JOURNAL OF APPLIED MICROBIOLOGY IN FOOD INDUSTRY
Year:2017 | Volume:3 | Issue:2 |Papers Count:6

The aim of this study was to investigate the possibility of replacing the oil with inulin in date bread and production of a functional food product called "synbiotic date bread" in the presence of probiotic bacteria Bacillus coagulans. For this purpose, date bread was produced by 10 and 20 percent of oil replacement with inulin. Sensory properties, texture and moisture content of the samples were evaluated. The results showed that samples containing 20% inulin is desirable and the presence of inulin has retained moisture during cooking and storage, reduced stiffness and improved the taste of the samples. Addition of inulin to samples did not cause significant changes in their color. In the next stage, date bread was prepared with 20% inulin and Bacillus coagulans. After cooking and storage of samples at ambient temperature, they were evaluated in terms of the survival of the probiotic bacteria at 1, 60 and 120 days of post-production. In samples containing inulin, the least decrease in the number of Bacillus coagulans was observed.

Bisphenol-A (BPA) is an industrially important compound used in the production of polycarbonates, epoxy resins and thermal papers in many chemical manufacturing plants throughout the world. So, this dangerous chemical toxin may be taken up via the diet and have adverse effects on human health. On the other hand, inducing beneficial bacteria is an effective way to improve the biosafety and health level. The induction process can be done by supplements containing large amounts of probiotics. Combination of compatible probiotic strains from different species may improve synergistic relation among bacteria and increase the effectiveness of treatment. In this study we try to investigate and quantify the effect of commercial probiotic formulations exist in Iran pharmaceutical market on reduction of bisphenol A. For this purpose, the amount of environmental BPA was measured during a 24-hour treatment with the mixture of probiotic strains. Our results showed a significant drop in BPA concentration compared with the toxicity of the control group. The experimental framework was arranged in a way to determine the most efficient strains. Almost all groups could reduce about 80% of BPA in the first hour. Also, these results suggest that regular usage of probiotic supplementation with special mixture of strains can suppress the harmful effects of BPA.

In this study, soy protein isolate (SPI) was hydrolyzed using Alcalase with the aim of generating natural antibacterial components. Then, antibacterial activities of resulting protein hydrolysates were investigated against some indicator bacteria including Escherichia coli, Bacillus cereus, and Staphylococcus aureus. Enzyme to substrate ratio (E/S) and hydrolysis time were chosen as process variables. Degree of hydrolysis (DH) and its effects on hydrolysates activity were also evaluated. The maximum DH was observed after protein hydolysis for 90 min at E/S value of 1.5%, which was not significantly different from that observed after 60 min at E/S of 2.5%. According to the results, enzymatic hydrolysis effectively enhanced antibacterial activity of SPI. The obtained hydrolysates showed the highest activity against E. coli and the least effect on B. cereus. Applying higher enzyme concentration showed significant effect on hydrolysis progress and also on inhibitory activity of hydrolysates against E. coli, but not against B. cereus and S. aureus. The effect of increase in hydrolysis time on the inhibitory activity of resulting hydrolysates against different tested bacteria was highly varied. In overall, the results of this study showed that with controlled enzymatic hydrolysis of SPI, peptides with considerable antimicrobial activity against E. coli may be obtained that can be used in food formulation.

In this study, the effect of barley sourdough containing Pediococcus stilesii starter with different dough yield (160, 270 and 450) on phytate content of produced dough and Barbari bread was investigated. For this purpose, after applying 28, 32, 36°C fermentation temperatures and 16, 24, 32 h fermentation times, the amount of phytate was evaluated using a spectrophotometric assay based on the measurement of iron absorption. The results of statistical analysis showed that the pH and phytic acid content of produced dough and Barbari bread were significantly (P £ 0.05) decreased with increasing fermentation time and temperature, while titratable acidity was significantly increased (P £ 0.05). Furthermore, increasing yield dough from 160 to 450 resulted in significant increase (P £ 0.05) in titratable acidity and significant decreases (P £ 0.05) in pH and phytic acid content of produced dough and Barbari bread. Regression equation between sourdough titratable acidity and phytic acid content of produced dough and Barbari bread had respectively correlation coefficients equal to 0.947 (linear model) and 0.842 (logistic power model), and by increasing of sourdough titratable acidity, the contents of phytic acid were also decreased. Based on obtained results, controlled fermentation of sourdough can effectively reduce the amount of phytic acid of Barbari bread in comparison to control sample.

In this study the effect of controlled fermentation of whole wheat sourdough and co-addition of pumpkin puree on quality properties and shelf life of Taftoon bread were evaluated. For this purpose, sourdoughs fermented in controlled conditions by specific starter culture in 28OC for 24 h, alone (25% of dough weight) and with different levels of pumpkin puree (10, 20 and 30%) were added to bread formulation. The effect of mentioned treatments on porosity, specific volume, sensory characteristics, microbial shelf life and staling during 2 until 96 h after baking of Taftoon bread were investigated. The lowest amount of bread firmness was observed in sourdough bread containing 30% of pumpkin puree. Mentioned sample obtained the maximum score of sensory evaluation, too. Furthermore, in all time intervals sourdough Taftoon bread containing 20% pumpkin puree had the maximum porosity (more than 20%) and specific volume (above 2 ml/gr) and the lowest microbial contamination among the fortified samples with pumpkin. Pumpkin introduced initially as a nutritional supplement in bread processing, but the results of this study showed that pumpkin puree had significant effect (P£0.05) on quality properties and shelf life of Taftoon bread produced using sourdough controlled fermentation and so on, have high potential for using in fortification of this product.

Nowadays, due to the popularity of vegetarian diet, lactose intolerance and high cholesterol content in dairy products, demand for non-dairy probiotic products has increased. In this study the effect of fermentation, refrigerated storage and adding Xylooligosaccharid (XOS) on viability of some probiotic bacteria in Barbery juice was evaluated. Barbery juice inoculated with two probiotic species included L.rhamnosus and B.lactis (each 108 cfu/ml) after the xylooligosachcarid (XOS) was added to samples at concentration of 0.5, 1 and 1.5 percent. Then the chemical characteristics including pH, acidity, sugar consumption and viability of probiotic bacteria were monitored during primary fermentation and refrigerated storage for 21 days. Data analysis showed the treatment type and storage time had significant effects on the chemical characteristics and viability of probiotic bacteria (p<0.05). Although increasing concenteration of Xylooligosaccharid led to more viability for B. lactis but had no effect in improving the survival of L.rhamnosus. However, L.rhamnosus could tolerate better the acidic conditions of Berbery juice and showed greater survival. The low pH and presence of inhibitors such as phenolic compounds in Barbey juice have negative effects on viability of probiotics during storage time but using the prebiotic comounds like Xylooligosaccharid can improve the viability of some probiotic bacteria such as B.lactis.