Combined effect of starter culture and temperature on phenolic compounds during fermentation of Taggiasca black olives.

The influence of two operative parameters on the fermentation process of table olives from Taggiasca cultivar were investigated. Laboratory scale fermentations were performed using Lactobacillus plantarum as the only starter and in combination with Saccharomyces cerevisiae at three different temperatures (23, 30 and 37°C). Control tests used for each trial were fermented only by indigenous microflora. pH and phenolic compounds were monitored in the brine and olive flesh during the fermentation. Higher temperatures (37°C) enhanced notably the release of phenolic compounds in the brine. High performance liquid chromatography (HPLC) analysis of brines evidenced the complete hydrolysis of oleuropein after 100 days of fermentation at 37°C for all treatments. The antioxidant power of the extracts was linearly correlated to their polyphenol contents. The results confirmed the efficiency of treatments compared with the control tests for debittering process of table black olives. Phenolic compounds in the brines can be then extracted and used in food, cosmetic and pharmaceutical industries.

A hemolytic peptide from the mycophilic fungus Sepedonium chrysospermum (Bull.) Fr.

The hemolytic activity of an extract of the mycoparasite Sepedonium chrysospermum (teleomorph Hypomyces chrysospermus) was detected and characterized. Extraction of the fungal biomass by methanol yielded a fraction in which the hemolytic activity against human red blood cells corresponded to a peptide with a molecular mass of 7,653.72 Da and an isoelectric point of approximately 5.8. The peptide was temperature resistant, and the hemolysis was only partially inhibited, even after a 30-min pre-incubation at 100°C. Its hemolytic activity was unaffected by treatment with proteolytic enzymes such as trypsin. Among the divalent cations assayed, Hg(2+) was the strongest inhibitor of hemolysis. The reducing agent, dithiothreitol, and the membrane lipid, cholesterol, demonstrated concentration-dependent inhibitory activities. Finally, hemolytic activity triggered by the peptide was analyzed by scanning electron microscopy, and a pore-forming activity was detected.