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  In this study, changes in color index (CI), refractive index (RI) and viscosity in a range of commonly frying oils during frying process were investigated, and their performance compared to the carbonyl value (CV) as a reference method in monitoring of the quality of frying oils was evaluated. It was observed that the CI of the frying oils linearly increased with frying time. The initial CI of frying oils was 0.36±0.15 on average, and it reached 1.73±0.24 after 48 h of the frying process. The CI had a linear relationship with the CV with a high determination coefficient, R² = 0.97, during the frying process. Assuming that the limit of acceptance for the CV is 43.50 µmol/g, this roughly corresponded to 1.12 for the CI. As the oxidation accelerated by heat proceeded, the value of RI linearly increased. On average, the RI of the frying oils changed from 1.468313±0.00051 (0 h) to 1.469671±0.00032 (48 h). The RI of the frying oils showed a high correlation with the CV (R² = 0.94). Assuming that the maximum level permitted for the CV is 43.50 µmol/g, the RI of a frying oil should be ≤ 1.469075. Viscosity of the frying oils at 30 °C increased with time and changed from 45.11±13.84 mPa s (0 h) to 75.03±12.47 mPa s (48 h) on average. There was a strong correlation (R² = 0.96) between the viscosity and CV of the frying oils. If 43.50 µmol/g of CV is the maximum level permitted in frying oils, viscosity of a frying oil should be ≤ 74.78 mPa s at 30 °C.

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Aims: The aim of this study was to investigate the effect of cooking (frying and microwave), chitosan additive and freezer storage on the fish fillet in terms of sensory and color evaluation and weight changes.
Methodes: Cultivated fish fillets, frozen at -18 ° C for 4 months. They were then transferred to the Fisheries Processing Laboratory of the Faculty of Fisheries, Gorgan University of Agricultural Sciences and Natural Resources, in the shortest possible time (day 0, day 2 and month 4). The fillets were frozen and cooked in a pan and microwave. The experiment was designed in 4 treatments: T₁ (fried sample without chitosan), T₂ (fried sample containing 1% acid-soluble chitosan), T₃ (microwave cooked sample without chitosan), T₄ (Microwave cooked sample containing 1% acid-soluble chitosan). Fillet weights were measured before and after cooking. Sensory evaluation and colorimetric evaluation of fillets were also performed after cooking.
 
Findings: The use of 1% acid soluble chitosan had no significant effect on sensory parameters and colorimetric factors (p> 0.05). Weight changes in fried fillets increased over time but decreased in microwave-cooked fillets over time.
Conclusion: The use of natural additives such as acid soluble chitosan 1% had no significant effect on the sensory indeces compared to the control group. In terms of colorimetric factors, chitosan had a positive effect on yellowness index. In terms of cooking and having a safe product, it is very important that the weight factor of the microwave cooked fillets is more favorable than the fried fillets.

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Oil in foodstuff deep frying heated to a long time and effect of some factors (humidity, temperature and oxygen) cause different chemical and physical changes of the oil (such as hydrolysis, oxidation and polymerization) and degrade the quality of the oil and product. The results of these changes increase of the free fatty acids, peroxide value, polar compounds and trans isomers, and also decrease of the unsaturated fatty acids, oxidation induction time, levels of tochopherol and phenolic compounds, which all indicate a decline the oil quality. Studies shows that the chemical composition of oil and especially natural antioxidants are important parameters in predictive the behavior of oil in the frying process. Independently to the commercial category of olive oil, is clearly resistant against the deep frying. In this paper, the oxidative stability of oil during frying according to the source, the presence of natural bioactive compounds (antioxidants) and fatty acid composition have been compared with olive oil

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Frying oils showed an increase in Peroxide Value (PV) at the initial stages of the frying process followed by a decrease, and there was no correlation between PV and Total Polar Compounds (TPC) in the same set of frying oils. All the frying oils had PVs lower than 4.42 meq O2 kg-1 oil during the frying process and, consequently, none of them was above the limit of 10 meq O2 kg-1 oil for edible oils. The variations of Conjugated Diene Value (CDV) presented a pattern different from that of PV. CDV had a good linear relationship with TPC during initial stages of the frying process and then reached a plateau (R2= 0.9838). The plateau occurred beyond the TPC of 24-27% for the frying oils, and there was an obvious increasing trend before the range mentioned. The contents found for con-jugated dienes of the frying oils during the frying process ranged from 5 to 42 mmol L-1. Assuming that the limit of acceptance for TPC is 24%, this roughly corresponded to 29 mmol L-1 for CDV.

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Grape seed oil is the vegetable oil which has essential fatty acids such as linoleic acid and antioxidant compounds such as tocopherols and polyphenols. Production and consumption of this oil has gained attention in recent years. Using this oil in diet due to its nutritional properties can have a significant role in health. Therefore, in this research, the effect of frying on some qualitative properties of grape seed oil has been investigated. For this purpose, grape seed oil was heated at 180 ºC for 0 (control), 30, 60 and 90 minutes. Then chemical analysis such as acidic value, peroxide, anizidin value, the amount of tocopherol, polyphenols, carotenoides, chlorophyll and oxidation stability were carried out on the oil. The results showed that the acidic value was increased significantly by heating. The peroxide value first was increased and then was decreased significantly by heating. The anizidin value increased significantly as the peroxide value was decreased. The amount of tocopherols, polyphenols, carotenoids and chlorophyll were decreased significantly during the heating process. The results of oxidation stability showed that the grape seed oil has not high oxidation stability against heating.  

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Major data about antibiotic residues in food limited to raw material. Because food was cooked before consumption, it’s necessary to assess effect of heat treatment on antibiotic residues. The goal of this study is to evaluate effect of frying on tylosin residue in meat. Tylosin was added in three levels  4, 8 and 16 µg to 20 g minced meat samples and they were fried at 180 ^oC during 3, 5 and 7 min. Tylosim amount was measured before and after frying by HPLC and tylosin reduction percent, samples center temperature and their weight reduction percent were determined after frying. In all treatments tylosin in fried samples was significantly less than raw samples (p< 0.05). Tylosin reduction (%)amount had significant and positive correlation with frying time, sample weight percent and center temperature. By increasing frying time, weight and tylosin lost and center temperature reductions have been increased. Although frying resulted in tylosin residue reduction in meat, it isn’t grantee for this goal therefore it is necessary to reduce tylosin residue in meat by its correct consumption in animals and withdrawal period consideration.  

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In recent decades, as the result of the expansion of industrial life, fast foods  and fried foods consumption has increased significantly. Consumption of fried foods including saturated fat and trans fatty acids is one of the important factors which endangers human health and the risk of heart disease, weight gain, cancer. With increasing consumer awareness of the health effects of dietary fat, tend to produce low-fat food consumption is increasing. Nowadays, the main challenge is to enhance the frying process by controlling and lowering the final fat frying of the fried foods. In this study the effect of microwave pretreatment levels 360, 600 and 900 W), on moisture and oil content, color and hardness of fried zucchini at three temperatures, 130, 160 and 180 ° C were studied. The results showed that the moisture content decreased with increasing frying time and oil hardening rate increases. The moisture content with increasing frying temperature is reduced and the amount of oil absorption is reduced. The highest oil uptake in control samples, and the lowest in samples treated with microwave 900W was observed respectively.  

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Fried foods are favored by consumers because of the crispy crust, desired flavor and color, but these properties are accompanied by some undesirable effects to the consumers due to the considerable amount of oil absorption during frying process. Nowadays, the main challenge is to enhance the frying process by controlling and lowering the final fat frying of the fried foods. In this study, the effect of hydrocolloids (methyl cellulose, pectin and methyl cellulose- pectin) on the quality of deep- fat fried Falafels at 150, 170 and 190 ˚C for 1, 2, 3, 4, and 5 min were evaluated. Moisture content decreased whereas oil content, hardness, volume and color of potatoes increased with increasing fried time, fried temperature. The lowest oil content values are given for samples coated with methyl cellulose- pectin. The control samples had the highest percentage of fat content in all the frying time range.      

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Frying technology is one of the oldest of food preparing that it used in household and industrial scale, widely. Due to the increasing tendency of consumers to use low-fat products, efforts to reduce oil uptake in fried products has been done. Eggplant absorbs high amount of oil during frying because of high amount moisture and porous texture. In this study effect of different frying times (90, 120, 150 and 180 seconds) and cooking times (1, 4, 7 and 10 minutes) on mass transfer kinetic (oil and moisture)eggplant samples during deep fat drying and cooling period was investigated. Results of analysis variance (ANOVA) showed that independent variables on oil and moisture content was significant (p<0.05).Results of this study showed that cooking pretreatment (hot water and atmospheric pressure) 60 %, decreased oil content in comparison with which did not any pretreatment (control). In mention that cooking time 7 minutes had higher than effect on oil content decreasing (72%). To investigate the kinetic relationships, eggplant samples for 1, 3, 5, 8, 10, 12, 15, 30, 60, 75, 90, 120 and 150 seconds were fried and after each stage of oil and moisture were measured. In addition, at the end of each of these times, were immediately removed from the oil in order to measure the surface oil, immersed in ether, and the amount of oil absorbed (structural) and surface oil samples were measured.Results of mass transfer kinetic during deep fat frying at 180°C, showed that oil content fried eggplant had maximum value on the first time of deep fat frying process and then decreased. Also fried eggplant moisture content decreased, quickly and then velocity of reducing the moisture content of the samples, also declined.

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Moisture loss and oil uptake are closely related during the process of deep-fat frying. The aim of this study was to evaluate the influence of ultrasound waves with combined frequencies on moisture loss kinetics during frying of potato strips as well as modeling the moisture loss. Ultrasound pretreatment was performed at 28 and 40 kHz for 30 minutes with separate and combined frequencies. Then, the frying process was done at 150, 170 and 190°C for 90, 180, 270 and 360 seconds. To model moisture loss, Fick’s second law was used. Effective moisture diffusion coefficient obtained from experimental data was between 1.823×10^-8 - 4.377×10^-8 m²/s. The average correlation coefficient between the experimental data and the data obtained from the Fick’s law was 0.96. The use of ultrasonic pretreatment with separate and combined frequencies increased the effective moisture diffusion coefficient. This increase was significant in some samples while it was insignificant in others. Empirical models were used to study the moisture loss kinetics during frying. In addition, effect of temperature on the effective moisture diffusion coefficient was calculated through the Arrhenius equation.

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Present research studies the effects of bleaching and deodorizing parameters on physicochemical properties consisting of fatty acid compositions (FAC), iodine value (IV), saponification value (SV), refract index (RI) and also oxidative stability evaluation containing peroxide value (PV), acid value (AV), oxidative stability index (Rancimat test) and Anisidine value. The percentage of bleaching clay 0.8, 1.0 and 1.2 (w/w), the temperature of 200 and 220 (°C) and the pressure of 2 and 3 (mbar) were used to refine frying oil. The results indicated the bleaching and deodorizing process had no significant effect on the FAC, IV, SV and the RI of frying oils. Investigation on oxidative stability distinguished the increase of bleaching clay led to more degradation of fatty acid peroxides; thus decreasing PV. In spite of obtained result for PV, the Anisidine value increased at the end of bleaching step. The secondary oxidation products were removed more at higher temperature. Rancimat test presented a decrease in the samples exposed by high temperature and pressure due to more remove of phenolic compound.

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Understanding the relation between different variables affecting deep-fat frying before and during the frying process through the modelling, could be used to set up the optimal conditions for controlling the process that results in improvement of the quality of final fried product. In the present study, the Response Surface Methodology (RSM) and Central Composite Design (CCD) was employed in order to investigate the effects of independent variables including blanching and soaking in different concentration (3, 5 and 7%) of sodium chloride solution as well as vacuum drying (1, 2 and 3 hours) prior to deep-fat-frying and also the effect of frying duration (40, 80 and 120 s) on oil uptake and quality features of deep-fried eggplant. The equations achieved through the examinations revealed that independent variables had significant effect (P < 0.05) on the parameters. Among the studied parameters, vacuum drying was found as the most efficient variable. Moreover, blanching had a significant effect (P < 0.05) on all of the treatments. Although it reduced the oil uptake, caused adverse effects on the quality of the final product such as increasing of shrinkage and colour changes. In conclusion, the optimization of variables showed that samples soaked in 3% sodium chloride solution, dried for 2 hours, and fried for 40 s had the least oil content (1.70 g/1 g of dry matter without oil), moisture content (5.70 g/1 g of dry matter without oil), percentage of shrinkage (32%) and colour changes (ΔE = 25) in comparison with the control sample.
 

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Fried foods are favored by consumers because of the crispy crust, desired flavor and color, but these properties are accompanied by some undesirable effects to the consumers due to the considerable amount of oil absorption during frying process. Therefore using methods for decreasing oil uptake, while retaining the desirable features seem necessary. In this research, the effects of edible coating of locast bean, Avicennia marina seed gums and mixture both on percentage of coating, moisture content, oil uptake and organoleptic properties of potato strips were evaluated. The results showed that coating percentage and moisture content increase whereas oil content of potatoes decrease with increasing in gum concentration. Coated samples had higher transparence and yellowness than control samples. Highest percentage of fat content was in control samples. Samples these coated with Avicennia marina seed gum 1.5% and mixture coating 1% respectively were best samples in organoleptic properties. The use of coating in fried potato strip can improve the nutritional value and organoleptic properties of final product.

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The aim of this study was to investigate the influence of different process and temperature on the chemical and sensory properties of sunflower seeds. For this reason, two types of nuts varieties of sunflower seeds from different markets (A and B) were treated with two methods ( frying and roasting) at 150, 165, 180, 195 and 210 degrees Celsius. peroxide, Iodine, saponification, anisidine, totox value, acid number and also sensory evaluation was investigate. The result showed by increasing temperature, the amount of peroxide, acidic number, saponification, anisidine and toxox value were rised. Based on the result, the highest peroxide value and unsaturated fatty acid was the roast sample B and fried sample A, respectively. The highest acidic number and saponificatoin was also found in rosted sample B at 210 °C. Results from analysis of anisidine and totox value showed highest amount in rosted sample B. Furthermore, appearance, tender texture and flavor of  fried samples at temperature 165 °C had the highest approval rating among the test panlist. According to results of chemical properties due to lower level oxidation and chemical degradation sample A has the higher rate than sample B. Also in consideration of the sensory evaluation of samples and chemical properties, fried samples have better quality than roasted samples. Finally, fried  sample A in 165 ° C was introduced as the best treatment.
 

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Chicken nugget is one of the most popular convenience food in the world. Because of high-fat content in preparation of nuggets with regular methods that causes obesity and other related diseases, other techniques like pretreatment using gum and drying came into attention. In this study, chicken nuggets coated with batter containing Balangu gum (0.25 and 0.5%) were cooked by infrared-frying method in three heat fluxes of 18.5, 21.6, 24.7 kW/m² for 12 minutes. The effects of the process and gum concentration on moisture content, fat, total weight loss, color parameters (a*, b* and L*) and texture properties of this product were investigated. The sample containing 0.5% gum had the highest moisture content (51.80%) and by increasing the power of the infrared radiation, moisture content decreased. The lowest fat content was related to the sample with a heat flux of 24.7kW/m² containing 0.5% Balangu gum. By decreasing gum concentration and decreasing the power of the infrared radiation, fat content of samples increased. Also, Color attribute L* which shows lightness had the lowest amount in the control sample because of higher heat during the cooking process. The hardness of chicken nugget in various treatments did not change significantly, which can be important in consumer acceptance, but cohesiveness of samples treated using infrared-gum treatment showed significant difference compared to the control sample (P<0.05).

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Fried foods due to suitable taste, flavor and mouth feel are very popular but they contain high level of oil. Frying time and temperature and coating before frying process are the main factors, affetcting oil content in fried products. In this study the effect of different concentrations of Balangu seed gum (0, 10 and 20 %W/V), frying temperature (150, 170 and 190 0C) and frying time (2, 4 and 6 minutes) on the quality and sensory attributes of fried zucchini slices were investigated and optimized by response surface method. Results showed that the amounts of water loss and oil uptake during frying process were reduced with increase of gum concentration in the coating agent, but the moisture content of sample was decreased by increasing of frying time and temperature while oil uptake increased. The L* index of the final products were decreased with increase of frying time and temperature and Balangu seed gum concentration. The most affecting factors on the a* and b* index are frying temprature, frying time and Balangu seed gum concentration respectively. The sensory evaluation results, showed that, total acceptance of fried zucchini slices increased with frying time and temperature incensement while decreased with Balangu seed gum incensement. Optimization results showed that the optimum processing conditions of fried zucchini slices were frying time of 2 minute, Balangu seed gum concentration 14.31% and frying temperature 177 0C and in these conditions the quality attributes of final products were in optimum level. Application of Balangu seed gum lead to produce low fat fried zucchini slices without adverse effect on sensory attributes of final product.