Optimization of water-heat treatment of barley batch (mix) in ethanol production

Abstract

Barley is a problematic raw material for ethanol processing due to its chemical composition. ?-glucans and pentosans high content increases the mass viscosity and digestible carbohydrates loss at еру water-heat treatment stage. The enzymes used to pre-treat grain prior to fermentation are traditionally ?-amylases and glucoamylases. The purpose of the work is to determine the optimal ratio of enzymes introduced in different periods of water-heat treatment. The object of study was barley: starch 52, protein 11.5, hemicellulose 5.1, ?-glucan 3.9, moisture 14.0. Enzyme preparations Alphaferm 3500L (0.5–1.0 AC / g starch), ViscoStar 150L (3700 units KS / cm3; 140 units ? – GcS / cm3; 1900 units CMC / cm3.), Prolive BS Liquid (600-750 units PS / cm?) were used in the work. The dynamics of viscosity change in the process of water-heat treatment was investigated in the work as well. It was found out that the dosage of the enzyme preparation Alphaferm 3500L has the greatest effect on the mass fraction of dry substances in the filtrate of barley mix, while the dosage of other enzyme preparations and the duration of the experiment have a smaller and similar effect. It was proved that the application of a multienzyme complex reduces the viscosity by 82% compared to the control. The method of indefinite Lagrange multipliers was used to determine the optimal mode of water-heat treatment. It was found out that the maximum accumulation of dry substances in the mixture is 16.4% and is achieved after 2.5 hours with the following doses of enzyme preparations: Alphaferm 3500 L - 0.6 units. AC / g starch; ViscoStar 150L - 0.025 units GCS / g starch; Prolyve BS Liquide 0.25 units PS / g starch.