A kind of peptide which posseses an yeaststatic activity was isolated from Astragalus membranaceus Bunge and following characteristics was obtained.
1. The isoelectric pH of this peptide was 8.2 and histidine, an alkaline amino acid, was identified from this peptide.
2. This substance showes conspicuous heat stability and does not indicate any remarkable reduction of yeaststatic activity even for 5 hours treatment at 100℃ or for 30 minutes at 121℃.
3. The inhibitory activity of the yeast growth is not originated from the yeastcidal action but yeaststatic effect of this sample.
4. The sample shows strong stability ranging from pH 2 to 10.
5. The saccharide; glucose, sucrose, maltose, gives no effect on the yeaststatic activity of the sample even high concentration, 15 percent, and also no effect gives by magnesium, calcium and phosphate salts.
6. The available concentration of this sample on the inhibition of yeast growth was located at the ppm extent, for example, the concentration of fifty percent growth inhibition to Saccharomyces cerevisiae or S. carsbergensis was 4 ppm and 3 ppm to Candida pulcherrima, 13 ppm to S. coreanus, 18 ppm to S. sake and 38 ppm to C. tropicalis.
7. On the alcohol fermentation of S. coreanus, the peptide, an yeast growth inhibitor, gives no effect at all.
8. This substance is named as Astradix-P (Astragalus membranaceus, Radix, Peptide).
|