During orange juice production, a half of fresh oranges weight is considered as production waste (peels, pulp, seeds, orange leaves and damaged orange fruits). An alternative for the management of these wastes is thei...During orange juice production, a half of fresh oranges weight is considered as production waste (peels, pulp, seeds, orange leaves and damaged orange fruits). An alternative for the management of these wastes is their treatment by addition of lime and a latter pressing, obtaining a press cake and a press liquor rich in sugars (10°Brix) and citric acid, protein, pectin and ethanol. For non-thermal concentration of press liquor to obtain citruss molasses (65°-70°Brix), the removal of pectin is necessary. Traditionally, depectinization of juices has been done by using pectinmethylesterase (PME) enzymes from external sources. In this work it performed the extraction of PME enzymes from orange peels to obtain the optimum extraction conditions. Two different methods of solventextraction were compared (conventional andultrasound-assisted methods). For the conventional extraction experiments, a central composite design with three variables ([NaCl], pH and time) and five replicates of the center point was used. For ultrasound-assisted extraction, experiments were done at pH = 5.5 and [NaCl] = 1.25M), varying extraction time (1-30 min). Response variables were PME activity, protein content and a ratio between them, named PME effectiveness (ηPME). At the same experimental conditions (pH =5.5, [NaCl] = 1.25 M, t = 15 min) it was found that conventional extractions led to slightly better results in terms of ηPME than ultrasound-assisted extraction method.展开更多
World wine industry transforms 10% - 25% of raw grapes into residues, mainly represented by lees, grape marcs, seeds and stems. These by-products are a rich source of polyphenols and therefore they can be used to prod...World wine industry transforms 10% - 25% of raw grapes into residues, mainly represented by lees, grape marcs, seeds and stems. These by-products are a rich source of polyphenols and therefore they can be used to produce new added value products. The aim of this work wasto determine the best process conditions(treatment time, % of ethanol and pH of the solvent)during solid-liquid extraction of polyphenolsfrom grape marcs, by analyzing the phenolic content of the extracts, namely: total polyphenol content, flavanols, flavonols, phenolic acids and anthocyanins. Antioxidant activity of the extracts was also determined. An extraction time of two hours was enough since longer times did not increase process yields. Best extraction yields were obtained for 75% ethanol solutions. Basic pH led to better yields in extracting media with low percentage of ethanol, whereas acid pH presented better extraction yields in extracting media with high percentage of ethanol. Among all the polyphenols extracted, anthocyanins were themost abundant representing over 40% of the total. In general, the best process conditions were 2 h ofextraction in a 75% EtOH liquid mixture at pH =2.展开更多
One third of the artichoke production is used in industrial processes, where up to 70% - 85% of the initial raw material is transformed into solid wastes. For an adequate management of these wastes, it is necessary to...One third of the artichoke production is used in industrial processes, where up to 70% - 85% of the initial raw material is transformed into solid wastes. For an adequate management of these wastes, it is necessary to know their water sorption properties, because physical, chemical andbiological changes which occur during theirstorage depend on water-solid interactions. The objectives of this work are to experimentally determine equilibrium sorption (adsorption anddesorption) data of artichoke wastes at different temperatures (25°C - 55°C), as well as correlate and predict water sorption isotherms using bibliographic models. Equilibrium moisture content ranged 0 - 0.6 kg water/kg dry solid (water activity 0.05 - 0.9). Water sorption isotherms were classified between Types II and III. Hysteresis phenomenon was not observed, neither was the dependence of the equilibrium data with temperature. BET, GAB, Oswin and Peleg correlation models were satisfactorily fitted to experimental data. A predictive model based on composition and physical state of artichoke waste components was also successfully used to reproduce experimental data.展开更多
文摘During orange juice production, a half of fresh oranges weight is considered as production waste (peels, pulp, seeds, orange leaves and damaged orange fruits). An alternative for the management of these wastes is their treatment by addition of lime and a latter pressing, obtaining a press cake and a press liquor rich in sugars (10°Brix) and citric acid, protein, pectin and ethanol. For non-thermal concentration of press liquor to obtain citruss molasses (65°-70°Brix), the removal of pectin is necessary. Traditionally, depectinization of juices has been done by using pectinmethylesterase (PME) enzymes from external sources. In this work it performed the extraction of PME enzymes from orange peels to obtain the optimum extraction conditions. Two different methods of solventextraction were compared (conventional andultrasound-assisted methods). For the conventional extraction experiments, a central composite design with three variables ([NaCl], pH and time) and five replicates of the center point was used. For ultrasound-assisted extraction, experiments were done at pH = 5.5 and [NaCl] = 1.25M), varying extraction time (1-30 min). Response variables were PME activity, protein content and a ratio between them, named PME effectiveness (ηPME). At the same experimental conditions (pH =5.5, [NaCl] = 1.25 M, t = 15 min) it was found that conventional extractions led to slightly better results in terms of ηPME than ultrasound-assisted extraction method.
基金The authors wish to acknowledge to the Enology Laboratory of the Institute of Food Engineering for Development-Polytechnic University of Valencia(Spain)for providing the grape marcs used in this workand FOMESA for the financial support.Author Luis Mayor acknowl-edges JCI2009-04923 grant to MINECO(Spain).
文摘World wine industry transforms 10% - 25% of raw grapes into residues, mainly represented by lees, grape marcs, seeds and stems. These by-products are a rich source of polyphenols and therefore they can be used to produce new added value products. The aim of this work wasto determine the best process conditions(treatment time, % of ethanol and pH of the solvent)during solid-liquid extraction of polyphenolsfrom grape marcs, by analyzing the phenolic content of the extracts, namely: total polyphenol content, flavanols, flavonols, phenolic acids and anthocyanins. Antioxidant activity of the extracts was also determined. An extraction time of two hours was enough since longer times did not increase process yields. Best extraction yields were obtained for 75% ethanol solutions. Basic pH led to better yields in extracting media with low percentage of ethanol, whereas acid pH presented better extraction yields in extracting media with high percentage of ethanol. Among all the polyphenols extracted, anthocyanins were themost abundant representing over 40% of the total. In general, the best process conditions were 2 h ofextraction in a 75% EtOH liquid mixture at pH =2.
基金Author Luis Mayor acknowledges JCI2009-04923 grant to MINECO(Spain).
文摘One third of the artichoke production is used in industrial processes, where up to 70% - 85% of the initial raw material is transformed into solid wastes. For an adequate management of these wastes, it is necessary to know their water sorption properties, because physical, chemical andbiological changes which occur during theirstorage depend on water-solid interactions. The objectives of this work are to experimentally determine equilibrium sorption (adsorption anddesorption) data of artichoke wastes at different temperatures (25°C - 55°C), as well as correlate and predict water sorption isotherms using bibliographic models. Equilibrium moisture content ranged 0 - 0.6 kg water/kg dry solid (water activity 0.05 - 0.9). Water sorption isotherms were classified between Types II and III. Hysteresis phenomenon was not observed, neither was the dependence of the equilibrium data with temperature. BET, GAB, Oswin and Peleg correlation models were satisfactorily fitted to experimental data. A predictive model based on composition and physical state of artichoke waste components was also successfully used to reproduce experimental data.
