فهرست مطالب ahmad kalbasi-ashtari

The effects of Dielectric Barrier Discharge (DBD) on crystal-sugar contaminated with Geobacillus  stearothermophilus   and Aspergillus niger was studied with combined variables of power (5–15 w), time (2-10 min), and voltage (15-22 kV). The total microbial loads of Gs (9×105) and An (9×104 CFU/g) loads were destructed (P ≤ 0.05) when the voltage and power were 22 Kv and ≥ 5 W. Additionally, their death values (D) were equal and below 1.18 min, respectively. Results showed that increasing voltage had at least 70% more effects on Gs sterilization than the time and power of DBD. Although the cold plasma has substantial destructive effects on the  cell membranes, DNA, and protein of microrganisms, Scanning Electron Microscopy (SEM) of A. niger,  and G.  stearothermophilus confirmed the disinfection process by changes happened in their sizes, configurations, and spores due to the cold plasma process. The DBD method (a non-thermal procedure) can be applied as a new antimicrobial practice to fully sterilized the purified crystal sugar and make it completely appropriate for pharmaceutical and baby food industry.

The increasing demand for pharmaceutical sugar requires higher quality (specifically microbial level) of standards compared to the sugar commonly used in the food industry. While different thermal processes are applied for microbial decontamination of crystal sugar, they usually destruct and degrade its bio-active compounds, that are undesirable. This research was conducted to evaluate the effects of freeze-drying (at – 42oC, and pressure of 0.1 mbar) on crystal sugar contaminated highly with heat resistant bacteria of G. stearothermophilus (9×105) and also most common fungi of A. niger (9×104 CFU/g). The results of this study showed that the non-thermal process of freeze-drying could eliminate > 99% of its original Gs and An microorganisms successfully. Physicochemical tests have indicated that the freeze-dryer process has made 10.4% decrease in crystal size and 23.5% decrease in ash content, that brings the characteristics of sugar crystals closer to international pharmaceutical standards. Furthermore, the microbial load of crystal sugar after freeze-drying process were below the permissible levels identified in European Pharmacopeia. In fact, there is a potential to use freeze-drying technique to decontaminate the conventional crystal sugar and make it appropriate for using (as ingredient) in pharmaceutical products.

Depectinized Date Juice (DDJ) was clarified with an ultrafiltration (UF) unit (containing PVDF-membrane with 30-40 nm pore sizes) and combined with an electric field (EF). The UF had 3 independent variables (temperature, pressure, and flow rate) respectively at [27 & 40oC], [1, 1.5, & 2 bar], and [10, 15, and 20 mL/s] levels. After applying a statistical tool, the optimized levels and affecting factors of temperature, pressure, and flow rate on the resulting permeate sequentially were 40°C & 55.23%, 1.5 bar & 43.01%, and 20mL/s & 1.76%. While the highest permeate flux of UF reached 2.5, it amplified to 5 Kg/m2h (100% increase) when it was joined with the EF at 5 V strength. Although UF permeate could recover 68% and 58% of the phenolic and antocyanin compounds of DDJ, the UF+EF processes improved these recoveries and reached 92% and 80%, respectively. Similarly, the sucrose and glucose in the permeate of UF+EF were at least 10% more than those obtained in the permeate of UF only. The redness color in retentates of DDJ after passing UF and UF+EF concentrated up to 213% and 292%, respectively.  Finally, the application of UF and UF+EF could eliminate the bacterial loads (Enterobacteriaceae, Escherichia coli, mold, and osmophilic yeast) of DDJ below the permissible levels. Overall, the combination of UF+EF could clarify the DDJ with richer bioactive compounds, more reducing sugar, brighter color, and lesser turbidity than those treated with UF only. It also produces a retentate with higher pectin content as a valuable source for making supplementary food.

In this research, nanoparticles of milk protein isolate (MPI) were produced by electrospraying method. In order to optimize the electrospraying conditions of MPI nanoparticles, the concentration of MPI solution (%wt.), the process voltage (kV), the moving distance of the particles between the tip of the needle and the collector (cm) and the pump flow rate (mL/h) in the form of a composite plot central (CCD) were investigated and modeled and analyzed by the response surface method (RSM). The results showed that the concentration of MPI solution had the greatest effect and the distance between the tip of the needle and the accumulator had the least effect on the diameter of nanoparticles. According to the results, by optimizing the concentration of MPI solution (2.5%wt.), pump flow rate (0.2 mL/h), the distance between the tip of the needle and the collector (15 cm) and voltage (17.5 kV), uniform MPI nanoparticles can be obtained. The images from the scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirmed the success of the electrospray method in producing spherical nanoparticles with an average diameter of 329.3 nm and maximum uniformity in particle size distribution. Also, Fourier transform infrared spectroscopic (FTIR) analysis revealed the chemical structure of nanoparticles.

The usage of membrane technology can improve the quality of sugar syrup in the clarification of date juice. Also, reducing the consumption of clarifying chemical agents and saving more energy are among the advantages of this technology. This research was conducted in order to investigate the efficiency of the membrane process in the clarification of date syrup and to evaluate the mechanism of membrane clogging resulting from organic and inorganic substances in date liquid sugar. In this study, the effect of temperature, flow rate and hydrostatic pressure on the permeate flux in the ultrafiltration process was investigated, and the membrane fouling mechanism was evaluated in different operating conditions. In addition, fouling analysis was performed using Hermia models. The results showed that the main mechanism of fouling in the membrane process of sugar syrup clarification is the mechanism of cake layer formation.

The aim of this study was to investigate the effect of saffron (Crocus sativus L.) petal extract, on the quality and shelf-life of rainbow trout fish fillet. In this study, saffron petals extract, prepared by enzymatic method and free-radical scavenging activity and phenolic compound of the extract were evaluated. The fish fillets were divided into three groups: control, containing free saffron peral extract and treated with encapsulated extract (maltodextrin-whey protein isolate. 1:1) and the chemical (total volatile base nitrogen;: thiobarbituric acid reactive substances, peroxide value, and free fatty acid) and microbial (Total viable microorganism; Psychrotrophic count lactic acid bacteria) properties of samples were investigated during 15 days at 4±1 °C. Based on the results, the total phenol content, total flavonoid compounds, and total anthocyanin of petal saffron extract were 177.55± 2.37 mg.GAE/g; 158.87± 3.06 mg/100g dw and 159.42±3.02 mg/100g dw, respectively. The DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical scavenging activity (DRSA) of the extract was 83.96± 2.30%. Saffron petal extract (free or encapsulated) reduced the oxidation rate of rainbow trout fillets as compared to the control sample (P < 0.05). The total volatile base nitrogen content of the control sample in 6th day was 19.06 mg N2/ 100g; while, in the samples containing free or encapsulated extract, this index reached to this value after 9 and 12 days. Although the samples containing the extract significantly reduced the microbial load of the fillets, but the difference between the samples containing free and encapsulated extract was not significant. Saffron petal extract showed a good ability to maintain fish quality. The shelf life of the fish treated with encapsulated saffron petal extract was one week longer (shelf life 12-12 days) than the control one (6-7 days).

Saffron petal was dried from 85% to 10% moisture content with fixed layer bed (FLB), semi fluidized bed (SFB) and fully fluidized bed (FFB) at temperatures (t) of 35, 45 and 55 °C. The airflow (v) of FLB, SFB and FFB were 0.2, 0.7 and 1.7 ms-1</sup>, respectively. When the t/v ratio increased in each method, the dehydration time decreased considerably. The dehydration times and drying rates of saffron petal for FLB (v = 0.2 ms-1</sup>& t = 35 </sup>°C) and FFB (v = 1.7 ms-1</sup>& t = 55 </sup>°C) were “570 & 30 min” and “0.13 & 2.50 gH2</sub>O/min”, respectively. When the airflow increased from 0.2 to 0.7 and then to 1.7 ms-1</sup>, the phenolic, anthocyanin & antioxidant contents of dried saffron petal improved to about 6, 15 & 15% and then to 15, 20 & 42%, respectively.  However, by increasing air temperature from 35 to 45°, their phenolic and anthocyanin contents did not change significantly. However, sharp reductions of 20, 23 and 41% respectively were noticed in phenolic and anthocyanin contents and antioxidant activities of saffron petal when the drying temperature exceeded 45 and reached to 55 </sup>°C. Overall, the fresh saffron petal dehydrated at 45 °C with FFB had the highest phenolic and anthocyanin contents and antioxidant activities.

Saffron petal was dried from 85% to 10% moisture content with fixed layer bed (FLB), semi fluidized bed (SFB) and fully fluidized bed (FFB) at temperatures (t) of 35, 45 and 55 °C. The airflow (v) of FLB, SFB and FFB were 0.2, 0.7 and 1.7 ms-1, respectively. When the t/v ratio increased in each method, the dehydration time decreased considerably. The dehydration times and drying rates of saffron petal for FLB (v = 0.2 ms-1& t = 35 °C) and FFB (v = 1.7 ms-1& t = 55 °C) were “570 & 30 min” and “0.13 & 2.50 gH2O/min”, respectively. When the airflow increased from 0.2 to 0.7 and then to 1.7 ms-1, the phenolic, anthocyanin & antioxidant contents of dried saffron petal improved to about 6, 15 & 15% and then to 15, 20 & 42%, respectively. However, by increasing air temperature from 35 to 45°, their phenolic and anthocyanin contents did not change significantly. However, sharp reductions of 20, 23 and 41% respectively were noticed in phenolic and anthocyanin contents and antioxidant activities of saffron petal when the drying temperature exceeded 45 and reached to 55 °C. Overall, the fresh saffron petal dehydrated at 45 °C with FFB had the highest phenolic and anthocyanin contents and antioxidant activities.

This research aimed to investigate the process of pistachios solar drying in two different conditions of the designed dryer (recycle and without recycle modes). As well, in this study, the drying kinetics curves of pistachio were drawn and its dewatering behavior was monitored by empirical models. Furthermore, the mass transfer rate (MTR) of the examined product during drying in two noted modes was determined by Fick’s 2nd law. Maximum, minimum, and average values of collector output air temperature were recorded 54.20, 32.30 and 42.99°C & 47.10, 30.70 and 40.03°C in air recycle and without air recycle modes, respectively. The results dedicated that, 18.75 % saving in drying time was obtained for air recycle mode compared with without air recycle mode. Also, the obtained data revealed that the drying rate of pistachio nut under recycle mode was higher than that of pistachio nut under without recycle mode, especially during the first hours of drying. Moreover, the empirical modeling showed that the Parabolic and Diamante et al. models were found to be the most suitable for describing the drying curve of the thin layer solar drying process of whole pistachio nut under recycle and without recycle modes, respectively. In addition, the highest value of effective moisture diffusivity was observed in solar dried pistachio nut under air recycle mode with the Deff value of 2.26×10-6 m2/h (R2=0.9265).

In the process of producing saffron, petals are discarded as waste materials. As a result, in Iran, annually, 7257625 kg saffron petals are obtained as a sub-product. So finding a solution for recycling this huge amounts of waste is very important.This study conducted to find the most appropriate models for saffron petal dehydration with the use of semi-fluidized drier (SFD) and fluidized bed drier (FBD).س For this purpose, a fluidized bed drier was designed to measure the temperature and air flow velocity, and also with the ability of weighing the samples at different intervals with high precision and then. The airflow and temperatures ranges used in SFD and FBD were 0.7-1.7 ms -1 and 45-55 °C, respectively. When the air temperature and airflow respectively increased from 45 to 55°C and 0.7 to 1.7 ms -1 , the dehydration time in SFD or FBD decreased significantly. At air temperature of 45°C and similar conditions, the SFD and BFD could dehydrate saffron petals in airflow and drying times of 0.7 ms -1 for 96 min and 1.7 ms -1 for 30 min, respectively. However, at equal temperature of 55°C and airflow of 0.7 ms -1 , the petal dehydration time of SFD and FBD changed to 36 and 96 min, respectively. The effective moisture diffusivity coefficient in SFD and FBD systems varied from 9.548 × 10-10to 2.455 × 10- 9m 2 s -1 and from 1.114 × 10-9to 1.963 × 10-9m 2 s -1 , respectively. The calculated activation energy in SFD was ranged from 56.83 to 78.78 KJ/mol. Among eleven semi-experimental models tested for the saffron petals dehydration, only two models including logarithmic and modified form of Henderson and Pabis formula were found appropriate to fit the obtained data and show the actual trend of changing moisture ratio versus drying time of saffron petals. Because these models showed highest determination coefficients, lowest root mean squared and minimumsum-squared errors with the actual data.

Oily cakes are susceptible to oxidative and microbial spoilage due to their relative high levels of unsaturated fatty acids and moisture content. Plant extracts have a good antimicrobial and antioxidant potential. However, bioactive compounds of these extract are unstable in processing and storage conditions. Encapsulation technique is considered as one of the best strategies to overcome this challenge. Therefore, the aim of this study was to investigate the efficacy of free and encapsulated extract of Butcher’s broom (Ruscus hyrcanus L.) leaves (0.7% w/w) in retarding physicochemical, microbial and sensory spoilage of oily cake during 45 days storage at 23±3˚C. The results show that the moisture content of treated cakes with Butcher’s broom extract was significantly higher than control ones (P < 0.05). At the end of storage, the lowest total color difference (ΔE) value was recorded for treated with encapsulated extract (9.4). The Butcher’s broom extract showed a significant antifungal and antioxidant potential. The lowest yeasts and mold counts, free fatty acid and peroxide value was obtained in cakes contained microparticles. The total sensory score of samples treated with encapsulated extract was higher than 3 (threshold acceptable limit) for around 40 days. While this time was 15 days for control samples. The shelf-life of oily cakes containing free and encapsulated was 1.8 and 2.3 times of control samples, respectively. Overall, encapsulation of Butcher’s broom extract with maltodextrin/gum arabic (50:50) is recommended to improved shelf-life of oily cake itsby protection effects against chemical and microbial degradation.

Mentha piperita L., known as mint or peppermint used extensively in the food, pharmaceutical, and cosmetics industries. Although different techniques have been studied for drying mint leaves, there is not enough information on solar drying of peppermint (especially the Persian variety) in the literature. In this study, thin layers of peppermint leaves were dehydrated evenly with three methods of shade (MI), sun (MII), and solar heat collector (MIII). The air temperature rise and drying time in I, II, and III were (1, 5, and 18ºC) and (880, 300, and 150 min), respectively. The particle size, porosity, and rehydration rate of peppermint dried in III were significantly higher than those dried with I and II. While the overall color (∆E) of peppermint dried in I and III did not change, the greenish index and chlorophyll of peppermint dried in II were ~21% and ~15% less than those in III because it was exposed to direct sunlight radiation. The peppermint dried with III had lower bulk density, higher sensory attributes (minty aroma, flavor, cooling mouthfeel, and visual color), and overall acceptance scores than II and I. The solar dryer produced high quality dehydrated peppermint with renewable energy and without environmental contamination.

One of the most popular nuts in Iran is Pistachio (Pistachia vera L.). This nut is used as a food additive due to its high and uniquenutritional properties. Postharvest operations such as handling, cleaning, packaging and storing conditions have considerable effects on sensory attributes, the nutraceutical benefits, and shelf-life. Therefore, this research aims to predict the EMC of ground pistachio nut (GPN) undergoing 20oC storage based on two key criteria [i.e. T and ERH= (aw×100)] and application of the intelligent system of fuzzy logic.

The fuzzy logic model (FLM) was used to foresee of the EMCs (ads. /des.) behavior of GPN. First, the data obtained for EMC were run in MATLAB software & the fuzzy logic package was applied for EMC modeling of GPN. The variables were divided into two groups: inlet including storage temperature and water activity (aw) and outlet is EMCs. Next, effective verbal variables were defined for both dependent and independent variables.

The FLM could predict EMCs (ads. /des.) of GPN with an R 2 value equal to 0.9959 and 0.9869, respectively

Totally, the obtained results of present study are operational by workstations of GPN producer & theirplants to control the shelflife.

Pistachio nut is one of the main Iranian non-oil exporting goods. Due to the importance of drying method to prevent of the quality properties of product from pistachio kernel and also utilizing renewable sources of energy, a solar dryer equipped with air recycle system was designed and fabricated, and its results were compared with traditional drying method (exposing to direct sunlight). Fresh Kalle-Ghuchi variety whole Pistachio was purchased daily from one of the gardens of Sabzevar County. To test the solar dryer, daily data recording was conducted from 9:00 AM to 15:00 PM. Some quality properties of dried pistachio such as shrinkage, moisture content, color indexes and sensory attribute were measured and evaluated. The results indicated that the solar drying method reduced the drying time by 31.57% compared to the traditional method. Investigation of quality properties showed that solar dried pistachio nut in air recycle mode had the lowest shrinkage, moisture content and color change. Also the results illustrated that the traditional method had the highest score in roasting index. Overall, according to Iran’s high potential of solar energy, using it for drying agriculture crops, especially pistachio nut, is recommended and emphasized.