The antimycotic effect of ellagitannins from raspberry (Rubus idaeus L.) on Alternaria alternata ŁOCK 0409

Alternaria spp. fungi, characterized by a high tolerance to unfavorable environmental conditions, are one of the threats for foods of plant origin. The increasing incidence of diseases caused by a demanding lifestyle, and a higher social awareness of the role of a diet in maintaining health and good condition, results in the dynamically growing demand for natural protective measures that would be safe for consumers. Ellagitannins, i.e. a group of bio-active polyphenols, may constitute an alterna-tive for chemical preservatives. Studies demonstrated that the raspberry (Rubus idaeus L.) ellagitannin formula limited the growth of Alternaria alternata 0409. The minimal inhibitory concentration (MIC) was determined (0.156mg/ml), along with the minimal fungicidal concentration (MFC) (0.312mg/ml). The fungistatic (FA) activity and the ratio of linear growth (T) were also determined for the ellagitannin formula. A strong antimycotic activity of ellagitannins was demonstrated at the formula level of 0.1mg/ml. Unfortunately, the activity was not maintained over time and after 9days it was only 16.0%. For the ellagitannin formula, concentrations of 0.312mg/ml (MFC) and 0.5mg/ml (below the MFC value), a complete arrest of growth of Alternaria alternata 0409 was observed, and it was maintained for 9days. The antimycotic activity of the ellagi-tannin formula was also confirmed in food environment, with cottage cheese and cherry tomatoes used as the matrix. Results confirmed that ellagitannins from raspberry (Rubus idaeus L.) could be successfully used as a natural food preservative.