POSOUZENÍ KVALITY ČERSTVÉHO A SILÁŽOVANÉHO PIVOVARSKÉHO MLÁTA V PRŮBĚHU SKLADOVÁNÍ

Abstract

The main objective of this paper is to assess the changes of content of essential organic nutrients, yeasts and moulds and effect of aerobic fermentation when the fresh (untreated) and treated brewers grains (BG) is stored in the stall conditions. Both the fresh brewers grains from Radegast brewery and that treated by mixture of sodium benzoate (22.9%) sodium propionate (8.3%) and following 90 days anaerobic fermentation were mounded in the entrance of stall and tested in two tests, one during the winter period in February, the other one during the summer period in June. Influence of treatment was evident on the process of fermentation, levels of the nitrogen-free extract substances (NFES) and number of forming colony units (FCU) of moulds in the winter period. The fermentation activities in both tested masses were documented, however the decrease of intent of NFES in treated variants was highly conclusive (P < 0.01) lower than that of untreated variants. Stagnation of increase of formol titration in treated BG matches the same tendency. Significant (P < 0.01) limitation of mould growth was noted at treated BG, the number of FCU of moulds stagnated since 1st to 5th to day of testing. On the other hand the number of FCU of moulds in untreated BG was redoubled after 4 days since the start of testing. Treatment influenced monitored parameters above all in the early gout after the start of tes­ting. NFES content in untreated BG in February statistically highly conclusive (P < 0.01) fell from ave­rage values 502.99 ± 8.704 in 1st day of testing on 437.533 ± 18.877 g . kg dry matter in 6th day of testing while at treated BG was fall behind the same period only conclusive (P < 0.05). There was ascertained highly conclusive growth (P < 0.01) of level of formol titration from 0.004 ± 0.001 in 1st day to 0.178 ± 0.038 in 6th day of the same testing at untreated BG, while the level of formol titration stagnated at treated BG. In June content of NFES at untreated BG statistically conclusive (P < 0.05) declined from 455.578 ± 9.515 in 1st day on 432.92 ± 9.515 g . kg dry mater in 5th day of testing. Near NFES content at treated BG statistically conclusive (P < 0.05) declined as late as 7th day. Alike formol titration level at untreated BG surged from 0.008 ± 0.001 in 1st day on 0.087 ± 0.036 in 5th day, on the contrary at treated BG come to statistically highly conclusive (P < 0.01) growth as late as 7th day of testing.Both monitoring demonstrate that the treatment of BG by mixture of sodium benzoate (22.9%) and sodium propionate (8.3%) and its subsequent 90 day anaerobic fermentation will reduce activity of moulds and fall of included NFES and retarded resolution of protein on subsequent manipulation up deliver form silage bag and during a short-period storage in stall.