Effect of different solvents on subcritical solvent extraction of oil from Assam tea seeds (Camellia sinensis var. assamica): Optimization of oil extraction and physicochemical analysis

Sunflower seed protein: defatting, structural characterization and property analysis

The preparation method and protein purity are crucial factors influencing the use of sunflower seed proteins in the food industry. In this study, sunflower seed press cake was defatted using subcritical butane, isopropyl alcohol and n-hexane, producing meal protein, protein concentrate, and protein isolate. A systematic analysis of the structural and functional properties of these proteins revealed that the subcritical butane and isopropyl alcohol extracted protein yield and color, protein structure was relatively loose, denaturation temperature was higher, the prepared sunflower seed protein solubility and other functional properties were better than traditional hexane extraction. Additionally, the protein isolate demonstrated superior solubility (46.38-52.34 %), emulsification stability (31.76-41.97 %), and oil holding capacity. The protein concentrate exhibited significant advantages in gel properties and water holding capacity. These findings supported the development of green, efficient, and sustainable methods for the optimal utilization of sunflower seed proteins at different purity levels.

A comprehensive foodomics analysis of rambutan seed oils: Focusing on the physicochemical parameters, lipid concomitants and lipid profiles

A foodomics approach was employed to systematically characterize and compare the quality parameters, antioxidant activity, minor-components, fatty acid composition, and lipid profiles of the seed oils from the three most popular rambutan varieties in China. The total lipid content ranged from 23.40 to 25.77 g/100 g. The fatty acids 9cC18:1 (39.84%-40.92%) and C20:0 (28.45%-30.23%) were identified as the dominant ones, which are uncommon among higher plants. All oil samples exhibited low AI and TI values. BR-7 exhibited the highest levels of squalene (21.48 mg/kg), cholesterol (144.43 mg/kg), and tocopherol (17.42 mg/kg), and the lowest levels of polyphenols (24.21 mg GAE/kg). Additionally, a total of 807 lipid species were identified, with TAG, DGTS, and PE being the predominant ones. Multivariate statistical analyses revealed significant variations in lipid profiles among the varieties, particularly in glycerophospholipids and sphingolipids. Fifty-seven distinct lipids were identified as potential markers for distinguishing between rambutan varieties. Furthermore, a hypothetical scenario was developed by linking relevant lipid metabolism pathways. These findings establish a theoretical framework for comprehending rambutan seed oil in depth and unlocking its high-value potential.

Multi-frequency ultrasonic-assisted enzymatic extraction of coconut paring oil from coconut by-products: Impact on the yield, physicochemical properties, and emulsion stability

Extraction of coconut paring oil (CPO) from processing by-products adds value to the product and reduces resource wastage. This study aims to assess the impact of 20 kHz, 20/80 kHz and 20/40/80 kHz of multi-frequency ultrasonic-assisted enzymatic extraction (MFUAEE) on the yield, physicochemical properties, fatty acid composition, total phenolic content, antioxidant activity, and emulsion stability of CPO derived from wet coconut parings (WCP). Results revealed that the CPO extraction yield with MFUAEE was 32.58 % - 43.31 % higher compared to AEE. The tri-frequency 20/40/80 kHz mode of multi-frequency ultrasound pretreatment exhibited the highest CPO extraction yield (70.08 %). The oil extracted through MFUAEE displayed similar fatty acid profiles to AEE, but had lower peroxide value, K232 and K270 values. Particularly, MFUAEE oil contained higher total phenolic content and exhibited potent DPPH free radical scavenging capacity. Results observed by SEM indicated that the pretreatment with multi-frequency ultrasound more efficiently disrupts the cellular structure of the WCP. Additionally, MFUAEE enhanced emulsion stability through the cavitation effect of ultrasound. These findings suggest that MFUAEE is a valuable approach for method for obtaining CPO with elevated extraction yield and superior quality, thereby enhancing the utilization of coconut by-products.

Lipidomics insight on differences in lipid profiles and phytosterol compositions of coconut oils extracted by classical and green solvents

Searching for green and ecofriendly solvents to replace classical solvents for industrial scale extraction of coconut oil is of great interest. To explore these possibilities, this study performed comprehensive comparative analyses of lipid profiles and phytosterol compositions in coconut oils obtained by extraction with n-hexane, absolute ethyl alcohol, deep eutectic solvent/n-hexane, dimethyl carbonate (DME) and cyclopentyl methyl ether (CPME) using a foodomics approach. Results indicated that CPME (64.23 g/100 g dry matter) and DME (65.64 g/100 g dry matter) showed comparable capacity for total lipid extraction of total lipids to classical solvents (63.5-65.66 g/100 g dry matter). Considering the phytosterol yield, CPME (644.26 mg/kg) exhibited higher selectivity than other solvents (535.64-622.13 mg/kg). No significant difference was observed in the fatty acid composition of coconut oil by the different solvents assayed. Additionally, total 468 lipid molecules were identified in the samples. For glycerolipid and sphingolipid, the five solvents showed comparable extraction capabilities. However, CPME exhibited higher extraction efficiency of polar lipids (glycerophospholipid and saccharolipid) than other solvents. Overall, these results may be a useful guide for the application of green solvents in industrial production of coconut oil.

Characteristics and Antioxidant Activity of Walnut Oil Using Various Pretreatment and Processing Technologies

This study was the first time the effects of pretreatment technology (microwave roasting, MR; oven roasting, OR; steaming roasting, SR) and processing technology (screw pressing, SP; aqueous enzymatic extraction, AEE; subcritical butane extraction, SBE) on the quality (physicochemical properties, phytochemical content, and antioxidant ability) of walnut oil were systematically compared. The results showed that the roasting pretreatment would reduce the lipid yield of walnut oil and SBE (59.53−61.19%) was the processing method with the highest yield. SR-AEE oil provided higher acid value (2.49 mg/g) and peroxide value (4.16 mmol/kg), while MR-SP oil had the highest content of polyunsaturated fatty acid (73.69%), total tocopherol (419.85 mg/kg) and total phenolic compounds (TPC, 13.12 mg/kg). The DPPH-polar and ABTS free radicals’ scavenging abilities were accorded with SBE > AEE > SP. SBE is the recommended process for improving the extraction yield and antioxidant ability of walnut oil. Hierarchical cluster analysis showed that processing technology had a greater impact on walnut oil than pretreatment technology. In addition, multiple linear regression revealed C18:0, δ-tocopherol and TPC had positive effects on the antioxidant ability of walnut oil, while C18:1n-9, C18:3n-3 and γ-tocopherol were negatively correlated with antioxidant activity. Thus, this a promising implication for walnut oil production.

Effect of Different Solvents on the Extraction of Oil from Peony Seeds (Paeonia suffruticosa Andr.): Oil Yield, Fatty Acids Composition, Minor Components, and Antioxidant Capacity

Peony seed oil is full of nutrition and exert positive effects on human's health. The influences of seven solvents (isopropanol, acetone, Hx:Iso (n-hexane/isopropanol, 3:2 v/v), Chf:Me (chloroform/methanol, 1:1 v/v), ethyl acetate, n-hexane, and petroleum ether) on the oil yields, lipid composition, minor components and antioxidant capacity of peony seed oil were compared in this study. Results indicated that the highest oil yield (35.63%) was obtained using Hx:Iso, while Chf:Me showed the best extraction efficiency for linolenic acid (43.68%), trilinolenoyl-glycerol (15.00%), and dilinolenoyl-linoleoyl-glycerol (18.01%). For minor components, Chf:Me presented a significant advantage in the extraction of tocopherol (601.49 mg/kg), and the peony seed oil extracted with petroleum ether had the highest sterols (4089.82 mg/kg) and squalene contents (66.26 mg/kg). Although the use of isopropanol led to a lower sterol content, its extracts showed a significant higher polyphenol content (68.88 mg GAE/kg) than other solvents and exhibited the strongest antioxidant capacity. Additionally, correlation analysis revealed that polyphenols were the most important minor component for predicting the antioxidant capacity of peony seed oil. The above information is valuable for manufacturers to select suitable solvents to produce peony seed oil with the required levels of fatty acids and minor components for targeted end-use.

Antioxidant capacity of phenolic compounds separated from tea seed oil in vitro and in vivo

Tea seed oil is rich in phenols with good antioxidant capacity. However, the antioxidant capacity evaluation of tea seed oil polyphenols is not deep enough, which mainly focusing on the evaluation of the chemical system. Thirty-nine phenols were tentatively identified by UPLC-ESI-MS/MS analysis, including flavonoids and phenolic acids. The antioxidant capacity of phenol extracts was investigated in vitro and in vivo. The chemical assays showed the extracts had good proton and electron transfer capabilities. The CAA assay indicated the IC₅₀ of the extracts was 77.93 ± 4.80 µg/mL and cell antioxidant capacity of the extracts was 101.05 ± 6.70 μmol·QE/100 g of oil. The animal experiments suggested phenol extracts could significantly improve the organ index, reduce malondialdehyde content, and increase superoxide dismutase, glutathione peroxidase and total antioxidant capacity (p < 0.05). This study was contributed to the antioxidant capacity of phenol extracts of tea seed oil by comprehensive evaluation.

Extraction and Characterization of Flaxseed Oil Obtained with Subcritical n-Butane

In this study, subcritical n-butane was adopted to extract oil from flaxseed. The extraction conditions i.e. extraction temperature, extraction time, and liquid-solid ratio were investigated and optimized by response surface methodology. The flaxseed oil obtained by subcritical n-butane were characterized and compared with those prepared by n-hexane and cold pressing. Results indicated that the optimal combination of parameters was 53.93℃, 56.82 min, and 19.98:1 mL/g. Subcritical n-butane had higher yield (28.75%) than n-hexane and cold pressing. GC analysis indicated that subcritical n-butane extraction had no obvious influence on the fatty acid composition. Nevertheless, the oil obtained by subcritical n-butane with higher contents of phytosterols (2.93 mg/g) and carotenoids (46.56 mg/kg), and presented a higher oxidation stability (9.27 h). Thus, it was suggested that subcritical n-butane extraction is a promising alternative to extract high quality flaxseed oil.

Optimization of ultrasound-assisted solvent extraction of hemp (Cannabis sativa L.) seed oil using RSM: Evaluation of oxidative stability and physicochemical properties of oil

In this study, the effect of solvent ratio of hexane to isopropanol (0:100, 50:50, and 100:0 v/v%), extraction temperature (30, 45, and 60°C), and time (30, 60, and 90 min) were investigated on the oil extraction efficiency, total phenol content, DPPH radical scavenging, peroxide value, and oil color index. Extraction conditions were optimized by response surface methodology and Box-Behnken design. The optimal conditions were obtained as hexane-to-isopropanol ratio of approximately 3:2, temperature of 40.26°C, and ultrasonication time of 54.40 min. Then, the hemp seed oil was extracted under the optimal conditions. The optimal predicted contents for oil yield (31.22%), total phenolics (3.19 mg GA/g oil), DPPH inhibition (73.86%), peroxide (4.62 meq/kg), and color index (28.2) were agreed with the predicted conditions because the RSE values were less than 5%. Hemp seed oil can be used extensively due to its high nutritional values, and antioxidant potential and ultrasound can improve oil extraction as a simple and fast method.