Posttranslational Modifications Drive Protein Stability to Control the Dynamic Beer Brewing Proteome

Area of Science:

• Food Science
• Biochemistry
• Brewing Science

Background:

• Mashing is a critical beer brewing step involving hot water extraction of malted barley.
• Starch and proteins are solubilized and digested into oligomaltose and free amino nitrogen during mashing.

Purpose of the Study:

• To investigate protein abundance and modifications during a small-scale pale ale mash using SWATH-MS.
• To understand how temperature, time, and proteolysis affect protein profiles in beer brewing.

Main Methods:

• Utilized SWATH-MS (Sequential Window Acquisition of all Theoretical Mass Spectra) for quantitative proteomic analysis.
• Performed microscale pale ale mash experiments with controlled time and temperature variations.
• Analyzed protein abundance profiles and correlated them with sequence and structural features.

Main Results:

• Protein abundance decreased significantly at higher mash temperatures due to unfolding and aggregation.
• Proteolytically clipped proteins were preferentially lost at high temperatures, while intact proteins remained soluble.
• Protein profiles were primarily governed by sequence and structure, influenced by barley proteases.

Conclusions:

• The beer brewing proteome is a dynamic interplay between protein solubilization and proteolysis.
• Barley variety, growth conditions, and brewing parameters critically influence these protein dynamics.
• Understanding these factors is key to optimizing the brewing process and final beer quality.