Ida Leskosek-Cukalovic

Electrostatic generation of alginate microbeads loaded with brewing yeast

Abstract The substantial concern with the possible use of immobilized yeast cells for beer production is reduction of internal mass transfer resistance during continuous fermentation. One way to minimise this problem is to use small-diameter beads. The effects of bead diameters in the range 0.3–2.0 mm on yeast cell immobilization and growth over a short-term cultivation were investigated. Bead diameters in the range 0.5–0.6 mm were optimal and provided rapid cell growth and the highest final cell concentration (2.33×10 9 cells/ml of beads). Electrostatic droplet generation was investigated as a technique for production of alginate microbeads. The effects of applied potential, internal needle diameter and electrode position on bead diameter were assessed. The results have shown that this method can be used for controlled production of small-size microbeads loaded with yeast. Depending on applied conditions it was possible to produce the beads in the range 250 μm–2.0 mm in diameter.

Beer Production Using Immobilised Cells

VIKTOR NEDOVI , RONNIE WILLAERT, IDA LESKOSEKUKALOVI , BOJANA OBRADOVI 3 AND BRANKO BUGARSKI Departement of Food Technology and Biochemistry, Faculty of Agriculture, University of Belgrade, Nemanjina 6, PO Box 127, 11081 Belgrade-Zemun, Serbia and Montenegro – Fax: +381 11 193659 – Email: vnedovic@EUnet.yu; Department of Ultrastructure, Flanders Interuniversity Institute for Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium – Fax: 32-2-6291963 – Email: Ronnie.Willaert@vub.ac.be; Department of Chemical Engineering, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia and Montenegro – Fax: +38111337038 – Email: bojana@elab.tmf.bg.ac.yu

Raspberry wine fermentation with suspended and immobilized yeast cells of two strains of Saccharomyces cerevisiae

The objectives of this study were to assess the differences in fermentative behaviour of two different strains of Saccharomyces cerevisiae (EC1118 and RC212) and to determine the differences in composition and sensory properties of raspberry wines fermented with immobilized and suspended yeast cells of both strains at 15 °C. Analyses of aroma compounds, glycerol, acetic acid and ethanol, as well as the kinetics of fermentation and a sensory evaluation of the wines, were performed. All fermentations with immobilized yeast cells had a shorter lag phase and faster utilization of sugars and ethanol production than those fermented with suspended cells. Slower fermentation kinetics were observed in all the samples that were fermented with strain RC212 (suspended and immobilized) than in samples fermented with strain EC1118. Significantly higher amounts of acetic acid were detected in all samples fermented with strain RC212 than in those fermented with strain EC1118 (0.282 and 0.602 g/l, respectively). Slightly higher amounts of glycerol were observed in samples fermented with strain EC1118 than in those fermented with strain RC212. Copyright

Beer as an Integral Part of Healthy Diets: Current Knowledge and Perspective

Beer is one of the oldest beverages. For the last decade, it has been the focus of significant medical research and the numerous results have given the scientific confirmation of the statement known for centuries: beer is far more than a thirst-quenching beverage. Published data have indicated that beer contains a wide range of nutrients with bioactive properties, and can be a useful part of a healthy diet, if consumed moderately. Beer can have a potentially positive influence on atherosclerosis and cardiovascular diseases, and may help protect against gallstones and kidney stone formation, dementia, osteoporosis, etc. However, beer contains some substances with potential harmful effects as well. They may cause problems, especially for individuals with gout and intolerance to gluten.