The simultaneous saccharification and fermentation of malt dust and use in the acidification of mash

Abstract

In brewing, the mash or wort is frequently acidified by the addition of lactic acid or the bioacidification of the mash. The present study provides an alternative approach for mash or wort acidification by the simultaneous saccharification and fermentation (SSF) of malt dust. In this method, fermentable carbohydrates released by the enzymatic breakdown of the cellulosic portion of the malt dust are converted to lactic acid by lactic acid bacteria. The effect of temperature, ranging between 45 and 51°C, solid loading of malt dust at 2, 5 and 10% (w/v) on a dry basis, and enzyme loading at 0.65, 2.6 and 6.5 filter paper units (FPU) per gram malt dust on SSF and change in pH in mash acidification were examined. The final pH and lactic acid concentration and final glucose concentration of the SSF media were significantly affected by the temperature of the process (p < 0.05). The highest lactic acid titre (9.7 g/L) and the lowest pH (3.12) were obtained by SSF of 10% (w/v) malt dust at 45°C with 6.5 FPU/g. The pH of the mashing solution [containing 20% (w/v) ground malt] decreased to around 5.4 and 5.2 after adding 1.9 and 2.9% of SSF media with pH 3.39.

High-Temperature Hydrothermal Extraction of Phenolic Compounds from Brewer’s Spent Grain and Malt Dust Biomass Using Natural Deep Eutectic Solvents

“…Malt dust (MD), a novel and underutilized biomass side stream, is investigated in this study. Comprising about 1% of total malt produced, MD is a fine powder residue which is separated from the malted and dried barley after the malting stage [11]. It, therefore, remains unused in subsequent beer production steps, retaining potential nutritional compounds.…”

“…MD presents an untapped biomass stream for further valorisation. MD has been effectively utilized in enzymatic lactic acid production for beer acidification [11] and demonstrated promise for conversion to monosaccharides and organic acids through acidand base-catalysed hydrolysis [12]. However, to the best of the authors' knowledge, the usage of MD for the green extraction of PC is a novel valorisation pathway that has not yet been explored in the literature.…”

Valorization of brewery waste

“…Baltaci ve Hamamci[35], malt tozu selülozik yapısının enzimatik hidrolizi ile ortaya çıkan glikozu laktik asit üretiminde ve ürettikleri laktik asidi de mayşe ve şıranın asitlendirilmesinde kullanmışlardır. Çalışma ile malt tozunun, bira üretimindeki mayşe veya şıranın asidifikasyonunda kullanılabileceği bulunmuştur.…”