Determinación del contenido de antioxidantes naturales en frutos secos

Los frutos secos contienen un alto contenido de ácido oleico y/o ácidos poliinsaturados, por lo que su ingesta reduce los niveles de colesterol total y colesterol LDL en sangre, lo que se asocia a una menor incidencia de enfermedades cardiovasculares. A su vez, los frutos secos podrían tener efectos beneficiosos en la salud humana debido a la presencia de antioxidantes (polifenoles y tocoferoles). En el presente trabajo se determinó el contenido de lípidos, el perfil en ácidos grasos y el contenido de polifenoles y tocoferoles de algunos frutos secos: nueces, nueces pecan, avellanas, almendras, maní, pistachos y castañas de cajú. Se optimizó la extracción de los polifenoles en avellanas mediante la utilización de diferentes mezclas de solventes y distintas condiciones de temperatura y tiempos de extracción. Con la mezcla agua/acetona (80:20) a 25 ºC, durante 24 horas, se obtuvo el mayor contenido de polifenoles. El contenido de polifenoles de los extractos obtenidos de los frutos secos presentó valores en el rango entre 427 ppm (almendras) y 8805 ppm (nueces), mientras que el contenido de tocoferoles, entre 160 ppm (castañas de cajú) y 358 ppm (nueces). Se concluye que los frutos secos analizados poseen contenidos importantes de antioxidantes, pero en cantidades diferentes. Además, la cáscara ofrece una barrera para enlentecer los procesos de oxidación del aceite presente en el fruto

Determinação do conteúdo de antioxidantes naturais em frutos secos

Nuts contain a high content of oleic acid and/or polyunsaturated acids, so their intake reduces the level of total cholesterol and LDL cholesterol in the blood, which is associated with a lower incidence of cardiovascular diseases. Besides, nuts have beneficial effects on human health due to the presence of antioxidants (polyphenols and tocopherols). In this study, lipid content, fatty acid profile and polyphenols and tocopherols content of some nuts were determined: walnuts, pecans, hazelnuts, almonds, peanuts, pistachios and cashews. The extraction of polyphenols in hazelnuts was optimized by using different mixtures of solvents as well as several conditions of temperature and extraction times. The mixture water/acetone (80:20) at 25 °C during 24 hours showed the highest content of polyphenols. The polyphenol content of the extracts obtained from the nuts showed values in the range between 427 ppm (almonds) and 8805 ppm (walnuts), while the content of tocopherols, ranges between 160 ppm (cashews) and 358 ppm (walnuts). Thus, the analyzed nuts have important antioxidant contents but in different amounts. Furthermore, the nutshell offers a barrier to slow down the oxidation processes of the oil present in the product.Los frutos secos contienen un alto contenido de ácido oleico y/o ácidos poli-insaturados, por lo que su ingesta reduce los niveles de colesterol total y colesterol LDL en sangre, lo que se asocia a una menor incidencia de enfermedades cardiovasculares. A su vez, los frutos secos han demostrado tener efectos beneficiosos en la salud humana debido a la presencia de antioxidantes (polifenoles y tocoferoles). En el presente trabajo se determinó el contenido de lípidos, el perfil en ácidos grasos y el contenido polifenoles y tocoferoles de algunos frutos secos: nueces, nueces pecan, avellanas, almendras, maní, pistachos y castañas de cajú. Se optimizó la extracción de los polifenoles en avellanas mediante la utilización de diferentes mezclas de solventes y distintas condiciones de temperatura y tiempos de extracción. Con la mezcla agua/acetona (80:20) a 25ºC, durante 24 horas, se obtuvo el mayor contenido de polifenoles. El contenido de polifenoles de los extractos obtenidos de los frutos secos presentó valores en el rango entre 427 ppm (almendras) y 8805 ppm (nueces), mientras que el contenido de tocoferoles, entre 160 ppm (castañas de cajú) y 358 ppm (nueces). Se concluye que los frutos secos analizados poseen contenidos importantes de antioxidantes, pero en cantidades diferentes. Además, la cáscara ofrece una barrera para enlentecer los procesos de oxidación del aceite presente en el fruto.Os frutos secos possuem alto teor de ácido oleico e/ou ácidos poliinsaturados, razão pela qual sua ingestão reduz os níveis de colesterol total e LDL no sangue, que está associado à menor incidência de doenças cardiovasculares. Além disso, os frutos secos apresentam efeitos benéficos à saúde humana devido à presença de antioxidantes (polifenóis e tocoferóis). No presente trabalho, foram determinados o teor de lipídios, o perfil de ácidos graxos e o teor de polifenóis e tocoferóis de alguns frutos secos: nozes, noz-pecã, avelã, amêndoa, amendoim, pistache e castanha de caju. A extração dos polifenóis nas avelãs foi otimizada pelo uso de diferentes misturas de solventes em diferentes condições de temperatura e tempos de extração. Com a mistura água/acetona (80:20) a 25 °C por 24 horas, obteve-se o maior teor de polifenóis. O teor de polifenóis dos extratos obtidos dos frutos secos apresentou valores na faixa de 427 ppm (amêndoas) a 8805 ppm (nozes), enquanto o teor de tocoferol, entre 160 ppm (castanha de caju) e 358 ppm (nozes). Consequentemente, os frutos secos analisados têm um conteúdo antioxidante significativo, mas em quantidades diferentes. Além disso, a casca oferece uma barreira para retardar os processos de oxidação do óleo presente

Measurement of proton-distribution radii of neutron-rich nitrogen isotopes

Measurement of root-mean-square radii of proton distributions of 17–22N from charge-changing cross section shows the emergence of thick neutron skin towards the neutron-drip line. Signature of N = 14 shell gap has been found in nitrogen isotopes along with the emergence of neutron halo in 22N. The measured radii are in good agreement with the shell model calculations

Measurement of proton-distribution radii of neutron-rich nitrogen isotopes

Measurement of root-mean-square radii of proton distributions of 17–22N from charge-changing cross section shows the emergence of thick neutron skin towards the neutron-drip line. Signature of N = 14 shell gap has been found in nitrogen isotopes along with the emergence of neutron halo in 22N. The measured radii are in good agreement with the shell model calculations

Structure of ¹³Be studied in proton knockout from ¹⁴B

The neutron-unbound isotope 13Be has been studied in several experiments using different reactions, different projectile energies, and different experimental setups. There is, however, no real consensus in the interpretation of the data, in particular concerning the structure of the low-lying excited states. Gathering new experimental information, which may reveal the 13Be structure, is a challenge, particularly in light of its bridging role between 12Be, where the N = 8 neutron shell breaks down, and the Borromean halo nucleus 14Be. The purpose of the present study is to investigate the role of bound excited states in the reaction product 12Be after proton knockout from 14B, by measuring coincidences between 12Be, neutrons, and γ rays originating from de-excitation of states fed by neutron decay of 13Be. The 13Be isotopes were produced in proton knockout from a 400 MeV/nucleon 14B beam impinging on a CH2 target. The 12 Be-n relative-energy spectrum d σ /d Ef n was obtained from coincidences between 12Be(g.s.) and a neutron, and also as threefold coincidences by adding γ rays, from the de-excitation of excited states in 12Be. Neutron decay from the first 5/2+ state in 13Be to the 2+ state in 12Be at 2.11 MeV is confirmed. An energy independence of the proton-knockout mechanism is found from a comparison with data taken with a 35 MeV/nucleon 14B beam. A low-lying p-wave resonance in 13Be(1/2−) is confirmed by comparing proton- and neutron-knockout data from 14B and 14Be