مجله میکروبیولوژی کاربردی در صنایع غذایی
سال پنجم شماره 3 (پاییز 1398)

Mahyave is a traditional Iranian fish sauce made from fish, salt, spices and water by the fermentation process. Although fish sauces have a high nutritional value, they contain biogenic amines as anti-nutritional compounds. This study aimed to investigate the effect of Bacillus polymyxa at a concentration of 108 cfu/ml on the chemical (pH, acidity, salt percentage, TVB-N, histamine and tyramine) and microbial (population of Enterobacteriaceae, Bacillus, Halophiles, Lactic acid bacteria and fungi in mahyaveh sauce. This study was administered in 4 experimental groups including control and treatment groups (containing bacteria) on 30 and 45 days. The results of microbial analysis showed that the population of Bacillus, Halophiles and fungi was significantly (p <0.05) decreased during fermentation. The colony population of Lactic acid bacteria and Enterobacteriaceae significantly increased during fermentation (p <0.05). Chemical analysis of the treated and control samples also showed that pH, salt percentage, histamine and tyramine content decreased in 45 days of fermentation, but acidity, TVB-N and protein concentration increased during 45 days of fermentation (p <0.05). Also Bacillus polymyxa reduced the amount of histamine and tyramine content in the product by effect on the fermentation process. The results show that addition of Bacillus polymyxa starter is an effective strategy for reducing biogenic amines in fermented fish sauces.

Parkinson's disease after Alzheimer's is the most common neurodegenerative disease. It is the second most commonly reported neurodegenerative disorder. To create an animal model of Parkinson's disease, the black dense component of rats in 6-hydroxy dopamine (6-OHDA) was unilaterally destroyed in a stereotactic device. After 3 weeks, in order to evaluate the degradation rate, intra-peritoneal rats were given apomorphine they received. The number of spins was counted for one hour after the injection. These rotations were the main parameter for diagnosis of Parkinson's disease in rats. After a month, they received probiotic treatment for one month. After this, once again, the apomorphine test was performed and the result was compared with the previous series. In the Parkinson's group who received probiotics, the number of spins from apomorphine injected significantly decreased compared with the Parkinson's group receiving probiotics (p≤0.001). In addition, Parkinson's group showed more rotation than the sham group. The results showed that, on the one hand, neurotoxin-6-hydroxy dopamine can cause Parkinson’s formation in rats, with dopamine agonist injections rotate. Probiotics, on the other hand, can reduce the number of rotations and play a role in improving it. One of the main causes of Parkinson's disease is the imbalance between free radicals and antioxidants. The use of probiotics increases the antioxidants and reduces free radicals. Many studies have shown the role of dopamine receptor agitation in neurological disorders such as Parkinson's. According to the results of this study, the probabilistic probability of Bacillus coagulance with increasing dopamine expression led to improvement of neurological disorders and treatment of Parkinson's disease in rats. The black body is the main source of dopamine secretion that plays an effective role in controlling voluntary movements and coordination in musculoskeletal conditions. Regarding the fact that in this study, 6 hydroxy-dopamine degrading regions of the brain reduced the concentration of dopamine and created Parkinson's. Probiotics may improve the disease through the concentration of dopamine in other centers of the central nervous system.

In this study the composite edible films consist of methylcellulose (1, 2.5 and 4 percent), whey protein concentrate (2, 4 and 6 percent), corn starch (1, 2 and 3 percent) and glycerol as a softener in concentration Constant (2.5 percent) and Lactobacillus rhamnosus (GG) (at 1.5*107 CFU/ml concentration) was produced. The physicochemical tests (thickness, permeability to water vapor, moisture, solubility and color changing) and mechanical properties (percentage of elongation and length of breeding) and the survival rate of Lactobacillus rhamnosus (GG) were measured. A viable bacterial study showed that the use of methyl cellulose and whey protein concentrate improved the survival of probiotic bacteria. The results of this study showed that the base formula of the film (methylcellulose concentration of 2.8 percent, whey protein concentrate 2.13 percent and corn starch 1.14 percent) improved the physico-chemical and mechanical properties of the film. The results showed that increasing the percentage Methylcellulose, whey protein and corn starch increased the amount of thickness, moisture, breaking force, color changes and viability of Lactobacillus rhamnosus (GG), and decreased solubility and water vapor permeability.

Microencapsulation technique with various hydrocolloidal coatings is used to improve viability potential of probiotics in processed food. As a probiotic product, canned jam should contain a sufficient number of viable probiotic bacteria. In this study, we evaluated the protective effects of Arabic gum and alginate on the survival of two important probiotic bacteria, Lactobacillus acidophilus DSM 1643 and Bifidobacteriumbifidum1644. Microencapsulation of these two probiotic bacteria was carried out by alginate and Arabic gum, and their impacts on the survivability and the sensory characteristics of canned carrot jam were examined for one month. According to our results, although the reduction in the number of probiotics in canned jam at different time was significant, this product was able to retain a good number of probiotic bacteria. There was a significant difference between the dropped number of coated and free bacteria. However, no significant difference was observed in the survival rate of probiotics coated by Arabic Gum and alginate. Moreover, the addition of free and encapsulated probiotics had no significant impact on texture, color and flavour of the final product during the maintenance time. The probiotic survival can be enhanced by cell protection through encapsulation.

This study was conducted to evaluate the effect of formalin and Trachyspermum ammi (ajwain) of three concentrations on the microbial population and morphology of broilers. 150 one-day-old male broiler chicks were randomly divided into groups comprising of three replicates in each group. Each replicate contained 10 chicks. Five experimental diets composed of 1) basal diet with no additive 2) basal diet+ 175 ppm T. ammi 3) basal diet+ 350 ppm T. ammi 4) basal diet+ 700 ppm T. ammi 5) basal diet+ 0.1 percent formaldehyde. At the end of the experiment intestinal morphometric indices and microbiota counts were determined. In ileum, the count of bifidobacteria decreased in the groups received formaldehyde; ajwain at 700 ppm decreased the number of Lactobacilli but had no adverse effect on beneficial bacteria (Lactobacilli and Bifidobacteria). Also, formaldehyde and ajwain at 350 and 700 ppm decreased clostridia population in Ileum. In caecum, ajwain increased Bifidobacteria population at the concentration of 700 ppm and decreased Clostridia number at the concentration of 350 and 700 ppm. There was no difference between Coliforms counts in groups in Ileum and caecum. In duodenum, villus height increased in the groups with 175 ppm ajwain, villus height and villus height to cryptal depth ratio at 350 ppm ajwain. Use of ajwain at 700 ppm has no effect on duodenum morphology. However, formaldehyde increased villus height, villus width and crypt depth but had no impact on villus height to cryptal depth ratio. In jejunum, there was no difference in intestine morphology between the groups fed by basal diet and other groups except formaldehyde increased villus height. In conclusion, both ajwain and formaldehyde could improve intestine morphology and decrease undesirable bacterial counts.

The objective of present study was to investigate technological properties of nine Streptococcus thermophilus strains isolated from South Khorasan Masske butter. Masske butter is a traditional sheep’s butter in South Khorasan region which Streptococcus thermophilus accounts for 15 percent of its microbial population. After the examination, strains showed positive reactions to following properties: di- acetyl production, proteolytic activity (7 out of 9 strains) excluding two strains, exo-polysaccharide production (8 strains). Also, all strains lost lipolytic activity in tributirin agar and urease activity. Acidification evaluation revealed a noticeable rate of reduction in pH during the first 24 hours, but in second 24- hours, pH reduction rate declined. The highest acidification activity was related to B251 (3.09±0.339) and B272 (3.08±0.1) strains and the lowest one was attributed to Y75 (4.01). Autolysis activity of strains, after 48 hours' incubation, was observed as reduction in optical density. The highest autolytic activity was related to Y106 strain (0.158±0.019) and the lowest one for Y19 (0.446±0.016). In conclusion, it is revealed that excluding y75 and y106, other strains had high proteolytic activity. Also, strain B251 which experienced the highest acidification rate in the first six hours, can be exploited as a suitable strain for starter culture or adjunct (secondary) culture in cheese or yogurt production.