Black chokeberry(Aronia melanocarpa) belongs to the Rosaceae family and is native to eastern North America. Chokeberry was introduced in Europe in the 20th century, and countries introduced it to the public some 6-7 years ago and it is now grown on farms. Chokeberry consists of anthocyanins, proanthocyanins and chlorogenic, neochlorogenic acid, which contain flavonoids and phenol, which have effects on a variety of physiological functions. The Aronia contain high levels of flavonoids, mostly anthocyanins and proanthocyanidins. Which are known as condensed tannins. The dominant chokeberry proanthocyanidins are (-)-epicatechin and (+)-catechin. The concentration of chokeberry proanthocyanidins is higher than in other berries. There is a significant amount of epidemiological data that suggest that tannin intake may prevent the onset of chronic disease such as cardiovascular disease and cancer. But, the concentration of tannins, which may explain their potent astringent taste, are, thus, not favored as table fruits. Therefore, the purpose of this study is to evaluate the effect of black chokeberry on the reduction in tannins by yeast isolated from regional Jeotgal.
We isolated strains of yeast with high ß-glucosidase activity from Jeotgal, with the MT-Y-2 strains exhibiting a reduction in final tannin concentration according to TLC analysis. This strain was shown to have low sugar availability using an API kit test. MT-Y-2 was confirmed as Kazachstania servazzii using an 18S rDNA sequence and named as Kazachstania servazzii MT-Y-2. It has been confirmed that the optimal cultivation temperature and pH of the strain are 20~30℃ and 4~9, respectively. In addition, the addition of chokeberry extract inhibited growth in proportion to its concentration.
Kazachstania servazzii MT-Y-2 showed most significant growth when K.servazzii MT-Y-2 was cultured in a solution of 10%(w/v) glucose, 3%(w/v) tryptone and 0.1%(w/v) sodium chloride. Growth was 11% higher than in the YM broth with 5% chokeberry extracts. According to the HPLC analysis, the (+) - catechin peak is present, but (-) - epicatechin peak was unrevealing with respect to growth.