JOURNAL OF APPLIED MICROBIOLOGY IN FOOD INDUSTRY
Year:2017 | Volume:3 | Issue:1|Papers Count:6

Yogurt is a fermented dairy product that nowadays the use of reduced-fat varieties are interest to consumers. By reducing fat the firmness and sensory properties of yogurt is reducing. To improve the texture and sensory properties of yoghurt can be used hydrocolloids and adjunct starter cultures such as probiotics respectively. The aim of this study was to evaluate the effects of single and combined probiotic on physicochemical and sensory properties of low-fat yogurt containing the xanthan gum. Production samples from the point of view of microorganisms viable cell counts, pH, acidity, syneresis, total and free amino acid content and sensory properties during 28 days of storage at 4oC were evaluated. Increasing the storage time resulted in increase the acidity and syneresis and decrease the viable cell counts. Treatments containing S. thermophilus have highest viability of probiotic microorganisms. Results of Measuring amino acid showed that the amount of total and free amino acids during storage were uptrend, however, only threonine amino acid amount decreased during storage period. The results of sensory evaluation of low-fat probiotic yoghurt samples showed that treatments contain Bifid bacterium pseudocatenulatum has the highest sensory scores compared to the control group and was introduced as the superior treatment.

In this study, the effect of prebiotic compounds (Inulin and wheat fibers) and fat (0%, 2% and 3.5%) on viability of Lactobacillus casei in symbiotic yogurt, its physicochemical properties, proteolysis, inhibition of angiotensin I-converting enzyme (ACE- inhibitory) and antioxidant activity during 21 days storage at 5±1oC was investigated. According to the results, adding prebiotic compounds significantly increased water holding capacity, proteolysis and ACE inhibitory of all treatments (P<0.05). Also statistical analysis showed that by increasing storage time, proteolysis increased but after going to a certain extent this trend began to decrease. The results confirm that the prebiotic compound had a positive effect on survival of probiotic organism (P<0.05) but effect of fat level was not significant (p<0.05). The antioxidant activity was significantly affected by presence of prebiotic compound (P<0.05).

Local dairy products are one of the most important sources of growth and production of enterotoxin by species of Staphylococcus bacteria. Hence, the aim of this study was to isolate Staphylococcus bacteria and identify Staphylococcus aureus enterotoxins encoding genes by molecular methods (SEA, SEB and SEC) as well as determining any probable correlation among the presence of the enterotoxin encoding genes with microbial and chemical parameters in Kalat city local cheese. For this purpose, 30 samples of local cheese were collected and transferred from Kalat city to the laboratory under sterile conditions. Samples were then cultured on Bread Parker Agar Medium and serological identification was done using coagulase method. PCR was performed according to 16SrRNA gene in order to identify the species of isolated bacteria. Also, the SE serotype enterotoxin genes in each bacterium were examined. Results showed that 100% of samples are contaminated with Staphylococcus aureus. Also, PCR results showed that 70% of the isolated Staphylococcus aureus produce one of the enterotoxins. The frequency of SEA, SEB and SEC genes in the isolated Staphylococcus aureus, were respectively 36.6%, 36.6% and 0%. Also, only 3% of Staphylococcus aureus were containing both SEA and SEB genes. The correlation coefficients of the presence of genes SEA and SEB with a range of pH, salt, acidity, moisture%, mesophilic bacteria total count and enumeration of Staphylococcus aureus were0.733-0.505, 0.536-0.690, 0.797-0.924, 0.632-0.788, 0932-0935 and 0.427-0.629, respectively.

Aopoptosis induction is one of the best method cancer therapy and funding the anti-cancer component, especially inducing opoptosis is of the significant important. This study aimed to assess cytotoxic effects of heat-killed probiotic bacteria and induced apoptosis on gastric cancer AGS cells compared to normal cells (HEK-293). AGS cancer cell line AGS was cultured in RPMI medium, and cell line HEK-239 was selected as the control. Both cell lines received 0.01, 0.1, 1, 10, 100, and 1000 mg/ml of heat-killed lactobacillus paracasei for periods of 24, 48, and 72 hours. Viability of cells was measured using MTT assay. Apoptosis assay was performed in IC50 of cell culture by Annexin V and propidium iodide staining methods in 48 hours. According to MTT assay, heat-killed bacteria reduced viability and proliferation of gastric cancer cell line AGS in pattern of time, dose and strain dependent. The highest cytotoxic effect was observed in 1000 mg/ml for 72 hours. Annexin V staining and flow cytometry confirmed induced apoptosis in AGS cell line in pattern of time, dose and strain dependent. Heat-killed probiotic bacteria showed cytotoxic and induced apoptosis effects on AGS gastric cancer cell line, with slight cytotoxic effect on HEK-239 compared to AGS. Further studies are still required to confirm these bacteria as a biological anti-cancer product in treatment and prevention.

In recent decades the use of chemical pesticides caused harm to human health and the environment. On the other hand, the wasteful use of pesticides and fungicides can cause pathogen resistance. Accordingly, the plant extracts can be used as an environmentally compatible way. In this study, it was used of water and methanol extracts of lavender, anise, eucalyptus, thyme and watermint to control gray mold disease caused by Botrytis cinerea of apples in the lab with mixing into medium method and disk medium, and also plant extracts was used in the store was with 4oC. Results showed water lavender extract with 500 micrograms per milliliter concentration had the best inhibition of pathogen with 22 mm diameter of pathogen colony. Also, the methanol extract of lavender with a concentration of 500 micrograms per milliliter and 31.62 mm diameter inhibition of pathogen, was the best extract. Watery and alcoholic extracts of lavender was the best extracts with 63.05 and 77.61% inhibition of the pathogen, respectively, compared to the control at a concentration of 500 micrograms per ml. Based on the results, after the lavender plant extract the fennel extract in watery extracts, and the eucalyptus extract in methanol had the best effect controllers in both tests. In store tests, watery extracts of lavender and fennel with a concentration of 6 in 1000 had the lowest diameter of spots with 8.57 and 11.72 cm compared to other treatments and control treatment. Based on the results of the laboratory and storage test, the lavender and fennel extract are introduced as natural compounds with high potential controller of B. cinerea.

The aim of this study was to use inulin as a peri-biotic compound as well as pomegranate peel extract as an antioxidant to increase the shelf-life of Bifid bacterium bifidium in soy sauce. For this purpose, 3, 5 and 7% pomegranate extract and inulin were used at 5, 10, 15 and 20% then viscosity, pH and Bifid bacterium bifidium survival were evaluated. The treatments were evaluated on the days of zero, seventh, fourteenth and twenty one.13 treatments were evaluated in three replications in a randomized complete block design. Results showed that treatments higher than 3% of pomegranate peel extract and 5% inulin significantly reduced the probiotic bacteria survival. Finally, a decrease in the number of treatments points with increasing percentages Inulin and pomegranate peel extract. The pH also significantly decreased with increasing storage time and the ratio of inulin and pomegranate peel extract significantly decreased. The highest Bifid bacterium bifidium survival (T1) with 5% inulin and 3% of pomegranate peppermint extract was associated with a decrease in logarithmic equivalents and a population of 1×108 CFU/ml. The highest reduction in the population of Bifid bacterium bifidium belonged to the control treatment at 5 logarithmic cycles, and the lowest of T1 treatment was 2.33 and T2 treatment was 3.33 logarithmic cycles at the end of the 21st day of storage (p<0.05).