Modelling the drying characteristics of the traditional Indonesian crackers "kerupuk"

Abstract

An oven drying method was used to dry traditional Indonesian crackers, popularly known as kerupuk, applying drying temperatures of 50, 60 and 70°C and three different flavours, i.e., garlic, chili and seaweed. Newton, Page, Two terms, Midilli, Logarithmic and Henderson & Pabis mathematical models were used to fit the best model while the standard error of estimate (SSE), root mean square error (RMSE) and coefficient of correlation (r) were chosen as the criteria to determine the equation of the best fit drying model. The Midilli model was the best fit for all the kerupuk flavours. The effective moisture diffusivity was in the range of 1.0413 × 10<sup>–10</sup>–1.6363 × 10<sup>–10</sup> m<sup>2</sup>·s<sup>–1</sup> for the garlic flavour, 1.0007 × 10<sup>–10</sup>–1.5619 × 10<sup>–10</sup> m<sup>2</sup>·s<sup>–1</sup> for the chili flavour and from 1.0000 × 10<sup>–10</sup> to <br /> 1.6228 × 10<sup>–10</sup> m<sup>2</sup>·s<sup>–1</sup> for the seaweed flavour. The activation energy of the garlic flavour, chili flavour and seaweed flavour kerupuk are 20.64, 20.64 and 22.57 kJ·mol<sup>–1</sup>, respectively. Furthermore, in the present study, the physical properties, i.e., the colour and hardness of the kerupuk crackers after the drying process was investigated.

Drying behavior of anchote (Coccinia abyssinica[Lam.]Cogn.) tuber slices as affected by predrying treatments and drying temperature

“…All the values of E a in this study lie in the range of 12.7-110 kJ/mol, which is common for most food materials (Aghbashlo et al, 2009;Akoy, 2014;Kusumaningrum et al, 2019). But the E a for drying anchote tuber slices was found to be higher compared with other food crops such as potato (39.5-42.5 kJ/mol), yam (20.9-28.3 kJ/mol), tomato (31.2 kJ/mol), and mango (38.0 kJ/mol) slices (Aghbashlo et al, 2009;Akinola & Ezeorah, 2019;Akoy, 2014;Azeez et al, 2019;Xiao et al, 2012).…”

“…The D eff for anchote tuber slice, assumed as slab, estimated by Equation (5) derived from Fick's second diffusion law for slab geometry as described by Kusumaningrum et al. (2019) and Zafer and Filiz (2010) by considering the first term for longer drying time from plotting ln MR against the drying time ( t ).where D eff is the effective diffusivity (m 2 /s); L is the thickness of the slab ( m ), and t is the drying time (min).…”

“…The E a was determined using Arrhenius equation (Equation 6) and further simplified to Equation (7) as described by Kusumaningrum et al. (2019). where D 0 is the Arrhenius factor (m 2 /s), D eff is the effective diffusivity (m 2 /s), E a is the activation energy (kJ/mol), R is the universal gas constant (8.314 × 10 −3 kJ mol −1 K −1 ), and T is the absolute temperature (K).…”

“…(1) The D eff describes all possible moisture movement mechanisms within the material that may include liquid diffusion, vapor diffusion, surface diffusion, capillary flow, and hydrodynamic flow (Akoy, 2014). The D eff for anchote tuber slice, assumed as slab, estimated by Equation ( 5) derived from Fick's second diffusion law for slab geometry as described by Kusumaningrum et al (2019) and Zafer and Filiz (2010) by considering the first term for longer drying time from plotting ln MR against the drying time (t).…”

“…The E a was determined using Arrhenius equation (Equation 6) and further simplified to Equation (7) as described by Kusumaningrum et al (2019).…”