Ultrasound-assisted extraction of oilseeds-sustainability processes to obtain traditional and non-traditional food ingredients: A review.

Oilseeds are sources of not only major compounds such as oil and meal but also of bioactive compounds. Their conventional extraction is related to long extraction time, large non-renewable solvent consumption, high temperature, and therefore, high energy consumption. Ultrasound-assisted extraction (UAE) has emerged as a new and green technology, which can accelerate and/or improve the extraction process of these compounds. Moreover, the possibility of using renewable solvents in the UAE enhances its application and allows obtaining both extracted and remaining products more compatible with current human consumption requirements. This article examines the mechanisms, concepts, and factors that impact oilseeds' UAE with an emphasis on the extraction yield and quality of oil, meal, and bioactive compounds. Furthermore, the effects of combining UAE with other technologies are addressed. Gaps detected in the analyzed literature about oilseed treatment and quality and properties of products, in addition to perspectives about their uses as food ingredients, are also included. Moreover, it highlights the need for increasing research on process scalability, on environmental and economic impacts of the whole process, and on the phenomenological description about the effect of process variables on extraction performances, which will be a key tool for process design, optimization, and control. Understanding ultrasound processing techniques for the extraction of different compounds from oilseeds will serve as useful information for fats and oils and meal scientists in academia and industry to explore the possibility of employing this sustainable approach during the extraction treatment of various crops.

An overview of structure engineering to tailor the functionality of monoglyceride oleogels.

Monoglyceride (MG)-based oleogelation is an effective strategy to create soft matter structures with the functionality of fats, but with a nutritional profile similar to edible oils. MG oleogels are mainly studied to replace or reduce trans and saturated fats as well as to develop novel products with improved physical and organoleptic properties. The process consists of direct dispersion of MGs into the oil at temperatures above the melting point. This is followed by a cooling period in which the gelator network is formed, entrapping the oil in a crystalline structure. MG composition and concentration, oil type, process temperatures, stirring speed, shear rate during cooling, and storage time play a role in the kinetics of MG crystallization within an MG-oil system, which leads to the formation of lipid materials with different properties. A deep understanding of MG oleogelation processing parameters allows for the tailoring of oleogel properties to meet desirable characteristics as solid fat replacers. This review provides insight regarding manipulating physical process parameters to engineer structures with specific functionality. Furthermore, ultrasound technologies and optimization methodologies are discussed as tools for the production of oleogels with specific properties based on their potential use as well as the development of bi- and multi-gelators oleogels using MGs. Finally, the food applications in which MG oleogels have been tested are summarized in addition to the identified gaps that require further research.

Preparation of highly stable oleogel-based nanoemulsions for encapsulation and controlled release of curcumin.

Oleogels have been proposed as suitable systems for the encapsulation and delivery of lipophilic bioactive compounds. This work aimed to produce stable nanoemulsions of gelled-oil particles using monoglyceride (MG) oleogels loaded with curcumin. High-speed homogenization followed by ultrasonication was used for obtaining colloidal dispersions. The effects of ultrasonication processing parameters and formulation were evaluated to optimize particle size, polydispersity index (PDI), and stability during storage. All sonication parameters had a significant effect on particle size and PDI. A Pluronic F-68 + Tween 80 surfactant mixture with the lowest oleogel/aqueous phase ratio (5/95) produced nanoemulsions which were at least 10-month stable. The nanoemulsions showed a higher encapsulation efficiency than the sample without the gelator (73.85-91.05% vs. 56.99%). Furthermore, it was corroborated that structuring oil particles with MG crystals produces a matrix that entraps curcumin molecules and slows down their release. These findings provide useful information for the development of new nutraceutical products.

Tailoring physical properties of monoglycerides oleogels using high-intensity ultrasound.

The effects of high-intensity ultrasound application (HIU-20 kHz, 96 W, 3 pulses: 10 s on/5s off) and cooling rate (0.1 and 10 °C/min) on physical properties of monoglycerides (MG) oleogels (3, 4.5, and 6 wt%) were evaluated. Oleogels melting profile, rheological and textural properties, crystal microstructure, crystal length (Lc), polymorphic behavior, oil binding capacity (OBC), and solid fat content (SFC) were determined after 24 h of storage at 5 or 25 °C. HIU caused significant changes in the MG crystallization behavior, producing a decrease in Lc and a stronger and more elastic network with higher OBC. HIU increased the adhesiveness of all samples whereas did not affect their cohesiveness. The effects of HIU application were enhanced by cooling at 0.1 °C/min and storing at 5 °C. Neither SFC nor thermal behavior were affected by HIU and the desired ß' polymorphism was obtained in all oleogels. This study shows that physical properties of MG oleogels can be significantly improved by HIU application to obtain suitable fats with low level of saturated fatty acids for food applications.

Effects of cooling temperature profiles on the monoglycerides oleogel properties: A rheo-microscopy study.

The oleogelation process has become in a great interest area for the food sector. The aim of this study was to understand the effect of cooling temperature profiles (CTP) applied during oleogelation on microstructure and some macroscopic properties of monoglycerides (MG) oleogels. To this purpose, oleogels from MG and high oleic sunflower oil were produced using programed CTP corresponding to the actual temperature evolution of the samples when they are left at rest to progress in a specific ambient temperature (AT). In order to evaluate the crystal formation during the gelation process, a torsional rheometer equipped with a rheo-microscope (RM) module was used. This allowed us to carry out simultaneously rheological measurements and record images of the gels during their formation process. Overall, microstructural characteristics were determined: fractions of crystalline material and oil, crystal length and shape, the Avrami index, and the fractal dimension. Although crystal formation took place during a similar range of temperatures (~55-46 °C), significant morphological differences in the distribution and size of crystal and aggregates were observed depending on the applied CTP, and the area occupied by the crystals and oil phase did not depend on CTP used. RM images were useful to follow the kinetics of crystallization as well as to identify a more restricted time domain in the rheological behavior allowing to find more accurate Avrami index values. Furthermore, the analysis of RM images turned out to be an efficient approach to obtain accurate measurements of the fractal dimension. High fractal dimension values were associated with gels exhibiting high number of homogeneous small crystals. Oleogels composed by this network generated a material with high capacity to retain oil. A weak-link regime approach applied to the dynamic systems was appropriate to describe the relationship between the elastic modulus and the crystal formation during the oleogels structuration. In conclusion, these findings may serve to the food industry to achieve a better understanding of the oleogelation process that allows it to control the quality of obtained oleogels, which could be utilized to replace and/or reduce the trans and saturated fats in food formulations.