others. This investigation concluded that hot smoking and drying at elevated temperatures of 80, 100 and 120°C could extend shelf life of Heterotis niloticus as a result of reduction TBA and FFA values; furthermore, there were higher values of protein and ash than in other samples.

Publisher Summary Many crops in developing countries, such as plantains, soybeans, tigernuts, and breadfruits, possess inherent nutritional values and therapeutic properties that could be exploited for enhancement of human nutrition and well-being. Such nutritional values could be transformed into human use by wheat-composite flour technology for bread production. Composite flours are mixtures of different vegetable flours–rich in starch, protein, and/or other nutrients–—with or without wheat flour. The ingredients used in composite flours depend on the availability of raw materials in the country concerned. The goal is to minimize cost of production compared to the cost of imported wheat because this would enable affordability of the final product by consumers. The presence of at least 70% wheat flour is required for good dough formation in wheat-composite flour for bread production. Irrespective of the low level of flour from crops that could be successfully adopted in composite flour/bread technology, it will accrue in great savings of the scarce resources of most developing countries, especially in Africa, where wheat cultivation does not thrive for climatic reasons.