Low-temperature brewing by freeze-dried immobilized cells

Area of Science:

• Biotechnology
• Food Science
• Microbiology

Background:

• Traditional brewing relies on yeast fermentation, which can be time-consuming and temperature-sensitive.
• Developing stable, efficient biocatalysts is crucial for optimizing brewing processes.

Purpose of the Study:

• To develop and evaluate a novel immobilized biocatalyst for brewing applications.
• To assess the performance of freeze-dried immobilized yeast at low temperatures.
• To analyze the impact of this biocatalyst on beer quality parameters.

Main Methods:

• Immobilization of cryotolerant Saccharomyces cerevisiae on delignified cellulosic material.
• Freeze-drying of immobilized cells without cryoprotectants.
• Repeated-batch fermentation of wort at various temperatures (15°C, 5°C, 0°C).
• Analysis of fermentation time, productivities, and beer composition (polyphenols, bitterness, diacetyl, alcohols, ethyl acetate).

Main Results:

• The freeze-dried immobilized biocatalyst significantly reduced fermentation time and increased productivity compared to free freeze-dried cells.
• The biocatalyst demonstrated suitability for low-temperature brewing (0-15°C) with high operational stability over 13 months.
• Beers produced showed lower polyphenol content, bitterness, and diacetyl, with altered alcohol and ester profiles, especially at 0°C.

Conclusions:

• Freeze-dried immobilized Saccharomyces cerevisiae offers a stable and efficient biocatalyst for brewing, particularly effective at low temperatures.
• This novel approach enhances fermentation efficiency and improves key sensory attributes of beer.
• The biocatalyst's performance justifies its use for improved aroma and taste in low-temperature brewing.