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Oxidative deterioration of vegetable oils is of great importance in the food industry. In China, vegetable oils produced via thermal pretreatment are popular owing to their strong oil flavor and enhanced yield. Here, we review: (i) the currently employed thermal treatment methods of oilseeds before oil extraction; (ii) effects of thermal treatments on the physicochemical properties, contents of minor lipid components, and oxidative stability of vegetable oils; and (iii) Maillard model systems that are related to oil and oilseed chemistry. Among the thermal pretreatment technologies, microwave and infrared radiations are promising, but these are not performed on the same large production scales as roasting. For most oilseeds, thermal treatments increase the yield of extracted oil and content of minor lipid compounds in the oil, such as polyphenols, tocopherols, and phytosterols. In addition, some Maillard reaction products (MRPs) generated by heating oilseeds have been extracted. The presence of both minor lipids and MRPs in the oil confers improved oxidative stability. However, the mechanism or relationship between thermal treatment and oxidative stability is yet to be clearly elucidated because vegetable oil oxidation is dependent on variables such as unsaturation, concentration and types of minor lipid components, MRPs, and the potential synergistic effects of these components. Recently, several Maillard reaction models related to thermally treated oilseeds have been established, suggesting that MRPs play a critical role during oxidation. However, comprehensive identification of antioxidants and the mechanism by which they inhibit oxidation are lacking. Future research can be performed to establish models that would help elucidate the antioxidative mechanisms of MRPs for more oilseeds. Using these models, it will be possible to predict the oil quality after processing, based on the presence of MRPs and oil chemistry.

Lipid generated from housefly (Musca domestica L.) larvae fed by municipal waste is a renewable lipid resource, however, the low unsaturated degree prevents it from producing trimethylolpropane fatty acid triester as lubricant, due to its poor low-temperature performance. A new fatty acid esters complex consisting of trimethylolpropane fatty acid triester and 2-ethylhexyl fatty acid ester was produced from housefly larval lipid. Separated from molecular distillation, the acylglycerols were first trans-esterified into fatty acid methyl ester and then further trans-esterified with trimethylolpropane into trimethylolpropane esters. The purified trimethylolpropane fatty acid triester is with purity of 98.4% and further blended with 30 wt% 2-ethylhexyl fatty acid ester derived from housefly larval free fatty acid. The pour point was substantially lowered from −3 °C to −12 °C while the lubricity performance is within standard of ISO VG 32, with minor improvement of water separability compared with pure trimethylolpropane fatty acid triester. By blending two type bio-lubricants with different advantages on viscosity and pour point, the ester complex with favorable properties was produced using saturated non-food lipid source rather than unsaturated virginal vegetable oil. This study also offers a cleaner and energy-efficient approach for high value-added product production for non-food lipid industry.

Linusorbs (LOs, cyclolinopeptides) are a class of naturally occurring cyclic hydrophobic peptides found in flaxseed oil, whose oxidation states indicate the oxidative stability and bitterness of flaxseed oil. Subjected to 63 °C accelerated oxidation, most Met-containing LOs in cold-pressed flaxseed oil entirely depleted by the 6th day except CLP, and MetO

Linusorbs, known as cyclolinopeptides, are a group of cyclic hydrophobic peptides derived from flaxseed oil with various health benefits. However, the current research efforts on both the biological activities and antioxidant capacities of linusorbs are limited because of existing issues with their purification and characterization. A practical method based on preparative HPLC for isolating 12 linusorbs simultaneously was developed and factors such as the solvent selection, gradient elution program, flow rate, loaded mass, and loading concentration, were optimized. The optimum conditions were an initial acetonitrile (ACN) to water ratio of 40%, final ACN ratio of 80%, eluting time of 21 min, a flow rate of 16 mL/min, sample load of 12.5 mg, and concentration of 80 mg/mL (in methanol). The 12 linusorbs obtained were verified using off-line MS/MS, recording purities of above 95.5%. The method could serve as a practical and fast isolation method enabling further investigation of minor linusorbs.

Biolubricants are gaining increased attention because of their low toxicity, high biodegradability, and miscibility with additives. These features render them ideal for lubrication, especially in total-loss processes. In this study, housefly ( Musca domestica ) larvae were used as low-cost, non-food biolubricant feedstock. A larval lipid with high acid value (AV) of 63 mg KOH/g was used as feedstock for esterification to produce 2-ethylhexyl fatty acid esters (2-EH esters). We developed a method of producing high-purity 2-EH esters in which housefly larva free fatty acids (HLFFAs) were derived from larvae fed with kitchen waste. HLFFAs were esterified with 2-ethyl-1-hexanol (2-EHOH) catalysed with benzenesulfonic acid (BSA). The optimum esterification conditions were as follows: catalyst loading, 0.5 wt%; 2-EHOH-to-HLFFAs molar ratio, 3:1; temperature, 130 °C; and reaction time, 2 h. These conditions yielded 98.6% esterification rate. Excess 2-EHOH was removed by molecular distillation at 80 Pa and 110 °C. Residual fatty acids were neutralised by alkali refining. The chemical and physical properties, including the tribological properties, of the produced high-purity 2-EH esters (>99.7%) were also tested.

Litsea cubeba (LC) kernel is a kind of waste after LC essential oil processing, which oil was found to be rich in medium chain fatty acids. Such oil was originally applied as a potential feedstock for the synthesis of trimethylolpropane fatty acid triester (TFATE) as a biolubricant base oil with desirable lubricating properties. LC kernel oil was firstly decolorized, and then treated by glycerolysis and methanolysis to produce LC fatty acid methyl ester (FAME). The biolubricant base oil was produced by the transesterification of LC FAME with trimethylolpropane (TMP) catalyzed by TMP-potassium, where reaction conditions were FAME to TMP ratio (4:1), catalyst dosage (10 % based on TMP), pressure (100 Pa), temperature (130 °C) and time (1 h). The products from each processing step were characterized by GC-FID, ATR-FTIR, and DSC to make sure the reaction complete. The purified product with 92.0 % of TFATE was finally obtained by molecular distillation, which lubricating properties were qualified according to ISO VG 32 standard. The present findings proposed that LC kernel oil could be used as a promising alternative biolubricant feedstock as its derived TFATE product could achieve good oxidative stability (35 min, ROBT 150 °C) and low-temperature performance (pour point of -15 °C).

With the cost of traditional lipid feedstocks constituting 70% of the total cost of biolubricant production, it is urgent to find a new lipid source for the biodiesel and biolubricant industry. With the elevated acid value (61.8 mg of KOH/g) of housefly larval lipids, converting the free fatty acid (FFA) into a biolubricant could serve as a value-added approach to the larval diesel industry, other than pretreatment by acid-catalyzed esterification for biodiesel production. This study developed a method of producing high-purity fatty acid n-octyl esters (FAOEs) from housefly (Musca domestica L.) larvae. The housefly larva free fatty acids (HLFFAs) from the larva lipids were obtained by wipe-film short-path distillation. FAOEs were produced by esterifying n-octanol with HLFFAs (catalyzed by benzenesulfonic acid under the following conditions: catalyst loading, 2 wt %; molar ratio of n-octanol to FFA, 3:1; temperature, 100 °C; time, 2 h). Excess n-octanol was effectively removed by high-vacuum (80 Pa) distil...

Hydrotalcite (HT) loaded with potassium carbonate (K2CO3) was originally applied as a promising heterogeneous solid base catalyst for the production of trimethylolpropane fatty acid triester (TFATE) as the biolubricant base oil through transesterification of fatty acid methyl esters (FAME) from waste cooking oils and trimethylolpropane (TMP), in which FAME to TMP ratio (3:1), catalyst dosage (2% w/w), pressure (300 Pa), temperature (160 °C) and time (2 h) were optimized in order to obtain the best TFATE yield (80.6%). Based on the above, K2CO3 dosage (30% w/w) and calcination temperature (500 °C) in the preparation of HT/K2CO3 catalyst were optimized to improve the TFATE yield to 93.9% along with 97.7% of conversion rate of FAME (CRF). The catalyst recycling was also investigated to determine the suitable reactivated method. Besides, HT/K2CO3 catalysts in various states were characterized for better comprehension of their functional mechanisms and appropriate potential applications.

Food waste, as a major part of the municipal solid waste has been generated increasingly worldwide. Efficient and feasible utilization of this waste material for productivity process is significant for both economical and environmental reasons. In the present study, Musca domestica larva was used as the carrier to conduct a bioconversion with food waste to get the value-added maggot protein, oil and organic fertilizers. Methods of adult flies rearing, culture medium adjuvant selection, maggot culture conditions, stocking density and the valorization of the waste have been explored. From the experimental results, every 1000 g culture mediums (700 g food waste and 300 g adjuvant) could be disposed by 1.5 g M. domestica eggs under proper culture conditions after emergence in just 4 days, 42.95 ± 0.25% of which had been consumed and the culture medium residues could be used as good organic fertilizers, accompanying with the food waste consumption, ∼53.08 g dried maggots that contained 57.06 ± 2.19% protein and 15.07 ± 2.03% oil had been produced. The maggot protein for its outstanding pharmacological activities is regarded as a good raw material in the field of medicine and animal feeding. Meanwhile, the maggot oil represents a potential alternative feedstock for biodiesel production. In our study, the maggot biodiesel was obtained after the procedure of transesterification reaction with methanol and the productivity was 87.71%.

With various applications in the food, pharmaceutical and cosmetics industries, L-Alpha-glycerylphosphorylcholine ( l -α-GPC), is a valuable cholinergic substance whose natural resources is limited. Reported enzymatic pathway seems promising comparing chemical synthesis, while the low solubility of PC in water hinders its scaling-up production and involvement of organic solvent entails potential risks. A novel water-in-soybean oil solvent-free medium was applied in enzymatic preparation of l -α-GPC catalyzed by phospholipase A1, where 99.1% of the PC in soy lecithin was hydrolyzed with l -α-GPC yield of 95.8% (conditions: oil to PC ratio 4:1, water addition 30 wt%, enzyme loading 5 wt%, 55 °C, 3 h). The purity and recovery of purified (silica chromatography) l -α-GPC a with 94.8% and 83.0%, respectively. Efficient and intensive l -α-GPC preparation could be achieved using soybean oil medium, and the proposed system is with advantages of solvent-free, significant reduction of water, offering a green and practical approach for future l -α-GPC production.

A facile strategy for dehulling of six Canadian flaxseed cultivars using ethanol wash in combination with wet-screening was reported. Quantitative determinations of nutritional components including oil, sterol, protein, carbon and cyclolinopide in each separated fraction were also performed. Results showed that an efficient separation of hull, kernel and oil from the whole seed is achieved, because ethanol wash can eliminate the stubborn interference of flaxseed oil, thus facilitating the shell and kernel separation procedure. Among six flaxseed cultivars, the separated hull, kernel and oil account for 20.52–26.66%, 36.02–43.23% and 29.82–32.00% of whole seed, respectively. Triglyceride and sterol contents in separated hull, kernel, oil, whole seed are 2.13–3.34%, 24.68–27.46%, 97.26–98.84%, 37.70–45.82% and 0.02–0.11%, 0.04–0.08%, 0.28–0.53%, 0.11–0.23%, respectively. Besides, flaxseed oil is rich in cyclolinopepides, including new orbitides Q, R and S that have never been reported in these flaxseed varieties. Protein and carbon contents in separated hull, kernel and whole seed are 19.01–26.46%, 34.91–43.80%, 20.15–24.65% and 55.39–56.59%, 45.11–45.93%, 49.61–50.94%, respectively. In addition, the milled flaxseed hull shows a concentration-dependent intrinsic viscosity. This study presents a convenient method for flaxseed dehulling and preliminarily reveals the distribution of different nutrient elements in different parts of flaxseed.

A novel biodiesel production process using waste cooking oil (WCO) as feedstock was developed in this work. Free fatty acids (FFAs) from WCO were esterified by crude glycerol catalyzed by NaOH, which lowered the content of free fatty acids of WCO. The conversion of FFA in the WCO (acid value: 124.9 mg KOH/g) to acylglycerols is 99.6% under the optimal conditions (1.4:1 molar ratio of glycerol to FFA, 4 h, 210 °C, catalyst loading 0.5 wt.% based on WCO weight). After the transesterification of esterified WCO with methanol catalyzed by NaOH, the yield of the final product is 93.1 wt.% with 98.6 wt.% of fatty acid methyl ester (FAME). The crude glycerol and the catalyst from transesterification were recycled as reactant for esterification during the biodiesel production. Soap formed from the subsequent processes maintained a high catalyzing activity for FFA esterification after being recycled for 13 times. This new glycerol esterification process using alkali (soap) catalyst provides a promising solution to convert feedstock with high FFA levels to biodiesel. This biodiesel production process has distinct advantages compared with traditional two-step methods, including lower cost of catalyst for both esterification and transesterification processes, less energy consumption for methanol recovery, recycling of the glycerol byproduct and catalyst (soap), and no requirement of anti-corrosive equipment.

A new bibenzyl derivative (1), 4-acetoxy-3,5,3′,4′-tetramethoxybibenzyl, along with eight known compounds (2–9), was isolated from the twigs and leaves of Schefflera arboricola (Araliaceae). The isolated compounds were elucidated mainly by means of one-dimensional, two-dimensional NMR and MS, and by comparison with the literature data. Compounds 2–5 and 7–9 are first reported from this plant. In the in vitro assays, compound 1 displayed moderate nuclear factor-kappaB inhibitory activity.

A new bibenzyl derivative (1), 4-acetoxy-3,5,3',4'-tetramethoxybibenzyl, along with eight known compounds (2-9), was isolated from the twigs and leaves of Schefflera arboricola (Araliaceae). The isolated compounds were elucidated mainly by means of one-dimensional, two-dimensional NMR and MS, and by comparison with the literature data. Compounds 2-5 and 7-9 are first reported from this plant. In the in vitro assays, compound 1 displayed moderate nuclear factor-kappaB inhibitory activity.