Fraktionierung von Sojalecithin mit Alkoholen

Fractionation of Soy Lecithin with Alcohols Commercial soy lecithin contains about 55% phosphatides, which consist of about 30% phosphatidyl choline (PC), 20% phosphatidyl ethanolamine (PE) and phosphatidyl inosite (PI) and phytoglykolipids (each 15%). For many scopes or application lecithin preparations with a higher PC-content are desired, which can be obtained as known for long by fractionation of raw lecithin by alcohols. It was tested in systematic trials which solvent or solvent mixture the highest selectivity has and which yield the different extraction processes have. Products with highest PC/PE quotient were obtained by use of a) anhydrous methanol, b) water containing methanol or ethanol with 5 to 20% water and c) the ternary mixture methanol-isopropanol-water (55 + 40 + 5% v/v). The extraction yield of the one-step process was between 30 and 40%. It could be increased up to about 80% by simultaneous use of non polar solvents, e.g. hexane, or by use of counter current technic.     

Bestimmung der Oxydationsstabilität von Ölen und Fetten mit Hilfe einer automatischen Version des SWIFT-Testes

Determination of Oxidation Stability of Oils and Fats by an Automated Version of SWIFT-Test An automated method has been developed for the determination of the duration of induction period in SWIFT-Stability test. The method is based on following principle: If air current, emerging from SWIFT-tubes, is bubbled into a vessel containing water in which a zinc/copper element is immersed, voltage of the latter increases as soon as it comes in contact with the low molecular acids that are formed during the process of oxidation. The termination of the induction period is indicated by a sudden alteration in the direction of the time-voltage curve. The method can be carried out without constant supervision; it is suitable for the determination of quality of edible oils and fats, assessment of the effect of refining processes and of pro- and antioxidants, as well as for the optimum selection of fat blends.     

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Functional Enzyme Mimics for Oxidative Halogenation Reactions that Combat Biofilm Formation

Transition‐metal oxide nanoparticles and molecular coordination compounds are highlighted as functional mimics of halogenating enzymes. These enzymes are involved in halometabolite biosynthesis. Their activity is based upon the formation of hypohalous acids from halides and hydrogen peroxide or oxygen, which form bioactive secondary metabolites of microbial origin with strong antibacterial and antifungal activities in follow‐up reactions. Therefore, enzyme mimics and halogenating enzymes may be valuable tools to combat biofilm formation. Here, halogenating enzyme models are briefly described, enzyme mimics are classified according to their catalytic functions, and current knowledge about the settlement chemistry and adhesion of fouling organisms is summarized. Enzyme mimics with the highest potential are showcased. They may find application in antifouling coatings, indoor and outdoor paints, polymer membranes for water desalination, or in aquacultures, but also on surfaces for food packaging, door handles, hand rails, push buttons, keyboards, and other elements made of plastic where biofilms are present. The use of natural compounds, formed in situ with nontoxic and abundant metal oxide enzyme mimics, represents a novel and efficient “green” strategy to emulate and utilize a natural defense system for preventing bacterial colonization and biofilm growth.     

Dextran: Influence of Molecular Weight in Antioxidant Properties and Immunomodulatory Potential

Dextrans (α-d-glucans) extracted from Leuconostoc mesenteroides, with molecular weights (M_W) of 10 (D10), 40 (D40) and 147 (D147) kDa, were evaluated as antioxidant, anticoagulant and immunomodulatory drugs for the first time. None presented anticoagulant activity. As for the antioxidant and immunomodulatory tests, a specific test showed an increase in the dextran activity that was proportional to the increase in molecular weight. In a different assay, however, activity decreased or showed no correlation to the M_W. As an example, the reducing power assay showed that D147 was twice as potent as other dextrans. On the other hand, all three samples showed similar activity (50%) when it came to scavenging the OH radical, whereas only the D10 sample showed sharp activity (50%) when it came to scavenging the superoxide ion. D40 was the single dextran that presented with immunomodulatory features since it stimulated the proliferation (~50%) of murine macrophages (RAW 264.7) and decreased the release of nitric oxide (~40%) by the cells, both in the absence and presence of lipopolysaccharides (LPS). In addition, D40 showed a greater scavenging activity (50%) for the hydrogen peroxide, which caused it to also be the more potent dextran when it came to inhibiting lipid peroxidation (70%). These points toward dextrans with a 40 kDa weight as being ideal for antioxidant and immunomodulatory use. However, future studies with the D40 and other similarly 40 kDa dextrans are underway to confirm this hypothesis.