Oil has extensively been extracted from oil-bearing crops and traded globally as a major food commodity. There is always a huge demand from the fats and oils industries to increase oil yield because of profitability benefits. If extraction is conducted under mild operating conditions to preserve and improve the oil quality, then it would be an added value. Ultrasound that works on the cavitational action helps to fulfil the gap. Ultrasound is gaining tremendous interest as an alternative to replace the current conventional extractions approach because of its multiple benefits. Cavitation generated by ultrasound eases the release of oil from cell matrices, thereby allowing the extraction to be carried out under mild processing conditions. The effect enhances the oil yield whilst preserving the quality of the oil. In ultrasound, green solvents can be used to replace toxic organic solvents. Recent up-to-date approaches utilised a combination of ultrasound with enzyme, microwave and supercritical technology to further enhance the oil extraction. This review highlights a comprehensive work of the impact of ultrasound and ultrasound in combination with other technologies on oil extraction, which emphasises the extraction yield and physicochemical properties of the oil, such as fatty acid composition, oxidative stability with the retention of the lipophilic phytochemicals and iodine, saponification values and colour parameters. Understanding of ultrasonication techniques for oil extraction served to be essential and useful information for the fats and oils scientists from academia and industries to explore the possibility of employing a sustainable and mild approaches for extracting oil from various crops.
Ultrasound-assisted solvent extraction (UAE) was applied to extract underutilized Madhuca longifolia seed oil. The effect of extraction time, temperature, solvent type, solvent/sample ratio, and amplitude on the oil yield and recovery were investigated. Approximately 56.97% of oil yield and 99.54% of oil recovery were attained using mild conditions of 35 min, 35 °C, 40% amplitude, isopropanol to acetone (1:1), and solvent to sample (20 mL/g). UAE oil yield and recovery were comparable with Soxhlet extraction (SXE) whilst mechanical pressing (ME) yielded
Nanofibrillated cellulose (NFC) from plant biomass is becoming popular, attributed to the protective encapsulation of bioactive compounds in Pickering emulsion, preventing degradation and stabilizing the emulsion. NFC, as a natural dietary fiber, is a prominent fat replacer, providing a quality enhancement to reduced-fat products. In this study, NFC Pickering emulsions were prepared at NFC concentrations of 0.2%, 0.4%, 0.6%, 0.8%, and 1% to encapsulate carotenoids. The NFC Pickering emulsions at NFC concentrations of 0.4%, 0.6%, 0.8%, and 1% were incorporated into margarine-like reduced fat (3%) spreads as the aqueous phase. Characterization of both NFC Pickering emulsion and the incorporated NFC Pickering emulsion, margarine-like reduced fat spreads, was conducted with mastersizer, rheometer, spectrophotometer, and texture analyzer. The particle size (73.67 ± 0.35 to 94.73 ± 2.21 nm), viscosity (138.36 ± 3.35 to 10545.00 ± 567.10 mPa s), and creaming stability (25% to 100% stable) of the NFC Pickering emulsions were increased significantly when increasing the NFC concentration, whereas the encapsulation efficiency was highest at NFC 0.4% and 0.6%. Although imitating the viscoelastic solid-like behavior of margarine was difficult, the NFC Pickering emulsion properties were still able to enhance hardness, slip melting point, and color of the reduced fat spreads compared to the full-fat margarine, especially at 0.6% of NFC. Overall, extensive performances of NFC can be seen in encapsulating carotenoids, especially at NFC concentrations of 0.4% and 0.6%, with the enhancement of Pickering emulsion stability while portraying futuristic possibilities as a fat replacer in margarine optimally at 0.6% of NFC concentration. PRACTICAL APPLICATION: Nanocellulose extracted from palm dried long fiber was utilized to encapsulate carotenoids and replace fats in margarine-like reduced fat (3%) spreads. Our study portrayed high encapsulation efficiency and successful fat replacement with promising stability performances. Hence, nanocellulose displayed extensive potential as encapsulating agents and fat replacers while providing quality and sustainability enhancements in reduced-fat food.