Search

In this study, supercritical carbon dioxide (SC-CO2) was used to extract diterpenes from spent coffee grounds (SCGs) and it is followed by the encapsulation of SCG extract into polyvinylpyrrolidone particles using a supercritical antisolvent crystallization method. In the extraction process using SC-CO2, the effects of three independent variables – temperature (40‒80°C), pressure (10‒30 MPa), and the ratio of ethanol as a modifier (0%‒10% v/v), on dependent variables: extraction yield and total diterpene content – were investigated using the response surface methodology and Box – Behnken design. The optimal conditions for the extraction yield and total diterpene content were predicted to be 40°C/30 MPa/10% v/v of ethanol and 80°C/25 MPa/6% v/v of ethanol, respectively. Notably, the predicted maximum total diterpene content was 15 times the amount obtained by the Soxhlet method using n-hexane, thereby confirming the selectivity of ethanol-modified SC-CO2 toward diterpenes. Subsequently, based on the supercritical antisolvent crystallization process, the SCG extract was successfully encapsulated into polyvinylpyrrolidone particles with an average particle size of 140 nm, and the water dispersibility of the SCG extract was enhanced by this encapsulation process. The encapsulation of SCG extract with water-soluble polymers enables the further use of SCG extract in food, cosmetic, and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

In this study, an atmospheric‐pressure nanosecond impulse discharge initiated above the pyrrole microemulsion surface is applied to polymerize pyrrole and obtain a polypyrrole film. The films obtained under different number of plasma discharge times and duration of argon gas input time are investigated using a field emission scanning electron microscope. Results show that the roughness and thickness of the polypyrrole film can be tuned by controlling discharge times and the gas feed time. Four‐point sheet resistance measurements of the films reflect that those with a smoother and more complete surface have better electrical conductivity. The films are identified as polypyrrole by Fourier‐transform infrared spectroscopy, X‐ray diffraction, and X‐ray photoelectron spectrometry. Also, N2 is a critical factor in polymerizing polypyrrole and the gas–liquid plasma polymerization mechanism, which has three steps, is discussed. [ABSTRACT FROM AUTHOR]

This study aims to improve the efficiency of lycopene extraction from gac (Momordica cochinchinensis Spreng.) by the Z‐isomerization induced with microwave irradiation pre‐treatment. Although 93.6% of lycopene exist as all‐E‐isomers in dried gac aril, the total Z‐isomer content reaches 35.6 and 58.5% by microwave irradiation at 900 W for 40 s and at 1050 W for 60 s, respectively. The 35.6 and 58.5% Z‐isomerization treatment improves lycopene content of extract (by 6.0 or 8.5 times for press extraction, 7.8 or 13.5 times for ethanol extraction, and 4.5 or 6.1 times for supercritical CO2 (SC‐CO2)extraction, respectively) compared with no treatment. In addition, the extracts containes high amounts of lycopene Z‐isomers, which have higher bioavailability and antioxidant capacity than (all‐E)‐lycopene. Practical Applications: This study clearly shows that lycopene recovery by press, organic solvent, and SC‐CO2 extraction from dried gac aril improved by the increase in the Z‐isomer content. It indicates that the Z‐isomers are more soluble in oil, organic solvent, and SC‐CO2 than the all‐E‐isomer. Moreover, the thermal Z‐isomerization pre‐treatment increases the content of lycopene Z‐isomers in the extract. Therefore, this procedure is important not only for improving the productivity of lycopene, but also for providing a highly functionalized extract. The effect of the Z‐isomerization, induced by microwave irradiation pre‐treatment of gac (Momordica cochinchinensis Spreng.) aril, on the lycopene recovery and lycopene content of the extracts obtained using press, ethanol, and SC‐CO2 extractions is investigated. For all extraction methods, as the content of Z‐isomers in the raw material increases, the recovery and lycopene content of gac extracts improve. [ABSTRACT FROM AUTHOR]