Palm-based fat crystallized at different temperatures with and without high-intensity ultrasound in batch and in a scraped surface heat exchanger

Abstract

The objective of this study was to compare the sonocrystallization process of a palm-based fat in batch to a continuous set-up using a scraped surface heat exchanger (SSHE). The sample was crystallized at 32, 30, 28, and 26 °C (Tc). High-intensity ultrasound (HIU, 20 kHz, 12.7 mm horn, 50% amplitude, 57W) was applied using 10s pulses. After crystallization, samples were stored (48 h/25 °C) and analyzed for crystal microstructure, melting behavior, oil binding capacity (OBC), hardness, and viscoelastic properties. HIU improved all physical properties of the material when crystallized in batch at all Tc; however, SSHE at 26 °C was the only condition improved by HIU. G’ and hardness were the highest in sonicated SSHE samples crystallized at 26 °C (141 kPa, 4.5N) and these values were higher than the ones obtained in batch. OBC was also improved in sonicated SSHE samples (77%) but in lower magnitude compared to the OBC obtained in batch (82%). Crystal size was not affected by HIU in the SSHE, but a reduction in crystal size was observed due to HIU in batch for all Tc. Similar behavior was observed for Tp, however, Ton and ΔH were not affected by HIU.