Apples are an important commodity, widely distributed around the world, and are used mostly for fresh consumption. Increased shelf-life and product quality are seen as desirable aspects by producers as well as by consumers. Post-harvest UVB irradiation has been demonstrated to be a promising technique to increase the health-promoting potential in peach fruits, at the same time improving shelf-life and quality. However, additional UVB is a source of reactive oxygen species (ROS) generation and when their formation exceeds the ability of detoxification, shelf life of fruits can be affected due to peroxidative damages to the cell. The level of carbon-centered free radicals is the result of an equilibrium between free radical production and their neutralization by antioxidants. The right balance among UVB supplemental dose, duration of treatment as well as induction of antioxidant synthesis could represent the recipe to obtain fruits which can sustain optimal storage conditions and may contribute to an antioxidant-rich diet with important health benefits. The study was focused on the identification of the type of free radicals generated in skin of apples “Red Delicious” supplemented with UVB (1.69 W.m-2) for 36 h. Changes in the levels of stable radicals was followed during storage in the dark for 21 days. Experiments were performed by using electron paramagnetic resonance (EPR) and the phosphorylated spin trap 5-(diethoxy-phosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO). In the UVB-treated apples a stable carbon-centered radical was identified. Following storage also control samples showed the appearance of stable radicals likely due to aging. The sample treated with UVB for 36 h maintained all over the storage period values of carbon-centered radicals always higher than the relative controls. Moreover, the difference in concentration between treated and controls fruits increased during time. The concomitant increase in some main cyanidins could have had a role in protective cells from oxidation. Indeed, supplemental irradiation of sample extracts in the presence of DEPMPO gave EPR spectra with the same hyperfine splitting constants of cyanidin, confirming its ability to radicalize in place of other molecules thus preventing damage to cell.
Free radical generation and evolution in UV-B treated apples: an EPR study
Cristina SgherriPrimo
;Mike Frank Quartacci;Anna Maria Ranieri;
2017-01-01
Abstract
Apples are an important commodity, widely distributed around the world, and are used mostly for fresh consumption. Increased shelf-life and product quality are seen as desirable aspects by producers as well as by consumers. Post-harvest UVB irradiation has been demonstrated to be a promising technique to increase the health-promoting potential in peach fruits, at the same time improving shelf-life and quality. However, additional UVB is a source of reactive oxygen species (ROS) generation and when their formation exceeds the ability of detoxification, shelf life of fruits can be affected due to peroxidative damages to the cell. The level of carbon-centered free radicals is the result of an equilibrium between free radical production and their neutralization by antioxidants. The right balance among UVB supplemental dose, duration of treatment as well as induction of antioxidant synthesis could represent the recipe to obtain fruits which can sustain optimal storage conditions and may contribute to an antioxidant-rich diet with important health benefits. The study was focused on the identification of the type of free radicals generated in skin of apples “Red Delicious” supplemented with UVB (1.69 W.m-2) for 36 h. Changes in the levels of stable radicals was followed during storage in the dark for 21 days. Experiments were performed by using electron paramagnetic resonance (EPR) and the phosphorylated spin trap 5-(diethoxy-phosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO). In the UVB-treated apples a stable carbon-centered radical was identified. Following storage also control samples showed the appearance of stable radicals likely due to aging. The sample treated with UVB for 36 h maintained all over the storage period values of carbon-centered radicals always higher than the relative controls. Moreover, the difference in concentration between treated and controls fruits increased during time. The concomitant increase in some main cyanidins could have had a role in protective cells from oxidation. Indeed, supplemental irradiation of sample extracts in the presence of DEPMPO gave EPR spectra with the same hyperfine splitting constants of cyanidin, confirming its ability to radicalize in place of other molecules thus preventing damage to cell.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
