Reducing total nitrogen and dimethyl sulfide content of dry malt extract powder via spray-freeze drying method

Abstract

Dry malt extract (DME) is powder prepared by dehydrating the wort, which is mainly produced by spray drying on the market. In addition, the beer industry has problems with the nitrogen content of wort, which is not easily controlled, and with the undesired volatile dimethyl sulfide (DMS), which is caused unpleasant odors in beer. In this study, DME was prepared using spray-freeze drying (SFD) technology by comparing with freeze dried DME and spray dried DME. The results show that SFD can be used as a novel engineering technique to improve the physical properties of DME having a narrow particle size distribution as well as high solubility and flowability. The freezing process was found to migrate proteins to the droplet surface by elemental analysis, and the drying process partially modified the surface protein and SFD powder fragility characteristics to achieve the purpose of reducing nitrogen content in DME.