Tailoring Crystalline Structure Using High‐Intensity Ultrasound to Reduce Oil Migration in a Low Saturated Fat

Abstract

The objective of this study was to use highintensity ultrasound (HIU) to change the crystalline structure of an interesterified soybean oil (IESBO) with 33% of saturated fats and to evaluate how these changes affect oil migration. The IESBO was crystallized at different temperatures (26, 28, 30, and 32 C) with and without HIU. Results show that oil migration was significantly affected by HIU (P < 0.05). HIU promoted crystallization and induced the formation of harder crystalline networks that were more resistant to oil migration with lower melting peak temperatures and sharper melting profiles. Samples processed with HIU had fewer crystalline clusters as observed by microscopy. Changes observed on the physical properties of the IESBO due to sonication that consequently improved oil migration were attributed to the ability of HIU to induce secondary nucleation and crystallize lowmelting point triacyclglycerols (SUU) that would not crystallize without the HIU and to the stronger and stable crystalline network formed capable of entrapping liquid TAG (UUU).

Sonocrystallization as a tool to reduce oil migration by changing physical properties of a palm kernel fat

“…Nevertheless, the effect of sonication is evident in reducing the amount of oil lost when measured after 90 min at 30 °C and after 48 hr at 25 °C. This reduction in OL is higher than the one observed in samples with lower content of saturated fatty acids as described by da Silva, Cooper, Lee, Gibon, and Martini (2020). However, the reduction in OM due to HIU was lower in samples with high levels of saturated fatty acids compared to the ones with low levels of saturated fatty acids (da Silva et al., 2020).…”

“…Secondary nucleation was attributed in a recent article to the induction of the crystallization of lower MP TAG that would not leave the metastable zone without the induction promoted by sonication. The induction of low TAG nucleation also increases the oil binding capacity showing lower ∆ H after OM (da Silva et al., 2020).…”

Sonocrystallization of a Palm‐Based Fat with Low Level of Saturation in a Scraped Surface Heat Exchanger

“…The greatest improvement was observed in position HIU‐3. Positions HIU‐2 and HIU‐3 were sites where more nucleation formed thus HIU can tailor secondary nucleation, inducing nucleation and more crystallization (da Silva et al, 2020).…”

“…HIU operates at high power levels and low frequencies (20 to 100 kHz), and is considered a sustainable, green, and economical technique to improve physical properties of low‐saturated lipids (Lee et al, 2018). Also known as sonocrystallization, HIU might play a key role as an external factor to control or tailor crystal structure and shape (Chen et al, 2013; da Silva et al, 2020; Ye et al, 2011), form stable polymorphic forms (Higaki et al, 2001; Ueno et al, 2003), reduce the induction time of crystallization (Gregersen et al, 2019; Martini et al, 2008), increase the rate of crystallization (Kadamne and Martini, 2018; Lee et al, 2018; Silva et al, 2017; Ye and Martini, 2015), improve oil‐binding capacity (da Silva et al, 2020), and delay phase separation (Jana and Martini, 2014). Most of the studies mentioned above were developed in a lab‐scale flow cell or in batch.…”

“…Only two studies have reported the use of HIU in a SSHE (da Silva and Martini, 2019, 2020) for a soybean‐based fat. Previous studies in our laboratory have shown that the effectiveness of HIU to change crystallization behavior is highly dependent on the triacylglycerol(s) (TAG) composition and the amount of saturated fatty acids in the fat (da Silva et al, 2020; Kadamne et al, 2017a, 2017b, 2018; Lee et al, 2018) and it is unknown if a palm‐based fat will behave similar to a soybean‐based fat during sonocrystallization in a SSHE. There is a need to provide evidence that HIU can be used in real crystallization process as in a scraped surface heat exchanger (SSHE) with different types of fats.…”