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The use of inappropriate equipment to crack bush mango (Irvingia gabonensis) nut to obtain the kernel has adversely affected the processing and utilization of the crop. The manual method of cracking the nut with stone, cutlass or pestle and mortar, is not only slow and risky, but also wasteful. Knowledge of the nut mechanical properties is important in the development of its processing equipment. This study was undertaken to determine some strength or mechanical properties of the nut at different moisture contents under lateral and longitudinal loading orientations, using the Universal Testing Machine (UTM). In the moisture range of 7.52%-20.6% (d.b) under the above loading orientations, results of tests showed that all the strength properties decreased with increase in moisture content. Only the rupture strength increased from 0.0507 to 0.0723 N mm-2 as moisture content increased in the above range, under lateral loading orientation. Loading along the longitudinal axis had higher strength property values than lateral loading. This implies that the nut will be easier to crack when loaded on the lateral axis. These findings will be useful in the development of a cracking equipment for bush mango (Irvingia gabonensis) nut. [ABSTRACT FROM AUTHOR]

Application of reversible thermodynamic principles to gain fundamental understanding of food--water interactions in foods has met with limited success due to the presence of moisture sorption hysteresis which is a manifestation of irreversibility. This study was aimed at understanding the nature and extent of influence of hysteresis on thermodynamic properties of two millet varieties namely EX-BORNO and SOSAT C88. Moisture sorption data (adsorption and desorption) in the water activity and temperature ranges of 0.07 -- 0.98 and 30°C - 70°C, respectively were used. Ratio of latent heat of moisture sorption to the latent heat of pure water was determined using Clausius-Clapeyron equation. Effect of moisture content on ratio of latent heat of sorption to latent heat of pure water was determined using Gallaher model. Net integral enthalpy was determined at constant spreading pressure with monolayer moisture contents calculated using Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) models. Spreading pressure was determined using an analytical procedure. Gibbs equation was used to evaluate net integral entropy. Net isosteric heat of sorpt ion and differential entropy were evaluated and used to investigate the enthalpy-entropy compensation theory. Latent heat of moisture sorption in the two millet varieties decreased with increase in moisture content and approached latent heat of pure water at a 'free water' point of between 32% and 42% moisture content (d.b.) in adsorption and desorption, respectively. Desorption latent heat of moisture was higher than the adsorption values and the difference decreased with increase in moisture content. Monolayer moisture content decreased with increase in temperature, with the GAB being higher than the BET values. Desorption monolayer moisture was higher than that of adsorption. Spreading pressure increased with increase in water activity, with adsorption isotherm being higher than that of desorption and temperature having no significant effect. Net integral enthalpy decreased with increase in moisture content with effect of hysteresis being more marked in EX-BORNO than in SOSAT C88. Net integral entropy decreased with increase in moisture content to minimum values and thereafter, maintained sinusoidal trend with adsorption curve lagging behind desorption and varnishing at 18% and 16% (db) moisture content in EX-BORNO and SOSAT C88 respectively. Net isosteric heat of sorption and differential entropy decreased with increase in moisture content with effect of hysteresis being more pronounced in EX-BORNO. Moisture sorption process in the grains was found to be enthalpy driven with differential enthalpy varying linearly with differential entropy. Inequality in isokinetic and harmonic mean temperatures confirmed the enthalpy-entropy compensation theory. Hysteresis was found to have effect on the isokinetic temperature, causing the values of desorption isokinetic temperature to be higher than the adsorption values. [ABSTRACT FROM AUTHOR]

Physical properties of Detarium microcarpum seed were investigated as a function of moisture content with a view to exploring the possibility of developing its bulk handling and processing equipment. In the moisture range of 8.2%-28.5% (d.b.), the major, intermediate and the minor axes increased from 2.95-3.21 cm, 1.85-2.61 cm, and 0.40-1.21 cm respectively. The arithmetic mean, geometric mean and equivalent sphere effective diameters determined at the same moisture level were significantly different from each other with the arithmetic mean diameter being of the highest value. The seed can be described as an irregularly shaped spherical disc. In the above moisture range, the surface area, one thousand seed weight, particle density and porosity increased linearly with moisture content from 354.62-433.19 cm², 3.184-3.737kg, 1060-1316 kg/m3 and 30% to 53.1% respectively, while bulk density decreased with increase in moisture content from 647.6-617.2 kg/m3. Angle of repose increased linearly with moisture content from 13.9o-28.4o. Static and kinetic coefficients of friction increased linearly with moisture content and varied with structural surface. Highest value of static coefficient of friction at each moisture level in the above range was on galvanized steel sheet, while the lowest value was on fiber glass. For the kinetic coefficient of friction, the highest values were on Hessian bag material, while the lowest values were on fiber glass. [ABSTRACT FROM AUTHOR]

Some physical, frictional and thermal properties of Brachystegia eurycoma seed were studied at different moisture contents in order to explore the possibility of mechanizing the handling and processing techniques. Results showed that the seed could be considered an oval disc in shape. In the moisture range of 2.79% to 27.13% (d.b.), the major, intermediate and minor axial dimensions increased with increase in moisture content from 2.29 mm to 2.45 mm, 1.65 mm to 1.91 mm and 0.34 mm to 0.52 mm, respectively. In the above moisture range, one thousand seed weight, particle density, porosity, roundness, sphericity, surface area and angle of repose increased linearly from 0.901 kg to 1.252 kg, 2270 kg/m³ to 2520 kg/m³, 11.23% to 15.46%, 35% to 47%, 67% to 82%, 7.67 cm² to 8.48 cm² and 16.8° to 29.2° respectively, while bulk density decreased from 745.4 kg/m³ to 613.6 kg/m³. Static coefficient of friction on different structural surfaces increased linearly with moisture content and had the highest values on galvanized steel sheet (0.445-0.639), and the lowest values on fiber glass (0.287-0.404). Kinetic coefficient of friction increased linearly with moisture content on different structural surfaces except on galvanized steel sheet where it decreased linearly with increase in moisture content in the above moisture range. It had the highest values on hessian bag material (0.266-0.389), and the lowest values on plywood with wood grains perpendicular to the direction of movement (0.204-0.271). Specific heat ranged from 1474 to 5992.7 J/kgK, and increased with increase in moisture content and temperature. Regression equations were used to express the relationships existing between the seed properties and moisture content. [ABSTRACT FROM AUTHOR]

The cracking of conophor nut using an impact test apparatus was carried out at different moisture contents (14.9% - 50.3% (d.b.)) and impact energy levels (0.05 - 0.19 J) under lateral and longitudinal loading orientations, in order to explore the possibility of developing an effective and appropriate technology equipment for cracking the nut. The data obtained on the quantity of fully cracked nuts with unbroken kernels, fully cracked nuts with broken kernels, partially cracked and uncracked nuts were subjected to statistical analysis. Results showed that moisture content, impact energy and loading orientation as well as their interactions significantly affected the crackability of conophor nut at 1% level of significance. The moisture content at which a combination of high whole kernel yield and minimum kernel damage was obtained ranged from 14.9% to 31.9% (d.b.). The impact energy range of 0.05 to 0.11 J gave the best combination of high whole kernel yield and minimum kernel damage at both lateral and longitudinal orientations. The study shows that the development of a spinning disc cracker, which uses impact to crack conophor nut is possible. It suggests that the radius and speed of the spinning disc should be such that would ensure that the impact energy generated and imparted on the nuts will not exceed 0.11 J and nuts should be conditioned to the dry basis moisture content that does not exceed 31.9% (d.b.) prior to cracking for optimum efficiency. [ABSTRACT FROM AUTHOR]

The specific heat of soya bean variety TGX 1 ,440-1 E, moringa oleifera seed, moringa oleifera kernel and mucuna flagellipes nut were evaluated and their variations with moisture content and temperature were investigated, using the method of mixture. The specific heat of soya bean, moringa oleifera seed, moringa oleifera kernel and mucuna flagellipes nut increased linearly from 1 780 to 2 646 J/(kg∙K), 1 520 to 2 516.121 J/(kg∙K), 1 625.24 to 2 458.214 J/(kg∙K) and 2 080 to 4586 J/(kg∙K) in the moisture content and temperature ranges of 6.16%-51.52% (d.b.) and 305.8-363 K, 8.43%-31.66% (d.b.) and 300-341.88 K, 6.75%-31.5% (d.b.) and 300-344.38 K, and 3.38%-10.7% (d.b.) and 300-330.75 K, respectively. While the specific heat of soya bean increased with increase in temperature up to a certain point and decreased with further increase in temperature, the specific heat of moringa oleifera seed and kernel increased linearly, and mucuna flagellipes nut exhibited a second order polynomial relationship between its specific heat and average temperature. Regression models, which could be used to reasonably predict the specific heat of these products at specified moisture content and average temperature, were established. [ABSTRACT FROM AUTHOR]

The effect of moisture content on some physical properties of bush mango (Irvingia gabonensis) nut was studied at four moisture levels in the range of 7.52%-20.6% (d.b). Results showed that the length, width and thickness of nut increased from 37.84 to 50.16 mm, 30.23 to 42.62 mm and 19.25 to 28.15 mm respectively, as moisture content increased in the above range. Nut sphericity decreased from 76.2% to 69.5% as moisture content increased. One thousand seed weight, bulk density, true density and angle of repose increased from 6.634 to 9.158 kg, 756.7 to 1095 kg m-3, 984.4 to 1265.8 kg m-3 and 25.3 ° to 38.9° respectively, in the above moisture range. Static coefficient of friction on different surfaces increased in the order of fiber glass (0.278 to 0.394), metal sheet (0.478 to 0.499) and plywood (0.577 to 0.602) as moisture content increased. Regression analysis showed that all properties followed a linear trend with moisture content. [ABSTRACT FROM AUTHOR]