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Particulate β-glucans were isolated from brewer’s yeast using three different procedures – alkaline (A), alkaline-acidic (AA) and alkaline-acidic with mannoprotein removal (AAM) and dried using three different methods – air drying (AD), lyophilization (L) and spray drying (SD). In this work, the obtained β-glucan preparations were tested for their microstructure, rheological properties, swelling, water-holding and oil-binding capacities. According to their rheological properties, suspensions containing 1 and 2 % (by mass) of spray-dried samples belong to the category of dilatant fluids. Among the spray-dried samples, rheological behaviour and water-holding capacity of the preparation AA-SD differed from those obtained by other two procedures (A-SD and AAM-SD). Concerning different drying methods applied, swelling was the lowest in the lyophilized samples and the most pronounced in the air-dried ones. Oil-binding capacity was the highest in the lyophilized preparations and increased proportionally to the number of processing steps applied in the isolation procedure., Netopljivi β-glukani izolirani su iz pivskog kvasca različitim postupcima – alkalnim (A), alkalno-kiselinskim (AK) i alkalno-kiselinskim s uklanjanjem manoproteina (AKM) te osušeni trima različitim metodama – sušenjem na zraku, liofilizacijom i sušenjem raspršivanjem. U pripravcima β-glukana ispitani su: mikrostruktura, reološka svojstva, bubrenje te sposobnost vezanja vode ili ulja. Prema njihovim reološkim svojstvima suspenzije koje su sadržavale 1 i 2 % (masenih udjela) uzoraka osušenih raspršivanjem pripadaju u kategoriju dilatantnih tekućina. Reološka svojstva i sposobnost vezanja vode AK uzorka osušenog raspršivanjem razlikovali su se od ostalih uzoraka osušenih istom metodom, a izoliranih A i AKM postupcima. S obzirom na različite metode sušenja, bubrenje je bilo najslabije u liofiliziranim uzrocima, a najjače u uzorcima osušenim na zraku. Sposobnost vezanja ulja najizraženija je u liofiliziranim pripravcima, a povećavala se proporcionalno tijekom izolacije.

Two different procedures have been used for isolation of water-insoluble ß-glucans from brewer’s yeast: alkaline-acidic isolation (AA) and alkaline-acidic isolation with mannoprotein removal (AAM). The obtained ß-glucans were then dried by air-drying, lyophilization and combination of sonication and spray-drying. ß-Glucan preparations obtained by AA and AAM isolations had similar values of dry mass, total polysaccharides, proteins and organic elemental microanalysis. The mass fractions of ß-glucan in total polysaccharides were significantly affected by different isolation procedures. Fourier transform infrared (FTIR) spectra of all preparations had the appearance typical for (1→3)-ß-D-glucan. Lyophilization and especially air-drying caused a higher degree of agglomeration and changes in ß-glucan microstructure. Sonication followed by spray-drying resulted in minimal structural changes and negligible formation of agglomerates., Netopljivi β-glukani izolirani su iz pivskoga kvasca primjenom dvaju različitih postupaka: alkalno-kiselinskog (AK) i alkalno-kiselinskog s uklanjanjem manoproteina (AKM). Dobiveni pripravci β-glukana osušeni su na zraku, liofilizacijom i raspršivanjem uz prethodnu obradu ultrazvukom. Takvi su pripravci, dobiveni AK i AKM postupcima, imali približno iste vrijednosti suhe tvari, ukupnih polisaharida i proteina, te udjele ugljika, dušika i kisika određene organskom mikroanalizom. Na udio β-glukana u ukupnim polisaharidima bitno su utjecali različiti postupci izolacije. FT-IR spektri svih pripravaka imali su izgled tipičan za (1→3)-β-D-glukan. Sušenjem na zraku i liofilizacijom došlo je do značajnih promjena strukture čestica i aglomeracije ß-glukana. Sušenje raspršivanjem uz prethodnu obradu ultrazvukom nije dovelo do stvaranja nakupina čestica kao ni do znatnih promjena njihove strukture.