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In this research, the effect of kombucha on physicochemical (pH, acidity, syneresis, viscosity, vitamin C and ethanol) and overall acceptability of yogurt samples were measured during 21 days of storage at 8ºC. Thus the amounts of 5, 10 and 15 %(V/V) of concentrate of kombucha layer grown up on black tea, with yoghurt starter, were inoculated to the milk containing 2.2 % fat. Meanwhile, the yogurt starter was applied for producing control sample. Fermentation in all samples was stopped when the pH reached 4.6. The results showed that during the storage, decrease of pH and increase of acidity were minor (p<0.01), and with raising the kombucha concentration, these changes were significantly less than control sample (p<0.01); syneresis in all samples (the same as control) increased while viscosity decreased (p<0.01) and increasing of kombucha concentration was caused increase of syneresis and decrease of viscosity (p<0.01); vitamin C decreased and ethanol increased very little (p<0.01) and as the kombucha concentration increased, the quantities of vitamin C and ethanol increased (p<0.01). Raising the kombucha concentration caused reduction of overall acceptability score in samples (p<0.01); and during storage, this score decreased (p<0.01) a little in comparison with that in control sample. After production and during storage, the best physicochemical and sensory properties was observed in sample containing yogurt starter and 5% kombucha concentrate.  

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     Due to the growing importance of replacing meat proteins with a healthy food source, the present study was conducted with the aim of investigating the results of replacing meat with fungus myco-protein. Since the fungus myco-protein have high nutritional value and attributes similar to meat, they can be properly replaced in meat products. According to the results obtained from the present research, which was carried out aimed at improving the nutritional value, health and texture of protein products containing meat, the complete replacement of meat with myco-protein leads to a significant reduction in the texture characteristics of the product, such as firmness, elasticity, gumminess and on the other hand, there was no significant change in the moisture content of the samples. Also, the results indicated that the samples with fungus myco-protein contain higher level of unsaturated fat and protein and less carbohydrates and ash than the samples containing meat, and therefore, the sausages made from these products have higher nutritional and health value than the beef products.
 

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Phospholipases are important groups of enzyme with wide applications in various industries. In this study, two-step optimization including Plackett-Burman screening design and response surface methodology (RSM) optimization were done with the goal of higher production level of phospholipase by selected mutant strains of Trichoderma atroviride sp.ZB-ZH292. First step was done by screening and evaluation of seven factors affecting the enzyme activity and biomass production by selected mutant, using Plackett-Burman design at two levels each namely temperature, time, amount of soybean phospholipids (as a carbon source), peptone level (as nitrogen source), equal ratio of mono and di-potassium hydrogen phosphate (as phosphorus source), seed size, and seed age. According to the result of screening design, incubation time (P<0.01), incubation temperature (P<0.01), and soybean phospholipids as a carbon source (P<0.05), had significant effect on the enzyme activity, so they were selected and used as independent variables in central composite design (CCD) under response surface methodology (RSM). In the analysis of 20 experimental runs, the effects of three independent variables including incubation temperature (20-30 °C), incubation time (3-5 day), and phospholipid concentration (3-9%) were evaluated on phospholipase activity. Analysis of variance (ANOVA) showed that the optimum values of soybean phospholipid, incubation temperature and incubation time were 4.32%, 29.73°C, and 101.76 h, respectively. At this optimum point, the phospholipase activity was found to be 3.57 (U/ml) which is in good agreement with the predicted value (3.56 (U/ml)) by the model.