Today renewable energies such as biodiesel have considerable role in the bio-based economy. Long production time and low efficiency are a number of problems in biodiesel production that is essential to be considered when designing and operating the biodiesel production systems. In this study, using safflower oil in a hydrodynamic cavity reactor, biodiesel fuel was produced in the possible shortest time and maximum efficiency. The effect of reaction time (30, 60 and 90 s), concentration of potassium hydroxide catalyst (0.75%, 1% and 1.25%), alcohol to oil ratio (6, 8 and 10) and rotor-stator distance (1 cm, 2 cm and 3 cm) on the reaction yield were analyzed. The results were analyzed by response surface methodology. Among the independent variables, reaction time was the most important factor on the reaction yield, which had a positive impact on the quality of methyl ester. The optimum values obtained were: 63.88 s reaction time, 0.94% catalyst concentration, 1: 8.36 alcohol to oil molar ratio, 1.53 cm rotor-stator distance, and 89.11% yield. Several properties and compounds of biodiesel obtained were measured and compared with ASTM D6751 (American Society for Testing and Materials) and EN 14214 standard (European Standards). The results showed that most of the features conform to the afore-mentioned standard. Therefore, transesterification of safflower oil with a hydrodynamic cavitation reactor can function as a good alternative to the diesel.
In this research, sour cherry juice (SCJ) was treated using a combination of the Ultrasound‐Pulsed electric field (UP) wave and Hydrodynamic‐Pulsed electric field (HP) systems. The main objective of this study was to investigate the effect of the combination of the pulsed electric field, ultrasonic wave, and hydrodynamic as new non‐thermal technologies on the inactivation of microorganisms, energy changes in one cycle of E. coli inactivation, and the quality of SCJ. The range of experimental conditions was as follows: electrical field intensity: 5–10 kV/cm, electric field time: 5–35 s, ultrasound power: 100–200 W, ultrasonic exposure time: 3–5 min, and hydrodynamic exposure time: 3–9 min. The results of the treatments indicated that the combination methods maintained the total phenolic content, anthocyanins, and vitamin C compared to the conventional method. By TOPSIS, a comparison between two combination methods showed that the pasteurization with UP performed better than the HP method. Practical applications One of the most effective ways for the utilization of nutritional benefits of fruits is to use their extracts or juices. Also, to kill any harmful bacteria, most juices thermally are pasteurized. Where such treatments often lead to a substantial decrease in their quality (vitamins, phenolics, anthocyanins, etc.). For this goal, researchers are following up on new methods to dispel the adverse effects of thermal pasteurization. The present research aimed to assay the simultaneous effect of the ultrasonic‐AC electric field and hydrodynamic‐AC electric field to eliminate microorganisms and preserve the quality of SCJ. The current research recommends a novel and combined method for SCJ pasteurization and this method can benefit the food industry.
The aromatic waters are one of the forms of the use of medicinal plants, mostly for edible or medicinal uses. They are required to control the microbial load. Common methods of pasteurization by reason of applying high temperatures cause the undesirable changes in taste, odor, medicinal properties, nutritional quality, and reduction in essential oil. Therefore, novel methods of pasteurization have been widely used recently. In order to determine the microbial inactivation by pulsed electric field and ultrasound, Escherichia coli at a concentration of 7 × 106/mL was inoculated to spearmint aromatic water. The field intensities of 5, 7.5, and 10 kV/cm with time durations of 5, 20, and 35 s and ultrasound powers of 100, 150, and 200 W with time durations of 3, 4, and 5 min were applied. The data obtained from the experiments were analyzed using response surface methods. The results showed that the effect of the four variables listed on the inactivation of microorganisms and energy consumption per cycle of microbial reduction are significant. At the end, the process was optimized. The optimum values for the electric field intensity, time of applying the field, the ultrasound power, and sonication time were 10 kV/cm, 35 μs, 185.90 W, and 4.47 min, respectively. It should be noted that the proposed method had minimal changes in the chemical composition of the raw spearmint aromatic water and was superior to conventional heating methods. Practical applications The mint aromatic water is used in food, pharmaceutical, and personal care industries; it is necessary to microbiological control of its content. Because of conventional pasteurization methods cause undesirable changes in taste, smell, and nutritional quality with a reduction in the amount of essential oil. For this purpose, researchers are looking for solutions that by combining new thermal and nonthermal approaches, the damaging effects of conventional pasteurization be removed. However, the main challenge facing the nonthermal technologies in food processing is the inactivation of pathogenic microorganisms and food spoilage agents, which can be achieved by various methods. The aim of the present research was examined the simultaneous effect of the ultrasonic and the electric field to remove microorganism and save quality and benefit chemical compositions of medicinal aromatic water. This research introduces an innovative and combined method for aromatic water pasteurization and this method can benefit to the food industry.
Implication for health policy/practice/research/medical education:Considering the benefits of grape juice, including blood purification, treatment of lung, kidney and skin diseases, its pasteurization processing and production are of special importance. Pasteurize grape juice in optimal conditions, a short time and better quality using a system consisting of microwave and ultrasound device to reduce the harmful effects of high temperatures will be valuable for the food industry. Please cite this paper as: Introduction:The thermal pasteurization is a common method for maintaining fruit juice and increasing shelf life, but the thermal processing changes the flavor and color of the products. The aim of this study was to investigate the effect of a new method of combining heat and ultrasound on the number of the Escherichia coli present in grape juice. Methods: In this study, the effects of the microwave power, temperature, ultrasound power and ultrasonic exposure time were evaluated on E. coli count of red grape juice. In order to determine the microbial inactivation by microwave and ultrasound, E. coli at a concentration of 6×10 6 per mL was inoculated to red grape juice. Results: The effects of microwave power, grape juice temperature, ultrasound power and ultrasonic exposure time on the reduction of E. coli were significant (P < 0.05). The model showed that in reducing E. coli the importance of the final temperature of the juice was higher than the microwave power. In addition, the ultrasonic power was more effective in E. coli reduction as compared to the microwave power. Conclusion: Both sample temperature and ultrasonic duration were important independent variables and effective factors on E. coli reduction.
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