Production of gluten–free Ale type beer in the conditions of microbrewery

Marzia Bianco

Diplomová práce

Abstract:

Gluten is a complex of proteins present in barley, wheat, rye and oats that triggers celiac disease in genetically predisposed individuals. With beer's rich history and the diversity brought by the craft brewery revolution, Ale beers are increasingly popular for their variety and brewing processes influenced by key ingredients. This study examines these processes, focusing on gluten-free top-fermented variants in response to rising demand from individuals with celiac disease. The experiment was conducted on three craft beer styles — Navoněná, Hořká, and Amber (N, H and A) — each brewed at two fermentation temperatures (14 and 22°C) with control (C) and enzyme-treated (E) variants. The aim was to evaluate the effectiveness of a prolyl-endopeptidase enzyme from Aspergillus niger in hydrolysing hordein, the rich-prolamin gluten protein in barley, into non-immunogenic peptides. Hordeins was quantified using the competitive R5-ELISA method, a widely recognized assay for detecting gluten immunogenic peptides in food and beverages. Statistical analyses were conducted using one-way ANOVA. Results indicate that E beers (N and H) achieved gluten levels below the legal threshold of 20 mg/kg, qualifying them as “gluten-free,” while A exceeded this limit and are classified as “low gluten content.” The enzyme’s effectiveness slightly varied with fermentation temperature, indicating that fermentation at 22°C determines lower gluten levels (e.g., 13.84 mg/L in N22E vs. 19.90 mg/L in N14E). Sensory evaluation revealed no significant differences in aromatic and taste profiles between the C22 and E22 samples, including their counterparts fermented at 14°C. However, in all styles, C samples show slightly higher bitterness intensity than the E ones, suggesting a reduction in perceived bitterness due to the enzyme. While the enzyme did not affect colour pleasantness in Amber and Navoněná, it reduced it in Hořká beers.

Keywords

celiac disease, deglutination, gluten-reduced, prolyl-endopeptidase, top-fermented beer

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 7. 12. 2024

Obhajoba závěrečné práce

• Obhajoba proběhla 10. 12. 2024
• Vedoucí: Ing. Luboš Paznocht, Ph.D.
• Oponent: Monica Agnolucci, externi

Česká zemědělská univerzita v Praze

Fakulta agrobiologie, potravinových a přírodních zdrojů

Magisterský studijní program:
Sustainable Agriculture and Food Security