Effect of gamma irradiation on physicochemical properties and microbiological quality of yellow noodle with addition of rice bran

Irradiation is principally used as preservation to improve food shelf-life. The effect of gamma irradiation on physicochemical properties and microbiological quality of yellow noodles with addition of rice bran were observed. Wheat flour was replaced with rice bran at different levels (5%, 10%, 15%, 20%). The rice bran yellow (RBY) noodles were exposed to different irradiation doses (4 kGy, 6 kGy 8 kGy) using Cobalt-60. Gamma irradiation significantly decreased the pH, moisture content, hardness, lightness and redness; whereas significantly increased the breaking length of RBY noodles. Total plate count of RBY noodles stored at 8°C was observed on day 0, 3, 5 and 7. No bacterial growth was observed at dose 6 kGy and 8 kGy on day 5 and 7. Micrograph of RBY noodles under SEM at 500x magnification showed that different gamma irradiation dose and replacement of rice bran resulted in small changes on starch granules. Additionally, increment of rice bran showed significant increase in moisture content, breaking length, redness, cooking yield and cooking loss; but significantly decreased the water activity at high dose, hardness, lightness and yellowness. In conclusion, irradiation positively impacted the microbiological quality and incorporation of rice bran gave positive effect on the cooking yield

Polysaccharides of Pleurotus flabellatus strain Mynuk produced by submerged fermentation as a promising novel tool against adhesion and biofilm formation of foodborne pathogens

Foodborne bacteria biofilms present a major concern for the food industry. Although their numerous biological activities are well established, there is little research to date on the use of polysaccharides of mushroom origin as a possible solution for preventing biofilm formation. Therefore, the aim of this study was to examine the anti adhesion and antibiofilm effects of several types of Pleurotus flabellatus strain Mynuk polysaccharide extracts (PFSMpe), produced by air-lift submerged fermentation, against American Type Culture Collection (ATCC) and clinical strains of foodborne bacteria, as well as the cytotoxicity of these extracts. PFSMpe exhibited antiadhesion activity toward clinical isolates, and the percentage of adhesion inhibition was highest for water (WE) and exopolysaccharide (EXOPE) extracts (> 50%) against Enterococcus faecalis. Selected ATCC strains were more resistant than clinical strains, indicating the antiquorum sensing mechanism of PFSMpe action. Antibiofilm activity was similar to antiadhesion activity and WE showed the strongest effect, again on E. faecalis. Differences in antiadhesion and antibiofilm effects of PFSMpe may be explained by differences in chemical composition, with crude extracts showing greater efficiency due to a synergistic effect. PFSMpe did not exhibit cyctotoxic activity against normal human cell lines. Overall, the findings of this study show that PFSMpe represents a promising novel strategy against bacterial biofilms