The objective of this work was to estimate the antioxidant potential of the extracts from pink shrimp residue and red grape pomaces (Merlot and Syrah varietals), evaluated according to its antioxidant activity with di...The objective of this work was to estimate the antioxidant potential of the extracts from pink shrimp residue and red grape pomaces (Merlot and Syrah varietals), evaluated according to its antioxidant activity with different analytical methods, associating these properties with the chemical composition of the extract and, as a consequence, with the extraction procedure. The shrimp residue was pre-treated combining cooking, drying, and milling, whereas the grape pomaces were dried and ground. The shrimp residue extracts were obtained by Soxhlet (SOX) and by maceration using hexane (Hx), hexane: isopropanol (50:50) (Hx:IPA), isopropanol, ethanol (EtOH) and acetone as solvents;by ultrasonic maceration (UME) with EtOH;by cold and hot oil extraction with soy and sunflower oils;and by Supercritical Fluid Extraction (SFE) with pure CO2 (100 -?300 bar;313.15 -?333.15 K) and with co-solvent (Hx: IPA and sunflower oil at 2%). The grape pomaces extracts were obtained by SOX using EtOH, ethyl acetate (EtOAc) and Hx;UME with water (H2O), EtOH, EtOAc and Hx;and by SFE performed with pure CO2 (150 -?300 bar;323.15 -?333.15 K) and with cosolvent (EtOH at 15%). The antioxidant activity was determined by the DPPH free radical scavenging procedure and by the β-carotene bleaching method. Higher antioxidant activities in shrimp residue extracts were observed by the β-carotene bleaching method in alcoholic and cetonic extracts, among the low pressure extraction methods, while for the SFE, the higher activities were achieved by the extracts obtained at elevated pressures. For the grape pomaces extracts, the best results were obtained by the DPPH method from the low pressure extractions proceeded with EtOH. The SFE with Merlot pomace at 323.15 K/150 bar (the lowest temperature and pressures tested) presented the best antioxidant activity by the β-carotene bleaching.展开更多
The vacuum residual from Iranian Light crude oil are separated into a series of 16 narrow fractions according to the molecular weight by the supercritical fluid extraction and fractional (SFEF) technology. The chemica...The vacuum residual from Iranian Light crude oil are separated into a series of 16 narrow fractions according to the molecular weight by the supercritical fluid extraction and fractional (SFEF) technology. The chemical element and the UV spectrum of each fraction are analyzed. The effects of several factors on the interfacial tension are investigated, which are the fraction concentration in oil phase, the ratio of oil component, the salts dissolved in the water phase and the pH value. The interfacial tension decreases rapidly as the concentration of the residual fraction in the oil increases, showing a higher interfacial activity of the fraction. The interfacial tension changes, as the amount of absorption or the state of the fractions in the interface changes resulting from different ratios of oil, different kinds or concentrations of salts in water, and different pH values. It is concluded that the interfacial tension changes regularly, corresponding to the regular molecular parameters of the vacuum residual fractions.展开更多
文摘The objective of this work was to estimate the antioxidant potential of the extracts from pink shrimp residue and red grape pomaces (Merlot and Syrah varietals), evaluated according to its antioxidant activity with different analytical methods, associating these properties with the chemical composition of the extract and, as a consequence, with the extraction procedure. The shrimp residue was pre-treated combining cooking, drying, and milling, whereas the grape pomaces were dried and ground. The shrimp residue extracts were obtained by Soxhlet (SOX) and by maceration using hexane (Hx), hexane: isopropanol (50:50) (Hx:IPA), isopropanol, ethanol (EtOH) and acetone as solvents;by ultrasonic maceration (UME) with EtOH;by cold and hot oil extraction with soy and sunflower oils;and by Supercritical Fluid Extraction (SFE) with pure CO2 (100 -?300 bar;313.15 -?333.15 K) and with co-solvent (Hx: IPA and sunflower oil at 2%). The grape pomaces extracts were obtained by SOX using EtOH, ethyl acetate (EtOAc) and Hx;UME with water (H2O), EtOH, EtOAc and Hx;and by SFE performed with pure CO2 (150 -?300 bar;323.15 -?333.15 K) and with cosolvent (EtOH at 15%). The antioxidant activity was determined by the DPPH free radical scavenging procedure and by the β-carotene bleaching method. Higher antioxidant activities in shrimp residue extracts were observed by the β-carotene bleaching method in alcoholic and cetonic extracts, among the low pressure extraction methods, while for the SFE, the higher activities were achieved by the extracts obtained at elevated pressures. For the grape pomaces extracts, the best results were obtained by the DPPH method from the low pressure extractions proceeded with EtOH. The SFE with Merlot pomace at 323.15 K/150 bar (the lowest temperature and pressures tested) presented the best antioxidant activity by the β-carotene bleaching.
基金Supported by the National Key Basic Research Programme (No.973-G1999022505),University of Petroleum Basic Research Fund(No.ZX9904)
文摘The vacuum residual from Iranian Light crude oil are separated into a series of 16 narrow fractions according to the molecular weight by the supercritical fluid extraction and fractional (SFEF) technology. The chemical element and the UV spectrum of each fraction are analyzed. The effects of several factors on the interfacial tension are investigated, which are the fraction concentration in oil phase, the ratio of oil component, the salts dissolved in the water phase and the pH value. The interfacial tension decreases rapidly as the concentration of the residual fraction in the oil increases, showing a higher interfacial activity of the fraction. The interfacial tension changes, as the amount of absorption or the state of the fractions in the interface changes resulting from different ratios of oil, different kinds or concentrations of salts in water, and different pH values. It is concluded that the interfacial tension changes regularly, corresponding to the regular molecular parameters of the vacuum residual fractions.
