مجله تحقیقات مهندسی صنایع غذایی
سال بیست و یکم شماره 2 (پیاپی 73، پاییز و زمستان 1401)

Electrical treatments play an important role in conventional methods of food technology. Ohmic processing is an electrical and thermal method based on the passage of electricity through a product that acts as an electrical resistor. In ohmic heating, the temperature rises without the need for heat transfer from the solid-liquid surface. In this research, an ohmic heating device was constructed, and for the heating process, three input voltage gradients (5, 7.5, and 10 V/cm) and three process temperatures (60, 75, and 90 °C) were selected. During the thermal process, the content of total phenol, total flavonoids, and soluble solids (Brix and PH) was examined. All experiments were performed in three replications using a factorial experiment in a completely randomized design. The results were analyzed using SAS software. According to the obtained results, the voltage and temperature gradients of the process on the total phenol content, the amount of flavonoids, pH, and total soluble solids were significant at the level of 1%. The highest amount of total phenol and flavonoid content was at the voltage gradient of 5 V/cm and process temperature of 60 ° C and the lowest value was at the voltage gradient of 10 V/cm and process temperature of 90 °C. The maximum pH was observed at a voltage gradient of 5 V/cm and a process temperature of 90 ° C and the lowest value was observed at a voltage gradient of 10 V/ cm and a process temperature of 60 °C. The highest output was at a voltage gradient of 10 V/cm and the process temperature was 90 °C; the lowest value was at a voltage gradient of 5 V/cm and the process temperature was 60 °C.

Sour cream contains 20-30% fat, to which aroma-producing bacteria (lactic acid) were added in order to create a special odor and taste. This type of cream is stored at 4 °C for at least 24 hours before distribution and then marketed. The aim of this study was to investigate the possibility of producing probiotic sour cream by adding probiotic bacteria and maltodextrin. In this study, the addition of probiotic bacteria (Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium bifidum) in the formulation of sour cream with 20% fat was used and the rheological properties of the cream were investigated. The results showed that all samples showed shear-thinning behavior under shear strain. The rheological Carreau model fits the sour cream flow behavior data well. In terms of viscoelastic properties, in all samples, including bacteria and maltodextrin, the storage modulus was higher than the loss modulus. Also, no significant difference was observed between the amount of maltodextrin addition and the type of bacteria in terms of rheological properties (P< 0.05).

This study aimed to combine the response surface methodology and COMSOL simulation to reduce the number of studied treatments, find the effective factors and their interactions and also the prediction model for final dried orange characteristics, and find the shrinkage model of apple fruit concerning the studied drying process factors. A definitive screen design of response surface methodology was designed by Design-Expert software. Factors such as drying time (A: 20-60 ℃), air velocity (B: 0.5-2.5 m/s), sample thickness (C: 3-7 mm), sample diameter (D: 4-6 cm), and drying time (E: 6000-10000s) were investigated. These treatments were simulated in COMSOL software 5.3a. After finding the treatments in Design Expert software, the simulation starts. Results show apple samples results show, that the air temperature and its interaction with other investigated factors, the sample thickness, and the air velocity are effective on the central temperature of the sample. The moisture rate and moisture content are depending on drying time. Apple shrinkage is a logarithmic model as a function of air temperature, sample thickness, and process time. Apple shrinkage during drying significantly affects the thickness of samples. To control the shrinkage rate during apple drying, controlling the time of process and sample thickness is more effective than other processing factors. This leads to a prediction model for drying apples and process control. The optimization is shown the minimum shrinkage is at 0.7mm thickness, 5.45cm diameter, and 9938s process time.

The purpose of this study was to look into the effect of coating French fries with gum zedo, which contained essential oils of thyme and tarragon, on the chemical composition and texture of the fries. The research hypothesis is that the process of frying French fries at a high temperature could reduce humidity effectively. Also, it affects the texture of sliced French fries as well as taste, smell, and the final product. The zedoary gum, which consists of two essential oils, affects the chemical composition and texture of sliced french fries and could increase the quality of food. In this study, Shirazi thyme and tarragon essential oils were extracted by distillation with water using the Clevenger apparatus. The coating solution was prepared using 1% zedoary gum, thyme essential oil, and tarragon to cover the potato slices. The results showed that by coating the potato samples with gum, the moisture content increased while the fat and protein content decreased. The hydrocolloid coating of zedo gum reduced the hardness index of fried potato tissue compared to the control sample. However, the use of thyme and tarragon essential oils had no significant effect on the chemical composition, texture, or hardness of the samples. Finally, the sample coated with a hydrocolloid coating of zedo gum without essential oil and containing thyme essential oil had the highest overall acceptance score among the samples.

Bisphenol A (BPA)-based epoxy resins are widely used in food contact materials such as metal can coatings. The adverse effects of bisphenol A on the consumer have led the food packaging industry to continually improve safety. In this study, epoxy coatings manufactured with nanoparticles are subjected to migration testing in order to identify bisphenol A diglycidyl ether (BADGE) migration from the coatings. Migration of BADGE from epoxy/TiO2/Al2O3 nanocomposite into ethanol 10% (v/v), ethanol 20% (v/v), ethanol 95% (v/v), and acetic acid 3% (w/v) food simulants was studied at conditions of contact filling (60 min at 60 and 121°C) and storage condition (10 days at 40 °C). High-performance liquid chromatography (HPLC) was developed to determine the level of bisphenol A diglycidyl ether (BADGE) that migrated from the nanocomposite to the food simulants. The results indicated the levels of BADGE migrating from epoxy/TiO2/Al2O3 nanocomposite to the food simulants under the conditions of contact filling and storage did not exceed the specific migration limits.

In recent years, due to concerns about the safety and health of synthetic antioxidants, there has been widespread attention to the use of natural antioxidants. Bioactive peptides are one of these types of natural antioxidants. Turkmen melon seeds are a rich source of protein. The purpose of this study, was to perform enzymatic hydrolysis of Turkmen melon seed protein with pancreatin and alcalase enzymes in the ratio of enzyme to substrate of 1% and at intervals of 20-200 minutes. The degree of hydrolysis and antioxidant properties (DPPH radical scavengingactivity, Fe3+ reducing power, and total antioxidant activity) of the obtained hydrolysates were investigated. Based on the results obtained from the effect of time on hydrolysis for alcalase-derived hydrolysates, the treatment was 20 to 120 minutes longer than pancreatin, while the treatment of pancreatin-derived hydrolysates for 140 to 200 minutes was higher than that of alcalase. The results showed that there was no significant difference between most of the hydrolysates from pancreatin and alcalase at 180 minutes compared to 200 minutes (about the free radical scavenging activity of DPPH hydrolyzes from alcalase, 160 minutes was determined as the best treatment). The highest scavenging activity of DPPH was total antioxidant by pancreatin enzyme after 160 minutes and 180 minutes of hydrolysis and respectively 72.49% and 1.27 (absorption at 659 nm). The results showed that the produced hydrolysates have a high ability to prevent food oxidation or be used as a medicinal compound.

Thermolysin enzyme is a heat-resistant metalloproteinase enzyme that binds (EC 3.4.24.4) a peptide containing hydrophobic amino acid leucine and phenylalanine. This enzyme`s immobilization is very important. Enzyme immobilization enhances the stability and reuse of the enzyme and improves the properties of the enzyme and facilitates the enzyme readiness of the product. In order to study the adsorption in the presence of ethanol, different concentrations of ethanol were investigated with enzyme. To investigate the presence of CMC, the enzyme was mixed with different percentages of CMC solution and the casein (substrate) was mixed with different amounts. The effect of CMC and alcohol on the enzymatic solution of CMC was obtained. The effect of CMC and alcohol was investigated. The effect of CMC 2%, 4%, 6%, 8% and 10% with 1% casein on the enzyme was investigated. In this study, it was shown that thermolysin increases activity and stability against temperature rise and then decreases at very high temperatures, and alcohol causes enzyme instability. CMC increases the activity and stability of the thermolysin enzyme, but the presence of CMC can increase the stability and resistance of the thermolysin enzyme to alcohol. CMC has been shown to stabilize thermolysin.

Packaging, transportation, and separation of agricultural products are among the processes that cause potential damage, losses, and increased waste, depending on the type of product. Therefore, determining the mechanical strength properties is one of the most important approaches to prevent mechanical damage. Using mechanical tests, such as compression tests, is a common approach to obtain information, but simulation methods can help determine a wider range of information, such as stress and strain distribution patterns in the fruit, at lower cost and higher speed. Quince (Cydonia oblonga), which like other fruits is susceptible to mechanical damage, is rich in various compounds such as flavonoids and phenolic acid, which contribute to anti-cancer, anti-inflammatory, anti-allergic, and antimicrobial properties. In this study, to determine the mechanical properties of quince, compression tests were performed on fruit specimens at a rate of 10 mm/min using a materials testing machine and supplemented by simulation using ANSYS software FEM. The results of the experiments and simulations showed that a viscoelastic model adequately describes the behavior of the fruit under quasi-static loading. The simulation results for loading rates of 5 and 20 mm/min showed that the specimen is subjected to higher shear and normal stresses at a rate of 20 mm/min. The minimum of shear and normal stresses is associated with the rate of 5 mm/min. According to the evaluation results, it is better to perform harvesting and post-harvesting of quinces in such a way that lower loading rates (5 mm/min) are applied to avoid losses as much as possible.

Rice is one of the essential food items; the agricultural residue obtained from it is rice husk. Most of the rice husk ash (87-98%) is composed of silica. Application of rice husk as a raw material for the synthesis of silica, compared to other methods, reduces environmental pollution and energy consumption. It is also economically viable due to its low cost. Silica is used as a nanocarrier in the nanoencapsulation of bioactive and pharmaceutical compounds due to its unique properties, such as its high specific surface area and uniform porosity. For this purpose, mesoporous silica nanoparticles were synthesized from rice husk by heat degradation at three calcination temperatures of 400, 600, and 800°C and glycerol mixing temperatures of 200, 225, and 250°C. Calcined silica at 600°C and 200°C glycerol were considered the optimal samples. This sample had a high purity (containing 94.07% silica) and an amorphous structure (2θ=22). The response surface method (RSM) was used to determine the optimal sample. Moreover, its particle size was 252 nm, as determined by dynamic light scattering. In addition, its specific surface area was high (51.653 m2 g-1).

The effects of soy protein isolate (SPI) and oat germ powder (OGP) were investigated on some characteristics of whey-less cheese. In this study, 6 different treatments were prepared in which part of the combination of milk protein concentrate (MPC) and skim milk powder (SMP) were replaced with different ratios of SPI and OGP (0: 0, 6.7: 3.3, 5: 5, 10: 0, 0:10 and 3.3: 6.7%). The results showed that the moisture, protein content and acidity of the samples increased with increasing SPI about 8.8, 25.2 and 6.8% and decreased with increasing OGP about 1.9, 26 and 18.7% respectively. The addition of SPI and OGP, the phenolic compounds increased from 99.3 to 303.99 and 169.65 mg/100g respectively (p<0.05). With increasing SPI and OGP, the L* index decreased and the b* index increased. But the a* index increased with increasing OGP and decreased with increasing SPI (p<0.05). The hardness and gumminess in the control sample was the highest and the samples containing 10% SPI were the lowest. Cohesiveness and springiness of 5% SPI and 5% OGP mixed samples were the highest and samples containing 6.7% SPI and 3.3% OGP were the lowest. The gumminess and chewiness decreased with increasing SPI and increased with increasing OGP (p<0.05). With increasing SPI and OGP, the overall acceptance score of the samples decreased but was not significant (p>0.05). It was concluded that, the mixture of 5% SPI and 5% OGP or 3.3% SPI and 6.7% OGP could be used in production of whey-less cheese.

In the present study, a composite gel was prepared based on gelatin and sesame seed protein containing a fixed amount of oleosome. The different ratios of sesame protein to gelatin (30:70, 50:50, 70:30 w/w%) and a constant amount of 20% (w) oleosome were used to prepare the composite gel. Then the physicochemical properties of sesame seeds, oleosomes and their extraction efficiencies were determined. The rheological, textural and microstructural properties of the gels were also investigated. Protein and oleosome extraction efficiencies from sesame seeds were 21±1.23% and 68.96±1.41%, respectively. The results showed that the amount of sesame seed protein had significant effect on the gelation behavior and gel hardening, and the storage modulus and loss modulus increased in the samples with the decrease of the process temperature from 50 to 4 degrees Celsius. With the increase of sesame protein ratio, the amount of storage modulus and loss modulus at 4 degrees Celsius temperature increased from 258 pascals to 149400 pascals and from 46.7 pascals to 37648 pascals, respectively. The accumulation of protein molecules in the gel structure was observed with increasing the proportion of sesame protein to 70% by light microscope. The results of the present research confirm that sesame seed oleosome can be used as a substitute for fat particles in food products.

The purpose of this study was to determine the influence of different levels of cadmium concentration of the soil on accumulation of cadmium in various parts of seven different types of common vegetable crops: lettuce, spearmint, coriander, cress, onion, parsley and leeks. A factorial experiment in a completely randomized design with three replicates and three treatments was conducted. The treatments included three levels of cadmium concentration in soil 50 mg.kg-1, 100 mg.kg-1 and control with no cadmium. The soil used in this study was prepared by using a sieve with a 2mm mesh and adding nitrate cadmium plastic pots were employed to cultivate vegetables. At the end of the growing season, samples were prepared from different parts of the plants to measure cadmium concentration. The SPSS software was employed to analyze the data. The results showed that cadmium concentrations were higher than 0.05 to 0.1 mg/kg and 0.2 mg/kg, the rates that Institute of Standards and Industrial Research of Iran and FAO/WHO, respectively, announced as safe for human consumption. Cadmium was found in stems: of lettuce, spearmint, coriander, cress, onion, parsley and leeks from highest to lowest; in leaves: of lettuce, cress, onion, coriander, parsley, spearmint and leeks; from highest to lowest; and in; roots: of cress, lettuce, spearmint, coriander, parsley, onion and leeks from highest to lowest. The results indicated that the highest amount of cadmium concentration among the different parts of the vegetables was founded in lettuce stem (6.8 mg/kg) and the lowest amount in leek root (0.77 mg/kg), both higher than what has determined as safe for human consumption. All treatments were considered as unsafe treatment while no sign of toxicity was found in control sample. The high accumulation of cadmium in lettuce, cress and onion, the vegetables that are consumed more, is critical due to their potential to accumulate this element in their leaves. These vegetables cannot be safe for consumption by human if is grown in soils with high concentration of cadmium.