Insulin restores metabolic function in cultured cortical neurons subjected to oxidative stress

We previously demonstrated that insulin has a neuroprotective role against oxidative stress, a deleterious condition associated with diabetes, ischemia, and age-related neurodegenerative diseases. In this study, we investigated the effect of insulin on neuronal glucose uptake and metabolism after oxidative stress in rat primary cortical neurons. On oxidative stress, insulin stimulates neuronal glucose uptake and subsequent metabolism into pyruvate, restoring intracellular ATP and phosphocreatine. Insulin also increases intracellular and decreases extracellular adenosine, counteracting the effect of oxidative stress. Insulin effects are apparently mediated by phosphatidylinositol 3-K and extracellular signal-regulated kinase signaling pathways. Extracellular adenosine under oxidative stress is largely inhibited after blockade of ecto-5'-nucleotidase, suggesting that extracellular adenosine results preferentially from ATP release and catabolism. Moreover, insulin appears to interfere with the ATP release induced by oxidative stress, regulating extracellular adenosine levels. In conclusion, insulin neuroprotection against oxidative stress-mediated damage involves 1) stimulation of glucose uptake and metabolism, increasing energy levels and intracellular adenosine and, ultimately, uric acid formation and 2) a decrease in extracellular adenosine, which may reduce the facilitatory activity of adenosine receptor

Effect of ultrasonication, thermosonication and ultraviolet irradiation on the quality of strawberies (fragaria anannassa) and red bell peppers (capsicum annuum L.)

The objective of this work was to study the effect of ultrasonication, thermosonication and UV-C irradiation on the quality attributes of strawberries (Fragaria anannassa) and red bell peppers (Capsicum annuum, L.). Thermosonication studies were carried out at 50ºC and 65ºC. Control water treatments at the same temperatures were conducted. The analysed quality factors were colour and texture for both products, in addition to anthocyanins content in the case of strawberries. Results showed that UV-C constituted a harmless treatment, with little or no effect on color, texture or anthocyanins content. Ultrasonication caused small colour changes and no significant effects on texture of both products. Thermosonication at 65ºC resulted in undesirable changes of color, anthocyanins and texture of strawberries, and color of red bell peppers. When compared to water treated samples, thermosonicated ones showed higher texture retention. This effect was much more pronounced on red bell peppers

Study on thermosonication and ultraviolet radiation processes as an alternative to blanching for some fruits and vegetables

The impacts of ultraviolet-C radiation, blanching by heat, and combination of heat/ultrasounds (thermosonication) were studied for Listeria innocua (inoculated) in red bell peppers, total mesophiles in strawberries and total coliforms in watercress, in the temperature range 50–65 °C. Quality attributes such as colour and firmness were studied for all products, and total anthocyanins content was additionally determined for strawberries. Results showed that ultraviolet- C radiation was the least effective treatment in terms of microbial load reduction and was equivalent to a simple water washing. Log reductions were 1.05±0.52 for L. innocua, 0.53±0.25 for total coliforms and 0.26±0.18 for total mesophiles. This treatment had the lowest impact on the quality parameters analysed. Thermosonication treatment was similar to heat blanching for all microorganism/product tested, excepted for total coliforms in watercress at 65 °C, in which thermosonication had a higher effect (p<0.05). Heat blanching at 65 °C allowed 7.43±0.12 log-cycles reduction, while loads were diminished by 8.24±0.13 log-cycles if thermosonication at the same temperature was applied. Thermosonication also allowed better quality retention, when compared to heat blanching at the same temperatures. The impact of thermosonication on microbial load reductions was statistically significant and thermosonicated samples retained quality attributes better than heat blanched ones at the same temperatures (p<0.05). Hence, it can be concluded that thermosonication is a promising process and may be a favourable alternative to the conventional thermal treatments

Influence of aqueous ozone, blanching and combined treatments on microbial load of red bell peppers, strawberries and watercress

The effectiveness of ozone in aqueous solution treatment on microbial inactivation was studied for three combinations microorganism/food: Listeria innocua/red bell peppers (artificially inoculated), total mesophiles/strawberries, and total coliforms/watercress, with two concentrations (0.3 and 2.0 ppm). Blanching treatments (50-60 degrees C) were also individually applied and in combination with ozone, for studying possible synergistic effects. In relation to ozone treatments, the highest microbial reductions were obtained for the highest concentration with the highest treatment time (3 min). Under those conditions. L. innocua/peppers, total mesophiles/strawberries and total coliforms/watercress were reduced respectively 2.8 +/- 0.5, 2.3 +/- 0.4 and 1.7 +/- 0.4 log-cycles. However, a substantial portion of the microbial populations were reduced by water washing alone, and the presence of ozone generally added an additional reduction of 0.5-1.0 log-cycles. If ozone at the highest concentration is used, the treatment impacts on L. innocua/peppers and total mesophiles/strawberries load reductions were equivalent to a blanching at 50 degrees C (for the same treatment times). Combining blanching and ozone did not generate synergistic effects, and in some situations microbial reductions were lower than the ones observed when treatments were applied independently.info:eu-repo/semantics/acceptedVersio

Effect of non-thermal methods on the safety of strawberries (Fragaria anannassa) and watercress (Nasturtium officinale)

Innovative non-thermal technologies have been studied as an attempt to substitute thermal methods on fruits and vegetables processing. The objective was to study the effect of methods, such as ultrasonication, and its combination with a milder heat treatment (thermosonication), and UV-C irradiation on safety of strawberries and watercress. Thermosonication studies were carried out at 50ºC, 55ºC, 65ºC and room temperature. Control water washings, at the same temperatures, were also performed. Safety was assessed in terms of total mesophyles and total coliforms, respectively on strawberries and watercress samples. For total mesophyles, results showed that thermosonication carried out at 65ºC and water washing at 50ºC were the most efficient treatments in microbial reduction. Results from UV-C treatments were not conclusive. For total coliforms, the most efficient processes were thermosonication and water-washing at 55 ºC. Results from UV-C treatments were identical to the ones obtained by ultrasonication and water washing at room temperature

Effect of ozone on the quality of fresh-cut green beans (Phaseolus vulgaris L.) and bell peppers (Capsicum annuum L.)

Ozone is a potent oxidant and disinfectant agent with multiple industrial applications. The efficacy of ozone treatments has been recognised in the sanitation of equipments and water disinfections. Recently, ozone started to be used as an innovative food processing technology that guarantees product safety. The objective of this work was to study the effect of ozone on the quality of fresh-cut green beans (Phaseolus vulgaris, L.) and green and red bell peppers (Capsicum annuum, L.). The quality factors analysed were enzyme (peroxidase) activity, colour and texture for green beans, and colour, texture and pH for bell peppers. Experiments were carried out in pilot equipment. An ozone generator was interconnected to a container filled with tap water. Ozone was continuously incorporated in water and its content was indirectly measured by potential difference. Green beans and bell peppers were cut in small portions. Samples were immersed in ozonated and non-ozonated water baths and removed after different times till a maximum of 180 minutes. Data from both treatments were compared by analysis of variance. For green beans, results showed that ozone treatment did not affect the colour, but significantly influenced texture (firmness) and peroxidase inactivation (at 7% significance level). After 40 minutes enzyme activity was reduced approximately 20%. This inactivation was verified for the rest of the sampling times. Ozone treatment affected pH and texture (fracturability) of red bell peppers (at 1% significance level). The other quality factors were not significantly influenced by ozone