90 research outputs found

    Kombucha fermentation on raw extracts of different cultivars of Jerusalem artichoke

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    Kombucha is a symbiosis between yeasts and acetic bacteria. It usually grows on sweetened black tea, but cultivation is possible on many other substrates. Jerusalem artichoke tubers extract is one of them. Tubers are suitable for the dietetic nutrition because of the low monosaccharide content and presence of some polyfructan ingredients which act as prebiotic. Five different cultivars of Jerusalem artichoke were used for the preparation of substrates for kombucha fermentation. The aim of this paper was the investigation of the influence of different Jerusalem artichoke cultivars on metabolic activity of kombucha. Composition of carbohydrates was followed using thin-layer chromatography and pH, reducing sugars content and yield of biomass were measured. Most of the samples with Jerusalem artichoke tubers extract contained fructose, probably small amount of glucose, fructo-oligosaccharides with different degree of polymerization and, inulin. Considering TLC chromatograms, Jerusalem artichoke cultivar did not affect significantly the composition of oligosaccharides in the fermentative liquid, as only minor differences were observed

    Određivanje fenmedifama i desmedifama u komercijalnom herbicidu tečnom hromatografijom pod visokim pritiskom

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    Betanal AM-11 is the herbicide that is using to control one-year old weeds with wide leafs in sugar beet fields. Active ingredients of the herbicide are phenmedipham and desmedipham. Commercial emulsifiable concentrate (EC) contains 80 g/L ( 10% of each active compound. We applied high performance liquid chromatography (HPLC) with diode array detector (DAD) at 254 nm for the determination of phenmedipham and desmedipham in commercial samples of Betanal AM-11. This method involves reversed-phase separation of the components on C-18 bonded silica with methanol-water (51+49, v/v) as the eluent. The procedure was highly selective and reproducible and can be successfully used in determining contents of phenmedipham and desmedipham on micro and macro levels.Betanal AM-11 je herbicid koji se koristi za suzbijanje jednogodišnjih širokolisnih korova na poljima sa šećernom repom. Aktivni sastojci herbicida su fenmedifam i desmedifam. Komercijalni koncentrat za emulziju (ES) sadrži 80 g/l ( 10% svake aktivne komponente. Za određivanje fenmedifama i desmedifama u komercijalnim uzorcima Betanala AM-11 je primenjena tečna hromatografija pod visokim pritiskom, DAD detektor i talasna dužina od 254 nm. Metod je obuhvatio razdvajanje komponenata na obrnutim fazama sa kolonom C-18 i eluentom metanol-voda (51+49, v/v). Postupak je veoma selektivan i reproduktivan i može se koristiti za određivanje makro- i mikro količina fenmedifama i desmedifama

    Batch fermentation of black tea by kombucha: A contribution to scale-up

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    Local domestic Kombucha was used in fermentation of 1.5 g L-1 of black tea (Indian tea, " Vitamin ", Horgoš, Serbia and Montenegro), sweetened with approximately 70 g L'1 of sucrose. Inoculation was performed either with 10% or 15% (v/v) of fermentation broth from previous process. The fermentation was conducted in geometrically similar vessels with 0.4 L, 0.8 L, 4 L and 8 L of substrate, at 22±1 °C for 28 days. The samples were analyzed after 3, 4 5, 6, 7, 10, 14 and 28 days, so that their pH values, content of total acids sucrose, glucose and fructose contents, as well as contents of ethanol and vitamin C were determined. Based on the experiment design, the response surface for the product pH, as a function of time, beverage volume and inoculum concentration, was defined in the form of a second-order polynomial. From the obtained response surface, a formula for scaling-up of the process was derived

    Influence of black tea concentrate on kombucha fermentation

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    Kombucha is cultivated on substrates prepared with different concentrations of black tea and substrate obtained by diluting a substrate with highest concentration of black tea with cold tap water. Qualify of produced beverages is compared with the beverage obtained in traditional fermentation of 1.5 g/L of black tea, sweetened with 70 g/L of sucrose. Inoculation was performed with 10% (v/v) of fermentation liquid from previous process, and the fermentation was carried out at 28°C under aerobic conditions, for ten days. Process of fermentation was monitored by following pH, total acids. D-gluconic acid and caffeine content. Beverages obtained in fermentation with diluted black tea concentrate had similar amounts of investigated metabolites compared with traditional one. Use of diluted black tea concentrate as a substrate needs the shorter time for the substrate preparation, which significantly saves energy

    Long Range Hydration Effects in Electrolytic Free Suspended Black Films

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    The force law within free suspended black films made of negatively charged Aerosol-OT (AOT) with added LiCl or CsCl is studied accurately using X-ray reflectivity (ca. 1{\AA}). We find an electrolyte concentration threshold above which a substantial additional repulsion is detected in the LiCl films, up to distances of 100 {\AA}. We interpret this phenomenon as an augmentation of the Debye screening length, due to the local screening of the condensed hydrophilic counterions by the primary hydration shell.Comment: 4 pages, 4 figures, to be published Phys. Rev. Let

    Ribonucleic acids in different tea fungus beverages

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    In human nutrition, nucleic acids have to be balanced and limited up to 2 g/day because purines are degraded to urate, and excessive production of urate is a cause of gout which primarily affects adult males. Tea fungus beverage is a well known drink with high nutritional value and certain curative effects. Its benefits have been proved in a number of studies but it is still necessary to examine some potential harmful effects of this beverage. The aim of this paper was to investigate content of ribonucleic acids (RNA) produced during tea fungus fermentation on a usual substrate sweetened black tea, and on Jerusalem artichoke tubers (J.A.T) extract using method by Munro and Fleck (1966). pH, ribonucleic acids and also the production of proteins that affect purity of nucleic acids preparations were monitored. A higher value of RNA has been noticed in J.A.T. beverage (0.57 mg/ml) and with observation of usual daily dose of the beverage it is completely safe and useful one

    Use of milk-based kombucha inoculum for milk fermentation

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    In this investigation fermented milk beverages with 0.9% of milk fat were produced using 10 and 15% (v/v) of traditional and milk-based kombucha inoculum by application of appropriate technological process. Milk fermentation using two types and concentrations of kombucha inoculum were stopped when the pH reached 4.5. Sigmoidal fermentation profiles were noticed with traditional kombucha inoculums and linear with milk-based kombucha inoculums. Chemical content and physico-chemical characteristics of kombucha fermented milk beverages were typical and yoghurt-like for all obtained products. The best textural and sensory characteristics possesed beverage obtained in fermentation of milk using 10% (v/v) of milk-based kombucha inoculum

    Antifeeding and insecticidal activity of Ailanthus altissima and Morus alba extracts against gipsy moth (Lymantria dispar (L.), lepidoptera, lymantridae) larvae under laboratory conditions

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    Gypsy moth (Lymantria dispar (L.) is one of most important defoliating pests of deciduous trees. Due to increased environmental demands, the use of plant-based preparations is gaining in importance as a control option for this pest in forestry, agriculture and horticulture. The aim of this study was to evaluate antifeeding and insecticidal activity of 0.5, 1 and 2% extracts of Ailanthus altissima bark and leaves, and Morus alba leaves, against L. dispar larvae under laboratory conditions. Antioxidant capacity of plant extracts was determined, as well as the content of phenolic compounds by spectrophotometric and HPLC-DAD methods. Antifeeding and insecticidal effects were tested in a “no-choice” test. The highest content of all bioactive phenolic compounds was in A. altissima bark and M. alba leaf extracts. The lowest leaf consumption after 24 and 48 h was in A. аltissima bark (5.03, 9.30%, respectively) and M. alba leaf (1.44, 3.22%, respectively) extracts. A. altissima bark and M. alba leaf extracts expressed strong antifeeding activity. After 24 h, all extracts expressed slight insecticidal effect (2.25-17.50% of mortality). The mortality increased after 48 h in treatments with A. altissima bark extract, at all applied concentrations (40.0-57.50%) and M. alba leaves at 1 and 2% concentrations (30.0-62.50%). Our results indicate that extracts of A. altissima bark and M. alba leaves may act as effective low-cost natural protectants able to control the presence of gypsy moth in ecosystems. Extracts of A. altissima bark and M. alba leaves expressed strong antifeeding activity and significant insecticidal effect on gypsy moth larvae, at all applied concentrations
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