Showing 8 results for Azizkhani
Volume 7, Issue 2 (Spring 2018)
Abstract
Aims: Today, a part of studies on food science has investigated the effect of cooking methods on the oxidation of various types of meat and the use of natural herbal preservatives instead of synthetic preservatives. The aim of the present study was to evaluate the oxidative stability of pre-cooked rainbow trout (Oncorhynchus mykiss) fillet treated with Dill (Anethum graveolens L.) essential oil (EOs).
Materials and Methods: In the present experimental research, rainbow trout fillet with dill EOs and Butylated hydroxytoluene (BHT) were treated, each at 3 different concentrations, and cooked by 3 methods, including frying, oven baking, and steaming. The cooked samples were stored at -18◦C for 4 months and analyzed at the end of each month. The extracted oil was used to measure the value of free fatty acid (FFA), peroxide value (PV), and thiobarbituric acid (TBARS). The data were analyzed by SPSS 20, using two-way ANOVA, Tukey's post hoc, Kruskal-Wallis, and Mann-Whitney U tests.
Findings: The FFA formation showed increase in all samples, especially oven baked rainbow trout fillets (p<0.05). The highest value of PV was also obtained from the fried fillets treated by BHT. After cooking, TBARS values in treated samples with essential oil showed decrease in all samples cooked with EOs. FFA, PV, and TBARS increased in all samples, but the samples cooked with EOs had lower FFA, PV, and TBARS than the control samples.
Conclusion: In rainbow trout, the lipid oxidation increases with the thermal process, but the essential oil postpones the oxidation during the storage period as frozen. The samples cooked with Dill EOs have lower amount of FFA, PV, and TBARS compared with the control peers.
Volume 8, Issue 1 (Winter 2019)
Abstract
Aims: Considering the high importance of food poisoning bacteria in terms of public health threats and economic damages, this research aimed at evaluating food poisoning bacteria in some commercially important fish species collected from markets in Mazandaran, Iran.
Materials and Methods: For this purpose, 200 frozen fish belonging to 4 species were purchased from the stores and transferred to the laboratory. Samples were tested for total counting of aerobic bacteria, Escherichia coli count, Staphylococcus aureus count, Vibrio parahaemolyticus and detection of Salmonella according to Iranian national standard methods.
Findings: In the studied samples, Salmonella, and Vibrio parahaemolyticus were not observed. Comparing the results with the Iranian national standards, the total number of aerobic bacteria and Staphylococcus aureus in all samples was in normal range. The number of E. coli in 14% of samples of Rain bow trout, 20% of Clupeonella Cultriventris, 20% of Hypophthalmichthys molitrix and 10% of Scomberomorus commerson samples was higher than the standard range, due to the importance of pathogenicity of different strains of E. coli in humans, microbial control of the packed fish is very important.
Conclusion: The results of microbial investigations of frozen raw fish collected from stores in different cities of Mazandaran province can be defined satisfactorily, since the majority of samples conform to reference standards.
Volume 16, Issue 90 (August 2019)
Abstract
PCR quantifies dead cells beside live cells and this makes the judgment of microbial quality of food samples complicated. The objective of this study was comparing the efficacy of ethidium monoazide-qPCR and propidium monoazide-qPCR in quantifying live pathogen cells (E.coli, Staphylococcus aureus, Enterococcus fecalis and Listeria monocyogenes) by real time PCR, in low-fat and high-fat milk, lactic cheese (low-fat) and processed cheese (high-fat). Different proportions of live and heat killed pathogen cells were inoculated into food samples. After separating bacterial pellets, EMA and PMA treatments qPCR was conducted. One-way ANOVA followed by Turkey’s Multiple Comparison tests were applied to analyze the data. In low-fat milk, EMA treatment resulted in 18, 20, 23 and 30% decrease in cell count of E.coli, S.aureus, E. fecalis and L. monocyogenes, respectively, compared to conventional culturing. Also, following treatment by PMA, 6, 3, 8 and 12% decrease in cell count was obtained for E.coli, S.aureus, E. fecalis and L. monocyogenes, respectively, compared to conventional culturing. In high-fat samples as processed cheese, a reduction of 20, 27, 30 and 25% in EMA treatment and 9, 6, 5 and 10% in PMA treatment was observed in cell count of E.coli, S.aureus, E. fecalis and L. monocyogenes , respectively. The inhibitory potential of EMA and PMA against signal emission was variable in different bacterial species and the fat content of the samples exerted no significant effect (p>0.05) on PMA and EMA functionality.
Hadi Delavari, Atefeh Azizkhani, Pooya Shiuooei,
Volume 17, Issue 10 (1-2018)
Abstract
Energy saving, low robot mass to carried mass ratio, more ability to work in various environments, easier delivery of parts and lower production costs in flexible robots make these robots more attractive than rigid robots to many researchers and industries. But due to nonlinearities in flexible robot system and high vibration in operation points and also more sensitivity against external disturbances, control of these robots is more difficult and complex. In this paper a controller for a flexible link manipulator based on fractional calculus is practically implemented. At first the dynamic model of a single flexible-link robot is introduced. Then various controllers such as fuzzy control, PID control, and fractional order PID torque control are practically implemented on a single flexible-link robot made in laboratory, and then the performance of each controllers in decreasing of arm vibration in final desired point and tracking error reduction are investigated. Further, to compare the robustness of the designed controllers, a same constant disturbance is applied to all controllers and their performance are compared. Finally, the simulation results and experimental results show that the fractional order PID torque controller has the best results among the implemented controllers.
Volume 17, Issue 103 (September 2020)
Abstract
Malachite Green is extensively used as an antiparasite and antifungal agent in aquaculture. Treatment with malachite green leads to the remaining of the metabolite of this compound (luecomalachite green) in aquatic animal tissues and the production of carcinogenic compounds. The aim of this study was to investigate the presence of luecomalachite green in the flesh of Rainbow trout in Mazandaran province. Fish specimens with approximate weight of 0.5 and 1 kg were collected from 20 farms in Mazandaran province (Haraz and Tonekabon) during 2018. Luecomalachite green was measured in samples using ELISA 96-well kit produced by Europroxima Co. (Netherlands). The highest and lowest levels of luecomalachite green (0.0001 mg/kg) were obtained from samples of 0.5 kg and 0.22 mg/kg in 1 kg samlpes, respectively. In some samples of 0.5 and 1 kg collected from Tonekabon, luecomalachite green content was less than the detection limit of the kit, and the highest amount of luecomalachite green was equal to 0.0047 mg/kg in 1 kg samples. Comparison of the results of all samples showed that the lowest contamination of luecomalachite green was observed in samples of 0.5 and 1 kg of Tonekabon region and the highest level of luecomalachite green were observed in samples of 1kg of Haraz area. The results of luecomalachite green contamination in this study were lower and also in the allowed standard range compared to previous studies, this indicates the improvement of sanitary condition of aquaculture stations, effective monitoring and control strategies, use of substitutes and safe alternatives to reduce fungal contamination and hence less malachite green consumption.
Volume 17, Issue 106 (December 2020)
Abstract
Escherichia coli O157:H7 is one of the most important and common foodborne pathogens in the world which is being resistant against some current synthetic antimicrobials. The aim of this study was to determine the minimum inhibitory concentration (MIC) and the minimum bacterial concentration (MBC) of Artemisia dracunculus (tarragon) essential oil and its nanoemulsion for enterohemorrhagic strain of Escherichia coli and then the effect of sub-MIC concentrations on growth rate and gene expression of virulence genes (stx1A and stx2A). Nanoemulsion of tarragon essential oil was prepared by the ultrasound method and the droplet size and zeta potential were determined. MIC and MBC of essential oil and nanoemulsion were determined using the broth microdilution method. The growth rate and expression of stx1A and stx2A genes in Escherichia coli were assessed after treatment with different concentrations of sub-MICs of essential oil and nanoemulsion. Estragol was identified as the main component in the essential oil. The average diameter of nanoemulsion particle was 50 nm and the zeta potential was -30mV. The MIC values of essential oil and nanoemulsion were 0.58±0.11 and 0.33±0.07mg/ml, respectively, and their MBC were 0.65 ± 0.20 and 0.38 ± 0.15 mg/ml, respectively. Nanoamulsion had a greater inhibitory effect against bacterial growth than free essential oil. At the end of the 72-hour period, nanoemulsion treatment at 75% MIC resulted in a reduction in stx1A and stx2A transcription of 3.75 and 4.10 folds, while at 75% MIC of essential oil stx1A and stx2A transcripts were reduced 1.91 and 2.02 folds compared with control, respectively. Higher activity of nanoemulsion of tarragon essential oil to reduce the growth and shigatoxin production of E. coli compared to pure EO, reveals its potential to be used as a natural food preservative and a solution to the global problem of emergence of antibiotic-resistant microbes.
Volume 18, Issue 113 (july 2021)
Abstract
The fortification process is carried out to improve the micronutrient intake in the target community. The aim of this study was to produce energy food fortified with micronutrients using zedo and watercress seed gums and to investigate the effect of the gums on the stability and recovery of minerals and vitamins. The formulation included meat powder, soy powder, oil, fat-soluble vitamins, minerals (iron and zinc) and sodium chloride. Among the formulations that had the highest amount of energy and viscosity, 5 were selected and the amount of minerals, iron and zinc, vitamins A, D, E and K and the amount of water activity were measured. Formula A had the highest amount of energy and viscosity with 0.92% of watercress seed gum and 1.23% of zedo gum. The data showed that the presence of gums preserves the content of fat-soluble vitamins in the samples and there is no significant difference between the amount of vitamins A, D, E and K on days 0 and 14, but in the control the amount of vitamins decreased. The response obtained from the simultaneous presence of zedo gum and watercress in the formulation of energy food showed that the type and concentration of gum had no effect on the preservation of minerals (iron and zinc). The best formulation in this study contained 35.25% protein and 0.5% minerals, which provides 277.03 kcal of energy, the total daily requirement of vitamins A, D and E, 62.5% of the daily requirement of vitamin K and 100% of the daily requirement of iron and zinc.
Volume 19, Issue 127 (September 2022)
Abstract
In this study, Alyssum homolocarpum (AH) and Lepidium sativum seed gum (LS) at different ratios 1:0, 1:1, and 0:1 utilized to encapsulate red onion extract (ROE) for beef coating through immersion. Different concentrations of ROE (400, 800, 1200 and 1600 ppm) showed high antioxidant activity due to phenolic and flavonoid compounds. In terms of mean size, the lowest particle size was observed in ROE encapsulated in Alyssum homolocarpum gum (7.4 3 89.3 nm). And nanoemulsions prepared in Lepidium sativum seed gum had higher particle size (145.7 3 2.3 nm). Negative-zeta potential was observed in all nanoemulsions. Meat samples were kept at 4 ° C for 20 days and the values of thiobarbituric acid, color indices L *, a *, b *, total bacterial count were examined at 4-day intervals. The results showed that ROE encapsulated in LS and AH was more effective in delaying the microbial and chemical reactions of coated meat fillets. Due to reduced bacterial growth, decreased thiobarbituric number and microbial growth, shelf life increased from 4 days to 16 days. This study confirmed that ROE encapsulated in the combined coating of AH and LS is a potential coating to improve the quality and shelf life of beef fillets.
