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 In this research, the effect of microwave pre-treatment on qualitative characteristics and sensory properties of air-dried potato sticks was investigated. Different powers (180-900W) and times (1-5 minutes) of microwave were used before air-drying of samples. The moisture content, rehydration, shrinkage, browning, colour indices and sensory properties (taste, colour, shape, strength, and total acceptance) of potato samples were evaluated after the drying process and the response surface method (RSM) was used to determine the optimal conditions for the microwave ‌ pre-treatment. Used for the highest levels of physicochemical and sensory properties. ‌The results showed that, with increasing the power and time of the microwave oven resulted in an increase in the moisture content, shrinkage, rehydration and total colour change of the samples. Sensory evaluation results showed that in the microwave pre-treatment, only the scores of the taste and colour of potato samples were influenced by the microwave power and time. According to the results of optimization by the surface response method, the power of 180 Watts and the time of 3.5 minutes for the microwave pre-treatment were introduced as optimum conditions.
 

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Dairy products fortified with minerals and vitamins play an important role in the development of functional foods. Among lactic acid bacteria, yogurt starters have a special role in the industry, and their health-promoting function has been confirmed. The long duration of fermentation time by lactic acid bacteria in dairy products, takes time and energy and leads to increased production costs. Therefore, the identification of appropriate conditions and factors affecting the growth of different strains are the basic necessities of production. Hence, in this research, the effect of adding manganese sulfate (0, 0.006 and 0.03%) and vitamin B₁₂ (0 and 0.5 ppm) alone as well as their combination on the physicochemical, textural, and sensory properties of fermented milk produced in the presence of Lactobacillus bulgaricus subsp. Delbrueckii and Lactobacillus acidophilus La-5 were investigated. The results showed a decrease in pH and an increase in acidity during the storage period. The L* and b* index decreased and the values ​​of a* increased during the storage period (P<0.05). Also, textural characteristics and syneresis rate in samples containing 0.006% manganese sulfate and 0.5 ppm of vitamin B₁₂ alone and their combination treatment, containing 0.006% manganese sulfate+0.5 ppm vitamin B₁₂ were significantly improved (P<0.05). As the storage time proceeded, the sour taste of samples enriched with vitamin B₁₂ and manganese increased (P<0.05). While the off-odor and off-taste were not felt in these samples. Also, storage time had no significant effect on these sensory characteristics (P˃0.05).

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Gelatin is mainly produced by collagen denaturation. Gelatin obtained from cold-water fish has low sol-gel transition temperatures. Chemical and physical treatments can be used to modify the gelatin network by establishing cross-links between the gelatin chains to improve the properties of the gel. In this study, cross-linking in cold-water fish gelatin-based hydrogels was established by tannic acid (TA) and caffeic acid (CA), each at concentrations of 1, 3 and 5%. The effect of CA and TA concentrations on the physicochemical properties of gelatin hydrogels was investigated. The strength of the gel and the degree of crosslinking increased with increasing the concentration of tannic acid from 1 to 3%, which increased the strength of the gel from 325.00 to 343.62 N/mm² and the degree of crosslinking from 82.01 to 84.99%. At higher levels of tannic acid, a decrease in gel strength and degree of crosslinking was observed 301.90 N/mm² and 75.48%, respectively. However, these properties of hydrogels increased steadily with increasing levels of caffeic acid (p <0.05). The swelling rate also decreased due to the combination of different levels of tannic acid and caffeic acid. The maximum swelling rate for the control was 1732.30% and the minimum swelling rate for 3% tannic acid was 594.79%. The crosslinked gelatins by tannic acid significantly improved the denaturation temperature and their thermal stability was higher than that of caffeic acid. This temperature was 89° C in untreated hydrogels and increased to 94 °C and 98 °C in caffeic acid and tannic acid treated hydrogels, respectively. Scanning electron microscopy images of the hydrogel samples showed that the structure of the hydrogels based on cold-water fish gelatin was spongy. The addition of crosslinking agents only slightly reduced the pore size of the gelatin and had no significant effect.

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The objective of this study was to investigate the synergistic effect of nano titanium dioxide (TiO2-N) and Mentha piperita essential oil (MEO) on the equilibrum moisture sorption isotherm and microbial growth rate of Staphylococcus aureus of cassava starch film. For this purpose, cassava starch biocomposite film with the addition of 1, 3 and 5% TiO2-N and 1, 2 and 3% MEO, and glycerol as a plasticizer were obtained by the casting method. The equilibrium moisture absorption isotherm and antibacterial activity of prepared nanobiocomposite films against Staphylococcus aureus were examined. The obtained results demonstrated that by addition of nanoparticles and essential oil to the starch biocomposites, the equilibrium moisture absorption isotherm curve was shifted to lower moisture content. The microbial tests stated that the pure cassava starch film (control) showed no antibacterial activity against the Staphylococcus aureus and the antibacterial activity significantly increased with increasing concentration of both TiO2-N and MEO in the starch films (p<0.05). However, the antibacterial activity of TiO2-N nanoparticles was higher than MEO. Addition of TiO2-N and MEO increased lag phase and decreased log phase in microbial growth curve. Finally, according to the obtained results in this study, it can be concluded that incorporation of TiO2-N and MEO combination improved the antibacterial activity of cassava starch biocomposites against Staphylococcus aureus and these bionanocomposite films can be used for packaging and extending the shelf life of food products.

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Vegetables have a short shelf life, and because they are eaten fresh, it is necessary to use healthy and natural methods to increase their shelf life. The present study has investigated the effect of active packaging containing the active ingredient of thymol on the color and pH measurements, microbial evaluation, total mold and yeast count, and the sensory properties of seasonal salad during six-day storage refrigerator temperature. For this purpose, seasonal salads were packed with oriented polypropylene (OPP) and low-density polyethylene (LDPE) films immersed in thymol essential oil for 1, 2, and 3 days. Results show that season salads packed with OPP and LDPE films immersed in thymol essential oil for three days had higher pH and lower mold and yeast count than control and other treatments. The mold and yeast count were significantly lower (p < 0.05) in a sample packed with OPP films containing essential oil compared to the LDPE/ thymol essential oil. The L* and a*values decreased during storage time. The L* and -a * indices of season salads were lower in OPP and LDPE films immersed in thymol essential oil for three days than the neat and other groups. Sensory evaluation showed that immersion in thymol essential oil improved sensory attributes (p <0.05).  The coated films, especially OPP, improved the color, reduced the number of mold and yeast, increased the shelf life, and improved the sensory attributes of seasonal salads. Therefore, films treated with thymol essential oil can act as active packaging.

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Celiac disease is a long-term autoimmune disorder that primarily affects the small intestine  and occurs in susceptible individuals by gluten intake. The basis of treatment for celiac disease is a gluten-free diet. The production of gluten-free breads, as a constant part of the diet of patients with celiac disease, can have a significant impact on the prevention of complications from the disease for patients with it. In this study, the possibility of producing gluten-free bread with the desired quality and high nutritional value was investigated using lactic sourdough.  In order to make lactic acid paste, Lactobacillus plantarum DSM20179 microorganism was used as a starter strain and its use in the production of gluten-free bread with corn and rice flour was investigated at two levels of 5 and 10%. Physicochemical experiments performed on bread. These included pH measurement, total acidity (TTA), humidity, tissue measurement, ash content, color changes and general counting of mold and yeast in bread samples. Each treatment was performed in three replications and the results were statistically analyzed.  The overall result of this study confirmed the importance of producing rich bread prepared with 5 and 10% lactic yeast with a favorable effect on the sensory and rheological characteristics of bread. in general the results showed that increasing the percentage of dough makes the samples more acceptable.
Keywords:  Corn sourdough lactic acid, Lactobacillus Plantarum, Celiac Bread

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Today, biodegradable packaging materials have received a great deal of attention due to growing concerns about non-degradable materials; Therefore, the aim of this study was to investigate the effect of betanine pigment on surfaces (0, 2/5, 5 W/V%) and CuO nanoparticles on surfaces (0, 2, 4 W/V%) in nanocomposite film based on whey protein isolated / pectin in the form of a central composite design on the mechanical properties and physicochemical properties of the film is produced. The results showed that with increasing the percentage of betanine pigment and CuO nanoparticles, the thickness and moisture of the samples increased and the solubility decreased (P­<0.05). Also, by adding high levels of betanin pigment, redness (a) increased and brightness (L) and yellowing (b) of the samples decreased. Addition of nanoparticles decreased b value while it had no significant effect on a value of the samples. Also, by adding pigments and nanoparticles, tensile strength and elongation of film samples increased significantly (P <0.05). According to all the results, the use of CuO nanoparticles and betanine pigment in nanocomposite film leads to the production of a film suitable for food packaging with desirable physicochemical and mechanical properties.

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The aim of this study was to prepare an active film based on polyethylene containing thymol and linalool (%0, 1, 1.5, 2) and use it as packaging in mozzarella cheese. For this purpose, the mechanical and barrier properties of the polyethylene films containing thymol and linalool were analyzed. The results showed that the use of thymol and linalool did not significantly reduce the oxygen permeability of the polyethylene film(p < 0.05). Water vapour permeability was significantly decreased by incorporating linalool and thymol ( 1.5, 2%). Tensile strength and elongation at break were significantly lower (p < 0.05) in polyethylene films containing thymol and linalool than in the control sample. Results show that mozzarella packed with polyethylene films containing thymol and linalool had higher pH and lower acidity than the control sample. The sensory analysis results revealed that coated cheese with polyethylene composed of linalool(1.5%) and thymol 2% was the most attention by panellists compared with others. Based on the results,  films containing thymol and linalool improved the chemical and sensory properties of mozzarella cheese. Therefore, films treated with thymol and linalool can act as active packaging.