Drying kinetic of industrial cassava flour: Experimental data in view

In this data article, laboratory experimental investigation results on drying kinetic properties: the drying temperature (T), drying air velocity (V) and dewatering time (Te), each of the factors has five levels, and the experiment was replicated three times and the output: drying rate and drying time obtained, were observed. The experiment was conducted at National Centre for Agricultural Mechanization (NCAM) for a period of eight months, in 2014. Analysis of variance was carried out using randomized complete block design with factorial experiment on each of the outputs: drying rate and drying times of the industrial cassava flour. A clear picture on each of these outputs was provided separately using tables and figures. It was observed that all the main factors as well as two and three ways interactions are significant at 5% level for both drying time and rate. This also implies that the rate of drying grated unfermented cassava mash, to produce industrial cassava flour, depend on the dewatering time (the initial moisture content), temperature of drying, velocity of drying air as well as the combinations of these factors altogether. It was also discovered that all the levels of each of these factors are significantly difference from one another. In summary, the time of drying is a function of the dewatering time which was responsible for the initial moisture content. The higher the initial moisture content the longer the time of drying, and the lower the initial moisture content, the lower the time of drying. Also, the higher the temperature of drying the shorter the time of drying and vice versa. Also, the air velocity effect on the drying process was significant. As velocity increases, rate of drying also increases and vice versa. Finally, it can be deduced that the drying kinetics are influenced by these processing factors.


b s t r a c t
In this data article, laboratory experimental investigation results on drying kinetic properties: the drying temperature (T), drying air velocity (V) and dewatering time (Te), each of the factors has five levels, and the experiment was replicated three times and the output: drying rate and drying time obtained, were observed. The experiment was conducted at National Centre for Agricultural Mechanization (NCAM) for a period of eight months, in 2014. Analysis of variance was carried out using randomized complete block design with factorial experiment on each of the outputs: drying rate and drying times of the industrial cassava flour. A clear picture on each of these outputs was provided separately using tables and figures.
It was observed that all the main factors as well as two and three ways interactions are significant at 5% level for both drying time and rate. This also implies that the rate of drying grated unfermented cassava mash, to produce industrial cassava flour, depend on the dewatering time (the initial moisture content), temperature of drying, velocity of drying air as well as the combinations of these factors altogether. It was also discovered that all the levels of each of these factors are significantly difference from one another. In summary, the time of drying is a function of the dewatering time which was responsible for the initial moisture content. The higher the initial moisture content the longer the time of drying, and the lower the initial moisture content, the Value of the data • The data on drying rate of industrial cassava flour will be useful for the industries that are planning to embark on large production of cassava flour. • The data on drying time of industrial cassava flour will be useful also for the industries to know the time needed for the cassava flour to dry at different levels of temperature and velocity. • The data can be useful for the quality assurance of any cassava flour processing company.
• The data will be useful in food processing, post harvest and bio-system engineering studies.
• The data can be useful for educational purposes and nutrition assessment studies.
• The data is useful in the study of drying kinetic of food processing into powdered particle.
• Several known statistics, for example, root mean squared error (RMSE), linear regression, and complete randomized design (CRD) can be applied which provides alternatives to analysis with randomized complete block design (RCBD) with factorial experiment used in this paper.

Data
The data describes the kinetic properties of industrial cassava flour. The raw data which consist of 375 rows, with each row having five columns: dewatering, temperature, velocity, and two outputs (drying time and drying rate) can be assessed as Supplementary data. Statistical summary of the drying time and drying rate distributions of industrial cassava flour are presented in Table 1. It was observed that the average drying time of industrial cassava flour is 6088 s equivalent to 2 h: 9 min. The least and the highest drying time so far recorded in the experiment are 870 and 33,300 s respectively.
Histogram for the drying time distribution is presented in Fig. 1. It can be observed from Fig. 1 that the Drying time distribution is not normally distributed, it skewed to right. The histogram for the Drying rate of industrial Cassava Flour is presented in Fig. 2, which also skewed to right.

Methods and materials
Randomized complete block design with factorial experiment (5 3 ) was used for this analysis. The 5 3 factorial experiment means three (3) factors (dewatering, temperature, and velocity) each at five    3.0 m/s). Each of these experiments was replicated three times. The total units of experiment were 5 × 5 × 5 × 3 which is 375 altogether. Analysis of variance (ANOVA) table was derived on each output. Several studies have been conducted on the cassava . Similar data articles on cassava that applied statistical tools can be helpful, readers are refer to [22][23][24]. Table 2 presents the analysis of variance results for drying time; it was observed that all the main factors as well as two and three ways interactions are significant at 5% level. This also implies that the time for grated unfermented cassava mash to get dry depends on the dewatering (the initial moisture content) of the grated unfermented cassava mash, temperature of the dryer, the air velocity of the machine as well as the combinations of these factors altogether.  Tables 3-5 present further tests, refer to as post hoc tests, to determine if there are differences in the mean results of levels of dewatering, temperature, and air velocity respectively. It was observed that all the levels of each of these factors are significantly different from one another. It was observed that the time of drying reduces with increase in the temperature levels. At the lowest temperature level 40°C, the highest average time of drying was observed to be 2 hs: 57 min. This was followed by temperature level 55°C with average drying time of 2 h: 22 min observed, then by 70°C, and the average time of drying was 1 h: 47 min. At the next temperature level which is 85°C, the time of  drying was 1 h:30 min. The highest temperature level, which was 100°C, the average time of drying was 1 h: 25 min.
Figs. 3-5 present the graphs indicating the magnitude of interactions between each pair of these factors, that is, dewatering and temperature; dewatering and velocity; temperature and velocity respectively.
Likewise, Table 6 presents the analysis of variance results for drying rate. It was also observed that all the main factors as well as two and three ways interactions are significant at 5% level. This also implies that the drying rate of cassava flour depends on the dewatering (the initial moisture content) of the grated unfermented cassava mash, temperature of the dryer, the air velocity of the machine as well as the combinations of these factors combined.     Tables 7-9 present post hoc tests for dewatering, temperature, and air velocity respectively. Again it was observed that all the levels of each of these factors are significantly difference from one another. It was observed that drying rate of the grated unfermented cassava mash increases as the dewatering time increases at different air velocity levels of the drying process. In addition, the temperature increases with the drying rate of grated unfermented cassava mash.
Figs. 6-8 present the graphs indicating the level of interactions between each pair of these factors, that is, dewatering and temperature; dewatering and velocity; temperature and velocity respectively.
In summary, both the drying time and drying rate of any quantity of grated unfermented cassava mash depend on the initial moisture content (dewatering) of the mash, the temperature of the dryer, the air velocity of the machine and the effects of their interactions in pairs and the three factors altogether.

Acknowledgement
This work is a benefit of sponsorship from the Centre for Research, Innovation and Discovery, Covenant University, Ota, Nigeria. Also, we thank the management of National Centre for Agricultural Mechanization (NCAM) Idofian, Ilorin, for making the data available for us.

Transparency document. Supplementary material
Transparency document associated with this article can be found in the online version at http://dx. doi.org/10.1016/j.dib.2017.10.008.

Appendix A. Supplementary material
Supplementary data associated with this article can be found in the online version at http://dx.doi. org/10.1016/j.dib.2017.10.008.