Biogenic Amine Changes Related to Lactic Acid Bacteria During Brewing

Area of Science:

• Food Science
• Microbiology
• Biochemistry

Background:

• Biogenic amines (BAs) are nitrogenous compounds found in fermented foods, potentially impacting human health.
• Tyramine, a significant BA, can form during beer fermentation, influenced by microbial activity.
• Understanding the relationship between microbial contamination and BA formation is crucial for beer quality control.

Purpose of the Study:

• To investigate the formation of biogenic amines, specifically tyramine and tryptamine, during beer fermentation.
• To determine the correlation between microbial contamination (wild yeasts and lactic acid bacteria) and tyramine production.
• To evaluate the efficacy of phosphoric acid washing in mitigating tyramine levels.

Main Methods:

• Monitoring biogenic amine content throughout industrial and pilot-scale beer fermentation.
• Quantifying wild yeast and lactic acid bacteria (LAB) using colony-forming units (CFU).
• Identifying isolated LAB species and assessing the impact of phosphoric acid washing on brewer's yeast.

Main Results:

• Tyramine formation varied significantly (8–30 mg/l), while tryptamine remained low (<3.5 mg/l).
• A positive correlation was observed between tyramine formation and LAB counts; no link to wild yeasts.
• Specific LAB counts correlated with distinct tyramine levels, with Pediococcus spp. identified as the primary producers.

Conclusions:

• Lactic acid bacteria, particularly Pediococcus species, are key contributors to tyramine formation during beer fermentation.
• Controlling LAB populations is essential for managing tyramine levels in beer.
• Phosphoric acid washing of brewer's yeast is an effective method for reducing Pediococcus contamination and subsequent tyramine production.