The physical properties of grain, such as temperature and moisture content are two key factors in grain storage. Temperature and relative humidity are two crucial factors for stored grain. In this study, three different storage conditions (room temperature at , 25°C; cooling at , 4 °C; and freezing at , -20°C) were investigated. Yellow dent corn (Zea mays L.) maize(variety Blue River 571136) from Iowa, harvested in 2011 was used. Maize grain was stored in two hermetical sealed binsarrels (50-cm diameter x 76-cm height). Five logger sensors were installed inside the cylindrical bin to measure temperature and relative humidity of the maize graingrain. The sensors were located at the top, center, bottom, left and right at about 12 cm part. After placing each barrel into storage condition, temperature and relative humidity values were measured every minute for 9 days throughout the duration of the experiment. Model validation was carried out by comparing predicted with measured maize grain temperature data data in three differences points of plastic cylindrically bin the radial and vertical directions. arrel.The temperature in the hermetically sealed cylindrical bins varied, mostly in the radial direction and very little in the axial vertical directions. No noticeable change in temperature was observed in room condition. Moreover, the temperature in the grain changed more rapidly in the freezing conditions than in the room and cooling conditions. Furthermore, the lag time between the center temperature and the side (right, left, top, and bottom) was greater in the radial direction as compared to vertical temperature. Model validation was carried out by comparing predicted with measured maize temperature data in three differences points of plastic cylindrically barrel. Predicted data were closely followed measured data. The model can be used to predict the grain temperature changes in room, cooling and freezing under hermetic conditions.The maximum difference between predicted and measured temperature was ±1.5°C. The predicted and measured values of maize grain temperature at radial and vertical directions were found to be in good agreement. The model shows a good potential application to predict the temperature of maize grain stored at room, cooling and freezing conditions under hermetic storage.

Sitophilus zeamais (maize weevil) is one of the most destructive pests of maize stored in tropical and subtropical regions. This study determined the resistance of flint corn and dent corn to infestation by S. zeamais (Motschulsky), the maize weevil. Improved King Philip hybrid flint corn and Fontanelle 6T-510 hybrid dent corn were used in this experiment. Two temperature conditions (10 °C and 27 °C) and two storage times (15 days and 30 days) were used. Results showed that flint corn was more resistant to insect damage than dent corn at 27 °C and 30 day storage time. After 30 days storage time and 27 ºC death rate was significantly higher in flint corn (R2 = 0.945) compared to (R2 = 0.634) in dent corn. Damaged seed was 10% higher in dent corn then in flint corn at 27 ºC and 30 days. However, no significant difference was observed for seed weight loss between flint corn and dent corn at the same storage conditions. Both dent and flint corn are extensively cultivated in developing countries. It appears that storage of flint corn may be one promising solution to reducing corn damage and infestation problems in the tropics and in developing countries, but more research is needed.

Agriculture is the backbone of Tanzanian economy. It accounts for about one-third of the gross domestic product (GDP), provides 85 percent of all exports and saves as a livelihood to over 80 percent of the total population. Maize is the primary staple crop; it’s grown in nearly all agro-ecological zones in the country. Tanzania is a major maize producer in Sub-Saharan Africa. In the last four decades, Tanzania has ranked among the top 25 maize producing countries in the world. In the 2013/14 growing seasons Tanzania produced over half billion metric tons of maize of these maize smallholder farmers produced around 85%. Despite the steady production of maize over the past three decades, post-harvest losses of maize remained significant, up to 30-40 % in some rural areas. Post-harvest handling, poor infrastructure, weather variability, biotic factors such as insects and pests, bacteria, pathogens, viruses, and fungi, often aggravate such losses. Mycotoxin producing fungi pose a major risk. Mycotoxins are toxic secondary metabolites of fungi that frequently contaminate the maize in the field and/or during storage. Mycotoxin contamination of maize poses a health risk to humans and animals if not properly managed. The most important mycotoxins in Tanzania are the aflatoxins, fumonisins and Ochratoxin. The objective of this paper was to review current literature on the production trends, consumption, post-harvest losses, and mycotoxins contamination of maize and to provide strategies to control and prevent postharvest losses and mycotoxins contamination in Tanzania.

Techno-Economic Analysis (TEA) plays an important role in assessing economic performance and potential market acceptance for new technologies. Previous work has shown that the construction and operation of a cellulosic bioethanol plant can be very expensive. One of the largest cost categories is pretreatment processing. The purpose of this study was to conduct a detailed cost analysis to assess low moisture anhydrous ammonia (LMAA) pretreatment process at the commercial-scale, and to estimate the breakeven point in large-scale production. In this study, capital expenses, including annualized purchase and installation fees, and annual operating costs associated with each unit operation were determined. This research compared the unit cost per year between different scales of the LMAA process, and focused on exploring the optimal cost-effective point for this pretreatment method for bioethanol production.

The knowledge of physical and thermal properties in cereals, grains and oilseeds establishes an essential engineering tool for the design of equipment, storage structures, and processes. The physical properties and thermal properties for Chia, Kañiwa, Farro and Triticale grains were investigated at three levels of moisture content: 10 %, 15 % and 20 % (d.b). Physical properties determined where 1000 seed weight, seed dimensions, arithmetic and geometric mean diameter, surface area, volume sphericity and aspect ratio. The result shows 1000 seed weight increased linearly with moisture content from 2.0 to 3.5 g for chai, 2.5 to 4.0 g for Kañiwa, 42.7 to 48.3 g for Farro and 51.0 to 53.7 g for Triticale. Likewise, the bulk and true density decreased as moisture content increased. The porosity for Farro and Triticale increased from 38.71% to 44.17 %, 40.37 % to 44.65 % respectively as moisture increased from 10 to 20 %. The angle of repose for Chia, Kañiwa, Farro and Triticale all increased as moisture content increased. In general, the values of L, a* and b* increased with moisture content. Thermal properties showed a very good correlation to moisture content. The negative relationship was observed for the specific heat capacity and thermal conductivity while the thermal diffusivity had a positive linear increase trend with moisture content. This study showed that physical and thermal properties varied from grain to grain as a function of moisture content. The findings of this study will broaden the knowledge of physical properties of Chia, Kañiwa, Triticale and Farro and provide useful data for industries and researchers.

The worldwide decline and overexploitation of ocean fisheries stocks had provided incentive for rapid growth of aquaculture. The aquaculture industry has been recognized as the fastest-growing food production system globally, with a 10% increases in production per year, and is one of the most reliable and sustainable growth markets for manufactured feeds. Extrusion technology has been extensively used in the modern aquatic feed manufacturing, due to nutritional, physical properties improvements and cost effectiveness of feeds. Cost related to aquatic feed remains the biggest challenge, especially for small-scale producers. In this study a single screw extruders and three different scenarios (i.e. 0.2 tons/day, 2 tons/day, 20 tons/day) throughput were used to develop techno-economic models for small-scale producers of extruded aquatic feeds. The results show annualized capital costs decreased as production capacity increased. Thus, aquatic feed producers could use this tool to evaluate annual costs and benefits to determine processing economics.