مجله میکروبیولوژی کاربردی در صنایع غذایی
سال هفتم شماره 2 (تابستان 1400)

Wound healing is a dynamic and complex process. Wound dressings have gain considerable attention because of antimicrobial properties and accelerating wound healing process. Chitosan is a biodegradable polymer with antibacterial effects which has great application in production of novel wound dressings. The aim of this study was production a novel wound dressing based on the metabolite of Lactobacillus reuteri and chitosan and evaluation of its effect on excisional wound model. For this purpose, cell free supernatant of the bacterium was prepared and mixed with chitosan: polyethylene glycol suspension. The suspension was dried after casting and evaluated. Then, 45 male wistar rats (3 weeks and 200-240 g body weight) were randomly divided in 3 groups (Ctrl-: without treatment, Chitosan: treatment with chitosan dressing, Postbiotic: treatment with bacterial supernatant: chitosan dressing). After 10 days of adaptation, a cutaneous wound with 1.3 ×1.3 cm2 diameter was created on the back of animals. Immediately, the wounds were covered with correlated dressings and stabilized. Three rats from each group were selected and sacrificed on days 1, 3, 7, 14, and 21 of post wounding. Wound healing effect was evaluated by identification of wound surface area and histological analysis. Besides, the level of IL-1 and IL-6 gene expression were quantified by RT-PCR methods. Results showed that application of postbiotis dressing accelerated wound healing process in rats. Histological analysis proved the positive effects of this dressing in accelerating of inflammatory phase and elastin-collagen deposition. It could be concluded that postbiotic dressing improve wound healing process by reducing the inflammatory phase and initiation of proliferative phase.

The cheese whey is in an abundant residue obtained during the cheese processing and its disposal in the environment causes several drawbacks. The bioconversion of this by-product in added-value ones is an important alternative to overcome this environmental problem. In this study the application of cheese whey as carbon source for xanthan gum production was investigated Using strain of Xanthomonas campestris PTCC 1473 by submerge fermentation. Four factor each in 4 level including: whey heat treatment time ]10, 20, 40, 80)minute)[, nitrogen source types (ammonium nitrate ,ammonium nitrate& yeast extract, ammonium nitrate & pepton ,yeast extract &pepton) KH2PO4 concentrations (0,1,2,3% V/W) and PH (5, 6, 7, 8). were evaluated by Taguchi methodology in order to improve the xanthan gum production. Also the viscosity of xanthan gum was determined and FTIR analysis was measured for xanthan production confirmation. Three of four factors including KH2PO4 concentration, nitrogen source type and substrate heat treatment time had significant effects on xanthan gum production confirmers. (P

Bread currently accounts for the majority of the population's diet;and a strict lifelong gluten-free diet is currently the only available treatment to cope with gluten intolerance. Therefore, food experts are constantly finding ways to produce and improve the quality of gluten-free bread. This study was performed to qualitatively evaluate the effect of aspergillopepsin enzyme on degradation of gluten during in wheat dough fermentation. The qualitative effects of aspergillopepsin expressed in bakery yeast on gluten protein and on the rheological properties of wheat flour dough were studied and the rheological properties of the dough were investigated by a rheometer. In addition, initial flour tests were evaluated such as measuring the amount of crude fiber, fat, moisture, wet gluten, protein, pH, ash. Samples prepared with engineered yeast dough had low elasticity, no gas production, relatively loose texture and no specific odor, which confirmed that the gluten network was not formed. Finally, the study of the rheological properties of the dough showed that this enzyme affects the texture of the dough. For this purpose, here we investigate the effectiveness of aspergillopepsin enzyme have been shown to effectively Therefore, the feasibility of producing high-quality bread from wheat flour treatment with aspergillopepsin has been shown

The emergence of antibiotic resistance has a serious challenge to the control and treatment of pathogenic bacterial infections. Nanotechnology and the use of nanoparticles are some of the most effective approaches to overcome this topic. Silver nanoparticles have been studied as an antibacterial agent more than other nanoparticles by researchers. In this study, the antibacterial effect of silver nanoparticles synthesized by three methods including; bacterial, plant extract, and chemical procedure were compared. So, we synthesized silver nanoparticles using the supernatant of Bacillus spp. with Zarshouran gold mine source, oregano extract, and sodium borohydride chemical. Then, the minimum inhibitory concentrations (MIC) of silver nanoparticles against Escherichia coli, Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa were investigated. Comparison of the MIC results showed that the antibacterial effect of nanoparticles synthesized with Bacillus spp. was more than fivefold higher than the plant extract and chemical synthesis method. We showed that the minimum inhibitory concentration of nanoparticles synthesized with Bacillus spp., oregano extract, and sodium borohydride ranged from (1.4-5.6 μg / mL), (5.6-22.5 μg / mL), and (22.5-45 μg / mL), respectively.

This study was conducted to investigate the effects of In ovo feeding of grape seed extract (GSE) and vitamin C on hatchability, performance, microbial count of ileal digesta, and weight of lymphatic organs of broiler chickens during starter and grower period. The first study was carried out in a randomized block design with 7 treatments, 5 blocks, and 98 eggs per block. Experimental treatments included: Control (no puncture), Control (punctured), Sham control (0.5 ml saline), 3 mg vitamin C, 3, 4.5 or 6 mg GSE. In ovo feeding of 4.5 mg GSE caused higher hatchability compared to control groups. In the second experiment the hatched chicks of the first trail were reared in a completely randomized design with 5 replicates and 8 chicks per each up to 22 d. The results showed that in ovo injection of 4.5, 6 mg GSE or 3 mg vitamin C per egg increased GPx concentration in chicks hemolysate. In ovo feeding of 4.5 mg GSE or 3 mg vitamin C per egg increased the chicks body weight gain compared to control groups during starter period. In ovo injection of different levels of GSE or vitamin C decreased E. Coli count in ileum contents at 10 d

Milk is one of the most widely consumed dairy products in the world that has a high nutritional value. Due to the presence of several bioactive compounds, this food has different biological properties such as antimicrobial activity. In recent years, the tendency to consume milk from domestic animals other than cattle such as donkey, horse and camel milk has increased. This study aimed to evaluate and compare the natural antimicrobial properties of raw milk of horse, donkey and camel againstBacillus cereus (as an important foodborne pathogen). Also, the effect of storage temperature on the antimicrobial properties of milk samples of these animals was studied. After a random collection of samples, the B. cereus was inoculated into the samples and they were incubated at 5, 10 and 20 °C for 96 h. To evaluate the inhibitory activity of milk samples against the behavior of this bacterium, samples were cultured on the selective medium every 24 h. At temperatures of 5 and 10 °C, the milk of these animals showed a better antimicrobial activity compared to 20 °C. The antimicrobial effect of horse and camel milk at 5 and 10 °C was higher than donkey milk after 96 h of storage, while the effect of donkey and horse milk at 20 °C was stronger than camel milk particularly during 72 h of storage. According to the findings of this study, it can be concluded that the level of natural antimicrobial activity of milk varies depending on the animal species and storage temperature.