دکتر علیرضا صادقی

The aim of the current research was microencapsulation of Streptococcus thermophilus and Lactobacillus bulgaricus bacteria by coacervation complex method and sodium caseinate and pectin coatings. Sodium caseinate and pectin have electrostatic attraction together at pH=4 and form a complex. Using a scanning electron microscope, the morphology of coacervates was investigated. The properties of pectin and sodium caseinate complexes were investigated by infrared spectrometry tests and measuring the size and distribution of particles. Physicochemical characteristics such as water absorption, pH and acidity and sensory characteristics were also investigated. The results showed that the efficiency of microencapsulation of bacteria by coacervation method was 66.6%. The particle size was 1.565 micrometers and the zeta potential was reported as -16 mV. Electron microscope images showed spherical coacervate without holes and wrinkles on the surface. The results of infrared spectroscopy also showed the creation of electrostatic interactions between pectin and sodium caseinate. Also, microencapsulation of bacteria caused a significant change (p>0.05) in pH (4.6 ± 0.091) and yogurt acidity (1.1 ± 0.03) compared to pH (4.6 ± 0.1). And the acidity of yogurt (0.8±0.01) produced with free bacteria did not. The water content of yogurts produced with microencapsulated bacteria (40±1.1) was reduced compared to yogurts produced with free bacteria (45±0.9) (p<0.05). Bacterial encapsulation has a negative effect on color sensory characteristics. It did not have the smell and taste of the produced yogurts (p>0/05), but a significant difference was observed in the texture of the yogurts produced with microencapsulated bacteria compared to the yogurts produced with free bacteria (p<0/05).

Simultaneous application of modern baking methods with fermented substrates is of great importance in controlling bread mouldiness. In the present study, predominant LAB was isolated from rice bran sourdough and after molecular identification, it was used as a starter culture in sourdough bread processing. In the next step, effect of using oven-infrared radiation, oven-supersaturated vapor and oven baking systems was investigated on the inhibition of surface mouldiness in produced breads. Sequencing results of the PCR products led to the identification of Pediococcus acidilactici. The lowest level of surface mouldiness with 27.06% was observed in bread containing controlled fermented rice bran baked in an oven-supersaturated vapor, which was significantly (P≤0.05) lower than the control sample. Wheat breads containing rice bran sourdough in all the three baking processes had less fungal surface expansion and more porosity, compared to the control bread. The highest amount of crumb hardness was belonged to wheat bread containing controlled fermented rice bran and baked with oven-supersaturated vapor, and the lowest hardness was related to the control bread baked with this process. The overall acceptability of the produced breads did not differ much from each other, and there was mainly no significant difference among them. Considering the appropriate techno-functional capabilities of the LAB isolated from fermented rice bran, it can be used as a protective starter culture in the fermentation industry. Using the infrared process in bread baking can be useful due to the relatively high baking speed and low energy consumption, antifungal effect and uniform heating.

Production of probiotic (PRO) cereal-based products is an important strategy to increase consumption amounts of these beneficial microorganisms in our daily diet worldwide. In the present study, textural features, sensory properties and viability of an adjunct PRO culture were determined in supplemented cupcake with fermented black rice (FBR) and coated with malt. Based on the obtained results, survival of the PRO yeast in malt edible coating reached to 106 CFU/g after 6 days of storage in cupcake samples supplemented with FBR. In addition, crumb hardness (1529.77 g) and gumminess (962.14) of the produced cupcake supplemented with FBR were significantly (P<0.05) higher than those of the control sample. Meanwhile, proper porosity and overall acceptability were observed for the aforementioned FBR added cupcake. Accordingly, application of a potential PRO yeast via malt coating as a proper carrier can maintain viability of this adjunct culture during shelf-life period of the product in the recommended dose for PRO products. Considering the health-promoting potentials of PRO and consumed amounts of cupcake, it is a good choice to consume a high dose of PRO in our today’s diet style.

Wheat bread is a staple food worldwide, and bread making using sourdough is one of the oldest technologies. In this regard, the use of legume sourdough is important in improving the quality of wheat bread. Sprouted legumes are also proper substrates rich in bioactive compounds for sourdough fermentation to produce enriched products. Furthermore, application of herbal extracts in sourdough formulation is a simple way to enhance organoleptic properties and mold-free shelf-life of the produced sourdough bread. Considering positive effects of sourdough on techno-functional properties of the produced bread, the aim of the present study was to enhance quality parameters of wheat bread using controlled fermented sprouted lentil containing fennel extract.

In the present study, predominant lactic acid bacteria (LAB) were isolated using the sequential back-slopping process from fermented sprouted lentil containing fennel extract.  The isolates were screened based on their antifungal activities against Aspergillus niger. The selected isolates were identified through amplification of the target sequence with 1500 bp from its 16S rDNA gene and sequencing of the PCR products. After that, controlled fermentation containing selected LAB isolates (as a starter culture) was performed in processing of wheat bread. Crumb hardness, specific volume, water activity, overall acceptability and surface growth rate of the target fungus were compared in the produced breads. In order to determine the effects of the substrate, fermentation and germination, suitable samples were produced. The results of the present study were also analyzed in a completely randomized design with three replications, and Duncan test at P<0.05 significant difference was used to compare the mean.

Sequencing results of the PCR products (amplicons) led to the identification of Pediococcus acidilactici as the selected LAB isolate. Addition of lentil sourdough to wheat bread significantly (P<0.05) reduced the weight loss and crumb hardness of wheat bread and also increased its specific volume without significant effect. Among the produced breads, the lowest specific volume was belonged to the sample containing lentil and the highest specific volume was observed in the control sample. Moreover, fermentation and sprouting reduced the surface growth of A. niger in the produced breads. The surface growth rate of the fungus in the bread containing fermented sprouted lentil was also significantly lower than those of the control sample. In addition, wheat bread containing fermented sprouted lentil received the highest overall acceptability score among the produced enriched breads. It is reported that the positive effects of controlled sourdough on textural features of the produced bread are mainly associated with the acidification activity of the starter culture used. Production of organic acids and other inhibitory metabolites by the sourdough starter culture is also involved in its antifungal activity in the product. Moreover, production of volatile and non-volatile aroma precursors during sourdough fermentation affect sensory attributes of the sourdough bread.   

Nowadays, consumer demand for healthy products with minimal processing and with no synthetic additives such as clean-label foods, and the use of bio-preservatives (application of microorganisms and their metabolites to prevent spoilage and increase the shelf-life of the product) has become a growing trend. Application of legumes as a good source of protein, other nutrients and essential components in bread formulation is important for their use in the daily diet. According to the results of the present study, controlled fermented sprouted lentil containing fennel extract can be used as an antifungal compound and texture improver in bakery industries. Overall, the use of plant extracts with antifungal effects as well as controlled fermentation of sourdough with selected LAB as protective/starter culture can reduce the use of chemical preservatives in bread.

Cake is one of the products consumed by the baking industry, which has an important place among people due to its change in taste and appearance, long shelf life (about 4 weeks) and ease of consumption. Normally, this product is produced with wheat flour that contains gluten. Gluten is a combination of food products found in some grains, such as gliadins and glutenins in wheat, hordins in barley, and secolins in rye, which causes an immunological reaction in celiac patients. Today, the only way to treat this disease is to use a gluten-free diet throughout the patient's life. a gluten-free diet prohibits the consumption of bread, cereals or other foods made from wheat, barley, oat, rye and triticale flour. For this purpose, gluten-free cereals (rice, millet, sorghum and corn) and pseudo-cereals (quinoa, buckwheat and amaranth) can be used in the production of gluten-free products. In the process of rice milling to prepare white rice, a significant part of its minerals and fiber is lost, in the preparation of gluten-free products based on rice flour, the flour of other cereals, the flour of some legumes, or permitted additives should be used so that the resulting product is Nutrients have a good balance and meet the needs of celiac patients, also in rice-based products, compared to wheat-based products, the technological quality is lower due to the lack of proteins forming the viscoelastic network of gluten. producing and improving the characteristics of gluten-free products for celiac patients is one of the most important challenges in the food industry. For this reason, the aim of this study was to investigate effect of replacement of rice flour with raw and sprouted mung bean flours in order to improve the physicochemical characteristics of gluten-free cake and dough. Mung beans with the scientific name Vigna radiate is an annual plant belonging to the Fabaceae family and is a cheap and convenient source of protein, minerals and vitamins and belongs to the group of gluten-free legumes. Whole mung bean contains several anti-nutritional factors such as saponin, phytic acid and tannin. Sprouting is a conventional and inexpensive way to improve the nutritional properties of legumes, and during this process, a significant part of these factors removed. During germination, which is a natural process during seed growth, the stored compounds that are usually used for respiration and the synthesis of new cells before the growth of the embryo are destroyed and complex biochemical and physiological reactions occur that cause extensive changes in the composition or morphology of the beans. In the present study, the effect of 4 levels of raw and sprouted mung beans (5, 10, 15 and 20%) on the specific weight and consistency of the cake batter, as well as the volume and porosity, moisture and textural features of the gluten-free cake based on rice flour in a completely randomized design with 9 treatments were investigated. The results of analysis of variance showed that the use of whole and sprouted mung bean flour in the cake formulation led to a significant decrease (P<0.05) in the specific weight of the dough compared to the control sample, which could be due to the trapping of more air bubbles in the cake dough. The highest specific weight was related to the control sample and the lowest specific weight was related to TM15 treatment. The addition of sprouted mung bean flour at different replacement levels caused a significant (P<0.05) increase in dough consistency compared to the control sample containing 100% rice flour, and this increase was more significant when 20% of sprouted mung bean flour was used. Also, the addition of whole mung bean flour to the formulation caused a significant increase in the consistency of cake batter compared to the control sample, but the use of 15% and 20% levels of whole mung bean flour was not significantly different from each other. The reason for increasing the consistency of cake batter can be attributed to the increase in water absorption capacity and water trapping and connection with the protein network of batter flour, which leads to a decrease in their mobility. On the other hand, the presence of more protein in whole and sprouted mung bean flour can be another reason for increasing the dough consistency of cakes containing mung bean flour compared to the control sample. By examining the results of the effect of adding whole and sprouted mung bean flour on the cake volume index, it was found that the samples containing whole and sprouted mung bean flour increased this component at a significant level (P<0.05) compared to the control sample, the reason for which can probably be The high amount of protein in mung beans and the subsequent increase in the creation of protein networks as well as the improvement of protein network formation due to the increase in mung bean flour proteins and the increase in gas retention were attributed. The lowest specific volume related to the control sample and also the cake containing 20% sprouted mung bean flour had the highest specific volume compared to other samples. The improvement of the specific volume in these treatments can be related to the increase in the consistency and viscosity of the cake batter, and these changes increase the entry of air bubbles into the cake batter during mixing, as well as the storage capacity of the air bubbles inside the cake during baking. The results of the effect of adding raw and sprouted mung bean flour in the rice-based gluten-free cake formulation showed that the control sample had the lowest porosity and the TS20 treatment, which contains the highest amount of sprouted mung bean flour, had the highest porosity. The porosity of the treatments when sprouted mung bean flour was used was more than the porosity of the samples that used raw mung bean flour. The reason for this can be attributed to the amount of protein of mung bean flour combined with rice flour, which by increasing it to a certain amount, causes the stability of gas cells and delay in staleness. Also, the increase in porosity can be due to the decrease in size and increase in the number of gas cells and its uniform distribution in the product texture. in the present study, a direct relationship between volume and porosity was observed. on the baking day, the moisture content of the cake core increased significantly (P<0.05) when using sprouted mung bean flour at levels of 5-20% and whole mung bean flour at levels of 15 and 20% compared to the sample prepared from 100% rice flour. The sample prepared from the TS20 treatment had a higher moisture content than the other sprouted and whole mung bean flour treatments. Most of the changes were significant until the third day, and on the seventh day of storage, the moisture content of the samples decreased slightly, and as in the previous two days, the TS20 treatment sample had the highest moisture content. The increase in moisture content of cakes containing mung bean flour can probably be due to the absorption of more water and the ability to maintain more moisture of mung bean flour than rice flour. the cake core hardness of all samples increased with increasing storage time. The decrease in moisture and the easier migration of moisture from the core of the cake to the cake shell as a result of the absence of gluten is the main cause of staleness in gluten-free products. According to the results obtained from the hardness of the cake core texture on the same day of baking, it was found that increasing the amount of mung bean flour (raw and sprouted) reduces the hardness of the cake texture. The highest hardness on the day of cooking was related to the control treatment, which had a significant difference (P<0.05) with other treatments, and the lowest hardness was related to the TS20 treatment. The decrease in hardness in cakes prepared with rice and mung bean flour with increasing mung bean ratio is probably because the contents of fiber, lipids and proteins, by affecting gelatinization and staleness, cause a decrease in hardness. As a result, the results of this study showed that the use of sprouted mung bean flour has the potential to improve the quality characteristics of gluten-free batter and cake samples. In this way, to increase consumer demand for products without artificial additives, the use of sprouted mung bean flour can improve the quality of gluten-free products. According to the results of this study, the use of 20% sprouted mung bean flour can improve the quality of gluten-free products.

ß-galactosidases are enzymes of the glycoside hydrolase family EC (3.2.1.23) that catalyze the hydrolysis of some disaccharides with wide applications in the food industry. Also, some ß-galactosidases have transgalactosylation activity. This study aimed to isolate ß-galactosidase-producing fungi from several traditional cheese and whey samples and to determine the enzymatic activity under the various conditions (temperature, time, pH, and different cations).

Yeasts and molds were isolated and screened for the ability to produce beta-galactosidase by a chromogenic test containing 5-bromo-4-chloro-3-indolyl-Beta-D-galacto-pyranoside (X-gal) in the media. After screening, the most promising isolated molds and yeasts were identified genotypically by ITS rDNA sequencing. Then, the hydrolytic activity of crude beta-galactosidase was evaluated using ortho-Nitrophenyl-β-galactoside (ONPG) as the substrate under different conditions (different levels of temperature, time, pH, and various cations Mn2+, Mg2+, Zn2+, Cu2+). Finally, the possibility of transgalactosylation activity of the selected enzyme was investigated.

The results of PCR product sequencing resulted in the identification of isolates MM24, MT12, and MW14 as Kluyveromyces lactis H1-3 (99.57%), Kluyveromyces lactis E3 (97.53%), and Penicillium brevicompactum (100%), respectively. Investigating the activity of ß-galactosidase produced by MM24, MT12, and MW14 isolates showed a higher activity for the crude enzyme from K. lactis MM24. Moreover, the highest activity was found at 37°C, pH 7, and 30 min reaction time. Different cations did not significantly influence the enzymatic activity at 0.1 and 1mM, however it was completely inhibited against Cu+2 and Zn+2 at 10 Mm. Furthermore, 10 mM Mn+2 and Ca+2 inhibited enzymatic activity by about 80% and 65%, respectively. High-performance liquid chromatography (HPLC) analysis confirmed ß-galactosidase activity on lactose, whereas no transgalactosylation activity was observed in this study.

Overall, K. lactis MM24 isolated in the current study can be considered as a new isolate for ß-galactosidase production.

ß-galactosidases are enzymes of the glycoside hydrolase family EC (3.2.1.23) that catalyze the hydrolysis of some disaccharides with wide applications in the food industry. Also, some ß-galactosidases have transgalactosylation activity. This study aimed to isolate ß-galactosidase-producing fungi from several traditional cheese and whey samples and to determine the enzymatic activity under the various conditions (temperature, time, pH, and different cations).

Yeasts and molds were isolated and screened for the ability to produce beta-galactosidase by a chromogenic test containing 5-bromo-4-chloro-3-indolyl-Beta-D-galacto-pyranoside (X-gal) in the media. After screening, the most promising isolated molds and yeasts were identified genotypically by ITS rDNA sequencing. Then, the hydrolytic activity of crude beta-galactosidase was evaluated using ortho-Nitrophenyl-β-galactoside (ONPG) as the substrate under different conditions (different levels of temperature, time, pH, and various cations Mn2+, Mg2+, Zn2+, Cu2+). Finally, the possibility of transgalactosylation activity of the selected enzyme was investigated.

The results of PCR product sequencing resulted in the identification of isolates MM24, MT12, and MW14 as Kluyveromyces lactis H1-3 (99.57%), Kluyveromyces lactis E3 (97.53%), and Penicillium brevicompactum (100%), respectively. Investigating the activity of ß-galactosidase produced by MM24, MT12, and MW14 isolates showed a higher activity for the crude enzyme from K. lactis MM24. Moreover, the highest activity was found at 37°C, pH 7, and 30 min reaction time. Different cations did not significantly influence the enzymatic activity at 0.1 and 1mM, however it was completely inhibited against Cu+2 and Zn+2 at 10 Mm. Furthermore, 10 mM Mn+2 and Ca+2 inhibited enzymatic activity by about 80% and 65%, respectively. High-performance liquid chromatography (HPLC) analysis confirmed ß-galactosidase activity on lactose, whereas no transgalactosylation activity was observed in this study.

Overall, K. lactis MM24 isolated in the current study can be considered as a new isolate for ß-galactosidase production.

The use of controlled fermented legumes along with the aqueous extract of aromatic plants is important in terms of improving the quality characteristics of wheat bread. In the present study, after spontaneous fermentation of mung bean sourdough containing saffron petal extract, the predominant lactic acid bacteria (LAB) isolate was used as a starter culture in controlled fermented sourdough, and then the characteristics of the produced wheat breads in terms of texture, surface expansion of fungi and overall acceptability were investigated. Sequencing results of PCR products led to the identification of Levilactobacillus brevis as the predominant LAB isolated from sourdough. Processing of wheat bread with mung bean sourdough containing mentioned bacteria and saffron petal extract not only improved the textural features and overall acceptability of the produced bread, but also increased their resistance towards the surface expansion of Aspergillus niger. Based on the results, wheat bread containing fermented mung bean and saffron petal extract showed the best textural features compared to other samples with crumb hardness of 10.21 N and porosity of 16.16%. Furthermore, the mentioned sample with 44.33% inhibition had the highest ability to inhibit the growth of the indicator fungus compared to other samples. Although the use of mung bean and saffron petal extract alone in the formulation of wheat bread did not show a great effect on reducing the surface expansion of fungi, but their combined application was significantly (P<0.05) effective in reducing the surface growth of fungus. Due to the appropriate techno-functional capabilities of controlled fermented mung bean sourdough containing saffron petal extract, it can be used as a natural improver in the bakery industries.

Probiotic and antifungal properties of the yeasts isolated from fermented pseudo cereals have been rarely studied, yet. In the present study, after isolation of predominant yeasts isolated from fermented black rice, the yeast with the highest survival in simulated gastrointestinal conditions was selected for further studies. Then, the selected isolate was identified by PCR, and subsequently, its probiotic properties including antibacterial effects, antibiotic and antimycotic susceptibilities, aggregation, hydrophobicity and hemolytic potentials were also studied. Antifungal activity of the selected yeast was investigated against some of the foodborne fungi. Sequencing of the PCR products led to the identification of Rhodotorula mucilaginosa as the selected yeast isolate. The isolate maintained 84.39% of its survival in continues acid and bile treatment. Also, the inhibitory effect of the yeast isolate on Salmonella enterica was significantly (p<0.05) higher than the other foodborne bacteria. Yeast isolate had proper aggregation and hydrophobicity capabilities, and it was resistant to the antibiotics tested. Furthermore, the most inhibition of the yeast growth was observed in the presence of ketoconazole, while the selected yeast was resistant to propionate, sorbate, itroconazole and fluconazole. The studied yeast isolate had no hemolytic activity. The antifungal effect of the yeast isolate against Aspergillus flavus was also verified. In accordance with these results, the selected yeast isolate has a proper potential to use as a probiotic or protective culture in production of fermented foods.

Among the types of heat exchangers, shell and tube heat exchangers are the most common heat exchange equipment. The energy efficiency of a heat exchanger can be increased by improving the heat transfer properties. Nanofluids are a Colloidal suspension of nanoparticles are in a base fluid.The nanoparticles used in nanofluids are usually made of metals, oxides, carbides, or carbon nanotubes. The heat transfer rate is affected by the thermophysical properties of the nanofluid, which increases with the increasing volume of nanoparticles in the base fluid. Nanofluid properties are affected by nanoparticle concentration, purity level, and variable structure. The main purpose of this paper is to provide an overview of the use of nanofluids in shell and tube heat exchangers to increase heat transfer coefficients and simulate the parameters affecting the flow and heat transfer to predict temperature distribution, velocity, and pressure drop in different parts of the heat exchanger.

In this study, Camsol multiphysicas simulation software version 6 was used to build a computational model of shell and tube heat exchanger to simulate temperature, velocity, and pressure drop changes in the heat exchanger. Hot nanofluid (353.15 ° K) enters the tube and water (298.15 ° K) enters the shell. The role of geometry parameters used on heat transfer rate has been investigated and presented. The temperature and total heat transfer characteristics of the pipe wall are calculated and designed for theoretical, experimental, and numerical methods using the K- ɛ heat transfer model.

By performing a computational fluid dynamics study, and calculating the desired values of each of the studied parameters, a good agreement was obtained between the computational fluid dynamics study and experimental results. The results of temperature, velocity, and pressure drop counters show that the addition of nanoparticles to the fluid can effectively increase the thermal conductivity of the fluid the temperature of the added nanoparticles are directly related to the thermal conductivity ratio. The velocity changes in the shell are very small and in most areas of the shell, the speed according to numerical calculations and according to the colored guide bar is about 0.05 meters per second, but at the points of collision of the current with the baffles and inlet and outlet values are different and between 0.15 to 0.2 meters. Is seconds. From the numerical results, it can be seen that the velocity values in the vicinity of the walls are very low, which is due to the strong friction gradient. Examining the temperature-related contours, it can be seen that the heat transfer is not uniform throughout the length of the exchanger and the decrease in temperature in the direction of flow is visible.

The use of alumina nanoparticles in the base fluid by 4% increased the average output temperature by 0.9 degrees in a passing cycle of the system, which increases more and more with the repetition of this cycle. According to the pressure drop contour, the pressure drop of nanofluids is much higher than the base fluid and the pressure drop increases with increasing the concentration of nanofluid.

Evaluation of probiotic properties of lactic acid bacteria (LAB) isolated from fermented pseudocereals has crucial importance to prepare microbial cultures. In the present study, after molecular identification, probiotic properties of the predominant LAB isolate were investigated. Sequencing results of the PCR products led to the identification of Lactobacillus brevis SKA01 as the predominant LAB. The survival of the LAB isolate after continues treatment of acid and bile reached to 106 compared to the control sample (108 CFU/mL), and it showed the highest antibacterial effect on Staphylococcus aureus. Meanwhile, there was no significant difference (P>0.05) between inhibitory zone diameter of the S. aureus and Listeria monocytogenes in the present of the LAB isolate.  LAB isolate was capable of good auto-aggregation (36.19%) and co-aggregation with S. aureus (71.24%), and it had no hemolytic activity. Furthermore, it was resistant to most of the tested antibiotics. By considering the proper probiotic potentials of the L. brevis isolated from fermented amaranth, it is possible to use the isolate as microbial starter or probiotic culture in fermentation industries.

Evaluation of antimicrobial and probiotic properties of the microbiota isolated from fermented pseudo-cereals is important in order to prepare adjunct and starter cultures. Probiotics are live and active microorganisms that, if used in sufficient numbers, help the microbial balance of the gastrointestinal tract and improve its function. Probiotics are also used as a substitute for antibiotics and synthetic preservatives in the prevention and treatment of complications of many infectious and pathogenic gastrointestinal pathogens. Probiotic microorganisms include lactic acid bacteria (LAB) and yeasts, and despite numerous reports on the probiotic properties of LAB, the probiotic properties of yeasts are less reported. Probiotic yeasts are organisms resistant to antibacterial compounds and effective against pathogens, which can rapidly increase their population in the gastrointestinal tract. These yeasts have several properties such as antimicrobial effects, resistance to acid and bile, binding to mucosal surfaces, inhibitory activity against pathogens and also the inability to transmit antibiotic resistance genes. In the present study, after isolation of the predominant yeast from buckwheat sourdough, the probiotic and antifungal properties of the isolate were investigated. Based on the literature review, no study has been presented to evaluate the probiotic and antifungal capabilities of yeasts isolated from buckwheat sourdough. 

In the present study, predominant yeast was isolated from buckwheat sourdough, and then it was identified using PCR. Subsequently, probiotic properties of the isolate including survival in present of low pH and bile salt, antibacterial effect, antibiotic susceptibility assay, aggregation, hydrophobicity, haemolytic activity as well as its antifungal activity against Aspergillus niger and Aspergillus flavus were studied. After spontaneous fermentation of buckwheat, predominant yeast was isolated using ten-fold dilution of the sourdough sample and its spread plating. The predominant isolate was identified through PCR amplification of a 650 bp target sequence from its ribosomal gene and sequencing of the PCR product. Then, survival of the yeast was determined at pH=2 and 0.3% bile salt as simulated gastrointestinal conditions. Subsequently, simultaneous culture of the yeast with some food-borne indicator bacteria in chromogenic media was used to investigate the inhibitory activity of the isolate against the studied bacteria. After that, resistance of the yeast isolate against the common antibiotics and some antimycotic agents was evaluated using disc method. Co-aggregation ability and hydrophobicity capability of the isolate were also determined based on the absorbance tests. In vitro safety of the yeast isolate was checked through its cultivation on blood agar containing sheep blood. Next stage, overlay bioassay was conducted to investigate antifungal effect of the yeast on the selected fungi. Finally, one way analysis of variance (ANOVA) with the least significant differences (LSD) post hock at p<0.05 was used for statistical analysis of the data. 

Sequencing results of the PCR products led to the identification of Pichia kudriavzevii as predominant yeast isolated from buckwheat sourdough. Survival rate of the isolate after treatment in simulated gastrointestinal conditions was 79.26% in comparison with the control. Antibacterial effect of the isolate on Escherichia coli was also significantly (P<0.05) higher than the other studied food-borne agents. Meanwhile, the growth of Listeria monocytogenes was decreased 19.50% in the present of the isolate. Whereas, the yeast isolate had no inhibitory effect on Salmonella enterica. Hydrophobicity and auto-aggregation capabilities of the isolate were also 64.07 and 67.40%, respectively. Furthermore, the isolate showed resistance towards all of the antibiotics tested, while it was resistant against ketoconazole and fluconazole, and the yeast was semi-sensitive towards itraconazole as antimycotic agents. The yeast isolate had no hemolytic activity, and its antifungal activity against A. niger and A. flavus was also verified. Accordingly, it is concluded that P. kudriavzevii isolate exhibits proper potential to be used as probiotic or protective culture in fermentation industries.In accordance with the results, probiotic characteristics of P. kudriavzevii (as the predominant yeast isolated from buckwheat sourdough) were approved. Accordingly, the isolate can be used as a potential probiotic culture in food industries.

Characterization of lactic acid bacteria (LAB) isolated from rarely studied fermentation substrates can lead to isolate unique microorganisms. In the present study, predominant LAB was isolated from fermented acorn using repeat of back-slopping process, and then the isolate was identified by PCR. Subsequently, probiotic properties of the isolate (including resistance to acid and bile, antibacterial, auto and co-aggregations, antibiotic susceptibility and blood hemolysis), as well as its antifungal effect were studied. Sequencing results of the PCR products led to the identification of Pediococcus acidilactis as predominant LAB isolate. The survival percentage of the isolate in continuous acid and bile treatment was equal to 72%. The inhibitory effect of the isolate on Bacillus cereus was also significantly (P<0.05) higher than the other foodborne indicator bacteria. Furthermore, crude cell free supernatant (CFS) obtained from LAB culture completely inhibit the growth of B. cereus; meanwhile, its naturalized CFS had no inhibitory effect on Salmonella enterica. LAB isolate had also proper auto and co-aggregation (with E. coli) potentials and had no hemolytic activity. Antifungal activity of the isolate against Aspergillus niger was also verified. By considering the proper probiotic and antifungal potentials of the P. acidilactis isolated from fermented acorn it is possible to use the isolate as microbial starter, adjunct, probiotic and or protective culture in fermentation industries.

Recently, the tendency to use probiotic-potential starter cultures among lactic acid bacteria (LAB) isolated from non-dairy fermented substrates has been increased. The aim of this study was to isolate and molecularly identify the predominant LAB isolated from fermented germinated clover seeds, and also to evaluate its probiotic and antifungal properties. The LAB isolate was identified as Pediococcus pentosaceus, in accordance with the sequencing results of the PCR products. The antifungal and antibacterial effect of the isolate on Aspergillus niger and Staphylococcus aureus was significantly (P <0.05) higher than the other studied foodborne fungi and bacteria. Furthermore, P. pentosaceus isolate had a good survival (77.22%) in simulated gastrointestinal conditions. The isolate had no hemolytic activity, and its auto-aggregation activity was 35.51%. Also, the rate of co-aggregation of the isolate with Escherichia coli and S. enterica was equal to 48.71% and 18.43%, respectively. In addition, the bacterium was sensitive to the penicillin, cephalothin, ampicillin and cefazolin antibiotics.Accordingly, it is possible to use the isolate as a probiotic culture with potential biological preservative in the food industry

The study of the yeasts isolated from the least studied fermented sources may have the potential to deal with the unique isolates. In this study, one of the predominant yeasts was isolated from fermented buckwheat. The isolate was identified by amplifying the target sequence of 650 bp of its ITS gene and sequencing PCR products. Afterward, some potential probiotic features of the isolates, including survival in simulated gastrointestinal conditions, antibacterial effect, auto-aggregation, antibiotic resistance, antimycotic and hemolysis ability, as well as antifungal activity against Aspergillus niger and Aspergillus flavus were studied. Based on sequencing results of the PCR products, Rhodotorula mucilaginosa was identified as the yeast isolate. The isolate had 85.07% viability in simulated gastrointestinal conditions. The inhibitory effect of the isolate on Escherichia coli was significantly (P<0.05) higher than the other foodborne bacteria. The yeast isolate had 84.60% auto-aggregation and 60.10% hydrophobicity capabilities. However, no hemolytic activity was observed. The yeast isolate was resistant to all of the studied antibiotics, and it was sensitive towards Ketoconazole among the common antifungal agents. In conclusion, the yeast isolate had appropriate potential to be used as a probiotic culture to produce fermented food products.

Bread is the main source of nutrients and it is a cheap staple food in the daily diet of people in many parts of the world. One of the most important ways to improve the quality of bread is to ferment cereals and use fruit resources. Cereal fermentation has a well-known potential to improve the nutritional properties of the baked goods. It stabilizes the levels of various bioactive compounds, retards starch retrogradation and increases mineral bioavailability. A diet rich in cereal and fruit-based products could improve human health. Oat grain has a high functional potential due to its composition. This grain is known to be an excellent source of dietary fiber, antioxidants and a well-balanced protein fraction. Jujube fruit is also getting popularized due to the high content of vitamins, phenolic, polysaccharides and natural colorant agents. The quality of available commercially jujube depends on the contents of its bioactive compounds and micronutrients. There is no report about simultaneous application of fermented oat and jujube powder in processing of wheat bread. Accordingly, the aims of this study were to produce a supplemented wheat bread containing these ingredients, and evaluate the textural and antioxidant properties of the product.   

In the present study, controlled fermented oat containing selected LAB isolated from oat sourdough (as starter culture) was used to produce supplemented wheat bread. Crumb hardness, porosity, specific volume, overall acceptability and antioxidant activity in wheat bread containing fermented oat, jujube powder and their mixture were investigated in comparison with the control (wheat bread). All the experiments were done in triplicates. A complete randomized design with the least significance difference (LSD) post-hock was also used to statistical analysis of the data at p < /em>< 0.05 by SPSS (version 20) software.  

The highest amount of crumb hardness was observed in the sample containing mixture of controlled fermented oat and jujube powder, meanwhile the lowest amount of hardness was belonged to the control sample. The results of specific volume showed an inverse relationship between the values ​​of hardness and specific volume, and the lowest specific volume was observed in sample containing controlled fermented oat along with jujube powder. The highest amount of specific volume was also observed in the control sample. The porosity of all the produced breads was also significantly (p < /em><0.05) higher than the control sample, and the highest porosity was observed in the sample containing controlled fermented oat. The amount of produced gaseous compounds and carbon dioxide during fermentation affect the porosity of the produced bread. Furthermore, water retention capacity is also involved in increase in bread specific volume. Water reduces the stiffness of protein structures and allows better air to enter the dough texture and more specific volume of the product. Wheat breads containing controlled fermented oat + jujube powder and jujube powder (alone) had the highest antioxidant activity, and the control sample had the lowest antioxidant activity. During fermentation, the amount of phenolic compounds or flavonoids increases, and fermentation also causes the synthesis or release of various compounds that have antioxidant properties. Characterization of wheat bread containing the optimal formulation of controlled fermented oat and jujube powder didn’t show significant effect on the overall acceptability of the product. The presence of fiber in fortified breads is likely to increase water uptake, which in turn increases water retention capacity, reduces dough stability and increases overall acceptability. Fruits and whole grains are rich in phytochemicals such as phenolic compounds. Application of phenolic compounds in bread processing, in addition to improve antioxidant properties, affects the physicochemical properties of the dough and the quality characteristics of the produced bread due to various interactions with flour compounds such as gluten and starch. Accordingly, the combined use of plant-rich resources such as jujube powder and fermented oat, which are rich in minerals and micronutrients, can be used to improve the nutritional and quality characteristics of the supplemented wheat bread as a simple and efficient method. Due to the adverse effects of chemical additives and improvers, the importance of providing natural alternatives such as fermented substrates and plant resources in wheat bread processing is quite necessary. The best alternatives for this purpose include sourdough and fiber-rich plant. Wheat bread containing a mixture of controlled fermented oat and jujube powder had the highest crumb hardness and the lowest specific volume. Antioxidant activity in all samples was significantly higher than the control sample and wheat bread containing a controlled fermented oat and jujube powder with 90.52% had the highest amount of antioxidant activity. According to the results, controlled fermented oat and jujube powder, as functional ingredients, may be successfully incorporated into the wheat bread with positively effects on its quality characteristics.

Evaluation of probiotic and antifungal properties of lactic acid bacteria (LAB) isolated from fermented substrates has great importance in order to provide microbial cultures for fermentation industries. Among the fermented foods, dairy products play the main role as carriers of probiotics. Meanwhile, non-dairy fermented foods have been rarely studied in order to isolation and characterization of their probiotic microorganisms. Sourdough as a mixture of flour and water is a proper fermented ecosystem to isolate probiotic and antifungal LAB. Besides their desired health, probiotics must become active in the consumer''s gastrointestinal tract without any adverse effect. These bacteria can be used as starter, adjunct or preservative cultures to produce different fermented foods. Furthermore, antimicrobial metabolites of the LAB have also numerous potential applications as bio-preservatives in food and/or medical technologies.  < p >  < p >

In the present study, after continuous back-slopping process, predominant LAB was isolated from fermented quinoa. Then the LAB isolate was identified using PCR amplification of its partial 16S rDNA gene. Subsequently, probiotic properties of the LAB including its resistance to low pH and bile salt, antibacterial effects, aggregation potentials, antibiotic susceptibility and haemolytic activity were investigated. Antifungal effect of the LAB on Aspergillus niger was also determined using overlay bioassay. Finally, the one way analysis of variance (ANOVA) with the least significant difference (LSD) post hock (at p < /em>  < p >

Sequencing results of the PCR products led to the identification of Enterococcus hirae as predominant LAB isolated from quinoa sourdough. Sourdough fermentation depends on the several technological and environmental factors and therefore, different types of these complex stressful ecosystems have their specific microflora with unique properties. The LAB isolate had proper survival after continuous pH and bile treatments. Resistance to low pH and bile salt is not sufficient to predict the survival of the probiotics in the actual conditions of the gastrointestinal tract. However, these properties are necessary for assessment of viability and activity in this situation. Furthermore, the highest antibacterial activity of the LAB was observed against Bacillus cereus among the studied food borne indicator bacteria. The effect of crude cell free supernatant (CFS) obtained from LAB isolate on indicator bacteria was significantly (p < /em>

Evaluation of probiotic and antifungal properties of the lactic acid bacteria (LAB) isolated from different sourdoughs is so important to prepare microbial cultures for fermentation industries. In the present study, a predominant LAB was isolated from oat sourdough through the back-slopping process, and then it was identified using PCR. Subsequently, probiotic properties of the LAB isolate (including resistance to acid and bile, antibacterial effect, auto and co-aggregations capabilities, antibiotic susceptibility and hemolytic activity), as well as its antifungal activity against Aspergillus niger were studied. Sequencing results of the PCR products led to the identification of Pediococcus pentosaceus as predominant LAB isolated from oat sourdough. The survival rate of the LAB isolates after continuous acid and bile treatment was 59.80% in comparison with the control. The antibacterial effect of the LAB on Bacillus cereus was also significantly (p<0.05) higher than the other studied food-borne pathogenic agents. Crude cell-free supernatant (CFS) of the LAB completely inhibited the growth of B. cereus, but reduced the growth of Salmonella enterica by 65.68%. Meanwhile, naturalized CFS of the LAB had no inhibitory effect on these bacteria. Furthermore, the LAB isolates had a proper co-aggregation with Escherichia coli, and showed resistance towards streptomycin, ciprofloxacin, nalidixic acid and vancomycin antibiotics. The LAB isolates had no hemolytic activity, and its antifungal effect on A. niger was also approved. Accordingly, P. pentosaceus isolate has proper potential to use as probiotic or preservative microbial culture in fermentation industries.

In animal and food products, different types of chemical preservatives and antibiotics are used to inhibit the growth of Aspergillus flavus and other toxicogenic fungi. The aim of this study was to investigate the antifungal activity of Lactic Acid Bacteria Isolated from Masske, Chal, and local yogurt against Aspergillus flavus and Aspergillus niger. For this purpose, isolates previously tested for antibacterial effects were used. The isolates of Lactobacillus plantarum B38, Enterococcus faecium 8C and Lactobacillus ramonosus Y89 with the highest inhibitory effect on pathogenic bacteria were selected and their antifungal effects against toxin-producing molds were evaluated using the overlay method. The results showed that lactic acid isolates at the end of the fourth day prevented the growth of Aspergillus niger and Enterococcus faecium, Lactobacillus rhamnosus and Lactobacillus plantarum showed 70.84%, 37.65% and 43.31% of inhibitory activity, respectively. The results also showed that Lactobacillus rhamnosus had the highest (62.35%) inhibitory effect on Aspergillus niger (P< 0.05). The results of the study on the effect of lactic acid isolates on the growth of Aspergillus flavus showed that all tested bacteria had inhibitory properties on the molds and Lactobacillus rhamnosus with 83.8% had the highest inhibitory effect on Aspergillus flavus (P< 0.05). Consequently, due to the inhibitory ability of the lactic acid bacteria, they can be used as bio-preservatives along with synthetic preservatives in the food industry.

Masske butter or butter derived from yogurt is a traditional butter used in southern Khorasan with a wide range of lactic bacteria. The aim of this study was to investigate the antibacterial effect of lactate isolates against of Staphylococcus aureus and Salmonella enterica. In this research, lactic isolates were first detected by PCR method, and then microdilution method was used to evaluate the antimicrobial activity of the isolates. BLAST of sequences of S16 rDNA gene with sequences stored in the NCBI database led to the identification of the genus Lactobacillus bulgaricus, Enterococcus faecium, Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus delbrueckii and Enterococcus hirae. The results of antimicrobial activity evaluation against Staphylococcus aureus and Salmonella enterica bacteria showed that all isolates were able to inhibit the growth of these two pathogens, and their inhibitory percent from 55/46 to 84/49 and from 55/46 to 56/55 respectively was variables. Also, the results showed that Lactobacillus plantarum B38, Enterococcus hierae B224, Lactobacillus delbrueckii B37 had the highest inhibitory effect against Staphylococcus aureus (P>0.05) and Lactobacillus plantarum B38 showed the highest percentage of inhibition against Salmonella enterica (P<0.05). In addition, it was found that the inhibitory effect of all isolates against Staphylococcus aureus was significantly higher than Salmonella enterica (P< 0.05). Therefore, lactic acid bacteria isolated from the Masske butter can be used to control the food borne pathogens and food spoilage microorganisms.

Isolation and evaluation of the characteristics of lactic acid bacteria (LAB) from traditional fermented products have always the possibility of exposure to isolates with unique capabilities.In the present study after molecular identification of dominant LAB isolated from Tarkhineh, antibacterial and antifungal effects of the isolate and its bacteriocin-like substances on some foodborne indicators were investigated in accordance with the reference methods. Sequencing results of polymerase chain reaction led to the identification of Lactococcus lactis as dominant isolate. LAB isolate had proper antibacterial effect but there was no significant difference (P<0.05) between growth inhibitory diameter of S. aureus and E. coli in present of the isolate. Furthermore, the inhibitory effect of the crude supernatant was higher than that of the neutralized and treated supernatants against studied indicator bacteria. The highest reduction in the population of S. aureus (87.91%) was also observed in the presence of crude supernatant obtained from Logarithmic growth phase. The LAB isolate had the higher antifungal effect on A. flavus rather than A. niger, but the growth rate of A. niger compared to A. flavus was remarkably (P<0.05) higher in each of the third to sixth days of incubation in the presence of bacteriocin-like substances. Based on the results of this study, Lactococcus lactis isolate and its bacteriocin-like substrates can be used as starter culture in fermented food processing, or as bio-preservative in food and pharmaceutical industries.