SummaryPomegranate seed oil was extracted in a closed-vessel high-pressure microwave system. The characteristics of the obtained oil, such as fatt y acid composition, free fatt y acidity, total phenolic content, antioxidant activity and colour, were compared to those of the oil obtained by cold solvent extraction. Response surface methodology was applied to optimise extraction conditions: power (176-300 W), time (5-20 min), particle size (d=0.125-0.800 mm) and solvent to sample ratio (2:1, 6:1 and 10:1, by mass). The predicted highest extraction yield (35.19 %) was obtained using microwave power of 220 W, particle size in the range of d=0.125-0.450 mm and solvent-to-sample ratio of 10:1 (by mass) in 5 min extraction time. Microwave-assisted solvent extraction (MASE) resulted in higher extraction yield than that of Soxhlet (34.70 % in 8 h) or cold (17.50 % in 8 h) extraction. The dominant fatt y acid of pomegranate seed oil was punicic acid (86 %) irrespective of the extraction method. Oil obtained by MASE had bett er physicochemical properties, total phenolic content and antioxidant activity than the oil obtained by cold solvent extraction.

Soxhlet and microwave assisted extraction (MAE) methods were used to obtain non-polar compounds from pistachio hull. MAE parameters (liquid to solid ratio, microwave power, and extraction time) were studied to obtain maximum extraction yield. The optimal conditions were found to be liquid to solid ratio of 15:1 (v/w), microwave power of 250 W and extraction time of 12.5 min. The extraction yields were 9.81 and 9.50% for MAE and Soxhlet methods, respectively. The total phenolic content, antioxidant activity and tocopherol content of the extract obtained by MAE was found to be significantly higher than those of the Soxhlet extract (p < 0.05). The results showed that the extract contained α-tocopherols (567.65 mg/kg) and oleic acid (48.46%) as the major tocopherols and fatty acids. These findings propose that hull extracts can be considered as a good source of natural bioactive compounds and MAE can be a good alternative to the traditional Soxhlet method.

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A novel modified lipid was synthesized by enzymatic incorporation of a "hydrophobic and essential amino acid derivative" into 2-monoacylglycerol. This modified lipid contains mainly oleic acid at sn-2 position and N-acetyl-l-leucine at sn-1,3 positions. The product behaved as an oil above 10 °C. Caloric value of the novel oil-like product was reduced by 18.65%. The modified lipid may have the potential for replacement with the oil in food products such as margarine, shortenings, salad dressing, and mayonnaise.

This research aimed to analyze ultrasound (UAE) and microwave-assisted extraction (MAE) as novel technologies for utilizing gilthead seabream (Sparus aurata) by-products to produce high-quality fish oil for human consumption. The impacts of extraction parameters, namely, temperature, time, solvent-to-solid ratio, and their interactions on the extraction yield, are investigated using response surface methodology (RSM), and a central composite rotatable design. The optimized conditions are 15.47 mL g −1 of solvent-to-solid ratio, 38 min, and 42 °C for UAE and 15.84 mL g −1 of solvent-to-solid ratio, 18 min, and 40 °C for MAE. Under optimal conditions, the maximum extraction yields are 38.40 and 36.70% (g/g) for UAE and MAE, respectively. Both UAE and MAE have significantly higher mass transfer rates (61.70 and 121.58 g h −1 , respectively) than Soxhlet extraction (10.78 g h −1 ). The fatty acid composition, physicochemical, and oxidation analyses of fish oils confirm the suitability of both UAE and MAE for the recovery of high-quality oils from fish processing by-products. The valorized oils mainly include unsaturated fatty acids (≈75%) and are rich in oleic acid. Furthermore, scanning electron microscopy analysis reveals that the key driving force for fast oil extraction is the structural degradation of fish by-products caused by ultrasound and microwave. Practical Applications: Due to environmental and economic viewpoints, the validation of fish oil from fish industry by-products has become a popular research topic recently. Alternative recovery techniques such as ultrasound-(UAE) and microwave-assisted extraction (MAE) protocols may have additional benefits in producing functional oils. Interactive effects of process parameters determine the success of the extraction technique; therefore optimization is a critical approach when applying the extraction protocols. This study shows that UAE and MAE techniques significantly enhanced oil extraction rate from gilthead seabream (Sparus aurota) by-products at lower temperatures and by using lower amounts of solvent. UVA and MAE increase oxidative stability and do not change the fatty acid composition. Hence, the by-product of the gilthead seabream can be a sustainable and food-grade fish oil source and UAE and MAE can be a good alternative to the conventional (Soxhlet) extraction by providing high yield and quality oil.