Investigations into the Protein Stabilization of Musts and Wines by Aspergillopepsin under Different Enzymatic and Thermal Treatments

Protein removal with aspergillopepsin in combination with short-time heating has recently emerged as an opportunity for winemakers to prevent protein haze in wine. In this study, we first treated a protein-rich must and wine with two different aspergillopepsin preparations along an identical control treatment without enzyme addition on a pilot plant scale. While treating wines was rather ineffective, treating musts was effective in reducing protein concentrations by up to 86%, leading to haze-stable wines according to the common heat test. Varying thermal loads in further experiments, a rather mild heat treatment of 65 °C for 30 s compared to those in earlier studies was found sufficient for enzymatic protein degradation. Treating must from a fungus-resistant variety (cv. Fidelio) was as successful as treating must from a blend of conventional varieties (cv. Gewürztraminer/Müller-Thurgau). Triangle sensory tests found no clear evidence of an effect on the quality by heat treatments with and without enzyme dosage.