Abstract
This study investigated the impact of tumbling on mass transfer mechanisms occurring in small beef meat pieces during biltong production, by measuring salt, water and acetic acid profiles within the meat for different experimental tumbling conditions. Tumbling conditions significantly impacted the solute concentration profiles, except for that of water. Values of both salt and acetic acid diffusion coefficients obtained clearly showed that tumbling increased solute transfers inside meat, with diffusion coefficient values ranging from 2 to 27 x 10(-9) m(2) s(-1) and from 0.2 to 8.6 x 10(-9) m(2) s(-1), respectively. The tumbling mechanical effect related to the device used impacted the most on mass transfers (p-value < 0.01 for salt and acetic acid diffusion), followed by tumbling time (p-value < 0.01 for salt and acetic acid diffusion), and to a lesser extent, the use of vacuum (p-value < 0.01 for salt diffusion and p-value < 0.05 for acetic acid diffusion). Further studies should define the best salt and acid concentration profiles generated when tumbling, so as to obtain the best trade-off between good sanitary protection of meat and a sufficiently tender and organoleptically acceptable end-product after the final drying operation.