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Factors influencing proteinase A activity during the production of unpasteurised beer
Author(s) -
Wang Cheng,
Tu Jingxia,
Hao Jianqin,
Liu Jing,
Wang Deliang,
Xiong Dan,
Zhang Yanqing
Publication year - 2020
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/jib.634
Subject(s) - food science , chemistry , production (economics) , economics , macroeconomics
Compared with pasteurised beer, a decline in foam retention during storage is an issue for unpasteurised beer. The major reason for this is that proteinase A is able to slowly breakdown foam promoting proteins in beer. Therefore, controlling the activity of proteinase A is key to solving this problem. In this study, foam quality in unpasteurised beer was studied systematically on a commercial scale considering factors including yeast activity, strain, generation number and storage time. Accordingly, yeast handling procedures to manage proteinase A activity were established: (1) yeast strain P with reduced proteinase A should be used in production; (2) storage time of recovered yeast should be no more than two days; (3) proteinase A activity in recycled yeast slurry should be less than 10×10 ‐5 U/mL and (4) the number of yeast generations should be less than three. With the application of these measures, proteinase A activity was significantly decreased, and the corresponding foam quality was improved. © 2020 The Institute of Brewing & Distilling