The intensification of processes is essential for the sustainability of the biorefinery concept. ... more The intensification of processes is essential for the sustainability of the biorefinery concept. Enzyme catalysis assisted by ultrasound (US) may offer interesting opportunities in the agri-food sector because the cavitation effect provided by this technology has been shown to improve the efficiency of the biocatalysts. This review presents the recent advances in this field, focused on three main applications: ultrasound-assisted enzymatic extractions (UAEE), US hydrolysis reactions, and synthesis reactions assisted by US for the manufacturing of agri-food produce and ingredients, enabling the upgrading of agro-industrial waste. Some theoretical and experimental aspects of US that must be considered are also reviewed. Ultrasonic intensity (UI) is the main parameter affecting the catalytic activity of enzymes, but a lack of standardization for its quantification makes it unsuitable to properly compare results. Applications of enzyme catalysis assisted by US in agri-foods have been mo...
Limiting flux (JL) determination is a critical issue for membrane processing. This work presents ... more Limiting flux (JL) determination is a critical issue for membrane processing. This work presents a modified exponential model for JL calculation, based on a previously published version. Our research focused on skim milk microfiltrations. The processing variables studied were the crossflow velocity (CFV), membrane hydraulic diameter (dh), temperature, and concentration factor, totaling 62 experimental runs. Results showed that, by adding a new parameter called minimum transmembrane pressure, the modified model not only improved the fit of the experimental data compared to the former version (R2 > 97.00%), but also revealed the existence of a minimum transmembrane pressure required to obtain flux (J). This result is observed as a small shift to the right on J versus transmembrane pressure curves, and this shift increases with the flow velocity. This fact was reported in other investigations, but so far has gone uninvestigated. The JL predicted values were correlated with the Reyno...
Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
World Journal of Microbiology and Biotechnology, 2016
Lactose-derived non-digestible oligosaccharides are prominent components of functional foods. Amo... more Lactose-derived non-digestible oligosaccharides are prominent components of functional foods. Among them, galacto-oligosaccharides (GOS) outstand for being prebiotics whose health-promoting effects are supported on strong scientific evidences, having unique properties as substitutes of human milk oligosaccharides in formulas for newborns and infants. GOS are currently produced enzymatically in a kinetically-controlled reaction of lactose transgalactosylation catalyzed by β-galactosidases from different microbial strains. The enzymatic synthesis of GOS, although being an established technology, still offers many technological challenges and opportunities for further development that has to be considered within the framework of functional foods which is the most rapidly expanding market within the food sector. This paper presents the current technological status of GOS production, its main achievements and challenges. Most of the problems yet to be solved refer to the rather low GOS yields attainable that rarely exceed 40 %, corresponding to lactose conversions around 60 %. This means that the product or reaction (raw GOS) contains significant amounts of residual lactose and monosaccharides (glucose and galactose). Efforts to increase such yields have been for the most part unsuccessful, even though improvements by genetic and protein engineering strategies are to be expected in the near future. Low yields impose a burden on downstream processing to obtain a GOS product of the required purity. Different strategies for raw GOS purification are reviewed and their technological significance is appraised.
The performance of an ultrafiltration membrane bioreactor for galacto-oligosaccharides (GOS) synt... more The performance of an ultrafiltration membrane bioreactor for galacto-oligosaccharides (GOS) synthesis using high lactose concentrations (470 g/L) and -galactosidase from Aspergillus oryzae was assessed. Tested processing variables were: transmembrane-pressure (PT), crossflow-velocity (CFV) and temperature. Results showed that processing variables had significant effect on the yield, the enzyme productivity and the flux but did not on GOS concentration and reaction conversion obtained. As expected, the use of high turbulences improved mass transfer and reduced the membrane fouling, but the use of very high crossflow-velocities caused operational instability due to vortex formation and lactose precipitation. The use of a desirability function allowed determining optimal conditions which were: PT (4.38 bar), CFV (7.35 m/s) and temperature (53.1 • C), optimizing simultaneously flux and specific enzyme productivity Under these optimal processing conditions, shear-stress and temperature did not affect the enzyme but long-term operation was limited by flux decay. In comparison to a conventional batch system, at 12.5 h of processing time, the continuous GOS synthesis in the UF-MBR increased significantly the amount of processed substrate and a 2.44-fold increase in the amount of GOS produced per unit mass of catalyst was obtained with respect to a conventional batch system. Furthermore, these results can be improved by far by tuning the membrane area /reaction volume ratio, showing that the use of an UF-MBR is an attractive alternative for the GOS synthesis at very high lactose concentrations.
Effects of wine grape cultivar, application conditions and the winemaking process on the dissipat... more Effects of wine grape cultivar, application conditions and the winemaking process on the dissipation of six pesticides. Cien. Inv. Agr. 41(3):375-386. Pesticide residue in primary products is an important issue for producers and consumers, even though little information is available on the effect of application conditions on residue persistence and the transfer to primary elaborated products. During the 2012 season, field and laboratory studies were conducted to determine the dissipation of lambda-cyhalothrin, buprofezin, pyrimethanil, tebuconazole, imidacloprid and acetamiprid in Sauvignon blanc and Pinot Noir cultivars and their residue dynamics during the winemaking process. Half-life values (DT 50) for each pesticide applied alone and as a tank mix of all pesticides were similar and had averages of 6.4, 14.0, 19.7, 26.0, 14.5 and 13.4 days for lambda-cyhalothrin, buprofezin, pyrimethanil, tebuconazole, imidacloprid and acetamiprid, respectively. The grape cultivar did not affect pesticide DT 50. All pesticides were transferred from the raw material (grape) to red and white wines except lambdacyhalothrin. The transfer factors of buprofezin, tebuconazole pyrimethanil, imidacloprid and acetamiprid ranged from 3 to 23% in red wine and 9 to 30% in white wine. Alcoholic fermentation, pressing (through pomace) and malolactic fermentation were the steps in which the greatest residue losses occurred in red wine, whereas pressing (through the grape and stem), alcoholic fermentation and clarification with bentonite had the greatest residue loss in white wine. In both cases, bottled wine showed substantial residue reduction after ten months.
ABSTRACT The Casablanca Valley is one of the youngest wine grape regions of the Chilean appellati... more ABSTRACT The Casablanca Valley is one of the youngest wine grape regions of the Chilean appellation of origin. The growers of this area note the presence of microclimates within the valley as one of its main features. These microclimates have historically been associated with two geographical zones: the Zona Alta and the Zona Baja. The objective of this research was to explore the effects of climate variables and anthocyanin profiles in Pinot Noir wines of the Casablanca Valley as a differentiator of productive zones. The climate variables were measured using weather stations located at different points across the valley. Wine samples from the same locations were characterised according to their anthocyanin profiles. The data were processed using analysis of variance, principal components analysis and partial least squares discriminant analysis to determine differences between the two groups explored. The results indicate a strong correlation between variables and zones (98.3% R2Y), leading to the conclusion that there are significant differences between the Zona Alta and Zona Baja group. Finally, the existence of a vineyard that does not belong to the Zona Baja group suggests a reassessment should be performed of the vineyards belonging to the administrative areas defined as part of the Casablanca Valley.
The intensification of processes is essential for the sustainability of the biorefinery concept. ... more The intensification of processes is essential for the sustainability of the biorefinery concept. Enzyme catalysis assisted by ultrasound (US) may offer interesting opportunities in the agri-food sector because the cavitation effect provided by this technology has been shown to improve the efficiency of the biocatalysts. This review presents the recent advances in this field, focused on three main applications: ultrasound-assisted enzymatic extractions (UAEE), US hydrolysis reactions, and synthesis reactions assisted by US for the manufacturing of agri-food produce and ingredients, enabling the upgrading of agro-industrial waste. Some theoretical and experimental aspects of US that must be considered are also reviewed. Ultrasonic intensity (UI) is the main parameter affecting the catalytic activity of enzymes, but a lack of standardization for its quantification makes it unsuitable to properly compare results. Applications of enzyme catalysis assisted by US in agri-foods have been mo...
Limiting flux (JL) determination is a critical issue for membrane processing. This work presents ... more Limiting flux (JL) determination is a critical issue for membrane processing. This work presents a modified exponential model for JL calculation, based on a previously published version. Our research focused on skim milk microfiltrations. The processing variables studied were the crossflow velocity (CFV), membrane hydraulic diameter (dh), temperature, and concentration factor, totaling 62 experimental runs. Results showed that, by adding a new parameter called minimum transmembrane pressure, the modified model not only improved the fit of the experimental data compared to the former version (R2 > 97.00%), but also revealed the existence of a minimum transmembrane pressure required to obtain flux (J). This result is observed as a small shift to the right on J versus transmembrane pressure curves, and this shift increases with the flow velocity. This fact was reported in other investigations, but so far has gone uninvestigated. The JL predicted values were correlated with the Reyno...
Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
World Journal of Microbiology and Biotechnology, 2016
Lactose-derived non-digestible oligosaccharides are prominent components of functional foods. Amo... more Lactose-derived non-digestible oligosaccharides are prominent components of functional foods. Among them, galacto-oligosaccharides (GOS) outstand for being prebiotics whose health-promoting effects are supported on strong scientific evidences, having unique properties as substitutes of human milk oligosaccharides in formulas for newborns and infants. GOS are currently produced enzymatically in a kinetically-controlled reaction of lactose transgalactosylation catalyzed by β-galactosidases from different microbial strains. The enzymatic synthesis of GOS, although being an established technology, still offers many technological challenges and opportunities for further development that has to be considered within the framework of functional foods which is the most rapidly expanding market within the food sector. This paper presents the current technological status of GOS production, its main achievements and challenges. Most of the problems yet to be solved refer to the rather low GOS yields attainable that rarely exceed 40 %, corresponding to lactose conversions around 60 %. This means that the product or reaction (raw GOS) contains significant amounts of residual lactose and monosaccharides (glucose and galactose). Efforts to increase such yields have been for the most part unsuccessful, even though improvements by genetic and protein engineering strategies are to be expected in the near future. Low yields impose a burden on downstream processing to obtain a GOS product of the required purity. Different strategies for raw GOS purification are reviewed and their technological significance is appraised.
The performance of an ultrafiltration membrane bioreactor for galacto-oligosaccharides (GOS) synt... more The performance of an ultrafiltration membrane bioreactor for galacto-oligosaccharides (GOS) synthesis using high lactose concentrations (470 g/L) and -galactosidase from Aspergillus oryzae was assessed. Tested processing variables were: transmembrane-pressure (PT), crossflow-velocity (CFV) and temperature. Results showed that processing variables had significant effect on the yield, the enzyme productivity and the flux but did not on GOS concentration and reaction conversion obtained. As expected, the use of high turbulences improved mass transfer and reduced the membrane fouling, but the use of very high crossflow-velocities caused operational instability due to vortex formation and lactose precipitation. The use of a desirability function allowed determining optimal conditions which were: PT (4.38 bar), CFV (7.35 m/s) and temperature (53.1 • C), optimizing simultaneously flux and specific enzyme productivity Under these optimal processing conditions, shear-stress and temperature did not affect the enzyme but long-term operation was limited by flux decay. In comparison to a conventional batch system, at 12.5 h of processing time, the continuous GOS synthesis in the UF-MBR increased significantly the amount of processed substrate and a 2.44-fold increase in the amount of GOS produced per unit mass of catalyst was obtained with respect to a conventional batch system. Furthermore, these results can be improved by far by tuning the membrane area /reaction volume ratio, showing that the use of an UF-MBR is an attractive alternative for the GOS synthesis at very high lactose concentrations.
Effects of wine grape cultivar, application conditions and the winemaking process on the dissipat... more Effects of wine grape cultivar, application conditions and the winemaking process on the dissipation of six pesticides. Cien. Inv. Agr. 41(3):375-386. Pesticide residue in primary products is an important issue for producers and consumers, even though little information is available on the effect of application conditions on residue persistence and the transfer to primary elaborated products. During the 2012 season, field and laboratory studies were conducted to determine the dissipation of lambda-cyhalothrin, buprofezin, pyrimethanil, tebuconazole, imidacloprid and acetamiprid in Sauvignon blanc and Pinot Noir cultivars and their residue dynamics during the winemaking process. Half-life values (DT 50) for each pesticide applied alone and as a tank mix of all pesticides were similar and had averages of 6.4, 14.0, 19.7, 26.0, 14.5 and 13.4 days for lambda-cyhalothrin, buprofezin, pyrimethanil, tebuconazole, imidacloprid and acetamiprid, respectively. The grape cultivar did not affect pesticide DT 50. All pesticides were transferred from the raw material (grape) to red and white wines except lambdacyhalothrin. The transfer factors of buprofezin, tebuconazole pyrimethanil, imidacloprid and acetamiprid ranged from 3 to 23% in red wine and 9 to 30% in white wine. Alcoholic fermentation, pressing (through pomace) and malolactic fermentation were the steps in which the greatest residue losses occurred in red wine, whereas pressing (through the grape and stem), alcoholic fermentation and clarification with bentonite had the greatest residue loss in white wine. In both cases, bottled wine showed substantial residue reduction after ten months.
ABSTRACT The Casablanca Valley is one of the youngest wine grape regions of the Chilean appellati... more ABSTRACT The Casablanca Valley is one of the youngest wine grape regions of the Chilean appellation of origin. The growers of this area note the presence of microclimates within the valley as one of its main features. These microclimates have historically been associated with two geographical zones: the Zona Alta and the Zona Baja. The objective of this research was to explore the effects of climate variables and anthocyanin profiles in Pinot Noir wines of the Casablanca Valley as a differentiator of productive zones. The climate variables were measured using weather stations located at different points across the valley. Wine samples from the same locations were characterised according to their anthocyanin profiles. The data were processed using analysis of variance, principal components analysis and partial least squares discriminant analysis to determine differences between the two groups explored. The results indicate a strong correlation between variables and zones (98.3% R2Y), leading to the conclusion that there are significant differences between the Zona Alta and Zona Baja group. Finally, the existence of a vineyard that does not belong to the Zona Baja group suggests a reassessment should be performed of the vineyards belonging to the administrative areas defined as part of the Casablanca Valley.
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