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Influence of nutrients on proteinase A activity in draft beer during fermentation
Author(s) -
Hao Xin,
Xiao DongGuang,
Zhang CuiYing,
Chen YeFu
Publication year - 2010
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2010.02252.x
Subject(s) - fermentation , chemistry , biotin , food science , nitrogen , nutrient , ethanol , biochemistry , organic chemistry
Summary With the increase of α‐amino nitrogen concentrations from 90 to 230 mg L −1 , proteinase A (PrA) in wort fermentations was showing a downward trend while higher alcohols contents a U‐shaped one. The level of 210 mg L −1 of α‐amino nitrogen supplement, at which wort fermentation exhibited a low PrA activity and a level of higher alcohols below the industrial norm (90 mg L −1 ), was used as the optimised α‐amino nitrogen concentration for further exploring the effect of biotin levels on PrA activity. In the biotin range of 0–65 μg L −1 , PrA activity registered the lowest value when biotin level was at 50 μg L −1 . Medium with 210 mg L −1 of α‐amino nitrogen and 50 μg L −1 of biotin was therefore adopted for investigating influences of inorganic salt Fe 2 (SO 4 ) 3 , KH 2 PO 4 , ZnSO 4 and MgSO 4 on PrA production. It was shown that Fe 2 (SO 4 ) 3 and KH 2 PO 4 had significant influence on PrA production while ZnSO 4 and MgSO 4 did not. Based on above findings, an optimised set of nutritive elements was determined and used in fermentation. The results indicated that the activity of PrA reduced by 60% without noticeably effects of the fermentation performance and beer flavour.