Enzymatic activity profiles of selected strains isolated from raw sheep milk of native Epirus breeds with the highest potential for inclusion in natural starter cultures1.
The reactions were graded from 0 (negative) to 5 (strongly positive) based on the change in the color intensity after the addition of the ZYM A & ZYM B reagents in each well. Activity (approximate values) was expressed as arbitrary units of substrate hydrolyzed; 0: negative (similar to the first well-control); 1: liberation of 5 nmol; 2: 10 nmol; 3: 20 nmol; 4: 30 nmol; 5: 40 nmol or more (Samelis and Kakouri [24] 2025). Liberation of 20 to 40 nmol or more was considered a clearly positive enzymatic reaction. The basic starter strains S. thermophilus ST1 and Lc. lactis M78 were tested for comparison.
The authors wish to thank Vasiliki Zafeiropoulou and Maria Mavropoulou, Veterinary Laboratory, Food Hygiene Department, Ministry of Agriculture, Athens, Greece, for identifying the API 20 STREP code numbers of the present Streptococcus isolates with the apiwebTM software, not available in our laboratory.
Author contributions
JS: Conceptualization, Formal analysis, Methodology, Validation, Resources, Data curation, Project administration, Writing—original draft, Writing—review & editing, Investigation, Visualization. AK: Formal analysis, Validation, Writing—review & editing. Both authors read and approved the submitted version.
Conflicts of interest
The authors declare that they have no conflicts of interest.
Ethical approval
Not applicable.
Consent to participate
Not applicable.
Consent to publication
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Data are contained within the article. Raw data will be made available on request.
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