A food grade approach for the isolation of major alkylresorcinols (ARs) from rye bran applying tailored supercritical carbon dioxide(scCO(2)) extraction combined with HPLC

Tailored supercritical carbon dioxide (scCO(2)) extraction of alkyhesorcinols (ARs) from rye bran resulting in pre-purification of ARs already during extraction process. The pre-purification was achieved by splitting the extraction process in 2 steps.. In both steps, the CO2 pressure was set at 25 MPa with a flow rate of 10 g/min. The first step was carried out at 70 degrees C. 0.06% of ethanolic co-solvent for 2 h, followed by the second step at 45,C using 10% of ethanolic co-solvent for 4 h, resulting in a pre-purified ARs extract. From the pre-purified scCO(2) extract, chromatographed on C8 column, were obtained pure ARs homologues of C17, C19 and C21 (68% of total) eluting separately in a linear gradient of ethanol. Additionally, a rapid method for the isolation of high purified pools of ARs homologues using a disposable solid phase extraction SPE-C18 column and a step gradient of ethanol was developed. (C) 2009 Elsevier B.V. All rights reserved

Extraction of rosavin from Rhodiola rosea root using supercritical carbon dioxide with water

In this study, a new extraction method for the isolation of rosavin from dried crushed roots of Rhodiola rosea is being developed using supercritical CO2 and water. Rosavin extracts quantitatively and qualitatively were compared to commonly used solvents such as methanol, ethanol and ethyl acetate. By HPLC analysis rosavin was found to be the dominant compound in extracts obtained by both extraction methods. Quantitative differences were observed between the two extraction methods. Among the solvents, methanol yielded 3.3% while ethanol only 1.2% of rosavin. Supercritical CO2 and water at extraction temperature 80 degrees C and 5 h yielded 4.5% of rosavin. (C) 2009 Elsevier B.V. All rights reserved

Supercritical Fluids as Alternative, Safe, Food-Processing Media: An Overview.

The continuous growth of world population and its concentration in the urban areas require food supplies that are continuous, sufficient and of good quality. To resolve this problem techniques have been developed for increasing food quantity and quality. The techniques are applied throughout the food chain from production, conservation and during distribution to the consumers (from "the field to the fork"). During handling of food, chemicals are often deliberately added to achieve improved processing and better quality. This is one of the main reasons food undergoes different kinds of contamination. This overview focuses on the application of supercritical fluids as media for handling food materials during processing with the perspective of reducing chemical contamination of food. Examples of developmental applications of this technique and on research work in process are presented. Emphasis is given to extraction and biotransformation techniques

Optical Lectin Based Biosensor as Tool for Bacteria Identification

Biosensor techniques are based on biospecific interaction between the biological parts of biosensor with the analyte. In biosensor construction, antibodies are usually used for the detection of analytes such as microorganism, because of very strong and highly specific interaction. The disadvantages of this assay are a long time needed for antibody isolation and purification as well as difficult regeneration of biosensor chip. The use of lectins instead of antibodies could solve these problems because a several hundred lectins are commercially available and their stability in standard buffers is better compared to monoclonal antibodies. While antibody can only be used to detect that antigen it was designed for, lectin as low affinity molecule may bind several different pathogens. Using the discriminative effect of an artificial neural network the application of a lectin array will compensate for the lower specificity. Microbial surfaces bear many of the sugar residues capable of interacting with lectins. The ability of lectins to react with microbial glycoconjugates means that it is possible to employ them as probes and sorbents for whole cells, mutants and numerous cellular constituents and metabolites, and it makes them useful tools for identification or typing of bacteria. Lectins are attractive reagents for the clinical diagnostic laboratory because of their diverse specificity, commercial availability, a wide range of molecular weights, and their stability in standard buffers. The construction of lectin biosensor could be an advantage method for detection of pathogenic bacteria

Extraction of polar lipids from bifidobacteria by supercritical carbon dioxide (scCO(2))

This study describes an efficient isolation procedure for the extraction of polar lipids from two strains of bifidobacteria - Bifidobacterium longum and Bifidobacterium angulatum. We first compared the lipid profiles of two strains of bifidobacteria and showed that the strains of the same genus may differ by lipid composition of cell walls. The polar lipids were isolated using the following conditions: pressure 250 bar, temperature 45 degrees C, CO2 flow rate 5 g/min, hydromethanolic co-solvent concentration 10% (v/v). In the lipid extracts the carbohydrate moiety of glycolipids and in phospholipids phosphorus moiety were quantified and compared to the reference material isolated by classical extraction. Thrice the amount of glycolipids and phospholipids in comparison with classical method was found in the lipid extract from B. longum obtained with scCO(2), and twice the amount of more - from B. angulatum. By TLC were identified different glycolipid profiles of these strains, four glycolipids were detected from B. longum and seven glycolipids from B. angulatum. From 5 g of biomass during prolonged fractionated extraction (12 h) 2.80 and 3.11 mg of glycolipids, 1.86 and 1.88 mg of phospholipids from B. longum and B. angulatum was obtained, respectively. (C) 2011 Elsevier B.V. All rights reserved

Improvement of Industrial-scale Anaerobic Digestion by Enzymes Combined with Chemical Treatment

The effect of a new developed process for biogas boosting was studied at a municipal wastewater treatment plant in industrial scale over the period of three years. After pre-selection studies in the lab and short industrial setups, four hydrolytic enzymes and sodium citrate were combined and tested for a two-year period. The year 2007 was picked as reference year. In February 2008, the dosage was started. Some immediate changes in the digestion system could be observed like gas production increase and sludge volume reduction. Yet the adaption to the chemical dosage took several months. A stable production was achieved about 6 months after the start of the dosage. In 2009 it was assumed that the system had adapted to the chemical dosages and that stable running parameters were achieved. Mainly the results from the years 2007 as reference and 2009 as resulting year are compared, showing clearly positive effects on process stability, increased gas production by 16% and minimized sludge volumes by 13%

Supercritical Carbon Dioxide in the Biotechnology of Amphiphiles

This article is an overview, introducing the currently used supercritical carbon dioxide (scCO2) based technology in association to biotechnological applications. Within each application, the basic principles of the technique, a description of the instrumentation, methodology, and problems encountered, and advantages over the traditional methods are discussed. The areas covered in this paper include pure supercritical CO2 properties, coـsolvents role, and the interactions between the scCO2 and the amphiphiles involved. Extraction and reaction are discussed