INFLUENCE OF TEMPERATURE AND TSS ON PERFORMANCE OF EVAPORATION AND RHEOLOGICAL PROPERTIES OF PINEAPPLE CONCENTRATION BY MICROWAVE VACUUM

摘要

In the first part of this study, pineapple juice concentrated by microwavenvacuum evaporation (MVE) and rotary vacuum evaporation (RVE) processnwere compared in terms of evaporation rate, electrical energy, color andnapparent viscosity (ma). MVE provided 2.21 times higher evaporation rate andnused 5.32 times less energy than RVE. Pineapple juice concentrates from MVEngave better color quality than from RVE at the same evaporation condition.nHowever, there was a significant difference in ma of pineapple juice concentratesnbetween the two evaporation methods. The second part was to investigatenthe effect of temperature and total solid soluble (TSS) on rheologicalnbehavior of concentrate pineapple juice from MVE. The values of consistencyncoefficient (k) were in the range of 23.855–257.771 Pa·sn, which decreasednwith the increasing temperature and concentration. The effect of temperaturenon k was described by Arrhenius model. The activation energy of k was in thenrange of 9.74–10.13 kJ/mol K. The power equation showed that the consistencyncoefficient non-linearly increased with an increase in concentration. Theneffect of temperature and concentration on k of pineapple juice concentratencould be determined in terms of single logarithmic. Predicted models werendeveloped to calculate k as a function of temperature and concentration. Thenresult of validation showed the suitability of the mathematical model predictionnin describing k of pineapple juice concentrate