The Impacts of a β-glucanase Step Pre-Cooking on Alcohol Yields during Irish Rye Whiskey Production

AbstractRecent industry roadmaps such as Crops 2030 and the Irish Whiskey Association's Sustainability Roadmap 2022 emphasize the importance of increasing the use of Irish-grown grain in brewing and distilling. With the growth of the Irish distilling sector, there is a corresponding demand for raw materials and locally sourced grains. In Ireland, approximately 500 hectares of rye are harvested annually, with rye containing a similar range of starch as wheat. However, because rye contains more hemicelluloses and pentosans than other cereals, and because water-soluble pentosans tend to form viscous solutions in concentrated flour-water slurries, it is not widely utilised as a fermentation substrate. The purpose of this study is to examine pre-treatment with β-glucanase to enhance the alcohol output from rye flour. The research determined a baseline alcohol production of 187.1 LA/tonne dwb without the addition of β-glucanase. Using four predictor variables, response surface techniques were used to investigate the influence of β-glucanase on alcohol yield. A Box-Bekhan design was used to investigate time, temperature, calcium ions, and β-glucanase. When β-glucanase was administered at a dose rate of 3 U/g with the addition of 200 mg/L calcium ions and run at 50 °C for 30 min, the response surface approach yielded the highest alcohol output of 406 LA/tonne dwb. While, this yield is consistent with previous authors' findings; it is lower than average yields for malted barley, wheat, and maize.Keywords: Alcohol yieldsβ-glucanaseresponse surface methodsrye alcohol AcknowledgmentsThe authors are grateful to the Irish Whiskey Industry professionals who contributed to this research.Authors' contributionsConceptualization—SM, SW, JC, and DR; methodology-SM, and JB; validation—SM and JB; formal analysis—SM and JB; investigation—SM, data curation—SM; writing—original draft preparation-SM; writing—review and editing, -JB, SW, JC, and DR; supervision—DR; project administration—DR and SW.; funding acquisition—DR, SW, and JC. All authors have read and agreed to the published version of the manuscript.Disclosure statementNo potential conflict of interest was reported by the author(s).Data availability statementThe datasets generated for this study are available on request to the corresponding author.Additional informationFundingThis work was funded under the Department of Agricultural, Food and Marine grant [number 2019R563].