Moisture Diffusivity in Tylose Gel (Karlsruhe Test Material)

ABSTRACT: Tylose gel (the Karlsruhe test substance) is a meat analog commonly used for studying heat transfer during freezing and thawing operations. It has thermal properties similar to lean beef, which are well defined in literature; however, moisture diffusivities for Tylose gel are not available in the literature. In this article, the mass transfer properties of Tylose were investigated. This included determining a moisture isotherm for Tylose and measuring effective moisture diffusivity as a function of temperature using 2 different methods: a drying method and a concentration-distance method. The moisture isotherm was fit best using the Guggenheim-Anderson-de Boer (GAB) equation. The resulting moisture diffusivities were fit to an Arrhenius model for temperature dependence from 2.5 °C to 12 °C. The moisture diffusivities measured for Tylose ranged from 4.00 × 10-11 to 9.75 × 10-11 m2/ s, depending on temperature. The drying method resulted in moisture diffusivities that were found to have higher dependence on temperature than when the concentration-distance method was used. The concentration-distance method gave much more variation among measurements.