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Łukasz Wiśniewski, Monika Antošová and Milan Polakovič

Abstract

A mixture of galacto-oligosaccharides and non-prebiotic sugars was separated using a simulated moving bed unit equipped with eight packed-bed columns of a cation exchanger. In order to determine operating conditions using triangle theory, equilibrium adsorption isotherms of galactose, glucose, lactose, tri- and tetragalacto-oligosaccharide were measured. It was found that each column of the SMB unit had a maximum separation efficiency of more than 3000 theoretical plates. The achieved purity of galacto-oligosaccharides in the raffinate stream was 99.9 %, similarly 99.9 % of extract was formed by non-prebiotic sugars lactose, glucose and galactose. The productivities in the raffinate and extract, were 0.6 g/(L h) and 2.4 g/(L h), respectively.

Open access

Katarzyna Wrzosek, Juraj Moravčík, Monika Antošová, Viera Illeová and Milan Polakovič

Abstract

Optimal conditions of spray drying of a fructooligosaccharide-rich mixture prepared by enzymatic conversion of sucrose were investigated. It was found that efficient drying of the mixture containing about 40 % of monosaccharides and sucrose required addition of a compound with a high glass transition temperature. The addition of maltodextrin helped to achieve satisfactory solids yield and moisture. Optimized process parameters were the feed flow rate and solids concentration, drying air flow rate and inlet temperature.

Open access

Ľubomír Činčala, Viera Illeová, Monika Antošová, Vladimír Štefuca and Milan Polakovič

Abstract

2(E)-hexenal is a green note flavour molecule that is widely used in various compositions of aromas, flavours and perfumery. As there is considerable demand for naturally produced aromas this article deals with some aspects of this C6-volatile production with regard to the selection of plant source material and reaction conditions. The following plants were tested for this purpose: runner bean (Phaseolus coccineus), common bean (Phaseolus vulgaris), three (Capsicum annuum) bell pepper varieties, garden cress (Lepidium sativum), green slicing cucumber (Cucumis sativa), mung beans (Vigna mungo) and brown lentils (Lens culinaris). Selection of source material was considered on the basis of 2(E)-hexenal yield and productivity. The common bean leafs were able to produce up to 35 mg of 2(E)-hexenal/kg fresh leaves.

Open access

Viera Illeová, Pavel Ačai, Jakub Féher and Milan Polakovič

Abstract

Biotransformation of acetophenone to R-1-phenylethanol with Pichia capsulata immobilized in Caalginate gel beads was studied. Experiments were carried out in a batch reactor stirred on an orbital shaker (300 rpm) at 25 ℃. Based on experimental data, uncoupled parameters of reaction kinetics (measurements with free cells) and diffusion coefficients (sorption method) were estimated. The model expressing the conversion of acetophenone with immobilized cells in the batch reactor consisted of mass balance equations of acetophenone and R-1-phenylethanol in the liquid and solid phases. A satisfactory agreement between the experimental and predicted values of acetophenone and R-1-phenylethanol concentrations was achieved

Open access

Gábor Megyeri, Nándor Nemestóthy, Milan Polakovic and Katalin Bélafi-Bakó

Abstract

Cheap, renewable lignocellulosic materials are relevant to the future of biofuel production. Wood and agricultural wastes (e.g. straw, corn stover) provide a raw material source that cannot be used for human consumption, thus biofuels from such sources do not threaten the food supply. The aim of the work was to carry out the pre-treatment and hydrolysis of lignocellulosic material in the same ionic liquid solvent (1-n-butyl-3- methyl-imidazolium-chloride, [Bmim]Cl), using ground wheat straw and a mixture of corn (Zea mays) leaf and stover, as substrates. Our measurements show that it is possible to achieve an acceptable glucose content from the cellulose by applying Cellic® CTec2 and Cellic® HTec2 enzyme complexes.