مجله علوم و صنایع غذایی ایران
سال بیستم شماره 3 (پیاپی 136، خرداد 1402)

Enterotoxigenic Escherichia coli is the most common bacterial agent causing diarrhea by binding to the intestinal mucosa and producing heat-labile enterotoxins. The aim of this study was to elucidate the interaction of two forms of dextran exopolysaccharides (molecular weights of (11-9 kDa) and (76-60 kDa)) produced by the probiotic bacterium Leuconostoc mesenteroides with the heat-labile enterotoxin ((B-pentamer) (LTB)) by using surface plasmon resonance (SPR). According to the results of interaction kinetics at 298 K, both low and high molecular weight dextran types exhibited high affinity (KA) (1.07×106 M-1 and 0.95×106 M-1, respectively) for LTB toxin in vitro. From a thermodynamic point of view, the values calculated of the Gibbs energy were negative (ΔG <0), and also enthalpy and entropy achieved both positive values (ΔH> 0 and ΔS> 0) via the van’t Hof equation, indicating that the interaction was spontaneous, endothermic, and disordered, respectively. With these findings, hydrophobic interactions appear to be important in the interaction between dextran and LTB toxins with hydrogenic bindings. Therefore, dextran molecules are capable of binding to LTB toxin and relatively displaying antitoxin effects. To sum up, these results could provide further insights for initiating extensive research with other lactic acid-derived exopolysaccharides in bacterial interactions and also with foodborne pathogen toxins.

The aim of this study was to evaluate the effect of aqueous extract of Shiitake mushroom on the survival of the probiotic bacterium Bifidobacterium bifidium and physicochemical properties in feta cheese during storage. In this study, the effect of Shiitake mushroom extract at the rates of 1, 1.5 and 2% on the survival of Bifidobacterium bifidum and the sensory features and physicochemical properties of Synbiotic feta cheese during 49 days of storage were investigated. Count of Bifidobacterium bifidum in probiotic cheese containing Shiitake mushroom extract on days 0 and 49, in groups containing 1, 1.5 and 2% of mushroom extract from Log CFU / g from 8.99 to 9.96 and from 8.95, respectively 22/10 and from 11/02 to 01/11 (P <0.05). The use of 2% mushroom extract in probiotic cheese improved the viability of Bifidobacterium bifidum at a rate of 1.99 Log CFU / g, while the use of 1.5% mushroom extract compared to 1% improved The survival of probiotic bacteria at Log CFU / g was 1.27 and 0.97.According to the results, acidity and pH increased and decreased during storage, respectively. Also, adding different concentrations of mushroom extract to probiotic cheese improved the texture, aroma, taste and increased the overall acceptance rank of the sample containing all three concentrations of mushroom extract compared to the control and probiotic cheese groups (P <0.05).In general, the addition of mushroom extract to probiotic cheese resulted in higher scores than the control groups.In general, the results of the study showed that the addition of Shiitake mushroom extract improved the viability of probiotic bacteria in cheese. Therefore, the combined use of shiitake mushroom extract as prebiotics and probiotics in cheese and other dairy products can be recommended as an effective and practical measure to improve consumer health and increase the nutritional value of products.

Tooth decay is one of the most common problems in the world, which is caused by the growth of biofilm and acid production by them. Many solutions have been used to solve this problem. However, due to the increase in antibiotic resistance of microorganisms and the increasing need for antimicrobial substances, efforts are being made to use natural antimicrobial substances. Lactoferrin is a protein in milk and saliva with antimicrobial and anti-biofilm properties. In this research, lactoferrin was encapsulated by nanoliposomes to increase its antimicrobial properties. In order to measure the effect of lactoferrin on the number of bacteria in the polymicrobial biofilm and acid production, each of the free substances or nanoliposomes in 4 concentrations (0, 1.5, 3, 6 mg/ml) in the Active Attachment biofilm model with saliva and culture medium was incubated.The results showed that lactoferrin nanocoating increased the ability to inhibit biofilm and acid production by this bacterium due to the slow release of lactoferrin from liposomes. When increasing the concentration of free and nanoliposomal lactoferrin to a concentration of 3 mg/ml, a significant decrease in the number of bacteria in the biofilm was observed compared to the control sample (P<0.01). However, increasing the concentration of free lactoferrin again increased the number of bacteria in the biofilm. Meanwhile, nanoliposomal lactoferrin at a concentration of 6 mg/ml still caused a decrease in bacteria in the biofilm, which was insignificant compared to the concentration of 3 mg/ml (P>0.01). From the obtained results, it can be concluded that nanoliposomal lactoferrin can be used to design products related to oral and dental health.

The stability of curcumin and its encapsulation efficiency in emulsion are among the most important factors determining its bioavailability and absorption in the body. For this purpose, parameters affecting these two factors, including time, pH, and cellulose concentration, were used as input variables in the present study. Curcumin stability and encapsulation efficiency were used as response variables in artificial neural networks and decision tree algorithms. In this regard, cellulose nanocrystal obtained from acid hydrolysis was used to prepare curcumin Pickering emulsion with oil:water ratio of 5:95 and cellulose concentration 1, 1.5, 2, 2.5, and 3% (w/v) and the encapsulation efficiency and stability of curcumin were measured during 8 days. The results showed that the encapsulation efficiency significantly increased as cellulose concentration increased. Encapsulation efficiency at pH 7 was higher than at pH 2 (p≤0.05). The curcumin content in the emulsions prepared at pH 2 drastically decreased during storage, while it was less degraded in emulsions at pH 7 after 8 days of storage. The modelling results for curcumin stability and encapsulation efficiency based on R2 and RMSE% statistics showed that MLP 3-6-1 (R2=0.99; RMSE%=10.00) and RBF 2-6-1 (R2=0.99; RMSE %=9.99) were had more accuracy than other models. Finally, the results showed that the artificial neural network algorithm performed better than the decision tree in predicting cellulose Pickering emulsions' encapsulation efficiency and curcumin stability.

Unlike the traditional processing methods, whose goal is to increase the digestibility of food, the recent trend of food processing containing starch has gradually changed to design foods with low glycemic index. The aim of this study was to investigate the simultaneous effect of ultrasound/microwave processes on the production of resistant starch type 3 (RS3) in rice and subsequently the production of Reshteh Ashi containing different levels of RS3. The produced starch was evaluated in terms of microstructure and crystal structure, and the rheological characteristics of Reshteh Ashi were analyzed. The results showed that at the 95% confidence level, the linear effect of both the ultrasonic power and microwave power variables, as well as the two-way interaction of ultrasonic power and microwave power, had a significant effect on the amount of RS3 in different samples (p<0.05). The amount of RS3 in different treatments of rice starch varied from 31.65 to 64.29%. The SEM studies showed that the starch granules had polyhedral or irregular shapes with a size in the range of 2.2-9.8 µm and an amorphous structure was formed by increasing the power of the two devices and subsequently increasing the amount of RS3 production. The application of ultrasound/microwave treatment led to the creation of new peaks and changes in the intensity of the peaks in the XRD spectrum. Alveograph results of Reshteh Ashi samples showed a significant change in the indices, including maximum overpressure, average abscissa to rupture, swelling index, area under the curve, configuration ratio and elasticity index. The results of this research showed that the use of resistant rice starch at the level of 10% can improve the technological characteristics of Reshteh Ashi in terms of textural characteristics, and as a result, the enrichment of Reshteh Ashi at the level of 10% RS3 is recommended.

Fibers obtained from the waste of fruits and grains are valuable sources in the preparation of various useful products such as yogurt. Considering the importance of consuming fibers in providing health, the purpose of this research was to investigate the physicochemical, textural and sensory properties of fat-free yogurt enriched with bamboo fiber. For this purpose, bamboo fiber was added to fat-free yogurt with percentages of 1, 2, and 3 %, and experiments including pH, acidity, total dry matter, syneresis, viscosity, colorimetry, and sensory evaluation were carried out during 3 weeks of storage in the refrigerator (4±1 °C). Produced samples were compared with fat-free yogurt and high-fat yogurt without fiber additives. Data showed that the addition of fiber to the yogurt samples significantly increased (P<0.05) the amount of acidity, total dry matter, viscosity, color index LÛ, aÛ and bÛcompared to non-fat and high-fat control samples. In addition, the results showed that the addition of fiber in yogurt samples significantly (P<0.05) reduces the syneresis, so that the non-fat control yogurt with 12.3% and the sample containing 3% fiber with 8.58 % showed the highest and lowest syneresis on the first day of production, respectively. In the sensory evaluation, the sample containing 2% bamboo fiber with the highest score was introduced as the best sample. Therefore, the application of bamboo fiber with a concentration of 2%, in addition to improving the textural, physical and chemical properties of yogurt, can also lead to consumer satisfaction. Hence, bamboo fiber can be used in the formulation of dairy products, including yogurt.

The purpose of this study was to investigate the conformity or non-conformity of traditional liquid Kashks supplied in Hamedan city with the national standard of Iran. To carry out this research, Kashk samples from manufactures of traditional dairy products (in Hamedan city) were prepared in two stages and transferred to the food quality control laboratory for examination. Microbial population (total count, staphylococcus, coliform, and mold-yeast), chemical properties (total solids %, salt, acidity, and pH) and color parameters including lightness (L*), redness (a*) and yellowness (b*) of tradition Kashk was examined and after statistical analysis, their results were reported. The average number of microorganisms (total count), staphylococcus and coliform in the Kashk samples were 7.28 Log cfu/g, 4.09 Log cfu/g, and 1.64 Log cfu/g, respectively. According to the national standard of Iran, the maximum number of mold and yeast in liquid Kashk should be 2 Log cfu/g, but the average number of mold and yeast in the prepared Kashks were 7.39 Log cfu/g, which is much higher than the specified standard for this product. The average of total solid of Kashks were 21.15%, which was less than the defined standard (at least 25%) for it. Also, the average of moisture, salt, acidity, and pH of examined Kashks in this research were 78.85%, 1.98%, 1.90%, and 4.09 respectively. Color parameters of Kashk samples were examined and the average color indexes including lightness, redness, and yellowness of the samples were 84.52, 1.53 and 6.43 respectively. Of course, no statistically significant difference was observed between the color indexes values of the samples (p>0.05).

Ajowan (Carum copticum) is a flavoring plant, which the seeds contain important chemicals such as thymol, carvacrol, terpinene, cymene and myrcene belonging to the group of phenolic compounds with distinct antimicrobial and antioxidant properties. Therefore, the objective of this study was to incorporate different contents of Ajowan seed powder (ASP) in formulation of chocolate cream to enhance its functional and antioxidant properties. For this purpose, ASP was added to the chocolate cream at levels of 0, 1, 2, 3, 4, and 5% (w/w). Nutritional characteristics including the amount of dietary fiber, polyphenolic compounds, antioxidant activity, technological and sensory characteristics such as spread ability, firmness, peroxide value, color, taste, mouthfeel and overall acceptance of the chocolate cream were examined. The results indicated that with the addition of ASP the amount of fiber, polyphenols, acid-insoluble ash and antioxidant capacity were significantly (p< 0.05) increased significantly compared to those measured in control. During the 75 days of storage, peroxide value was significantly (p < 0.05) decreased in the fortified produce with 5% ASP compared to the control. Nevertheless, sensory evaluation showed that increasing ASP level more than 3 % (w/w) led to decrease in overall sensory acceptance due to the fact that flavoring compounds of ASP would interfere in product taste and flavor.

The purpose of present study was to use nanocapsules carrying astaxanthin pigment in common sausage formulation as a substitute for sodium nitrite and search for pathogenic and spoilage microorganisms in the product. For this purpose, after extracting astaxanthin from Haematococcus pluvialis microalgae and producing nanocapsules carrying pigment with maltodextrin-sodium caseinate combined coating, five treatments using different proportions of sodium nitrite and nanocapsules carrying astaxanthin along with control were designed and evaluated in term of the presence of Clostridium perfringens, Staphylococcus aureus, coliform, salmonella, Escherichia coli, Clostridium botulinum, lacticacid bacteria bacteria, yeasts and molds during 28 days of storage at refrigerator temperature. The results showed that in the treatment with the permissible limit of sodium nitrite or 120 mg/kg (treatment A) and also the treatments that this limit was replaced by 30 mg/kg (treatment C) and 60 mg/kg (treatment D) of nanocapsules carrying astaxanthin, the counts of Clostridium perfringens, Staphylococcus aureus, and coliform bacteria were within the standard limit and recorded less than 10 cfu/gr. In treatments containing only 120 mg/kg nanocapsules carrying astaxanthin and also containing 30 mg/kg sodium nitrite and 90 mg/kg nanocapsules carrying astaxanthin (treatment E), only on day 28, the counts of three mentioned bacteria were more than 10 CFU/gr. Further, it was found that none of the research treatments contain Salmonella, Escherichia coli and Clostridium botulinum bacteria. Also, all five formulated treatments were within the standard range in terms of lactic acid bacteria during storage time. The results of counting molds and yeasts showed that this treatments, unlike the control sample, did not have any mold and yeast colonies in the whole of storage period. According to the findings of this research if 50% of permissible sodium nitrite limit using nanocapsules carrying astaxanthin is replaced, it is possible to produce a product free of health-threatening microorganisms.

Persian gum is an Iranian native gum which obtains from the trunk and branches of wild almond tree. This gum is found in different colors and there is a direct relation between its color and tannin content: darker the color, higher the amount of tannin. Since the bioavailability of proteins and minerals is limited by tannins, they are known as anti-nutrient compounds; hence, it is essential to remove tannin from Persian gum in order to increase its quality and amount of utilization in the food industry. Thereupon, tannin removal from Persian gum using different thermal and non-thermal methods was the main aim of this research. In this regard, soaking either in water or saline solutions (mono- and divalent salts) was considered as non-thermal method. On the other hand, autoclaving (121 ̊C for 20 min) and boiling (5, 10 and 15 min) were applied as thermal methods for tannin removal of Persian gum which was categorized based on color: white, yellow and brownish. As well, weight reduction of gum granules and rheological properties were investigated after tannin removal. According to the results, the highest tannin removal was observed in the case of brownish Persian gum and the most yield of tannin removal belonged to soaking in water for 180 min (75.67 ± 0.25 %), using CaCl2 solution at the concentration of 1% (w/w) (74.32 ± 0.54 %) and boiling for 15 min (67.08 ± 0.19 %), respectively (p < 0.05). Based on rheological analysis, apparent viscosity of samples after soaking either in water or CaCl2 solution as well as boiling, the treatments which had the highest tannin removal yield, was higher than control sample. However, the suitable rheological model for control and the treated gums was Herschel-Bulkley, indicating that type of flow behavior did not been affected by tannin removal.

To investigate the effect of molecular weight of chitosan and the type of plasticizer used in the composition of edible coating on internal quality parameters and morphology of eggshell, an experiment with 125 eggs in a completely randomized design with 5 treatments included uncoated eggs (control), coated based on chitosan with high molecular weight (450 kDa) or low molecular weight (65 kDa) and the use of glycerol or sorbitol and 3 replicates was conducted. Coating was done by immersion method and the eggs were stored at ambient temperature for 4 weeks. The internal quality parameters of eggs including weight loss (WL), Haugh unit (HU), yolk index (YI) and albumen pH were evaluated weekly. At the end of the storage period, scanning electron microscope (SEM) micrograph were prepared for eggshell morphology. The results showed that the edible coating based on chitosan improved significantly (P<0.05) all the evaluated parameters. At the end of the week 4, among these, the lowest values of WL (7.01 ± 0.90) and pH of albumen (8.90 ± 0.15) and the highest values of HU (± 3.23) 63.80) and YI (0.34 ± 0.06) were seen in eggs containing high molecular weight chitosan-sorbitol coating (P<0.05). In the SEM micrograph, more integrated and less porous and fractured in the mentioned group. Therefore, in order to improve the quality of edible coating based on chitosan as a biocompatible packaging to increase the storage time of eggs, chitosan with higher molecular weight and sorbitol as plasticizer are recommended.

The aim of the present study is to use wheat starch and modified potato starch instead of whole-wheat flour to prepare chocolate-coated muffins. For this purpose, wheat and potato starch were used in muffin preparation at 0-100, 10-10, 80-20, 25-75, and 30-70 levels, respectively. After preparing the samples, the best sample, which was very similar to the cake made of whole-wheat flour, was selected as the desired sample and covered with a chocolate layer containing the probiotic bacterium Lactobacillus casei. The results showed that with the removal of whole-wheat flour, the rheological, farinograph and extensograph were significantly (p<0.05) affected. The results showed by replacing whole-wheat flour with wheat starch and potato starch pH, moisture, protein, phenylalanine, ash, porosity, and specific volume of muffins were decreased, while fat and firmness were increased. For the cake crumb by replacing the whole-wheat flour, the L*, a*, b*, and browning index decreased while the total color changes significantly changed. The results of overall acceptability showed that there was no significant difference between control samples and muffins containing 20 and 25% of potato starch. Considering all the features, the muffin cake prepared from the 25% of modified potato starch and 75% of wheat starch was selected as the optimal sample and probiotic chocolate was used as a coating for one week. The probiotic count did not show a significant decrease.

The aim of this study was to optimize the formulation of coating of bulked corn products using maltodextrin, corn and spinach in order to improve the nutritional characteristics of puffed snacks. oil (55-65%) and powder materials (35-45%) as fixed components (80%) including milk powder, whey powder and salt (25, 50 and 5%, respectively) – and variable components (20%) including cheese powder, maltodextrin and corn starch were used to prepare the coating. Optimization was done with cross statistical design. After the physicochemical and sensory tests and selecting the optimal sample, spinach powder was added to the optimal formulation at 4, 6, and 8%, and sensory tests and uniformity evaluation were performed. The results showed that the oil absorption, hardness, redness, colloidal stability and sensory characteristics of the sample was increased by use of corn starch in the coating formulation, but overall acceptance was reduced, while redness and sensory characteristics increased by use of maltodextrin and oil absorption and hardness was reduced. The oil absorption, hardness, colloidal stability and flavor increased by use of cheese powder in the coating and redness and sensory characteristics reduced. Increasing the percentage of oil to 63% increased oil absorption and decreased the redness index (p<0.05). Increasing the percentage of oil to 60% significantly increased texture hardness, colloidal stability and color factor (p<0.05). The best optimal coating containing 10% each maltodextrin and cheese powder and 55% oil was obtained. The scores of sensory factors in the formulation containing 8% spinach powder were significantly higher than the others (p<0.05) and adding 8% of spinach powder to the optimal coating was recognized as the best sample. The results showed that in order to improve the uniformity and stability of the coating emulsion, maltodextrin and corn starch can be used and its nutritional value can be increased by using spinach.

The survival of probiotics in food products face various challenges during the production process. One of the emerging processes in the production of food products is 3D printing. The effect of this process on the viability of probiotics has not been studied so far. In this research, the effect of micro-encapsulation on cell viability during the process of 3D printing and cookie baking (based on waste from confectionery products) was investigated. First, the conditions for the production of micro-capsules were optimized by modulating the percentage of sodium alginate and calcium chloride solutions. Then, the effect of micro-encapsulation with different concentrations of micro-capsules (10, 5, 0% w/w) on the firmness of the dough texture was also investigated as an important factor in the printability of the dough. Finally, the cell viability was evaluated during the printing and baking process (150°C and 180°C for 10 minutes). The results of the microscopic images showed that with the increase in the concentration of sodium alginate and calcium chloride solution, the uniformity and sphericity of the micro-capsule increases. The efficiency of alginate-based micro-encapsulation in this method was 89.41%. The optimal concentration of micro-capsules in order to have the desired printability of baked dough, was reported as 5% w/w. Microencapsulation increased the survival rate of probiotics during 3D printing and baking. The survival percentage of microencapsulated probiotics (T2) after 3D printing and baking (150°C temperature) was 96.86% and 62.58%, respectively. Meanwhile, the survival percentage for the sample containing free cells (T1) was reported 60.77% and 43.05%, respectively. However, no viable probiotic cells were observed in both free and encapsulated cells conditions at 180°C.

Increasing and improving the stability of colors in food during processing and also controlling the release until consumption is one of the most important issues and challenges in the use of natural colors in food. Hence, the objective of this study was to produce phytocyanin-containing nanoliposomes coated with chitosan by thin-layer ultrasonic hydration method to increase the stability of phycocyanin and to investigate its physical properties and encapsulation efficiency during storage. In this study, phycocyanin was coated with different concentrations of chitosan (0, 0.1, 0.2, 0.4, and 0.6 mg/mL) and stored at two temperatures (4 and 25° C) for 28 days. Then, to determine the best concentration of chitosan for coating the nanoliposomes, encapsulation efficiency, particle size, and zeta potential tests were performed. The results revealed that by increasing the concentration of chitosan to more than 0.2 mg/mL, no significant change in encapsulation efficiency was observed (p> 0.05). The sample without chitosan had the lowest particle size which was not a significant difference from samples containing 0.2 and 0.4 (p> 0.05). Increasing chitosan in the coating of nanoliposomes has led to increased zeta potential. Finally, a sample containing 0.2 mg/mL chitosan was selected as the best sample. Findings from analyses performed during the storage of nanoliposomes showed that nanoliposomes containing phycocyanin, which did not have any chitosan coating, had the highest encapsulation efficiency. On the other hand, it was found that with increasing storage temperature and storage time, the encapsulation efficiency decreased but the particle size increased. The lowest zeta potential of the samples was related to the phycocyanin-free nanoliposome sample which did not change significantly until the 21st day of storage at 4 °C. Scanning electron microscopy (SEM) images of the samples also confirmed the results of particle measurements.