فهرست مطالب مسعود حبیبی نجفی

Passive packaging has an almost neutral mechanism in dealing with external and internal packaging factors such as gas penetration, cellular respiration and gas production, water loss or gain, ethylene production, production of oxidation compounds and possibly microbial contamination of food. While active packaging, by changing the packaging conditions, increases the shelf life of packaged food and improves its safety and sensory characteristics, while maintaining the quality of food. Among the types of active packaging applications, antimicrobial packaging is one of the most common technological applications of active packaging. Antimicrobial packaging is a system that is able to destroy or inhibit the growth of microorganisms and thereby increases the shelf life and safety level of food products. In antimicrobial packaging, the activity of an antimicrobial agent is carried out through the contact of the microorganism with the inner surface of the packaging material or the gradual release of the antimicrobial agent from the packaging material to the food. The controlled release of antimicrobial substances during the shelf life of food improves the safety of food and increases its shelf life. Antimicrobial substances increase the shelf life of food products by slowing down the growth rate and prolonging the lag phase of microorganisms or by inactivating and destroying them. Antimicrobial agents may be of natural or unnatural origin. The origin of natural antimicrobial substances can be plant, animal or microbial. In the design of antimicrobial systems, in addition to the characteristics of antimicrobial substances, the methods of adding antimicrobial substances, their penetration and evaporation, and many other factors such as the resistance of microorganisms, controlled release, release mechanisms, the chemical nature of antimicrobial substances and Foodstuffs, storage and distribution conditions, physical and mechanical properties of antimicrobial packaging materials, organoleptic properties and toxicity of antimicrobial materials should also be taken into consideration.

The bleaching process is important in the refining operation of edible oils. In this study, bleaching parameters were changed to evaluate the best condition for optimizing of bleaching in corn and sunflower oils. For this purpose, the effect of time (15, 25, 35, 45, and 55 min), temperature (80, 90, 100, 110, and 120 °C), and bleaching clay concentration (0.4, 0.6, 0.8, 1, and 1.2%) was evaluated using response surface methodology as statistical design in 5 levels by Central composite design with the aim of reducing the consumption of bleaching clay. The studied factors were including carotenoids, sterols, tocopherols, pigment and cations. After optimization, the best conditions for bleaching of corn and sunflower oils was different. For corn oil, the best conditions was time 39.59 min, temperature 103.61 °C, and bleaching clay concentration 1%, which meet 67% of our expectations. For sunflower oil with the aim of reducing the consumption of bleaching clay, the best conditions were time 37.49 min, temperature 97.53 °C and bleaching clay concentration 1%, which satisfied 70% of our expectations. The practical results did not show any significant differences with obtained theory values ​​using response surface methodology and confirmed these results.

One of the most important steps in the refining process for edible oils is the coloring step. Decolorization is an absorption process that involves the use of acid-activated clay to remove undesirable components of oil. Therefore, it is necessary to optimize the parameters of decolorization, mainly temperature, time and concentration of decolorizing soil in order to prevent adverse changes of the oil in the next stages and during storage. In this research, corn oil was selected and the effect of changing the dyeing parameters on the chemical properties of the oil was studied in order to optimize the process. For this purpose, the effect of time (15, 25, 35, 45 and 55 minutes), temperature (80, 90, 100, 110 and 120 degrees Celsius) and the concentration of soil-dye remover (0.4, 0.6, 0.8) , 1 and 1.2 percent) was investigated using the statistical design of the response level in 5 levels by the Central Composite Design method with the aim of reducing the consumption of soil-dye remover. The effect of decolorization parameters on oxidative stability (peroxide number, anisidine number, totox number, free fatty acid amount, Rancimet test and specific absorption at 232 nm and 270 nm), decolorization efficiency (carotenoid amount) and bioactive compounds (sterols amount) in Corn oil was studied. The results showed that after optimizing the best conditions for the decolorization stage in corn oil in order to minimize impurities, preserve bioactive compounds, and minimize the consumption of decolorizing soil, the time of decolorization was 35.59 minutes, the temperature was 103.61 degrees Celsius, and the soil concentration The dye was 1%, which was able to meet 57% of expectations. The practical results did not show any significant differences with the theoretical values ​​and confirmed these results.

In this study, the antibacterial effect of eucalyptus extract on different bacteria showed that the bulk of compounds present in the sap of eucalyptus leaves were formed by the phenolic compounds. starch was prepared for the production of starch film was used to improve the quality of film by 10 % of the volume of glycerol. ground beef production was evaluated by adding 0.5 and 1.5 percent of eucalyptus oil to the film, then ground mutton meat was packed with film, and microbial and chemical properties and transparency of meat after preservation in the fridge were studied in times 1, 3 and 6 days. according to the results, inhibition of DPPH increased with an increase in the amount of extract and the highest percentage was reported on day 3. also the results of TBA with a decrease in the amount of extract decreased and the maximum reduction rate was reported on day 3. according to the results, the total population count of microorganisms decreased with an increase in the amount of extract and the maximum reduction rate was reported on day 3, but did not have significant differences with the sample count on the day 6 with the spread of corruption. (P> 0.05) is based on the results that Staphylococcus aureus has decreased by increasing the amount of extract and the maximum reduction rate is reported on day 3. However, on the day 3 at 0.5 %  extract , its extracts and on the day 6 with the spread of corruption, the number of samples did not show significant differences. according to the results, the amount of transparency and color spectrum decreased with the increase of the extract and had significant differences with the sample. (p < 0.05)