Abstract:The object of this study was to discover an alternative therapeutic agent with fewer side effects against acne vulgaris, one of the most common skin diseases. Acne vulgaris is often associated with acne-related bacteria such as Propionibacterium acnes, Staphylococcus epidermidis, Staphylococcus aureus, and Pseudomonas aeruginosa. Some of these bacteria exhibit a resistance against commercial antibiotics that have been used in the treatment of acne vulgaris (tetracycline, erythromycin, and lincomycin). In the current study, we tested in vitro antibacterial effect of chitosan-phytochemical conjugates on acne-related bacteria. Three chitosan-phytochemical conjugates used in this study exhibited stronger antibacterial activity than that of chitosan (unmodified control). Chitosan-caffeic acid conjugate (CCA) showed the highest antibacterial effect on acne-related bacteria along with minimum inhibitory concentration (MIC; 8 to 256 µg/mL). Additionally, the MIC values of antibiotics against antibiotic-resistant P. acnes and P. aeruginosa strains were dramatically reduced in combination with CCA, suggesting that CCA would restore the antibacterial activity of the antibiotics. The analysis of fractional inhibitory concentration (FIC) indices clearly revealed a synergistic antibacterial effect of CCA with antibiotics. Thus, the median sum of FIC (∑FIC) values against the antibiotic-resistant bacterial strains ranged from 0.375 to 0.533 in the combination mode of CCA and antibiotics. The results of the present study suggested a potential possibility of chitosan-phytochemical conjugates in the control of infections related to acne vulgaris.
The objective of this study was to select an effective microbial strain to improve the functional qualities of Eisenia bicyclis water extract by fermentation. For this purpose, several microorganisms isolated from traditional Korean fermented foods were inoculated and cultivated in E. bicyclis water extract. Ultimately, yeast strain YM-1 was selected for further study based on its total phenolic compound (TP) content and antioxidant activity, which were enhanced by microbial fermentation. The extract fermented by YM-1 exhibited a superior TP content and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity compared to extracts fermented by other microbes. The highest TP content and DPPH radical scavenging activity were observed after one day of YM-1 fermentation. Yeast strain YM-1 was identified as Candida utilis based on an analysis of its physiological characteristics. During fermentation of the extract by C. utilis YM-1, no significant difference was observed in the proximate composition, including moisture, crude lipid, crude protein, and crude ash. Fermentation by C. utilis YM-1 resulted in enhanced biological activity, including increases in the TP content and antioxidant activity. Thus, fermentation by C. utilis YM-1 is an attractive strategy for developing value-added food ingredients.
The moisture sorption characteristics of Lactobacillus brevis‐fermented sea tangle powder were investigated. Moisture sorption isotherms were prepared at 4, 25, and 37°C in a water activity (aw) range of 0–0.96 and exhibited typical J‐shaped type III sorption characteristics, most likely due to the high carbohydrate content (65.7%) of the powder. The fermented sea tangle powder had greater moisture sorption capacity than those reported for other seaweeds, and changed to rubbery or liquid states when stored at aw > 0.5. The Peleg and GAB models accurately described the sorption isotherms, and the monolayer moisture contents were 0.176–0.443 g water/g dry matter. The moisture sorption was an exothermic, enthalpy‐driven, spontaneous process, and the enthalpy–entropy compensation existed with an isokinetic temperature of 448.1 K. The net isosteric heat of moisture sorption exponentially decreased from 15.02 to 0.49 kJ/mol as the equilibrium moisture content increased from 0.02 to 1.29 g water/g dry matter.
Practical applications
Sea tangle is known to possess various biological and nutraceutical properties, such as antitumor and anticoagulant, antiproliferative, and antioxidant activities, which is commercially available in Pacific and Asian countries as a traditional functional food. The present study investigating information of moisture sorption characteristics of L. brevis‐fermented sea tangle powder will be useful to understand its strongly hygroscopic nature and resulting low storage stability, which limits the easy and convenience of its handling and application. The information also will be important for improving its shelf life and retaining quality across postharvest processing.
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