جستجوی مقالات مرتبط با کلیدواژه « پرتودهی » در نشریات گروه « صنایع غذایی »

To increase the quality and shelf life of mango fruits (Manjifera indica cv. Langra), a factorial experiment was conducted in the form of a completely randomized design with three replications (18 fruits per replication). Mango fruits in mature green stage were harvested from a commercial mango orchard in Roodan city, Hormozgan province. The first factor was ultraviolet radiation (UV-C) with an intensity of 25 watts at three levels (0, 5 and 10 minutes), the second factor was ultrasonic radiation with a frequency of 35 kHz and a power of 280 watts at three levels (0, 3 and 6 minutes) and the third factor was storage time at five levels (0, 10, 20, 30 and 40 days). After the treatment with the mentioned proportions of UV-C and ultrasonic, the fruits were stored at 10°C and a relative humidity of 80-85%, and the sampling and the measurements were carried out at different times. Based on the results, ultraviolet and ultrasound treatments prevented the increase of L (lightness), a and b  and pH and the decrease of fruit ascorbic acid over time. In ultrasound treatments, the highest amount of ascorbic acid (11.3 mg/100 grams) was found in irradiation for three minutes. In ultraviolet treatments, the decrease of ascorbic acid with time was less than the control, but there was no significant difference between five and ten minutes. Ultrasound treatment for 6 minutes prevented the significant decrease in fruit weight. On the 40th day of storage, the lowest amount of L in fruit flesh (89.44) belonged to ultraviolet treatment for five minutes. Therefore, within 40 days of storage of mango fruit, ultraviolet treatment for five minutes due to maintaining the appearance of the fruit (L ) and ultrasound treatment for three minutes due to maintaining the maximum ascorbic acid of mango fruit are recommended.

The genetic algorithm (GA) optimization method can be used to overcome the inherent limitations of artificial neural network (ANN). Genetic algorithm–artificial neural network (GA-ANN) method has a high capability to find the optimum value of a complex objective function. In this study, first, to balangu seeds gum drying, an infrared dryer was used. In this infrared dryer, the effect of distance of samples from lamp at three levels of 5, 7.5 and 10 cm and the effect of height of the gum inside the container at three levels of 0.5, 1 and 1.5 cm on drying time and weight loss percentage of balangu seeds gum during drying time, were investigated. The results of balangu seeds gum drying using infrared method showed that with decreases in sample distance from the heat source and also with decreases in thickness of the gum in the sample container, drying time were decreased. With increasing in the lamp distance from 5 to 10 cm, the average drying time of balangu seeds gum increased from 62.6 minutes to 87.6 minutes. With sample thickness increasing from 0.5 to 1.5 cm, the average drying time of balangu seeds gum increased from 45.9 to 109.2 minutes. In the next step, this process was modeled by GA-ANN method with 3 inputs (radiation time, lamp distance from samples surface and thickness of samples) and 1 output (weight loss percentage). The results of modeling with GA-ANN method showed that the network with structure of 3-9-1 in a hidden layer and using the hyperbolic tangent activation function could predict the weight loss percentage of balangu seeds gum during drying in an infrared dryer with high correlation coefficient (0.999) and low mean squared error (0.788).

In order to evaluate the effect of moderate dose gamma irradiation (10 KGr) on ​​antioxidant and antibacterial properties of Zataria multiflora Boiss, edible active coating containing normal and irradiated extract (1.5%) on base of Na-caseinate solution (8%) was prepared and shelf life of coated rainbow trout fillet was evaluted. An experiment was carry out with 4 treatments without coating (control), fillets coated with Na-caseinate (T1), and fillets coated with Na-caseinate enriched with  normal (T2) or irradiated (T3) Zataria multiflora Boiss extract and 4 replicates during 10 days at refrigerated (4±1oC) storage. Chemical (TVN, TBA, PV) and microbial (TVC and PTC) tests were measured on days 0, 3, 6 and 10. The results showed irradiation of Zataria multiflora Boiss with a moderate dose of gamma rays, despite the possitive effects, did not cause significant changes in its antioxidant and antibacterial properties. But at the end of the storage period, the lowest levels of TBA (3.23±0.23 mg MDA/Kg), TVN (25.23±1.12 mg/100g) and psychrophilic bacteria counts (5.00±0.13 log cfu/g) was found in fillets containing active coating of Na-caseinate and irradiated Zataria multiflora Boiss extract (p <0.05). Therefore, Zataria multiflora Boiss extract can be used as normal or irradiated in the active coating of Na-caseinate, to increase the shelf life and quality of rainbow trout fillets at refrigerator temperature for at least 10 days.

Coating of fruits with edible gums increases the appearance quality, improves the color and reduces their shrinkage at the end of the drying process. In this study, Xanthan and Balangu gums were used to coating of apricot slices during drying in the infrared system and the drying kinetics of the samples were modeled. In this study, apricots were divided into three groups: control (without coating), coated with xanthan gum and coated with balangu seed gum, and then the effect of infrared lamp power (150, 250 and 375 W) and distance of samples from lamps ( 5, 7.5 and 10 cm) on the drying time of the samples were investigated. The concentration of used gum was 0.6% (w/w) and the thickness of apricot slices was 0.5 cm. The results of drying the apricot samples by infrared method showed that with increase in lamps power and decrease in samples distance from the heat source, the drying time decreases. Coating pretreatment increased the drying time of apricots and the drying time of samples coated with balangu seed gum was longer. The average drying time of the control samples, coated with xanthan and balangu gum was 73.11 min, 81.04 min and 83.74 min, respectively. This process was modeled by an artificial neural network with 3 inputs (type of coating, radiation lamp power and lamp distance) and 1 output (drying time). The results of artificial neural network modeling showed that the network with 7 neurons in a hidden layer and using the sigmoid activation function can predict the drying time of coated apricots using an infrared dryer (r=0.974).

Today, plant and commercial gums are used to improve the rheological, textural and sensorial properties of food. Basil seeds have significant amounts of gum (mucilage) with good functional properties that after extracting from the seeds and drying, can be used as a powder in the formulation of various products. In this study, to drying of basil seed mucilage, infrared radiation (IR) method was used. The effect of infrared lamp power (150, 250 and 375 W), the distance of sample from lamp (4, 8 and 12 cm) and mucilage thickness (0.5, 1 and 1.5 cm) on drying time of basil seed mucilage were investigated. The results of basil seed mucilage drying using infrared method showed that with increasing lamp power and decreases in sample distance from the heat source, drying time was decreased. With increasing in the lamps distance from 4 to 12 cm, the average drying time of basil seed mucilage increased from 131.37 minutes to 336.41 minutes. With increasing sample thickness from 0.5 to 1.5 cm, the average drying time of basil seed mucilage increased from 103.67 to 367.67 minutes. The process was modeled by an artificial neural network with 3 inputs (lamp power, lamp distance and thickness) and 1 output (drying time). The results of artificial neural network modeling showed that a network with 8 neurons in a hidden layer and using the sigmoid activation function could predict the drying time of basil seed mucilage using the infrared dryer (r=0.96). The results of sensitivity analysis by optimal neural network showed that sample thickness is the most effective factor in controlling the drying time of basil seed mucilage.

The carob moth, Ectomyelois ceratoniae (Zeller) and various diseases are the main limiting factors in postharvest life of pomegranate fruit. Including effective treatment to reduce pests and diseases of agricultural crops is gamma radiation. The effect of this treatment in reducing postharvest pests and diseases of pomegranate fruit has been also shown; however, its effect on fruit quality during cold storage has not been investigated. In order to study the effect of gamma irradiation on pomegranate quality this study, as factorial in frame of CRD, was conducted at Shahed University and Nuclear Agriculture Research School in 2015. For that pomegranate fruits cv. ‘Malas Saveh’ were harvested at maturity stage and treated with gamma radiation at doses of 0, 1, 3, 5 and 7 kGy and were stored at 6°C with 80% RH, and then were taken on 1, 2 and 3 months of storage. Results showed that application of gamma radiation in comparison to control increased weight loss and electrolyte leakage, and reduced soluble solid, total phenol, anthocyanin and vitamin C contents as well as antioxidant capacity. Nevertheless the effects of treatments at low doses, especially at 1 kGy, were not considerable, but fruit quality decreased more with increasing doses. Therefore low doses of this treatment can be effectively use in increasing postharvest life of pomegranate fruit.

In this study an experimental infrared system was designed and built to investigate the deactivation behavior of peroxidase in eggplant. Deactivation of peroxidase (90% reduction in enzyme activity) in eggplant slices was investigated during infrared irradiation at powers of 150, 250 and 375 watts and thickness of 5 and 10 mm in the range of 0 to 600 seconds. During the process, changes in cold spot temperature, moisture and peroxidase activity in slices of eggplant were measured. The results showed that using 150 W lamp at a thickness of 5 and 10 mm in, peroxidase was not inactivated after 600 seconds. The peroxidase enzyme was inactivated by using lamps with powers of 250 and 375 at a thickness of 5 mm after 500 and 150 seconds, respectively in which was associated with reduction of 50.06% and 31.62% of the initial moisture content at cold spot temperature of 73.76°.C and 44.72 ° C , respectively, using lamps with powers of 250 and 375 at a thickness of 10 mm after 600 and 200 seconds was associated with a reduction of 50.26% and 33.04% of the initial moisture content at cold spot temperature of 72.27 ° C and 73.86 degrees ° C, respectively, In conclusion, increase in power and decrease in thickness, increased inactivation rate of enzyme peroxidase furthermore, because of the shortening of the processing time when using lamps with larger power the less moisture is removed from the sample.

The effect of two factors, packaging (with high density poly ethylene) and irradiation with gamma ray (with 0, 1, 3 and 5 KGr) was investigated on chemical and microbiological characteristics of industrial breads produced in Kermanshah city by Randomized Complete Block Design (RCBD) with 4 repetition. ANOVA showed packaging had no significant effect on above characteristics, while irradiation had significant effect (P

Irradiation as an effective non thermal sterilizing method of meat preservation has excellent potential to extend the shelf life. In this study, quail meat was irradiated at doses of 0, 1.5, 3 and 5 kGy of electron beam irradiation and was kept in a refrigerator (4 ± 1°C) for 15 day. Then effect of irradiation and maintenance of refrigeration temperature were evaluated on microbial quality, chemical and organoleptical properties. The results of microbial analysis indicated that irradiation dose of 1.5, 3 and 5 kGy caused a significant decrease (P<0.05) in the number of aerobic mesophilic bacteria, lactic acid bacteria, fungi and yeasts. Irradiation dose of 1.5 and 3 kGy caused a significant decrease (P<0.05) in the number of coliforms. Microbial load of control and irradiated samples increased significantly (P<0.05), that speed of this increase was greater in the control samples, during the storage period under refrigerated conditions. The shelf life of irradiated samples was higher than 15 days while control samples were kept only 4 days under the same conditions. Irradiation significantly (P<0.05) increased the initial TBA of samples and storage in refrigerator was led to increase the TBA value significantly (P<0.05) in all samples. Irradiation had no significant effect on the organoleptical properties (P>0.05) and caused shelf life to increase of more than 15 days but, the control samples were kept only 5 days under the same conditions. Thus, this study clearly indicated that the electron beam irradiation of quail meat has positive effects on its overall characteristics and extend the shelf life during refrigerated storage.

In this study Quail meat was irradiated at doses of 0, 1.5, 3 and 5 kGy of electron beam irradiation and kept in a refrigerator (4±1°C). Then the effects of irradiation and maintenance of refrigeration temperature on microbial quality, chemical and cooking loss were evaluated. The results of microbial analysis indicate that all radiation doses of 1.5, 3 and 5 kGy caused a significant decrease (P<0.05) in the number of aerobic mesophilic bacteria, lactic acid bacteria, fungi and yeasts. Radiation doses of 1.5 and 3 kGy caused a significant decrease (P<0.05) in the number of coliforms. Irradiation significantly (P<0.05) increased the initial TBA of samples and refrigerated temperature increased the TBA value significantly (P<0.05) in all samples, so that the level of TBA increased from 0.3 to 3.58. In this study the cooking loss of control and irradiated quail meat was evaluated. About this value the results showed the irradiated quail meat was increased in comparison to nonirradiated samples significantly (P<0.05), so that the level of cooking loss increased from 31.56 to 41.65. Thus, this study clearly indicated that the electron beam irradiation of quail meat has positive effects on overall characteristics of quail meat and extend the shelf life during refrigerated storage.

Irradiation as a method of meat and poultry preservation has excellent potential to improve meat safety and extend the shelf life. The main concern of irradiating meat، however، is the organoleptic quality changes that occur. The present study was conducted to evaluate the combined effect of low-dose gamma irradiation (2/5 kGy) and chitosan edible coating (2%) on the shelf life of chicken breast meat. Samples were separated into four groups; uncoated and unirradiated control (C)، coated with chitosan (CH)، irradiated and uncoated (I) and coated with chitosan and irradiated (ICH). Samples were stored at 0-4°C and evaluated periodically for microbiological (aerobic mesophilic and psychrotrophic counts)، chemical (TBA، pH، aw) and sensory (odor، appearance and overall acceptability) characteristics. Microbial analysis indicated that gamma irradiation and coating had significant effects (P<0. 05) in reducing the mesophilic and psychrotrophic counts with at least a 14-day extension of shelf life. The chitosan-coated products showed lower TBA and pH values than the uncoated samples for up to 21day of storage at 0-4°C. No significant (P>0. 05) differences in TBA values of samples were observed due to irradiation. The results indicated that the application of chitosan coating significantly improved (P<0. 05) sensory quality of samples. None of the sensorial characteristics (odor، appearance، overall acceptability) was significantly affected by gamma irradiation (P>0. 05). This study thus clearly indicated that the effect of chitosan coating plus irradiation on samples was to retain their good quality characteristics and extend the shelf life during refrigerated storage، which was supported by the results of microbiological، chemical، and sensory evaluation analyses.