RESUMO
One of the challenges of the food industry is detecting the potential of novel non-dairy food matrices to deliver probiotic bacteria to humans as cholesterol-free products, suitable for people with lactose intolerance and sensitivity to dairy proteins. In this study, the possibility of adding sprouted quinoa milk (SQM) at 0%, 50%, and 100% levels in probiotic non-dairy dessert containing native Lactobacillus plantarum isolated from camel milk was investigated. Physicochemical, functional, microbiological, color, texture, and organoleptic characteristics of probiotic dessert samples were evaluated during 1, 7, and 14 days of storage at 4°C. According to the results, fat, protein, carbohydrates, and ash increased significantly during germination (p < .05). With boosting the SQM levels in the probiotic desserts, the number of soluble solids increased, and the syneresis decreased significantly (p < .05). The simultaneous increase in SQM levels and time caused an increase in acidity and decreased the moisture content of the samples. As the storage time increased, the intensity of the syneresis also decreased. The brightness index in all samples containing SQM was lower than in the control sample. During storage, the viable cell number of Lactobacillus plantarum in all samples decreased significantly. However, they were above the minimum required for FDA recommendation (6 log CFU g-1), varying from 4.6 × 108 CFU/mL to 4.3 × 107 CFU/mL for 50% SQM treatment. It was concluded that probiotic desserts containing SQM up to 50% could be properly presented in the market as gluten-free and functional food products.
RESUMO
The lack of cost-effective methods for producing antimicrobial peptides has made it impossible to use their high potential as a new and powerful class of antimicrobial agents. In recent years, extensive research has been conducted to decrease the cost of recombinant proteins production through microorganisms, transgenic animals, and plants. Well-known genetic and physiological characteristics, short-term proliferation, and ease of manipulation make E. coli expression system a valuable host for recombinant proteins production. Expression in periplasmic space is recommended to reduce the inherently destructive behavior of antimicrobial peptides against the expressing microorganism and to decline susceptibility to proteolytic degradation. In this study, a pET-based expression system was used to express buforin I at E. coli periplasmic space, and its antimicrobial, hemolytic, and cell toxicity activities as well as structural stability were evaluated. The hemolysis activity and cytotoxicity of His-tagged buforin I were negligible and its antimicrobial activity did not show a significant difference compared to synthetic buforin I. In addition, in silico investigating of stability of native and His-tagged buforin I showed that RMSF, RMSD and Rg curves had followed a similar trend during 150 ns simulation. Furthermore, evaluating the modelled structures, FTIR and X-ray methods of both peptides indicated an insignificant structural difference. It was concluded that the recombinant buforin I could be a viable alternative to some currently used antibiotics by successfully expressing it in the pET-based expression system.
