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The aim of this study was to determine the effect of mash enzymatic maceration and heating treatments before pressing on the antioxidant activities in selected berry juices. Total phenolic contents were determined by the Folin-Ciocalteau assay, antioxidant activities were determined by means of the oxygen radical absorbance capacity (ORAC) assay, and the intracellular antioxidant potentials were determined through the cellular antioxidant activity (CAA) assay. Blueberry juices exhibited the highest antioxidant activity, followed by black currant and raspberry juices. The mash enzyme treatment with Pectinex® Ultra Color enzyme preparation, improved the antioxidant activities in vitro. ORAC values correlated with CAA values (R 2 = 0.91) and a slightly positive correlation was observed between Folin-Ciocalteau and CAA assays (R 2 = 0.56). The findings support the observation that the mash enzymatic treatment of macerated fruits enhances their antioxidant activity. Considering the chemical assays (ORAC and total phenolic content), a combined treatment with heating to 85°C followed by mash enzymatic treatment was the most effective. Considering a biological model through the CAA assay, however, a comparable improvement in antioxidant activity resulted from the enzymatic and the combined treatments. Overall, the data showed that maceration enzymatic treatment improves the intracellular antioxidant activity in HepG2 human cells. To the best of our knowledge, this is the first report on the effect of the antioxidant potential of mash enzymatic and heating treatments assessed by means of a cellular approach.

Dry as well as wet coating techniques were developed to coat glass beads as filter media to remove manganese from water. For dry coating, powdered manganese oxide ore was fixed on the media surface. Wet coating was achieved by depositing synthetic manganese oxides onto the bead surface. The media were characterized by electron microscopy as well as by testing the removal of Mn2+ in a continuous stirred tank reactor. Image analysis of microscopic pictures illustrated that the surface area could partly be coated by powdered material using dry coating methods, whereas complete coverage was achieved using wet coating approaches. With regard to dry coating techniques, Mn sorption uptake was higher for the adhesively dry coated glass beads than for beads where a binding agent was used. The wet coating column approach proved to be more successful than the coating of beads in a stirred tank reactor. Mn removal capability of the beads increased with higher reactant concentrations during coating. Oxide-coated glass beads applied in filter systems have the potential to improve conventional demanganization processes.

Abstract:The demand for antioxidant-rich beverages is steadily expanding. At the same time, the possibility of manufacturing products with reduced sugar content, sweetened with natural ingredients, represents a decisive aspect of obtaining quality products with health benefits. Stevia rebaudiana Bertoni (stevia) is a natural sweetener that can help to control caloric intake and is also a good source of antioxidant compounds. The present study was designed to assess the feasibility of producing high-quality berry juices sweetened with dry-grinded stevia leaves or their crude extract. The effect of the stevia supplementation on the antioxidant activities of raspberry juices was determined at two different production steps by means of the Folin-Ciocalteu, the oxygen radical absorbance capacity (ORAC), and the cellular antioxidant activity (CAA) assays. The addition of stevia significantly increased the antioxidant activity of the juices and resulted in significantly higher ascorbic acid and total phenolic content. A positive correlation was observed between ORAC, CAA, and total phenolic values. These findings show that supplementation with stevia not only promotes a healthy diet by reducing sugar intake but may also enhance the antioxidant potential of the beverage.

The synthesis of quinolines from alcohols and 2‐nitrobenzaldehydes is described. Unreactive alcohols and 2‐nitrobenzaldehydes were concurrently converted to the reactive reactants for a Friedländer annulation via a hydrogen transfer. Tris(triphenylphosphine)ruthenium(II) dichloride [Ru(PPh3)3Cl2] appeared to serve the dual role of an efficient hydrogen transfer catalyst and a suitable Friedländer annulation catalyst.