Journal of Food Engineering, Vol.239, 104-113, 2018
Physical properties of acai-berry pulp and kinetics study of its anthocyanin thermal degradation
Knowledge about physical properties of food materials is essential for processing design and optimization. Although the market of acai-based products has been growing in these last few years, little information about physical properties of the acai pulp is available in the literature. This work evaluates the effects of solids content (dry matter - %) and temperature on the properties of acai, 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 acai pulp was carried-out for the temperature range from 40 degrees C to 80 degrees 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 acai industry and may be useful in other studies about alai pulp processing.
Keywords:Euterpe oleracea;Thermal conductivity;Specific heat;Thermal expansion coefficient;Thermal processing