This study presents the effects of process parameters on the energy demand for drying and quality indices of dried tomato slices. The experiment was designed and analyzed with the Box‐Behnken method of Design Expert and conducted for drying 1800 g batch of a local variety of tomatoes with a solar‐electric dryer. The study examined the impact of varying process parameters: air temperature (50°C, 60°C, and 70°C), sample thicknesses (10, 15, and 20 mm), and air velocities (1.0, 1.5, and 2.0 ms−1) on the total and specific energy requirements, drying time, lycopene content, ascorbic acid, nonenzymatic browning index, brightness, and ratio of redness to yellowness of dried tomato samples, with emphasis on process optimization and drying time. The prediction of the optimal process condition is obtained using the desirability index technique. The results obtained show that the total and specific energy requirements for a batch of tomato varied from 7.82 to 125.48 kJ h and 6.70 to 179.83 kJ h g−1. The results of the analysis of variance (ANOVA) indicate that all the studied process parameters were significant with P > .05; with the maximum (40.21%) and minimum (19.82%) percent energy contribution by air temperature and air velocity, respectively. The energy of activation varies between 20.26 and 39.35 kJ mol−1. At the optimum process conditions of 57.28°C, 14.08 mm, and 1.3 ms−1, the specific energy requirements, lycopene content, ascorbic acid content, nonenzymatic browning index, brightness, redness to yellowness ratio, and drying duration are obtained as 103.313 ± 2.35 kW h kg−1, 58.7 ± 2.19 mg/100 mg dry matter, 2.9 ± 0.26 mg/g, 0.51 ± 0.033 absorbance unit, 60.074 ± 1.44, 0.77 ± 0.021, and 61.88 ± 8.93 minutes, respectively. The results of the study are of immense benefit to the food drying industry, as it provides food industries with improved drying parameters for enhancing dried tomato quality, as well as increasing dryer energy efficiency and cost‐effectiveness. Sugestions on prospects for further studies were given.

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The modification in design of the hammer mill focused on the hammer pattern and arrangement; whereas the performance analysis was conducted based on the average particle of bambara nut, cassava, and maize samples. The average particle sizes of the samples were compared to those produced with standard hammer mill and burr mill. The result shows that although the three grinders had no course (C), few medium (M) and mostly fine (F) particle size particles. The least average particle sizes the modified hammer mill produced were 0.0098μmm, 0.0106 μmm, and 0.0088μmm compared to 0.019 μmm, 0.017 μmm and 0.03 μmm and 0.0066 μmm, 0.002 μmm and 0.002 μmm with the standard hammer mill and standard burr mill (control) for bambara nut, maize, and cassava respectively. Tests of significant mean difference undertaken using Tukey's method (P < 0.001) indicated that average particle sizes of bamabara nut and cassava using modified hammer mill and standard burr mill were not significantly different but significantly different with maize, whereas average particle sizes of all the samples produced with the standard hammer mill were significantly different. In conclusion, the use of the modified hammer mill drastically reduced the non-uniformed particle size associated with most hammer mills as well as eliminates the use of burr mill by farmers in the study area as alternative to produce fine grind. Recommendations for further works were stated.

The fracture resistance of food grains is an essential piece of information required for the optimum design and development of agricultural post-harvest machinery. In this study, the strength properties of two varieties of Bambara kernels (TVSU-1395 and TVSU-1353) were examined in terms of the mean rupture force, absorbed energy, and deformation as affected by the moisture content and kernel size. To achieve this, a quasi-compressive force was applied on the two varieties of Bambara kernels of varying moisture contents (5.43%, 7.24%, 9.01%, 11.54%, and 13.62% wb) and kernel sizes (small, medium, and large) in between the loading compartments of a universal Testometric device at a 20 mm/min loading rate. The experiments take ten treatments with 20 replications subjected factorially to a completely randomised design (CRD) into consideration. The results revealed that the force needed to initiate the kernel fracture increased with an increase in the kernel size and moisture content from 101.44 to 235.06 N and 74.69 to 190.49 N for TVSU-1395 and TVSU-1353, respectively; whereas the energy at the kernel fracture point increased in a range of 0.074 to 0.401 J and 0.062 to 0.141 J for TVSU-1395 and TVSU-1353, respectively. The kernel deformation increased with the moisture content and size from 0.654 to 3.746 mm. These infer that the large kernel size of the TVSU-1395 variety at a 5.4% moisture content had greater compressive strength than the TVSU-1353 variety. The kernel moisture and size exhibited a strong correlation (0.958 ≤ R² ≤ 0.997) with the strength parameters. The results of this study will help the food industry in designing energy-efficient post-harvest equipment for Bambara kernel processing. Further studies may consider the strength attributes of Bambara kernels at varying rates of loading, kernel orientations, and varieties to optimise the best process conditions for the post-harvest handling of different Bambara cultivars and develop labour-saving decorticating machines.