Optimization of artemisinin extraction from Artemisia annua L. with supercritical carbon dioxide + ethanol using response surface methodology.

Malaria is a high priority life-threatening public health concern in developing countries, and therefore there is a growing interest to obtain artemisinin for the production of artemisinin-based combination therapy products. In this study, artemisinin was extracted from the Artemisia annua L. plant using supercritical carbon dioxide (SC-CO2 ) modified with ethanol. Response surface methodology based on central composite rotatable design was employed to investigate and optimize the extraction conditions of pressure (9.9-30 MPa), temperature (33-67°C), and co-solvent (ethanol, 0-12.6 wt.%). Optimum SC-CO2 extraction conditions were found to be 30 MPa and 33°C without ethanol. Under optimized conditions, the predicted artemisinin yield was 1.09% whereas the experimental value was 0.71 ± 0.07%. Soxhlet extraction with hexane resulted in higher artemisinin yields and there was no significant difference in the purity of the extracts obtained with SC-CO2 and Soxhlet extractions. Results indicated that SC-CO2 and SC-CO2 +ethanol extraction is a promising alternative for the extraction of artemisinin to eliminate the use of organic solvents, such as hexane, and produce extracts that can be used for the production of antimalarial products.

Encapsulation of fish oil into hollow solid lipid micro- and nanoparticles using carbon dioxide.

Fish oil was encapsulated in hollow solid lipid micro- and nanoparticles formed from fully hydrogenated soybean oil (FHSO) using a novel green method based on atomization of supercritical carbon dioxide (SC-CO2)-expanded lipid. The highest fish oil loading efficiency (97.5%, w/w) was achieved at 50%, w/w, initial fish oil concentration. All particles were spherical and in the dry free-flowing form; however, less smooth surface with wrinkles was observed when the initial fish oil concentration was increased up to 50%. With increasing initial fish oil concentration, melting point of the fish oil-loaded particles shifted to lower onset melting temperatures, and major polymorphic form transformed from α to ß and/or ß'. Oxidative stability of the loaded fish oil was significantly increased compared to the free fish oil (p<0.05). This innovative method forms free-flowing powder products that are easy-to-use solid fish oil formulation, which makes the handling and storage feasible and convenient.

Development of free-flowing peppermint essential oil-loaded hollow solid lipid micro- and nanoparticles via atomization with carbon dioxide.

The main objective of this study was to overcome the issues related to the volatility and strong smell that limit the efficient utilization of essential oils as "natural" antimicrobials in the food industry. Peppermint essential oil-loaded hollow solid lipid micro- and nanoparticles were successfully formed using a novel "green" method based on atomization of CO2-expanded lipid mixture. The highest essential oil loading efficiency (47.5%) was achieved at 50% initial essential oil concentration at 200bar expansion pressure and 50µm nozzle diameter, whereas there was no significant difference between the loading efficiencies (35%-39%) at 5%, 7%, 10%, and 20% initial essential oil concentrations (p>0.05). Particles generated at all initial essential oil concentrations were spherical but increasing the initial essential oil concentration to 20% and 50% generated a less smooth particle surface. After 4weeks of storage, 61.2%, 42.5%, 0.2%, and 2.0% of the loaded essential oil was released from the particles formed at 5%, 10%, 20%, and 50% initial essential oil concentrations, respectively. This innovative simple and clean process is able to form spherical hollow micro- and nanoparticles loaded with essential oil that can be used as food grade antimicrobials. These novel hollow solid lipid micro- and nanoparticles are alternatives to the solid lipid nanoparticles, and overcome the issues associated with the solid lipid nanoparticles. The dry free-flowing products make the handling and storage more convenient, and the simple and clean process makes the scaling up more feasible.

Supercritical carbon dioxide extraction of corn distiller's dried grains with solubles: experiments and mathematical modeling.

Corn distiller's dried grains with solubles (DDGS) is a byproduct of the ethanol industry and has potential as a source of valuable compounds. In this study, corn DDGS was extracted using supercritical carbon dioxide (SC-CO(2)) at 50-70 °C, 34.5-49.6 MPa, and constant CO(2) flow rate of 1 L/min (measured at ambient conditions). The highest yield of total lipids (9.2%, w/w) was obtained at 49.6 MPa/70 °C. Apparent solubility of corn DDGS lipids ranged between 0.010 kg/kg CO(2) at 34.5 MPa/50 °C and 0.026 kg/kg CO(2) at 49.6 MPa/70 °C. The extract contained 107 mg/kg carotenoids, 1538 mg/kg tocochromanols, and 15904 mg/kg phytosterols at 49.6 MPa/70 °C. The Sovova model and Chrastil model were successfully used to describe the extraction of total lipids and apparent solubility of total and minor lipids, respectively. The study revealed that DDGS is a good inexpensive source of lipids and valuable minor lipid components and that SC-CO(2) extraction can be used as a "green" process to add value to corn DDGS by recovering such high-value lipids.

UV-C-irradiated Arabidopsis and tobacco emit volatiles that trigger genomic instability in neighboring plants.

We have previously shown that local exposure of plants to stress results in a systemic increase in genome instability. Here, we show that UV-C-irradiated plants produce a volatile signal that triggers an increase in genome instability in neighboring nonirradiated Arabidopsis thaliana plants. This volatile signal is interspecific, as UV-C-irradiated Arabidopsis plants transmit genome destabilization to naive tobacco (Nicotiana tabacum) plants and vice versa. We report that plants exposed to the volatile hormones methyl salicylate (MeSA) or methyl jasmonate (MeJA) exhibit a similar level of genome destabilization as UV-C-irradiated plants. We also found that irradiated Arabidopsis plants produce MeSA and MeJA. The analysis of mutants impaired in the synthesis and/or response to salicylic acid (SA) and/or jasmonic acid showed that at least one other volatile compound besides MeSA and MeJA can communicate interplant genome instability. The NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (npr1) mutant, defective in SA signaling, is impaired in both the production and the perception of the volatile signals, demonstrating a key role for NPR1 as a central regulator of genome stability. Finally, various forms of stress resulting in the formation of necrotic lesions also generate a volatile signal that leads to genomic instability.

Effect of the addition of a cocoa butter-like fat enzymatically produced from olive pomace oil on the oxidative stability of cocoa butter.

A cocoa butter (CB)-like fat was produced in a packed bed enzyme reactor using sn-1,3 specific lipase, and its blends with CB were prepared at different ratios (CB: CB-like fat; 100: 0, 90: 10, 80: 20, 70: 30, 60: 40, 50: 50, 0: 100). The oxidation kinetics of CB: CB-like fat blends was studied by differential scanning calorimeter (DSC). Samples were heated in DSC at different temperatures (130, 140, 150, 160 degrees C) under 100 mL/min oxygen. From DSC exotherms, oxidation induction times (OIT) were determined and used for the assessment of the oxidative stabilities of the blends. Oxidation kinetics parameters (activation energy, E(a); preexponential factor, Z; and oxidation rate constant, k) were calculated. In general, it has been observed that above 110 degrees C increasing the ratio of CB-like fat in the blend increased the k value with increasing temperature. It has been observed that for all blends the increase in k value with temperature was significant (P < 0.05). Increasing CB-like fat ratio in the blend decreased the content of major TAGs (1,3-dipalmitoyl-2-oleoyl-glycerol [POP]; 1[3]-palmitoyl-3[1]stearoyl-2-oleoyl-glycerol [POS]; 1,3-distearoyl-2-oleoyl-glycerol [SOS]), and decreased the oxidative stability of the blends.

Conversion of olive pomace oil to cocoa butter-like fat in a packed-bed enzyme reactor.

Refined olive pomace oil (ROPO) was utilized as a source oil for production of cocoa butter-like fat. Immobilized sn-1,3 specific lipase catalyzed acidolysis of ROPO with palmitic (PA) and stearic (SA) acids was performed in a laboratory scale packed-bed reactor. Effect of reactor conditions on product formation was studied at various substrate mole ratios (ROPO:PA:SA; 1:1:1, 1:1:3, 1:3:3, 1:2:6), enzyme loads (10%, 20%, 40%), substrate flow rates (1.5, 4.5, 7.5, 15 ml/min) and solvent amounts (150, 400 ml). The highest yield (10.9% POP, 19.7% POS and 11.2% SOS) was obtained at 40% enzyme load, 1:2:6 substrate mole ratio, 45 degrees C, 7.5 ml/min substrate flow rate, 150 ml solvent and 3h reaction time. The melting profile and SFC of the product were comparable to those of CB. Polarized light microscope (PLM) images showed no drastic changes in polymorphic behavior between CB and product.

Change in glyceride composition of olive pomace oil during enzymatic esterification.

Enzymatic esterification of free fatty acids of olive pomace oil with glycerol was investigated. The esterification reaction was carried out in the absence and presence of glycerol (glycerol to free fatty acids (FFA) molar ratio of 1/3 and 1/6). In the absence of glycerol, the FFA concentration decreased from 32 to 21% while the triglyceride concentration increased from 33 to 40% after of 8 h of reaction time. The most significant decrease in FFAs and increase in triglycerides was observed at the limiting concentration of glycerol (glycerol to FFA molar ratio of 1/3). The FFA concentration decreased to 2.5% and the triglyceride concentration increased up to 78%. The change in both FFA and triglyceride concentrations was found to be statistically significant (P < 0.05).