Rheological Characteristics of Fresh and Dried Okra Dispersions

The rheological properties of fresh and dried okra dispersions were investigated at different temperatures using power-law model. Sun-dried and oven-dried okra dispersions were more viscous than the fresh okra dispersion. All samples exhibited pseudoplastic behaviour with flow indices of 0.220 ≤ n ≤ 0.319, 0.182 ≤ n ≤ 0.323, and 0.120 ≤ n ≤ 0.348, respectively for oven-dried, sun-dried and fresh okra dispersions with shear thinning  effect. An increase in temperature decreased apparent viscosity. The  consistency coefficient, k, and the flow behaviour index, n, decreased with increasing heating temperature. The Arrhenius type equation was used to  study the temperature dependence with activation energies of 10.08, 8.20 and 6.22 KJ/mol for fresh, sun-dried and oven-dried okra dispersions  respectively. The relationship between the power-law parameters and temperature was analyzed

Thermal Properties of Kerstingiella geocarpa Seeds as Influenced by Moisture Content

The specific heat capacity, thermal conductivity and thermal diffusivity of Kerstingiella geocarpa seeds were determined as a function of moisture content. The initial moisture content of the seeds determined using the ASAE standard test was 10.0 % (d.b). The specific heat capacity of Kerstingiella geocarpa seed increased from 155.83 to 204.45 Jkg-1k-1, as the moisture content increased from 10 to 30 % (d.b). The thermal conductivity of the seed increased from 5.13 x 10-2 to 4.87 x 10-1 Wm-1k-1, as the moisture content increased. The thermal diffusivity of the seed increased from 2.35 x 10-4 to 3.66 x 10-3 m2s-1, as the moisture content increased. These values indicate the ability of the Kerstingiella geocarpa seed to retain heat when processed. The regression models that could be used to adequately express the relationships existing between the thermal properties of the Kerstingiella geocarpa seed and moisture content were established.Keywords: Kerstingiella geocarpa seed, specific heat, thermal conductivity, thermal diffusivity, moisturecontent

Evaluation of the Dehulling Efficiency of Soybean Using Attrition and Rice Milling Machines

A process for mechanical dehulling of soybean was developed. Soybean seeds were soaked in boiling water (100oC) for 5, 10, 15, 20 and 25 minutes respectively. The soaked seeds attained a moisture content of 17 – 24%, so as to facilitate dissolution of the gum layer, which bound theseed coats to the endosperm. Conditioned seeds were dehulled in the huller section of commercial rice milling machine and attrition milling machine. A dehulling efficiency (e) value of 55%, which corresponded to anextraction yield (E) of 44% was achieved using the huller section of a commercial rice milling machine, while 90% dehulling efficiency (e), corresponding to an extraction yield (E) of 72%

Effect of Annealing on the Physicochemical Properties of Some Under-utilised Legume Starches

Starches isolated from Jack bean (JBS), Detarium microcarpum (DMS), Bambara groundnut (BNS) and African yam bean (AYBS) seeds were annealed at 50oC for 24 h. Proximate composition of the starch samples revealed that the moisture content of the starches ranged from 8.65 to 9.88%. There was increase in the moisture level of the annealed starches compared to native starches. The protein, ash, fat and fibre contents reduced in all starch samples following annealing compared with the native starches. Annealing decreased the swelling power and solubility index (BNS > AYBS > JBS > DMS), peak viscosity (JBS > BNS > DMS > AYBS), setback viscosity (AYBS > BNS > JBS > DMS) and breakdown viscosity (AYBS > DMS > BNS > JBS). However, annealing increased pasting temperature (BNS > JBS > DMS > AYBS), water (JBS>DMS>BNS>AYBS) and oil (JBS > DMS > BNS > AYBS) absorption capacities

Qualities of fufu flour from white yam varieties (Dioscorea spp)

The physico-chemical and sensory properties of fufu flours from three local white yam varieties, Ozibo, Okpebe and Nwopoke were investigated. The tubers were peeled, sliced, blanched and dried in an oven set at 60°C to constant weight. The chips were milled into flour, passed through American Standard sieve number 10 and analyzed for moisture content (MC), loose bulk density (LBD), water absorption capacity (WAC), swelling capacity (SC) in water at 30°C and 50°C, blue value index (BVI), extensibility and the gelatinization temperature. Sensory evaluation of fufu reconstituted from the flour samples was carried out. The qualities assessed were texture, stickiness, appearance and general acceptability. The result showed that the swelling capacity at 30°C and 50°C of Nwopoke were significantly different (

Evaluation of the pasting and some functional properties of starch isolated from some improved cassava varieties in Nigeria

Improved cassava of 13 cultivars (NR01/004, NR01/0161, NR01/0071, CR14A-1, CR.41 – 10, AR38 – 3, TMS01/0040, TMS01/1086, TMS00/0210, TMS00/0203, TMS00/0214, TMS30572CK and Local best (CK) were converted into starch and analysed for some functional and pasting properties. Variations wereobserved in the functional properties of the starch samples; water absorption capacity ranged from 59.75 – 68.02%; oil absorption capacity 60.70 – 80.01%; swelling power 5.49 – 6.92% and solubility index 4.25 – 5.96%. Significant differences (P < 0.05) were observed in the functional properties of the starch samples. The peak viscosity ranged from 74.25 – 178.25 RVU. Starch from the local best CK had the highest peak viscosity (at a temperature of 63.80°C in 3.68 min) and TMS01/0040 had the lowest (at 63.90°C in 3.88 min). The breakdown viscosity ranged from 56.50 – 107.75 RVU with starch from local best CK having the highest and starch from TMS01/0040 had the lowest. The final viscosity ranged from 21.50 – 111.33 RVU. Starch from local best CK had the highest and that from TMS00/0203 had thelowest. The setback viscosity ranged between 9.75 – 49.25 RVU with starch from local best CK having the highest and that from TMS01/0040 having the lowest. The pasting temperature ranged from 63.00 – 64.70°C, with starch from TMS00/0214 having the highest and that from NR01/0161 having the lowest. There were significant differences (P < 0.05) in the pasting properties of the starch samples. The apparent starch amylose ranged from 13.88 – 16.35% with local best CK having the highest and that from AR 38 – 3 having the lowest; percentage starch content ranged between 48.25 – 52.05%. The localbest CK had the highest and that from TMS00/0203 had the lowest. Significant differences were observed in the amylose and starch contents of the cassava cultivars

Functional properties of chemically modified amylose and amylopectin fractions isolated from 'achi' Brachystegia eurycoma Starch

No Abstract

Modelling the Effect of Toasting Time on the Functional Properties of Brachystegia eurycoma Flour

The effect of toasting time on the functional properties of Brachystegia eurycoma flour was investigated. The water absorption capacity, swelling power and solubility index of the flour, increased with increase in toasting time, while the oil absorption capacity and amylose content of the flour decreased with increase in toasting time. The peak viscosity, final viscosity, break down and setback viscosity increased from 134.67 to 176.24 RVU, 460.33 to 650.43 RVU, 57.83 to 120.33 RVU and 405.70 to 581.17 RVU respectively, as the toasting time increased. The pasting temperature decreased from 88.25 to 78.32oC, as the toasting time increased from 0 to 12 min. Regression models that could be used to adequately express the relationships existing between the functional properties of the flour and toasting time were established.Keywords: Brachystegia eurycoma flour, pasting properties, toasting time