Heat treatment and loading orientation effects on some mechanical properties of steamed cashew kernels (Anacardium occidentale L.)

The economic interest has made many countries of the world to encourage the cultivation of cashew and it is fast becoming an export produce in many developing countries.  The necessary processing operations needed for cashew nut before obtaining the standard exportable quality of edible cashew kernel require lot of time, materials and human resources.  This study considers the wholeness of kernels obtainable by varying the drying duration and temperature. The cashew kernels were steamed, peeled and dried.  Mechanical properties of the dried samples of the kernels were determined at axial, lateral and longitudinal loading.  The breaking force and energy of cashew kernels followed a non-steady pattern with moisture removal at constant temperature and different durations of drying.  However, to save energy and time, drying at 80oC for 5 h and drying at 90oC for 3 h are recommended for high quality kernels

Physicochemical properties of sorghum (sorghum bicolor l. Moench) starch as affected by drying temperature

 N. A. Aviara1, J. C. Igbeka2, L. M. Nwokocha3(1. Department of Agricultural and Environmental Resources Engineering, University of Maiduguri, Maiduguri, Nigeria;2. Department of Agricultural and Environmental Engineering, University of Ibadan, Ibadan, Nigeria;3. Department of Chemistry, University of Ibadan, Ibadan, Nigeria) Abstract: Starch was isolated from sorghum (white) grains and its proximate composition determined.  Scanning electron micrograph and x-ray diffraction pattern of the starch were obtained using scanning electron microscope and x-ray diffractometer, respectively.  The effect of drying temperature in a tray dryer on starch physicochemical and pasting properties was investigated.  The open air dried starch had a composition of 10.73% moisture, 0.30% ash, 1.06% protein and 1.07% fat.  Amylose content was 21.08% and it had an average granule size and pH of 18.59 μm and 5.45, respectively.  The starch exhibited the A-type crystalline diffraction pattern, which was not altered by drying in a tray dryer at the temperature range of 40 to 60℃.  Water binding capacity and swelling power of the open air dried starch were not significantly different from those of starch dried at 40℃ (p<0.05).  Water binding capacity increased from 79.63 to 88.5%, while swelling power, solubility and percentage syneresis decreased from 12.01 to 8.96 g/g, 7.08 to 2.85% and 14.00 to 10.80%, respectively as the drying temperature increased from 40 to 60oC.  Paste clarity was low (22.50%–26.20%) but increased with an increase in drying temperature up to 50℃ and decreased with a further increase in temperature.  Pasting properties of open air dried starch differed significantly from those of starch dried at different temperatures.  Peak viscosity decreased from 398.75 to 325.25 RVU as the drying temperature increased from 40 to 60℃.  Setback viscosity increased with an increase in drying temperature up to a point and decreased with a further increase in temperature.  Final and breakdown viscosities as well as pasting temperature and peak time had polynomial relationships of the third order with drying temperature.  Regression equations that could be used to adequately express the relationships existing between the physicochemical and pasting properties of sorghum starch and drying temperature were established.  These models could be used to select the drying temperature that would yield starch of desired physicochemical properties for a functional application.Keywords: sorghum starch, degree of crystallinity, physicochemical properties, pasting properties, drying temperature, tray dryer Citation: Aviara N. A, J. C. Igbeka, and L. M. Nwokocha.  Physicochemical properties of sorghum (sorghum bicolor l. Moench) starch as affected by drying temperature.  Agric Eng Int: CIGR Journal, 2010, 12(2): 85-94. &nbsp

Predictive Model Equations for Palm Kernel (Elaeis guneensis J.) and Sesame (Sesamum indicum L.) Oil Colour

A 3-factor experimental design was used to determine the influence of moisture content, roasting duration and temperature on palm kernel and sesame oil colours. Four levels each of these parameters were used. The data obtained were used to develop prediction models for palm kernel and sesame oil colours. Coefficient of determination R2 , probability of prediction F, and analysis of variance technique were employed to authenticate the adequacy of the models. Colour intensity increased with increase in moisture content, roasting duration and temperature of both oilseeds. Rated by lovibond unit, palm kernel oil colour varied from 6.4 to 8.8 yellow and 2.7 to 3.8 red. Sesame oil colour varied from 5.8 to 8.3 yellow and 2.3 to 3.4 red. Therefore the three parameters investigated all had significant effects on palm kernel and sesame oil colour. Coefficients of determination R2 at 95 % confidence level for palm kernel and sesame oil colours were 0.94 and 0.93 respectively. Probability of prediction F, for palm kernel oil colour was 0.92 and 0.77 was recorded for sesame oil. Estimated error of ± 0.18 and ± 0.2 are envisaged while applying the models for predicting palm kernel and sesame oil colours respectivel

Comparison of Water Adsorption Characteristics of Plantain and Cocoyam in a Controlled Storage Condition.

This investigation was conducted to study the behaviour of dehydrated products of cocoyam and plantain in a controlled storage environment at temperature range of 25 and 40oC. Salt solutions were used to achieve water activity that ranged from 0.08 to 0.97. Equilibrium moisture content obtained was used to produce sorption isotherms at these temperatures. Sorption models of Halsey, Chung Pfost, and Henderson were evaluated on the experimental data as well as modified versions of Halsey and Henderson. Co-efficient of determination ranged from 0.80 to 0.97 in all the models. Most equilibrium moisture content obtained during the experiment reflected adsorption except for very low water activity. Chung Pfost equation gave the best fit for the absorption characteristics of these crops having the least residual mean square within 0.03 to 0.11%. Plantain exhibited higher affinity for water than cocoyam in all the relative humidity range. Least moisture content derived for storage stability of these crops varied from 6.5 to 8.2 and 6.3 to 8.2 % in cocoyam and plantain respectively. The region of local isotherm II of relative humidity between 23 and 65 % was identified as the region for optimum storage

Process Optimization of Oil Expression from Sesame Seed (Sesamum indicum Linn.)

Sesame seed (Sesamum indicum Linn ) is a tropical economic crop with high oil yield. A study was carried out to establish the degree of influence of moisture content, duration and temperature of roasting on oil expression from this crop using an oil expeller. Effects of these parameters were used to develop model equations, optimize oil yield and quality. 4 levels each of moisture content, roasting duration and temperature were used for the experiment, giving a total of 64 samples. Expressed oil was recorded as yield while free fatty acid, oil impurity and color were the criteria used in determining oil quality. Data were analyzed, employing multiple regression technique to generate mathematical models. Oil yield was maximized while oil free fatty acid; color and impurities were kept at acceptable levels. Mean oil yield, free fatty acid, impurity and color were 34.78 %, 2.57 %, 0.22 % and 6.7 respectively. The optimum moisture content, roasting duration and roasting temperature were 4.6 % wet basis (wb), 13.0 min. and 124.2 o C. These combinations gave 50.4 % oil yield, 1.1 % free fatty acid, 0.1 % oil impurity and 6.2 LUY. Error in prediction is not significance at P > 0.05. Expression of sesame seed at the obtained optimum parameters guarantees high yield and good quality virgin oil