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Valorization of rice bran: Modified supercritical CO2 extraction of bioactive compounds
Oscar Benito-Román,Sandra Varona,María Teresa Sanz,Sagrario Beltrán 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-
In this work, as afirst step in a comprehensive strategy for the valorization of rice bran, the extraction ofoil using supercritical CO2 and ethanol as cosolvent has been studied. The effect of extractiontemperature (40 and 60 C), pressure (30 and 40 MPa) and amount of ethanol used (0, 5 and 10%) has beenconsidered. The quality extracted oil has been evaluated in terms of antioxidant activity, fatty acid profileand bioactive compounds such as phenolics,flavonoids, g-oryzanols, and tocopherols content. Results revealed that, using neat CO2, the best oil in terms of antioxidant activity was obtained at 40 Cand 30 MPa. However, the addition of ethanol as modifier significantly increased the amount of bioactivemolecules extracted and hence the overall antioxidant activity of the oil, which was maximum at 40 MPaand 10% ethanol, regardless the temperature. The use of ethanol also affected the amount of fatty acidsand g-oryzanols extracted.
Kinetic study and hydrogen peroxide consumption of phenolic compounds oxidation by Fenton’s reagent
Ana de Luis,Amaia Menéndez,José Ignacio Lombraña,Fernando Varona 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.1
Synthetic solutions of phenol, o-, m- and p-cresol were oxidised by using Fenton’s reagent. The application of substoichiometric dosage of H2O2 led to the formation of intermediate compounds, continuing later the oxidation to complete oxidation. An important objective was to analyze the effect of hydrogen peroxide dosage applied and the reaction pH together with the iron oxidation state on the degradation level. A kinetic model was derived from a reaction mechanism postulated which was used to analyze the results of the experiments. Another aim was to analyze the hydrogen peroxide consumption. Noteworthy results include an increase in oxidant consumption to intensify phenol removal. Furthermore, oxidant consumption was analyzed through the ratio H2O2 to phenol removed and the average specific rate of removal (ASRR). By analyzing these two parameters it has been possible to ascertain the most favorable strategy for an efficient application of H2O2.