Physical properties of açai-berry pulp and kinetics study of its anthocyanin thermal degradation

Abstract

Knowledge about physical properties of food materials is essential for processing design and optimization. Although the market of açai-based products has been growing in these last few years, little information about physical properties of the açai pulp is available in the literature. This work evaluates the effects of solids content (dry matter – %) and temperature on the properties of açai, namely thermal conductivity and diffusivity, specific heat, density and volumetric thermal expansion coefficient. Both solids and temperature had a significant effect on the physical properties and the experimental data were in agreement with the predictive models of Choi and Okos. Also, a study of anthocyanin thermal degradation of the açai pulp was carried-out for the temperature range from 40 °C to 80 °C, which resulted in an activation energy of 24.16 kJ mol−1 and half-life times between 10.7 and 28.6 h. The achievements presented in this work may contribute with the açai industry and may be useful in other studies about açai pulp processing.