Modelling the Thin-Layer Drying of Beef Biltong Processed Using Hot Air Drying

Abstract

This study was conducted to evaluate the drying characteristics and establish the best thin-layer drying model of marinated beef under hot air drying. The drying experiments were conducted in a cabinet dryer at drying air temperatures of 30, 35, and 40 °C, and drying air velocity of 1.5 and 2.5 m s−1. The sample temperature and mass were measured throughout the duration of drying. The drying process occurred in the falling rate period. The temperature of the drying air significantly (p ≤ 0.05) influenced the drying characteristics. The velocity of the drying air had no significant (p ≥ 0.05) effect on the drying characteristics apart from the drying rate during the first falling rate period. Diffusion is the predominant mode of moisture transport during the drying of marinated beef. The drying kinetics of marinated beef during its processing to biltong is best described by the two-term model. The effective moisture diffusivity of marinated beef being processed into biltong ranges between 1.60 ⨉ 10−10 m2 s−1 and 2.28 ⨉ 10−10 m2 s−1, while, its activation energy is 28.21 and 17.71 kJ.mol−1 at a drying air velocity of 1.5 and 2.5 m s−1, respectively. The results from this study cover the range of temperature and air velocity commonly used in biltong processing; hence, they can be used to optimize the drying process of beef during biltong production.