Pasteurization is a thermal treatment method allowed by law for improving the microbiological shelf life of beer. The pasteurization unit (PU) is a measure of the intensity of beer pasteurization. One pasteurization unit is equivalent to holding the medium at a temperature of 60 °C for the period of one minute.
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PE |
= 1.393 Δt × pasteurization time in min |
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Δt |
= pasteurization temperature in °C, e.g., 60 °C |
This analysis tests whether the beer has undergone heat treatment over 5.5 PU.
Beer
The enzyme β-fructosidase (invertase, sucrose) is inactivated by heating beer to a temperature above 58 °C. For a complete inactivation of the enzyme, 5.5 PU are required. After pasteurization, fructosidase is inactivated and is no longer able to cleave sucrose added to the beer into reducing sugars. This analysis measures the grams of sucrose hydrolyzed in 100 ml of beer under certain conditions. The result is not only a measure of enzyme activity but also serves as a means for detecting and evaluating the pasteurization of beer.