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Background and Objective: In the recent years, the application of microwave–vacuum drying as a novel, effective, and low-cost method for dehydration of various foods has been investigated. Therefore, the objective of the present study was to evaluate the potential of this method in drying sour cherry, as well as to select an appropriate mathematical model for describing its drying kinetics. Materials and Methods: The experimental drying trials were performed at 4 nominal microwave power levels (360, 600, 840, and 1200 Watts) and 4 absolute pressures (200, 400, 600, and 800 mbar) using a microwave–vacuum dryer designed in our laboratory. The drying parameters were determined as functions of absolute pressure and microwave power. Moreover, the fitting rates of experimental data with seven semi-theoretical and empirical models based on R2, χ2 and RMSE values were determined and the most appropriate mathematical model was selected. Results: The findings showed that the microwave power and the vacuum level play the major role in the drying rate of sour cherry, such that increasing microwave power and decreasing the drying chamber pressure reduce the drying time significantly. Moreover, the drying process occurred in the falling rate period. Comparison of different models showed that the Middili and co-workers model can be the most suitable model due to its having the highest R2 and lowest χ2 , RMSE values. Conclusion: The findings of this study indicate that the drying process of sour cherry does not show any constant drying rate during dehydration using a microwave–vacuum dryer. Thus, microwave–vacuum drying has a high potential for dehydration of sour cherry and other food and agricultural products due to high efficiency and reasonably short proceesing times. Keywords: Modeling, Microwave – vacuum drying, Sour cherry, Thin-layer drying

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Browning button mushroom of Agaricus Bisporus is a common phenomenon which enzymaticaly convert melonogenic phenols to quinones and eventually produce melanin pigments. Browning button mushroom is detrimental to business of agriculture and food business. This review article surveys methods of inhibiting the enzymatic browning Agaricus Bisporus include: thermal inactivation, high isostatic pressure, gamma irradiation, thiol componds, calcium chloride added to the irrigation water, inactivators and inhibitors and its effects on enzymatic browning of Agaricus Bisporus. Keywords: Agaricus bisporus, Enzymatic browning, Polyphenol oxidase, Microwave, Inhibitors

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Background and objective: Antibiotic residue in food had made different concerns. Antibiotic residue may change during food processing before consumption especially cooking. The goal of this research is to determine the effect of two methods cooking of boiling and microwave on tylosin residues in meat. Materials and Methods: Tylosin was added to minced meat samples in three level 200, 400 and 800 ppb and samples were cooked by boiling (10, 20 and 30 min)and microwave (1, 1.5 and 2 min). Tylosim amount was measured before and after cooing by HPLC and its reduction percent amount was calculated. Results: In all treatments tylosim amount of cooked samples was significantly less than that of raw sample (p<0.05). However tylosin reduction percent amount was significantly increased by boiling and microwave time increment, tylosin first amount had no effect on its reduction in microwave method but its effect is in verse in boiling method. Overall interaction effect of cooking time and tylosin first amount on its reduction percent amount in meat was significance in boiling method and insignificant in microwave method. Conclusion: Although cooking result in reduction of tylosin residue in meat and its reduction amount in boiling is more than that in microwave, it isn’t grantee for tylosin reduction and it is necessary to reduce tylosim in meat by its correct consumption in animals and withdrawal time consideration. Keywords: Tylosin, Drug residue, Cooking, HPLC, Microwave

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Background and Objective: Nitrosamines are produced during processing of meat products from the presence of nitrite and amine compounds these compounds are mutagenic and carcinogenic. The present study optimized and determined the level of nitrosamines in sausage and salami samples in Tehran markets using microwave-assisted extraction and dispersive liquid-liquid microextraction followed by gas chromatography-mass spectrometry (MAE-DLLME-GC-MS), which is a fast, low-cost and precise method. Materials and Methods: The nitrosamine extraction was optimized using response surface methodology and a central composite design with 6 replications at the center point. The figures of merit of the proposed method were then evaluated. The proposed method was used to determine the nitrosamine levels in 18 samples at 3 factories of major producers of meat products in Tehran. One-way ANOVA was the statistical method used in this study. Results: The optimum volume of extraction solvent (100 µl), disperser solvent (500 µl), salt (11%), and the pH (7.5) were obtained. The figures of merit for the proposed method under optimum conditions were in the appropriate range. The lowest and highest concentrations of nitrosamines in real samples were 0.46 and 195 ng g-1, respectively. Conclusion: The capability and reliability of MAE-DLLME-GC-MS as a simple and fast method for trace determination of nitrosamines in sausage and salami samples was confirmed over the results of other methods. Keywords: Sausage and salami, Nitrosamines, Microwave-assisted extraction, Dispersive liquid-liquid microextraction, Gas chromatography-mass spectrometry

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Background and Objectives: Pectin is a complex mixture of polysaccharides that is widely used in the food industry as a gelling agent, stabilizer and emulsifier. The aim of this study was to compare the production yield and physicochemical properties of microwave-assisted extracted pectin from pineapple, samsuri and galia melons peels.

Materials and Methods: Pectins were extracted from pineapple, samsuri and galia melon peels assisted by microwave under the power of 700 W, time of 3 min, pH of 1.5 and liquid/solid ratio of 15:1 (v/w). Then the physicochemical properties of the extracted pectins such as galacturonic acid content, degree of esterification, emulsifying properties, solution behavior and FT-IR spectra were investigated.

Results: The results showed that pectins obtained from all the three products have a reseaonable yield (14-15%) and degree of purity (with galacturonic acid content above 65%). the study of degree of esterification showed that pectins obtained from pineapple and samsuri melons were LMP, and the galia melon peel pectin was HMP. The pectins’ emulsifying activity of all the three products was low. The viscosity results illustrated that the pectin solutions obtained from pineapple and samsuri melons have Newtonian flow behavior at all concentrations, but the solution of galia melon peel pectin showed different flow behavior at various concentrations. 

Conclusions: The high yield, good degree of purity and acceptable physicochemical properties of obtained pectin show that this agricultural waste can be used as a promising source for pectin production.

Keywords: Pectin, Microwave, Pineapple melon, Samsuri melon, Galia

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Background and Objectives: In recent years, microwave heating has been increasingly popular all over the world due to the unique characteristics of microwave energy, that can be used as a suitable heat treatment. This trend also seems to be associated with increased awareness about the advantages of nutritious and healthy foods as well as functionalities of certain phytochemicals in diets, which may act as neutraceuticals. Microwave heating is known for its operational safety and nutrient retention capacity with minimal loss of heat-labile nutrients, dietary antioxidant phenols and carotenoids. The aim of this study is evaluate and explain a suitable method for production functional foods and extraction of phenolic compounds and antioxidant for Specific goals.
Materials and Methods: Grapefruit juice was concentrated to achieve the final brix 42° by two different heating methods, including conventional heating and microwave heating, at various operational pressures (7, 36, and 100 kPa). The effects of each method on total phenolic content (Folin Ciocalteo Colorimetry method), anti-oxidant activity (DPPH method) and browning index (Hunter parameters) were investigated.
Result: The study shows significant difference created by the microwave in the content of total phenolic compounds, anti-oxidant activity and color concentrates compared to rotary evaporator, at a confidence level of % 5 (05/0 = α).
Conclusion: The results showed that microwave method can be used as an appropriate method to be used in functional foods production and extraction of phytochemicals.

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Background and Objectives: 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.
 Materials & Methods: 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: 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.
Conclusion: 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.

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Background and Objectives: 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.
 Materials & Methods: 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.
Results: 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%).
Conclusion: 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.

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Background and Objectives: In this study, effects of microwave pretreatment in optimizing conditions of enzymatic hydrolysis of pumpkin seed protein (Cucurbita maxima L.) was investigated using enzyme trypsin to achieve the maximum antioxidant activity using Design Expert software and response surface methodology.
Materials and Methods: The solution containing pumpkin seed concentrate was exposed to microwave energy with power of 450–900 W and time of 30–90 s. Enzymatic hydrolysis was carried out using trypsin enzyme with quantities of 0.5 to 2.5% per substrate, time intervals of 20 to 190 min and the optimum temperature and pH of trypsin. Antioxidant activity was assessed using DPPH free radical scavenging method, iron chelation activity and total oxidant activity (absorbance in 695 nm).
Results: The maximum DPPH free radical scavenging of 56.5%, iron chelation activity of 96.9%, total oxidant activity (absorbance in 695 nm) of 1.03 and hydrolysis degree of 22.3% in condition without pretreatment were achieved within 190 min at 1.5% E/S ratio. Using microwave pretreatment, the maximum DPPH free radical scavenging of 55.3%, iron chelation activity of 94.5%, total oxidant activity (absorbance in 695 nm) of 1.07 and hydrolysis degree of 25.8% were achieved within 105 min at 1.5% E/S ratio. These results were largely similar to those presented by the software (respectively without pretreatment in 165.1 min and 1.65% E/S 55.1%, 95.5%, 1.02, 21.35 and with pretreatment in 106 min and 1.37% E/S 51.1%, 93.7%, 1.05, 24.9).
Conclusion: Microwave pretreatment in enzymatic hydrolysis of pumpkin seed proteins using  trypsin enzyme has resulted in production of hydrolysates with appropriate antioxidant activity in addition to significant decreases of the hydrolysis time, which can be replaced by artificial preservatives in nutritional products as natural compounds.

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Background and Objectives: 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.
 Materials & Methods: 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.
Results: 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.
Conclusion: 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.

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Background and Objectives: 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.
 Materials & Methods: 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.
Results: 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.
Conclusion: 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.