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… Click to show full abstract
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 alternative 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 ellagitannin 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.
               
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