جستجوی مقالات مرتبط با کلیدواژه "microwave" در نشریات گروه "پزشکی"

It is critical to use modern extraction strategies to show ideal characteristics of the plant extricates. In this study, antioxidant and antimicrobial characteristics of the extracts of Scrophularia striata plant and olive leaves were assessed using microwave and ultrasound extraction strategies.

After designing the experiment using Box-Behnken method, extractions were carried out using microwave devices to check effects of microwaves and ultrasonic bath. Phenolic content and antioxidant characteristics were assessed using total phenolic compound and 2,2-Diphenyl-1-picrylhydrazyl methods, respectively. Microdilution broth method was used to assess the minimum inhibitory concentration for Listeria monocytogenes.

The most effective independent variable in extraction in the two methods and in plants was the ratio of solvent to plant. The ratio of ethanol in the extractor solvent affected total phenolic compound and yield. Ultrasound extraction yielded the highest total phenolic compound concentrations for olive leaves (5.34 ±0.26) and Scrophularia striata (2.89 ±0.14 mg.g-1). The best minimum inhibitory concentration (0.47 ±0.005 mg.ml-1) was reported for the olive leaves using ultrasound extraction.

The two extraction methods included various effects on characteristics of the extracts due to the structure and compounds in the two plants. The ultrasound extraction method extracted the highest quantity of phenolic compounds from the two plants. The highest quantity of antioxidant characteristics was linked to microwave extraction. It can be concluded that olive leaves and Scrophularia striata plants can potentially decrease Listeria monocytogenes contamination.

Modifying characteristics of starch to change or improve its quality characteristics was carried out using various methods including irradiation with electromagnetic waves in the present study.

Aiming use of a safe method to modify the functional characteristics of starch, effects of microwave, infrared and laser beams on characteristics of cornstarch were investigated for 15 and 30 min at 60 ºC. Water and oil absorption, transparency, swelling power, solubility, carbonyl and carboxyl contents, thermal characteristics and rheology of the treated samples were investigated as well.

The waves included significant effects on changes in the quality characteristics of the cornstarch, especially their functional characteristics. Using waves and increasing its duration by changing the structure of starch and intermolecular bonds increased solubility and water and oil absorption powers and decreased transparency. The highest solubility and absorptions of water and oil were observed in treated starch with microwave for 30 min and the highest swelling power was observed in starch treated with laser for 15 min. Using waves with increased oxidation caused increases in carbonyl and carboxyl contents with various intensities in the treated starches. Starting temperature of the gelatinization of the treated samples increased and temperature of the end of the gelatinization decreased and therefore melting temperature of the crystals and the necessary energy  in the treated samples were estimated lower, compared to the control. Starch suspension showed shear thinning behaviors and consistency coefficient and flow index of the control sample were higher and lower than those of the treated samples, respectively.

Selection of the appropriate treatment conditions varies depending on the desired characteristics of starch. The treated starch for 30 min with microwaves was reported superior to other samples for the most functional characteristics.

Deep fat frying is one of the oldest processes used to dry, cook, and formulate food products. The success of this process is due to its adaptability and flexibility in domestic and industrial scale. Fried foods are very popular owing to their good mouthfeel, high pleasantness, good taste, and texture. Foods absorb a significant amount of oil during frying, which increases the risk of such diseases as increased cholesterol levels, blood pressure, cardiovascular diseases, and cancer. The shift in consumer attitude and preference towards healthier options with lower fat content has markedly affected the fried food industry. Numerous attempts have been made globally to create low-fat products due to the excessive oil content in fried foods. There are novel methods to reduce the amount of oil in fried products. This review aimed to assess the effect of new technologies of blanching, microwave, and ultrasound on physicochemical properties, especially the reduction of oil absorption in fried products.

Potato fried, despite their large proportions of oil and adverse effects on health, are one of the most popular products in the food industry. Therefore, decreasing oil absorption during frying can be an important goal of French fries processing. In this study, effects of microwave pretreatment on oil absorption and qualitative characteristics of potato fries during deep frying were investigated.

Potatoes were stored in refrigerators at temperatures higher than zero (4 ℃ ) for 24 h before beginning the experiments. Microwave pretreatment was used with powers of 200, 300, 400 and 500 W and times of 2, 4 and 6 min and the frying process was carried out at temperatures of 160 and 180 ℃ . Furthermore, moisture content, oil absorption, color component, texture hardness and, shrinkage of the samples were assessed as well as sensory evaluation of the samples.

Microwave pretreatment included significant effects on moisture content, absorbed oil, color indices and texture hardness of the samples (p < 0/05) with no effects on shrinkage (p > 0/05). Of various treatments, the greatest effect was observed with the power of 500 W for 6 min at 160 and 180 ℃  (8.105 and 11%).

Results showed that at higher powers and times, the intensity of decreases in oil absorption increased. It can be concluded that use of microwave is an appropriate, easy available pretreatment to decrease oil content and improve quality characteristics of potato fries.

Free radicals originate from oxidation reactions decrease food quality and also promote incidence of various diseases such as cancer.

In this research the effect of four enzymes, alcalase, trypsin, pepsin, and pancreatin, without pretreatment and with microwave and ultrasound pretreatment under optimal hydrolysis conditions on the antioxidant capacity of edible mushroom hydrolyzed protein was compared. The hydrolysis process to reach the maximum antioxidant activity with a ratio of enzyme to substrate of 1% and at the optimum temperature of each enzyme with and without microwave and ultrasound pretreatment and ultrasound pretreatment with 160W power, then hydrolysis with enzyme was done in 60 minutes and for samples without pretreatment, hydrolysis time was 120 minutes for each enzyme.

The results showed that the highest amount of total antioxidant capacity was 1.64 with hydrolysis by pepsin enzyme, the highest reducing power of iron ion was 2.80 with hydrolysis by alcalase enzyme. The highest iron ion chelation power of 65.08% was achieved with hydrolysis by trypsin enzyme and the highest DPPH free radical inhibition activity of 80.57% with hydrolysis by pepsin enzyme, all in the samples pre-treated with 160W ultrasound in the hydrolysis time of 60 minutes.

The results showed that in order to create the desired antioxidant properties in the hydrolyzed protein obtained from edible mushrooms, a special combination of hydrolyzing enzyme and pretreatment should be used, and ultrasound pretreatment is more effective than microwave in this field. formulations.

Marination accompanied with the application of functional plant extracts is aconvenient method to preserve fish meat. The present study aims to extract Khandalcontaining antioxidant compounds by the use of microwave and applying it to marinatedfillets of Beluga in order to increase its shelflife at 4±1ºC. Microwave extraction optimization according to the solvent type,solvent ratio (5–15.5cc), time (10-30min) and power (90-270W) through RSM and applyingthe optimum extract in respect to the total phenolic compounds and the inhibitory potential ofDPPH free radicals for preparing marinates (i.e. control, treatments containing10 (T1),20 (T2),and 30% (T3) extract( and storage during 20days at 4±1ºC and monitoring the physical,chemical and sensory properties and comparing the results and data were carried out usingone-wayANOVA and chi-square methods. The results indicated that the optimal extract was obtained by the use of water for30min, at 90W and solvent ratio of 5. Moreover, it was revealed that TBA inT2wassignificantly controlled as compared to other groups and the amount of TVB-N, in T2 and T3were lower significantly (P<0.05) and being controlled. In terms of water activity, the highestamount was observed in T2 at days 0 and 10. The highest WHC was observed in the controlon day 0, which was decreased during storage time. The texture hardness, color, appearanceand odor didn’t show significant difference among the groups, but taste and oral sensationwere differed significantly over time. In terms of texture analysis, due to excessivemarinating, the samples became soft and watery and low score was obtained. Examination ofacid-salt taste showed that the marinated samples had acidic and salty taste. It is concluded that the sample containing 20% of extract was selected as thebest group in controlling chemical spoilage.

  Chlorophenol is one of the most dangerous and toxic pollutants in industrial effluents and wastewater. The removal of this material from groundwater and surface water is considered a serious problem. This study aimed to evaluate the degradability of 4-Chlorophenol using microwave / Na2S2O8 / Fe2+ process.

In this quasi-experimental study, the effects of variables, including initial pollutant concentration (0.5-5 mM), contact time (0-30 min), pH (3-11), persulfate concentration (8-80 mM), a dosage of Fe2+ (0.01-0.1 mM), and power output (180-600 W) were investigated on the removal of 4-chlorophenol in a modified domestic microwave. The residual 4-chlorophenol concentration was then measured using a spectrophotometer at 280 nm. The mineralization rate at optimum conditions was determined by assessing the total organic carbon (TOC) removal rate according to the B 5310 standard. Moreover, kinetic models of the process were investigated.

In this study, the optimum removal efficiency of 4-chlorophenol by microwave / Na2S2O8 / Fe2+ process was obtained at 91.38% at 60 mM sodium persulfate concentration, pH = 11, 0.5 mM initial concentration of 4-chlorophenol, and the presence of 600 W microwave radiation at 30 min exposure. In addition, it was revealed that 77% of TOC was removed at optimum conditions. The data followed the pseudo-first-order kinetic model.

 The MW / Na2S2O8 / Fe2+ process can be used as a post-treatment or final treatment of effluent considering the treatment objectives and existing standards for effluent discharge.

In the past decade, sulfated fucose-rich polysaccharides (fucoidan) have been much interested due to their diverse biological activities, including anticoagulant, antiviral, antitumor, anti-inflammatory, anti-blood lipid, antioxidant, gastric protection and therapeutic activities. In the present study, microwave was used as a green efficient technology for the extraction of bioactive compounds of fucoidan from Iranian macroalgae (Nizimuddinia zanardini). In addition, effects of microwave on chemical composition and antioxidant activity of fucoidan were assessed.

Fucoidan polysaccharides were extracted under optimized conditions of microwave power, processing time and temperature. The compound characteristics, including extraction efficiency, fucose content, sulfate content, uronic acid content and DPPH radical scavenging were assessed. Fourier-transform infrared spectroscopy was used at wavelengths of 400–4000 cm-1 at room temperature.

Results showed that microwave treatment was effective in improving the extraction yield of fucoidan. Fucoidan extraction yields under the microwave technique included 3.71 and 2.35%. The fucose content under the microwave technique (33.17%) was compared to that under the conventional technique (29.5%) with significant increases, indicating less thermal degradation of the polysaccharide structures under the microwave technique. The microwave improved fucoidan antioxidant activity by producing shorter chain polysaccharides.

In this study, fucoidan sulfated polysaccharides were extracted using microwave extraction technique in a much shorter time than the conventional extraction technique with higher efficiency and lower thermal degradation. In addition, the shorter process time decreased solvent use.

Plants have been always considered as one of the main raw materials to be used in food, pharmaceutical and cosmetic industries. Marine algae is a rich sources of bioactive compounds with antioxidant activity.

In this study optimization of extraction of antioxidant compounds including chlorophyll a and b, carotenoids and total phenolic contents of Caulerpa sertularioides has been carried out by microwave-assisted extraction, based on extraction time, microwave power, solvent type and solvent to sample ratio. Experimental design was performed by Design Expert with 25 runs and the amounts of antioxidant compounds were evaluated.

The results of chlorophyll a and b evaluation showed that among 4 studied factors only solvent type had significant effect (P<0.05). According to the results the optimum conditions of chlorophyll a and b extraction included methanol as solvent, microwave power of 180 watt, extraction time of 20 minutes and solvent to sample ratio of 12.5. Regarding carotenoid solvent was the only significant factor (P<0.05) and its optimum extraction conditions included methanol as solvent, microwave power of 90 watt, extraction time of 10 minutes and solvent to sample ratio of 5. Concerning total phenolic content none of the 4 parameters of extraction process had significant effect on its extraction (P>0.05).

According to the results of this study Caulerpa sertularioides is an important source of antioxidant compounds and by studying the effect of extraction factors on its antioxidant and phenolic compounds and determination of the optimum extraction conditions for each compound, this algae could be employed appropriately.

Basil contains high phenolic compounds and its seeds contain mucilages. By investigation the essential oils of this plant, and especially its phenylpropanoid compounds, have been identified as the main medicinal product.

In this research, basil leaves were dried by three

shadow, drying oven method at 40 and 60° C and microwave method at 180 and 360 W. In order to increase the heat transfer in short time some effective factors concerned with the leaves, namely moisture, iron, potassium,vitamin C and polyphenol contents were determined.

The first stage of drying rate is constant and controlled by external factors, was seen only in the shadow drying method. In two other methods, this stage has been almost eliminated.  Forced convection heat transfer coefficients is higher than natural convection coefficient. Therefore in the oven drying method, mass transfer rate is higher than the other methods. With increasing microwave power, drying time decreased. The determined amounts of iron, potassium and vitamin C showed that there is a significant difference between different drying methods (P <0.05).The longest drying time was in shadow with1800 minutes and the highest amount of vitamin C, iron and phenolic compounds was in the dried treatment in the shade.

According to the results, it can be stated that the drying of the basil leaf using shade drying and microwave drying at 180 W, are desirable because the amount of active ingredients in the plant is considerably retained.

Hydrodistillation is a current method to extract plant essential oils which is time consuming. It has been proposed that use of microwaves instead of direct heat could decrease the time of distillation. In this study, the effect of microwaves on chemical profile and antioxidant activity of Zatariam multiflora and Syzygium aromaticum essential oils in comparison to current hydrodistillation method was evaluated.

In this study, Zataria multiflora and Syzygium aromaticum essential oils were extracted by hydrodistillation and microwave assisted hydrodistillation method. Chemical profile of essential oils were determined by GC MASS. Their antioxidant activity in inhibition of free radicals were evaluated by DPPH method.

Microwave decreased the amount of thymol and eugenol in Zataria multiflora and Syzygium aromaticum essential oils respectively. Also, the antioxidant activity of essential oils extracted by microwaves decreased in comparison to current hydrodistillation method.

According to the results, it is necessary to evaluate the quality of essential oils before using microwaves to extract essential oils in the food, pharmaceutical and cosmetic industries. However, in order to confirm the effect of microwave waves on plant essential oils, study on more plant samples is essential.

 Acanthamoeba is a free-living and opportunistic amoeba that the potential of this parasite to convert to a cyst, making its treatment difficult. In this study, we investigated the effect of microwave radiation on Acanthamoeba cysts in vitro.

 Acanthamoeba cysts were reproduced in the culture medium. We divided 16 test tubes containing cysts into two groups. The contents of 8 tubes were irradiated with continuous microwave in the time range of 0-120 s, and the next 8 tubes were irradiated with repetitive microwave in the range of 0-360 s. The mortality of cysts at the end of irradiation was recorded and compared with control.

 Continuous and repetitive irradiation of microwave resulted in mortality of 100 (%) of Acanthamoeba cysts during 120 and 360 seconds, respectively. In continuous mode, parasite mortality in all groups was significantly different from the control group (P<0.0001). But in the repetition pattern only in groups that had been irradiated for more than 60 seconds, parasite mortality was significantly different from the control group (P<0.0001).

 The change of radiation mode from continuous to repetitive, reduces the thermal effects of the microwaves but does not affect the mortality rate of Acanthamoeba cysts. Therefore, probably the impact of microwaves was not only caused by the increase in ambient heat but also its another property is involved in the death of Acanthamoeba.