M. Vahedi Torshizi; M. Azadbakht; M. Kashaninejad
Abstract
Introduction Food is composed of various compounds, and when the food quality expires, it becomes inappropriate for consumption and the end of life leads to some pathogenic microorganisms in food. So food processing is essential. In recent years, various heat treatments have been considered that have ...
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Introduction Food is composed of various compounds, and when the food quality expires, it becomes inappropriate for consumption and the end of life leads to some pathogenic microorganisms in food. So food processing is essential. In recent years, various heat treatments have been considered that have various disadvantages, so researchers are looking for alternative technologies in industrial processing to overcome these problems. Electric treatments play an important role in food heating technology and one of the methods of electric thermal processing is ohmic processing, that ohmic heat is based on the flow of electricity through a product. The purpose of this study was to investigate the effect of voltage and weight loss on the amount of energy and exergy during this process in order to obtain the best amount of energy consumed during the heating process, since the most common way to heal the heating is by heating. In addition to maintaining the product's qualitative characteristics, the product has to carefully monitor its own system parameters. Materials and Methods The sour oranges were purchased from a garden located in the city of Gorgan, Golestan province. The prepared oranges were washed and divided into two halves in the middle and immediately after purchase, all samples of juice were taken manually in the same conditions and the samples were prepared to conduct the test during the ohmic process with voltage gradients and the percentages of different weight loss to investigate the amount of energy efficiency, exergy efficiency, exergy loss, and improvement potential during the process. For the heating process, three voltage gradients of 8.33, 10.83 and 13.33 V cm-1 and three percentage values of weight loss of 10% (from 90 g to 81 g), 20% (from 90 g to 72 g), and 30% (from 90 g to 63 g) were selected. Then, the energy and exergy consumed during the process were calculated and analyzed using a factorial experiment in a completely randomized design with SAS statistical software. Results and Discussion Based on the results, it can be concluded that the voltage gradient and weight loss percentages are significant for energy efficiency, exergy efficiency, exergy, and potential improvement at 1% level. Increasing the voltage gradient increases the efficiency of energy and exergy and reduces the potential for recovery and exergy is wasted. The highest energy efficiency was 91.6% in the 13.83 V cm-1 voltage gradient and the weight loss percentages 10% and the lowest value was 51.51% in the voltage gradient of 8.33 V cm-1 and the weight loss percentages 30%. The maximum improvement potential was 8.33 V cm-1 and the weight reduction was 30% and the lowest value was at 13.33 V cm-1 voltage gradient and 10% weight loss percentages. The highest exergy efficiency of 59.51% was found in the 13.83 V cm-1 voltage gradient and the weight loss percentage was 30% and the lowest value was 31.88% on a voltage gradient of 8.33 V cm-1 and a weight percentage of 10%. Conclusion - By increasing the voltage gradient, the energy efficiency had increased and there was a significant difference between all the volatility gradients. - For exergy efficiency, when the voltage gradient increased, the exergy efficiency amount increased, and in all percentages weight loss was a significant difference between the voltage gradient. - By increasing the voltage gradient, the amount of exergy loss decreased significantly and with increasing percentage weight loss, this amount was significantly increased. - The improvement potential was reduced by increasing the voltage gradient and there was a significant difference between the voltage gradients for the improvement potential.
M. J. Mahmoodi; M. Azadbakht
Abstract
Nowadays, the dielectric properties of food and biological products have become a valuable parameter in foodstuff engineering and coating technology, covering a remarkable spectral domain from 10-6 to 1012. In the present study, 27 completely healthy pears were selected and subjected to quasi-static ...
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Nowadays, the dielectric properties of food and biological products have become a valuable parameter in foodstuff engineering and coating technology, covering a remarkable spectral domain from 10-6 to 1012. In the present study, 27 completely healthy pears were selected and subjected to quasi-static and dynamic loading. The storage period was ten days. In this study, the qualitative characteristics and their relationship with changes in dielectric coefficient were investigated. At the end of the storage period, the fruits’ dielectric coefficient values and their qualitative characteristics were measured. The measurements were carried out for a capacitor plates’ distance interval of 11 cm, 10 V input voltage and 60 kHz input voltage frequency. According to the results, in the dynamic loading mode of 400 N, the highest dielectric coefficient with a value of 5.2989 was obtained. In dynamic loading mode of 400 N, the qualitative property had the minimum value. The antioxidant, phenol content, Vitamin C content and firmness were 33.925%, 14.523 mg/100g, 5.7 mg/100g and 5.5333 g, respectively. The results of the study indicated that increasing the loading force on the pear reduces all qualitative indicators for all loading modes and an increase in dielectric coefficients of the products was observed.
