Opuntia species exhibit beneficial properties when used to treat chronic diseases, particularly o... more Opuntia species exhibit beneficial properties when used to treat chronic diseases, particularly obesity, diabetes, cardiovascular disease, and cancer; however, the presence of spines and glochids in the species’ skin that easily stick into consumers’ fingers has limited their consumption. For this study, white and orange Opuntia ficus-indica fruits from the Canary Islands (Spain) were minimally processed, packed in a passive atmosphere, and stored at 7 °C. The effects of peeling (by hand or with an electric peeler) and two micro-perforated films (90PPlus and 180PPlus) were evaluated. Changes in the quality parameters, gas composition, bioactive compounds, sensory features, and microbial safety of fresh-cut prickly pears were examined during 10 days of cold storage. Both varieties, hand-peeled and electrically peeled, were microbiologically safe (aerobic mesophiles < 7 log(CFU/g fresh weight)) and retained suitable nutritional quality after 8 days of storage. The yield was greater...
Nanocellulose obtained from banana rachis (NCBR) was loaded (through simple impregnation) with a ... more Nanocellulose obtained from banana rachis (NCBR) was loaded (through simple impregnation) with a polyphenolic-rich extract (PRE) of Andean berries (Vaccinium meridionale). The adsorption/desorption of polyphenols onto NCBR and the thermal stability and antioxidant activity of the polyphenolic-NCBR nanocomplex (NCX) was studied. Thermodynamic properties (ΔH°ads, ΔS°ads and ΔG°ads) showed that polyphenols interact with NCBR by physisorption through a spontaneous and exothermic process. The NCX kept the original color of PRE (magenta) and released polyphenols in aqueous medium (80% of phenolic compounds in the first hour and 50% of anthocyanins in the first few minutes). The NCX showed high antioxidant activity, as evidenced by traditional assays, and inhibited the peroxyl radicals mediated oxidation of a tryptophan-containing peptide. Additionally, NCX inhibited lipid peroxidation in an emulsified system of Sacha inchi oil exposed to accelerated oxidative conditions. In conclusion, the NCX showed good properties as an antioxidant with potential use as a food additive.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2017
Helicobacter pylori (H. pylori) infection triggers inflammatory processes with the consequent pro... more Helicobacter pylori (H. pylori) infection triggers inflammatory processes with the consequent production of hypochlorous acid (HOCl), monochloramine (NHCl), and protein-derived chloramines. As the therapy for eradicating H. pylori is partially based on the use of tetracycline, we studied the kinetic of its consumption elicited by HOCl, NHCl, N-chloro-n-butylamine (NHCl-But, used as a lysine-derived chloramine model), and lysozyme-derived chloramines. In the micromolar concentration range, tetracycline reacted rapidly with HOCl, generating in the first few seconds intermediates of short half-life. In contrast, a slow tetracycline consumption was observed in the presence of high NHCl and NHCl-But concentrations (millimolar range). Similar chlorinated products of tetracycline were identified by mass spectrometry, in the presence of HOCl and NHCl. These results evidenced that tautomers of tetracycline are pivotal intermediates in all reactions. In spite of the low reactivity of chloramines towards tetracycline, it is evident that, in the concentration range where they are produced in a H. pylori infection (millimolar range), the reactions lead to oxidation and/or chlorination of tetracycline. This kind of reactions, which were also observed triggered by lysozyme-derived chloramines, could limit the efficiency of the tetracycline-based therapy.
Plant foods for human nutrition (Dordrecht, Netherlands), Jan 17, 2016
Using banana peel extract as an antioxidant in freshly squeezed orange juices and juices from con... more Using banana peel extract as an antioxidant in freshly squeezed orange juices and juices from concentrate was evaluated. Free radical scavenging capacity increased by adding banana peel extracts to both types of orange juice. In addition, remarkable increases in antioxidant capacity using 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical were observed when equal or greater than 5 mg of banana peel extract per ml of freshly squeezed juice was added. No clear effects were observed in the capacity to inhibit lipid peroxidation. Adding 5 mg banana peel extract per ml of orange juice did not substantially modify the physicochemical and sensory characteristics of either type of juice. However, undesirable changes in the sensory characteristics (in-mouth sensations and colour) were detected when equal or greater than 10 mg banana peel extract per ml of orange juice was added. These results confirm that banana peel is a promising natural additive that increases the ...
We demonstrate from kinetic studies that under the experimental conditions proposed for the ORAC ... more We demonstrate from kinetic studies that under the experimental conditions proposed for the ORAC protocol, ORAC values do not correlate with the capacity of antioxidants to trap peroxyl radicals (ROO˙), suggesting a dominant role of alkoxyl radicals (RO˙) in the assay.
During the last decades the ORAC (Oxygen Radical Absorbance Capacity) assay has been widely emplo... more During the last decades the ORAC (Oxygen Radical Absorbance Capacity) assay has been widely employed to evaluate the in vitro antioxidant capacity of polyphenol-rich fruits, vegetables and beverages. The method employs fluorescein (FLH) as target molecule and AAPH (2,2&amp;amp;amp;amp;#39;-azo-bis(2-amidinopropane)dihydrochloride) as the source of peroxyl radicals (ROO•). The protection of FLH, afforded by antioxidants (XH), is often characterized by kinetic profiles with clear lag times (LT), which are directly associated with the stoichiometry (n) of the XH-ROO• reaction. However, even for simple phenolic compounds, the LT measured imply large n values (defined as the number of ROO• moles trapped by each antioxidant molecule) which cannot be explained by a simple reaction mechanism. Nonetheless, they can be explained when considering the formation of alkoxyl radicals (RO•) from the recombination of two AAPH-derived ROO•. In the present work, we provide kinetic data showing that, in the zero order kinetic limit of FLH consumption, there is a low reaction rate incompatible with total trapping of ROO•. Thus, the consumption of FLH should be mostly related to its reaction with RO•. In addition, we present data regarding the assumption that in competitive measurements, the LT is due to efficient trapping of the ROO• by the added phenols, leading to high n values (1.7 to 23) for mono and polyphenols. These values are not in agreement with kinetic studies of the antioxidant consumption mediated by the presence of AAPH carried out by HPLC-DAD technique, which imply a competition by RO•. The results suggest that the use of FLH as probe at low concentrations give, for several antioxidants, ORAC values mainly related to their reaction towards RO• radicals instead of primary ROO•radicals.
Plant foods for human nutrition (Dordrecht, Netherlands), 2013
The purpose of this study was to analyze the extraction efficiency of antioxidants from mango pee... more The purpose of this study was to analyze the extraction efficiency of antioxidants from mango peel by comparing two techniques: microwave-assisted (MAE) and traditional solvent (TE) extraction. The number of extraction steps, water content in the extractant, peel weight-to-solvent volume ratio in extractions and extraction time all had an influence on obtaining extracts with high antioxidant capacity, but the extraction technique and the water content in the extractant were the factors with the greatest effect. Using three steps, a water content of 50 % in the ethanol:water extractant, an extraction time of 60 min and a weight-to-volume ratio of 1:10 or 1:50 (w/v) led to the highest antioxidant activity and phytochemicals content in extracts. The extraction time needed to extract phytochemicals from mango peel was similar when MAE and TE were used. However, the antioxidant capacity and phytochemical content were around 1.5-6.0 times higher in the extracts obtained by MAE.
In Europe, nutrition and health claims made on food must be based on scientific evidence, which m... more In Europe, nutrition and health claims made on food must be based on scientific evidence, which means a comprehensive evaluation by the European Food Safety Authority (EFSA) prior to authorisation. Processed foods are subject to numerous claims derived from the presence of bioactive compounds; however, natural food products, often the original sources of those compounds, are not habitually the subject of these claims. Although the consumption of persimmon fruit has important health benefits, up to date no specific health claims are authorised for this fruit. In this work, ‘Rojo Brillante’ persimmon fruits (Diospyros kaki L.), Protected Designation of Origin (PDO) ‘Ribera del Xúquer’ were characterized regarding the presence of fiber (soluble and insoluble), vitamin C (ascorbic and dehydroascorbic acids), carotenoids (neoxanthin, violaxanthin, β-cryptoxanthin, lycopene, β- carotene) and mineral elements (Fe, Cu, Zn, Mn, Ca, Mg, Na, K). Different fruit batches harvested in different s...
Opuntia species exhibit beneficial properties when used to treat chronic diseases, particularly o... more Opuntia species exhibit beneficial properties when used to treat chronic diseases, particularly obesity, diabetes, cardiovascular disease, and cancer; however, the presence of spines and glochids in the species’ skin that easily stick into consumers’ fingers has limited their consumption. For this study, white and orange Opuntia ficus-indica fruits from the Canary Islands (Spain) were minimally processed, packed in a passive atmosphere, and stored at 7 °C. The effects of peeling (by hand or with an electric peeler) and two micro-perforated films (90PPlus and 180PPlus) were evaluated. Changes in the quality parameters, gas composition, bioactive compounds, sensory features, and microbial safety of fresh-cut prickly pears were examined during 10 days of cold storage. Both varieties, hand-peeled and electrically peeled, were microbiologically safe (aerobic mesophiles < 7 log(CFU/g fresh weight)) and retained suitable nutritional quality after 8 days of storage. The yield was greater...
Nanocellulose obtained from banana rachis (NCBR) was loaded (through simple impregnation) with a ... more Nanocellulose obtained from banana rachis (NCBR) was loaded (through simple impregnation) with a polyphenolic-rich extract (PRE) of Andean berries (Vaccinium meridionale). The adsorption/desorption of polyphenols onto NCBR and the thermal stability and antioxidant activity of the polyphenolic-NCBR nanocomplex (NCX) was studied. Thermodynamic properties (ΔH°ads, ΔS°ads and ΔG°ads) showed that polyphenols interact with NCBR by physisorption through a spontaneous and exothermic process. The NCX kept the original color of PRE (magenta) and released polyphenols in aqueous medium (80% of phenolic compounds in the first hour and 50% of anthocyanins in the first few minutes). The NCX showed high antioxidant activity, as evidenced by traditional assays, and inhibited the peroxyl radicals mediated oxidation of a tryptophan-containing peptide. Additionally, NCX inhibited lipid peroxidation in an emulsified system of Sacha inchi oil exposed to accelerated oxidative conditions. In conclusion, the NCX showed good properties as an antioxidant with potential use as a food additive.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2017
Helicobacter pylori (H. pylori) infection triggers inflammatory processes with the consequent pro... more Helicobacter pylori (H. pylori) infection triggers inflammatory processes with the consequent production of hypochlorous acid (HOCl), monochloramine (NHCl), and protein-derived chloramines. As the therapy for eradicating H. pylori is partially based on the use of tetracycline, we studied the kinetic of its consumption elicited by HOCl, NHCl, N-chloro-n-butylamine (NHCl-But, used as a lysine-derived chloramine model), and lysozyme-derived chloramines. In the micromolar concentration range, tetracycline reacted rapidly with HOCl, generating in the first few seconds intermediates of short half-life. In contrast, a slow tetracycline consumption was observed in the presence of high NHCl and NHCl-But concentrations (millimolar range). Similar chlorinated products of tetracycline were identified by mass spectrometry, in the presence of HOCl and NHCl. These results evidenced that tautomers of tetracycline are pivotal intermediates in all reactions. In spite of the low reactivity of chloramines towards tetracycline, it is evident that, in the concentration range where they are produced in a H. pylori infection (millimolar range), the reactions lead to oxidation and/or chlorination of tetracycline. This kind of reactions, which were also observed triggered by lysozyme-derived chloramines, could limit the efficiency of the tetracycline-based therapy.
Plant foods for human nutrition (Dordrecht, Netherlands), Jan 17, 2016
Using banana peel extract as an antioxidant in freshly squeezed orange juices and juices from con... more Using banana peel extract as an antioxidant in freshly squeezed orange juices and juices from concentrate was evaluated. Free radical scavenging capacity increased by adding banana peel extracts to both types of orange juice. In addition, remarkable increases in antioxidant capacity using 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical were observed when equal or greater than 5 mg of banana peel extract per ml of freshly squeezed juice was added. No clear effects were observed in the capacity to inhibit lipid peroxidation. Adding 5 mg banana peel extract per ml of orange juice did not substantially modify the physicochemical and sensory characteristics of either type of juice. However, undesirable changes in the sensory characteristics (in-mouth sensations and colour) were detected when equal or greater than 10 mg banana peel extract per ml of orange juice was added. These results confirm that banana peel is a promising natural additive that increases the ...
We demonstrate from kinetic studies that under the experimental conditions proposed for the ORAC ... more We demonstrate from kinetic studies that under the experimental conditions proposed for the ORAC protocol, ORAC values do not correlate with the capacity of antioxidants to trap peroxyl radicals (ROO˙), suggesting a dominant role of alkoxyl radicals (RO˙) in the assay.
During the last decades the ORAC (Oxygen Radical Absorbance Capacity) assay has been widely emplo... more During the last decades the ORAC (Oxygen Radical Absorbance Capacity) assay has been widely employed to evaluate the in vitro antioxidant capacity of polyphenol-rich fruits, vegetables and beverages. The method employs fluorescein (FLH) as target molecule and AAPH (2,2&amp;amp;amp;amp;#39;-azo-bis(2-amidinopropane)dihydrochloride) as the source of peroxyl radicals (ROO•). The protection of FLH, afforded by antioxidants (XH), is often characterized by kinetic profiles with clear lag times (LT), which are directly associated with the stoichiometry (n) of the XH-ROO• reaction. However, even for simple phenolic compounds, the LT measured imply large n values (defined as the number of ROO• moles trapped by each antioxidant molecule) which cannot be explained by a simple reaction mechanism. Nonetheless, they can be explained when considering the formation of alkoxyl radicals (RO•) from the recombination of two AAPH-derived ROO•. In the present work, we provide kinetic data showing that, in the zero order kinetic limit of FLH consumption, there is a low reaction rate incompatible with total trapping of ROO•. Thus, the consumption of FLH should be mostly related to its reaction with RO•. In addition, we present data regarding the assumption that in competitive measurements, the LT is due to efficient trapping of the ROO• by the added phenols, leading to high n values (1.7 to 23) for mono and polyphenols. These values are not in agreement with kinetic studies of the antioxidant consumption mediated by the presence of AAPH carried out by HPLC-DAD technique, which imply a competition by RO•. The results suggest that the use of FLH as probe at low concentrations give, for several antioxidants, ORAC values mainly related to their reaction towards RO• radicals instead of primary ROO•radicals.
Plant foods for human nutrition (Dordrecht, Netherlands), 2013
The purpose of this study was to analyze the extraction efficiency of antioxidants from mango pee... more The purpose of this study was to analyze the extraction efficiency of antioxidants from mango peel by comparing two techniques: microwave-assisted (MAE) and traditional solvent (TE) extraction. The number of extraction steps, water content in the extractant, peel weight-to-solvent volume ratio in extractions and extraction time all had an influence on obtaining extracts with high antioxidant capacity, but the extraction technique and the water content in the extractant were the factors with the greatest effect. Using three steps, a water content of 50 % in the ethanol:water extractant, an extraction time of 60 min and a weight-to-volume ratio of 1:10 or 1:50 (w/v) led to the highest antioxidant activity and phytochemicals content in extracts. The extraction time needed to extract phytochemicals from mango peel was similar when MAE and TE were used. However, the antioxidant capacity and phytochemical content were around 1.5-6.0 times higher in the extracts obtained by MAE.
In Europe, nutrition and health claims made on food must be based on scientific evidence, which m... more In Europe, nutrition and health claims made on food must be based on scientific evidence, which means a comprehensive evaluation by the European Food Safety Authority (EFSA) prior to authorisation. Processed foods are subject to numerous claims derived from the presence of bioactive compounds; however, natural food products, often the original sources of those compounds, are not habitually the subject of these claims. Although the consumption of persimmon fruit has important health benefits, up to date no specific health claims are authorised for this fruit. In this work, ‘Rojo Brillante’ persimmon fruits (Diospyros kaki L.), Protected Designation of Origin (PDO) ‘Ribera del Xúquer’ were characterized regarding the presence of fiber (soluble and insoluble), vitamin C (ascorbic and dehydroascorbic acids), carotenoids (neoxanthin, violaxanthin, β-cryptoxanthin, lycopene, β- carotene) and mineral elements (Fe, Cu, Zn, Mn, Ca, Mg, Na, K). Different fruit batches harvested in different s...
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