Modeling of thin layer drying characteristics of blanch-assisted water yam (Dioscorea alata) slices

Abstract

The thin layer drying characteristics of blanch-assisted water yam slices were investigated with respect to its un-blanched water yam slices in a convective hot air oven. The yam slices (diameter 4 cm; thickness 0.8 cm) were dried at temperatures 50, 60 and 70 °C, respectively with a constant air velocity of 0.13 m/s. The drying data obtained were fitted into six existing drying models: Page, Newton, Midilli, Henderson and Pabis, Logarithmic and Diffusion model. Non-linear regression analysis was used to determine the model parameters; the coefficient of determination (R2) and standard error of estimates (SEE) in order to determine the model best fit. The study showed that the drying process occurred in the falling rate drying period. The blanch-assisted slices had a faster drying rate than the un-blanched yam slices. Among the models, the diffusion model gave the overall best fit for the drying data obtained. The effective moisture diffusivity ranged from 3.18×10-8 to 4.47×10-8 m2/s for the blanch-assisted slices and from 4.73×10-8 to 7.33×10-8 m2/s for the un-blanched slices. The activation energies of the blanch-assisted and un-blanched yam slices were 15.5 kJ/mol and 20.1 kJ/mol, respectively. These processing conditions obtained for water yam flour would be suitable for its process design and control thereby enhancing its utilization and overall acceptability.

Effect of pretreatments on solar dehydration of different varieties of apple (Malus domestica)

“…Therefore, the complete drying process for all apple varieties occurred within the range of the falling rate period. Similar results were obtained in drying studies carried out on various agricultural products such as peas Kucuk 2017), strawberries (El--Beltagy et al 2007), peaches (Kingsly et al 2009), and yam (Okeleye et al 2021).…”

Effects of steaming and drying on quality and antioxidant activity of white-fleshed sweet potato powder (Ipomoea batatas)

“…Based on the computed activation energy from the straight line slope (14.93 kJ/mol), 1 mol of water in the WFSP requires 14.93 kJ of energy to dry. This result was remarkably similar to the water yam's (Okeleye et al, 2021). Selvi (2020) reported that most agricultural products have E a values ranging from 14.42 to 43.26 kJ/mol due to various drying procedures.…”