IRANIAN JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
Year:2020 | Volume:17 | Issue:106|Papers Count:14

In the present research, microwave drying process of potato slices were thermodynamically analyzed and evaluated. During the experiments, potato slices with thicknesses of 3. 5, 5, 7 and 9 mm were dried using powers of 200, 400, 600 and 800 W. Specific energy consumption was obtained to be the range of 0. 83‒ 3. 29 MJ kg, and significantly increased (p < 0. 05) with increasing samples thickness. Energy efficiency of the process (13. 23‒ 35. 59) was significantly (p < 0. 05) improved with increasing microwave power and decreasing samples thickness. Average specific energy loss of the process varied from 0. 69 to 2. 71 MJ kg-1-1. Exergy efficiency and sustainability index of the process changed from 10. 03 to 28. 17 % and from 1. 11 to 1. 39, respectively. In General, according to the results obtained in this research, practicing higher microwave powers to dry thinner samples improved the thermodynamical performance and reduced the environmental footprints of the process.

Formation of nanocomposites in biopolymer coats can provide a new opportunity not only to improve the properties but also to reduce the price of these products. Also, nanocomposites, increase the efficiency of natural antibacterial materials. In order to investigate the antioxidant and antimicrobial effects of lemon grass extract and the amount of nanoclay on the efficacy of alginate-nanoclay composite coating of chicken fillet refrigerated storage, an experiment was performed in a completely randomized design with 6 treatments including alginate (2%) – nanoclay (1. 5 and 3%) nanocomposite coating, without and with levels of 1. 5 and 3% alcoholic extract of lemon grass and 3 replicates each treatment during 9 days. Results showed that contribution of nanoclay in the structure of nanocomposite coating was affected on its performance. Enrichment of alginate-nanoclay nanocomposite coating with lemon grass extract, added to its efficiency. Applying 3% of lemon grass extract in nanocomposite coatings, especially when using 3% nanoclay, significantly (p<0. 05) reduced the number of psychrophilic bacteria, tiobarbitoric acid index, free fatty acids and total volatile nitrogen compounds and increased chicken fillets water holding capacity during refrigerated storage. The contribution of nanoclay in without extract nanocomposite coating, did not significantly affect the number of psychrophilic bacteria at the end of the storage period. In general, the efficacy of alginate-nanoclay nanocomposite coating in increasing the shelf life of chicken fillets in refrigerated conditions depends on the appropriate contribution of nanoclay and enrichment with the appropriate concentration of lemon grass extract.

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 seeds and drying, can be used as a powder in formulation of various products. In this study, for basil seed mucilage drying, infrared radiation (IR) method was used. The effect of infrared lamp power (150, 250 and 375 W), distance of samples 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 increase in lamp power and decrease in sample distance from the heat source, drying time was decreased. With lamp distance increasing from 4 to 12 cm, the average drying time of basil seed mucilage increased from 131. 37 minutes to 336. 41 minutes. With sample thickness increasing 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 the network with 8 neurons in a hidden layer and using the sigmoid activation function could predict the drying time of basil seed mucilage using infrared dryer (r=0. 96). The results of sensitivity analysis by optimal neural network showed that samples thickness is the most effective factor in controlling the drying time of basil seed mucilage.

Mulberry is a fruit that has a considerable acceptance among consumers. The short harvest season and low persistence of this fruit have led to the use of methods such as freezing that have the least effect on phenolic compounds and antioxidant properties and sensory properties of the mulberry. One of the problems of sensory evaluation is the non-parametric results of the answers and the low accuracy of their analysis. Today, methods such as fuzzy logic allow inaccurate parameters to be analyzed by mathematical methods. In the present study, mulberry was stored in a freezer at-18 ° C for six months and removed from the freezer at 0, 72 h, one month, two months and six months. After juice making, the sensory evaluation was performed using five-point hedonic method and the data were analyzed using fuzzy logic methodology, while attributes were color, aroma, taste, and feel mouth. Also, pH, acidity, antioxidant activity and total phenol content were evaluated. Sensory evaluation of the samples showed that the freezing of the mulberry increased the overall suitability of the samples in 72 hours and did not show a decrease in sensory properties during 6 months. Panelists assessed the importance of sensory attributes including taste, mouthfeel, fragrance, and color, as well. Although, sensory evaluation did not decrease the sensory of juice, significant decrease of pH (19. 83%), increase in acidity (0. 31%) and a decrease in antioxidant activity (about 14%) and phenolic compounds (about 21%) during freezing was observed. According to the obtained results, freezing can be suggested as an acceptable method for long storage of mulberry fruit.

In this study investigated the use of modified atmosphere packaging (MAP) to extend the shelf life of Iranian flat bread (Taftoon). Four treatments of atmospheres including 100% CO2, 70% CO2-30% N2, 30% CO2-70% N2, normal air and a coveraged samples as a control were used. The bread samples were packaged in pouches of polyamid / polyethilen (PA/PE). Results showed that it is possible to prolong the shelf life of breads to about 17 days by using modified atmosphere packaging with high carbon dioxide concentration and high-barrier laminated. However, significant differences (P<0. 05) were obtained in the firmness of control bread compared to another treatment. In addition, firmness rate of breaniversityds packaged in normal air during storage was more than that compared to the samples stored in MAP, but there were not significant differences between samples packaged under atmospheres 100% CO2, 70% CO2-30% N2 and 30% CO2-70% N2. Modified atmosphere packaging extends shelf life of Taftoon as a flat bread and avoids mold growth in it.

Clove and Fennel have been widely used in traditional medicine for treatment of diseases. Regarding the existence of the active biological compounds in these plants, it seems that these plants have considerable antibacterial effects. In this experimental study, the Kirby– Bauer, the dilution method in the liquid medium and minimum bactericidal concentration (MBC) were used to evaluate and compare the antibacterial effects of the Clove and Fennel essential oils. The interactions were determined by calculating fractional inhibitory concentration (FIC), according to the European Committee for antimicrobial susceptibility testing protocol. The checkerboard method was performed using 96-well microtiter plates. The results showed that Staphylococcus epidermidis was the most sensitive strain to Clove and Fennel essential oils. The effects of interaction of Clove and Fennel essential oils with chloramphenicol antibiotic on all bacteria showed synergistic status (except for the fennel essential oil on Bacillus cereus). Calculation of fractional inhibitory concentration indicated that there was no interaction between the Clove and Fennel essential oils on Salmonella typhi, Enterobacter aerogenes and Staphylococcus epidermidis. Regarding the checkerboard data, one FICIs (>0. 5 to 1) indicated the additive effect (Bacillus cereus). Bacillus cereus is one of the most important bacteria that causing food poisoning, it is possible to use a combination of Fennel and Clove essential oils as a natural preservative in the food industry.

β _glucan is dietry fibre and water soluble hydrocolloid (gum). It has various physical properties such as thickening, stabilizing, emulsification, and gelation. in this study the effect of intensity and time at four different powers (0, 200, 300, 400 w) in three time (0, 3. 5 and 7 min) intrevals were investigated on the physicochemical and the rheological properties of extracted. ß _glucan. The results showed that ultrasound intensity and time were significant on ash, protein, fibre, carbohydrate and β-glucan content (p < 0. 05), While it was not significant on fats (p  0. 05). The highest amount of β-glucan (77. 1%) was observed at power 200 w for 3. 5 minutes, also the lowest amount of ß-glucan (55. 6%) was observed at power 400 w for 3. 5 minutes. Result showed that apparent viscosity decreased by increasing of the shear rate. All samples showed shear thinning behavior. The highest consistency coefficient, zero shear viscosity and lowest flow index was control sample., and the lowest consistency coefficient and zero shear viscosity and the highest flow index was observed at power 400 w for 3. 5 minutes. The results of fitting data using different rheological models showed Herschel and Carreau models have maximum R 2. Linear region assign about 0. 5 % using strain sweep test. Result of frequency sweep test showed initially, loss and storage modulus were increased by adding frequency, the storage modulus were reduced at high frequencies and in all samples were G    G.

Ovarian cancer is one of the deadliest cancer in women causing abnormal cancerous cells that can spread and metastasize to other parts of the body. Secondary metabolites are highly variable in terms of structural and chemical properties and they are very important for plants survival. In this study, the extracts of Ocimum basilicum and Impatiens walleriana using three different solvents (water, ethanol 80% and methanol 80%) and water bath extraction method were obtained. phenolic compounds of extracts were determined by Folin Sioculto method. DPPH (2, 2-Diphenyl-1-picrylhydrazyl) and FRAP (Ferric reducing ability of plasma) methods were performed for determination of antioxidant properties. The amount of phenolic compounds in two plants was higher in 80% methanol solvent and the most antioxidant activities were observed in water solvent of extracts. Water solvent had the highest antioxidant activity and was selected to investigate the anti-cancer properties of extracts on ovarian cancer cell line. Water extract of Ocimum basilicum within72 hours had the highest cytotoxic effect with an IC50 value of 1. 105 ± 0. 001 mg / ml. In current study, antimicrobial activities of extracts were determined on staphylococcus aureus by disc diffusion method. The highest antibacterial properties was observed only in ethanol extracts of two plants. In the measurement of MIC and MBC, ethanol and methanol extracts of Ocimum basilicum and water and ethanol extracts in Imatiens walleriana had the most inhibitory and bactericide effects.

Resistant starch type III as a dietary fiber is included in the prebiotic composition. It can be used to enrich low-calorie, gluten-free diets for celiac patients. The aim of this study was to investigate the possibility of improving the quantitative and qualitative properties of gluten free rice cake via replacement rice flour by resistant starch type III at levels of 0, 5, 10, 15, 20, 25 and 30%. Physicochemical, textural and sensory properties of the product were evaluated in a completely randomized design (P˂ 0. 05). The results showed that replacing the rice flour by resistant starch in the gluten free rice cake formulation reduced the specific gravity of batter and increased the moisture content of the final product. Also, by replacing rice flour by resistant starch up to 20%, the height, specific volume and porosity of the final product increased and then decreased. On the other hand, the sample containing 20% resistant starch had the lowest firmness at 2h, 3 and 7 days after production. In addition, the results showed that 25 and 30% replacements of the resistant starch in gluten-free rice cake formulation by rice flour, the L* value of the crust and crumb increased and the a* and b* were reduced. Finally, the panelists by evaluating the sensory properties such as shape, color, texture firmness and softness, taste and overall acceptance the sample containing 80% rice flour and 20% resistant starch type III introduced as the best sample. Therefore, according to the results of the physicochemical and sensory evaluation, replacement of 20% rice flour by resistant starch type III in gluten free cake formulation can produce a lower calorie product suitable for celiac patient.

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 dropletsize 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 andnanoemulsion. 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-30 mV. The MIC values of essential oil and nanoemulsion were 0. 58 ± 0. 11 and 0. 33 ± 0. 07 mg/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, respectively, 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 antibioticresistant microbes.

Ultrasound is used as a physical method to modify the functional properties of starch. In this study, the effect of ultrasound at 25, 45 and 65° C on the some rheological properties corn starch paste in the presence of Arabic gumwas investigated. Results showed that the amylose leakage increased with increasing temperature; but in the presence of Arabic gum, amylose leakage decreased. Sonicated samples showed lower paste clarity. Clarity decreased with increasing temperature; but in the presence of gum arabic the clarity was increased. Clarity changes were lower in the presence of Arabic gum. The least gelling concentration (LGC) was higher in ultrasonic samples and also LGC was higher in the Arabic gum contained samples. Ultrasonication and Arabic gum reduced the maximum and final viscosity of starch paste. Sample sonicated at 45º C was selected the best sample with minimum amylose content and showed the less changes clarity, higher LGC, minimum final viscosity. The presence of Arabic gum and the ultrasonic temperature are the important parameters that influenced the modification of starch properties.

Snack foods contain main parts of food habit among people in the world. Recently the high rate of consumption and variety of extruded snacks is proven to increase the attention to nutritional quality besides keeping desired acceptability of products. In this study, based on central composite design the effect of independent variables consist of the whole Oleaster powder (5-15%), moisture content (1220%), screw speed (120-180 RPM), were investigated on the physicochemical, textural and color of extrudates based on corn-wheat grit. results showed that, Increasing Oleaster content caused an increase in the density, hardness and solubility. Whereas, Increase screw rate and oleaster content simultaneously leaded to a lower density. In low amount of moisture content, improvement of oleaster content didn’ t significant effect on hardness. However by boosting recent factors gradually, the hardness of products increased dramatically. Moisture content and screw speed had absolute effect on lightness of extrudates. Meanwhile improvement of oleaster content caused a decrease in lightness. Optimum condition was determined to be the feed moisture content (13. 87%), oleaster content (5%) and screw speed rate (166. 7 rpm).

Texture analyzer is one of the important tools for analyzing and evaluating texture properties including hardness, softness, extensibility, tightness, fragility, adhesiveness, adhesion, compressibility, flexibility, shearability, elasticity, gel strength and springiness In this research, a texture analyzer was designed which, based on software and data processing ideas, while increasing the accuracy of performance and measurements, it provided calibration capabilities to make the output data close to real data. The main features of the texture analyzer are the ability to carry out the test in controlled temperature and humidity to analyze the texture parameters in order to reduce error in regions with different temperature and humidity. The results of the tests show that by carefully calibrating the calibration process and designing the calibration filter, the accuracy of the analyzer's performance is improved to 0. 05% of the read value. Also, using the micro-stapling algorithm and the use of the screw mechanism, the movement of the jaw is precisely less than 0. 005 mm and the speed of 0. 1 millimeter per second is controllable. All of these features, along with the USB connection with any personal computer, will be able to communicate directly with the EXCEL program, and save and simplify data analysis under the EXCEL program. The results of the tests show that there is no statistically significant difference between the relative humidity of the texture analyzer and the relative humidity for each sample (p <0. 05). Texture hardness of different samples of biscuits containing resistant starch was evaluated by commercial (C) and designed (D) instrument and there was no significant difference between the hardness of the texture obtained from both devices.

Jam is a product that uses a lot of sugar in its preparation, and this compound plays an important role in increasing the level of sugar. Since the increase in blood sugar is associated with diabetes and obesity, so reducing sugar consumption in this product can reduce the risk of these diseases which are caused by long-term use of this product. In this study, enzymatic invert sugar was used as a substitute for sugar in different ratios (0, 25, 50, 75 and 100%). Quince seed gum and pectin were also used as thickeners to improve the texture properties of jam. Measurement of acidity and pH, viscosity, brix, total sugar, reducing sugars, energy intake and sensory properties were measured. According to the results, with adding the gum and pectin, pH decreased, followed by acidity, brix, viscosity, reducing sugars, tissue hardness, yellowness and lightness index as well as sensory properties scores. Also, with increasing invert sugar, the acidity of samples increased, while brix and viscosity of samples decreased significantly (P˂ 0. 05). But as the invert sugar concentration increased, the taste and color scores of the samples increased. The color score of the samples was significantly increased (P˂ 0. 05) by adding quince seed gum. There was no statistically significant difference in odor of samples with increasing sugar replacement percentage (P≥ 0. 05). In general, based on the results of physicochemical and sensory tests, it can be said that jam samples containing 75% invert and 0. 25% of gum to (treatment number 15) were the best samples with 15% fewer calories than control samples.