Showing 9 results for Roomi
Volume 1, Issue 2 (7-2014)
Abstract
Volume 7, Issue 3 (Summer 2018)
Abstract
Aims: As a polycation polysaccharide, chitosan is produced by deacetylation of chitin. Chitosan is a non-toxic, decomposable, and biocompatible substance that has antimicrobial properties. The aim of this study was to investigate the effect of chitosan coating and Piper nigrum essential oil on shelf life of grass carp in modified atmosphere packaging (MAP) at the refrigerator temperature (4°C).
Materials and Methods: In this experimental study, Piper nigrum and grass carp were used. After immersion of the samples into Piper nigrum and chitosan essential oil, samples were packed with MAP. The treatments consisted of control treatment (no coating and essential oil), first treatment (0.1% essential oil), second treatment (0.5% essential oil), and third treatment (1% essential oil of Piper nigrum with chitosan coating). The chemical parameters, including peroxide value (PV), thiobarbituric acid (TBA), total volatile basic nitrogen (TVB-N), free fatty acid (FFA) and pH and total viable count (TVC) of mesophilic bacteria were evaluated at the intervals of days 0, 3, 6, 9, 12, and 15. Two-way ANOVA and least significant difference (LSD) tests were used.
Findings: Changes of pH and FFA progressively increased during the time of storage for all treatments. In all treatment, the level of PV did not exceed higher than the level of limit (mEq/kg). The lowest changes of TBA and TVB-N were related to 1% treatment of P. nigrum essential oil that were significant different with other treatments (p<0.05). TVC of the samples was significantly between treatments during storage (p<0.05).
Conclusion: The use of chitosan coating and 1% of Piper nigrum essential oil increases shelf life of grass carp fillet at refrigerator temperature to 9 days.
Volume 7, Issue 4 (Fall 2018)
Abstract
In the present study, the effect of ground sesame seeds in three levels of 0, 0.15 and 0.25% on features of biological, chemical and sensory evaluation silver carp surimi gel in vacuum packing for 4 months in freezing temperatures (-18°C) was investigated. The results showed that the highest levels of volatile nitrogen month 4 in the control (21.99±0.32mg per 100g), respectively. The thiobarbituric acid did not like the higher limit the amount of free fatty acids is increased. The highest bacteria in month 4 in the control (6.86±0.05Log cfu/g) treatment, respectively. The highest and lowest amount of lactic acid bacteria, respectively, on May 4 in group 1 (4.86±0.10Log cfu/g) and May 1 in all treatments (2.00±0.00Log cfu/g), respectively. Sensory evaluation factors during 4 months in freezing temperatures are not significantly different the colorimetric parameters (L*, a*, and b*) and tissue treatments poll 0.25% sesame seed powder was the best treatment. According to the results of chemical analysis, sensory and microbiological shelf life achieved the best treatment was 0.25% in the fourth month, ground sesame seeds.
Volume 8, Issue 1 (3-2024)
Abstract
Research topic:
The disparity between supply and demand is one of the main obstacles in transitioning from fossil fuels to renewable energy. Underground hydrogen storage derived from renewable sources is a suitable method for storing energy from these sources. However, a portion of the stored gas remains in the reservoir as cushion gas, which can add to the operational costs. It is therefore recommended to replace this cushion gas with less expensive alternatives, such as CO2 or sour gas, to reduce these costs. Nevertheless, this replacement can affect the purity and recovery factor of hydrogen, which can be controlled by specific operating parameters. This study will investigate how these parameters can be adjusted to maintain high purity and recovery factor for stored hydrogen.
Research Method:
In this section, a model of a partially depleted gas reservoir was initially constructed using the commercial simulator CMG. Following validation, this model was employed to evaluate the desired parameters. For this purpose, approximately 50% of the reservoir was depleted initially, followed by the injection of the cushion gas for one year. Subsequently, the hydrogen storage process was conducted over a period of 10 years. This research investigates the impact of various parameters, including the duration and rate of hydrogen injection and production, the soaking time and duration of cushion gas injection, the utilization of sour gas as the cushion gas, and the concentration of H2S within it, on the purity and recovery factor of the produced hydrogen.
Main results:
The results showed that increasing the rate of hydrogen injection and production enhances its purity and recovery factor. Reducing the injection period while increasing the extraction period decreases purity but improves recovery, provided that the extraction period does not exceed the injection period. Extending the cushion gas injection time and the interval between injection and hydrogen storage supports the purity and recovery factor of hydrogen. Additionally, in the cushion gas composition, increasing the proportion of H2S above 70% in the sour gas mixture reduces hydrogen purity and recovery by approximately 2% and 3%, respectively, confirming the potential of H2S as a cushion gas.
Volume 10, Issue 2 (Spatial Issue on Persian Gulf 2021)
Abstract
The aim of this study was to investigate the antioxidant effect of cucumber hydrolyzed protein (Holothuria leucospilota) and its effect on microbial and chemical properties of silver carp (Hypophthalmichthys molitrix) at refrigerator temperature. Enzymatic digestion of cucumber muscle was performed using alkalase enzyme (1.5% of weight of raw material, 55 °C and 4hr). Surimi was prepared from silver carp fillet and added to it at two concentrations of 0.5 and 0.1 mg/ kg of hydrolyzed protein. Antioxidant activity, peroxide value (PV), total volatile nitrogen bases (TVB-N), thiobarbituric acid (TBA), pH, volatile fatty acids (FFA), aerobic mesophilic bacterial count and psychrotroph bacteria on 0, 3, 6, 9, 12 and 15 days were performed. The rate of free radical scavenging by cucumber hydrolyzed protein at 0.5 and 0.1 mg/ kg was 92.24% and 62.11%, respectively, which showed a higher value than the commercial antioxidant BHT (p< 0.05). The amount of peroxide in the treatment was 0.1 mg/ kg until the ninth day and in the treatment of 0.5 mg/ kg until the twelfth day was within the allowable range. The results of TVB-N, TBA, FFA, aerobic mesophilic bacterial and psychrophilic bacteria in both treatments and on the days of the study did not exceed the allowable limit. This study showed that cucumber hydrolyzed protein is able to control bacterial load and oxidation process in silver carp surimi. Treatments containing cucumber hydrolyzed protein could increase the shelf life of surimi for 9 days compared to the control treatment.
Volume 13, Issue 60 (0-0)
Abstract
Volume 14, Issue 63 (6-2016)
Abstract
Volume 17, Issue 103 (September 2020)
Abstract
The aim of this study was to determine the effect of temperature, pH, salt, citrus aurantium L. and modified atmosphere packaging (50% carbon dioxide, 45% nitrogen and 5% oxygen) on control of Staphylococcus aurous in fish tofu of type. Descriptive-analytic study was carried out in the year of 2017-2018. In this research, pH was 5.5, 6 and 7.5, and temperature was 4, 25 and 37 ° C, salt at 0, 1.5 and 3%, and orange essential oil at 0.025 and 0.05% was considered. According to the results, it is found that the lower the pH of the tofu samples is lower, Staphylococcus aureus is more restricted. For example, at pH 5.5 with 0.025 and 0.05% of orange essential oil in tofu samples, bacteria did not grow, but at pH 6 and 7.5 there was no growth of bacteria and growth was more than usual. There was an enormous increase in Staphylococcus aurous at pH 7.5 with 1.5% salts and orange essential oil 0.025% at temperatures of 4, 25 and 37 ° C. Increasing temperature to 25 ° C and 37 ° C, as well as at pH 5.5, 6 and 7.5, the growth of Staphylococcus aurous in tofu fish has been increased. In this study, the essential oil of orange herb was stored at 0.05 % at 4 ° C, 3% salt and pH 5.5, to control the growth rate of Staphylococcus aurous in tofu fish for 8 days.
Mohammadreza Saviz, Vahid Roomi,
Volume 18, Issue 9 (12-2018)
Abstract
In this research, control of vibration in multilayered cylindrical panel with piezoelectric patch, under dynamic load is investigated, for the first time. The finite element method is used to solve the dynamic equations of the structure, which is based on first-order shear deformation theory, and equivalent single layer models with different rotations for the substrate and the piezoelectric patch is developed. The governing equations are obtained by using the Hamilton’s principle of virtual work, are discretized over the mid-plane, by using eight node shell element, leading into the matrix system of equations. The maximum controllability criterion is used for finding the optimal size and location of piezo-patch. According to the used control law, the applied voltage on the piezo-patch is proportional to the radial velocity component at the point, where the sensor is installed. In order to evaluate the performance of the formulation and finite element model, the natural frequencies obtained for the substrate laminated panel are compared with those in the literature. Then, having the dynamics of the optimal system, the frequency response for open and closed loop controls are studied. Finally, the effects of controller gain values and dimensions of panel and patch on the time response and damping rate of vibrations are illustrated.
