Sevastianos Roussos

Robusta coffee beans post-harvest microflora: Lactobacillus plantarum sp. as potential antagonist of Aspergillus carbonarius.

Coffee contamination by ochratoxigenic fungi affects both coffee quality as well as coffee price with harmful consequences on the economy of the coffee exporting countries for whom which is their main source of income. Fungal strains were isolated from coffee beans and identified as black Aspergilli. Ochratoxigenic moulds like Aspergillus carbonarius were screened and selected for detailed studies. Also lactic acid bacteria (LAB) were isolated from silage coffee pulp and their antifungal activity was tested on dual-culture agar plate. Ten of the isolated LAB demonstrated antifungal effect against A. carbonarius. API 50 CH and APIZYM were used to perform phenotypic identification. 16S rDNA sequencing was made to confirm the results.

Gamma irradiation of air-dried olive leaves: Effective decontamination and impact on the antioxidative properties and on phenolic compounds

Olive leaves are commercialized for their antioxidative value due to their valuable phenolic compounds. The present study aimed to evaluate the effect of gamma irradiation on microbial load, on antioxidative properties and on phenolic compounds of air-dried olive leaves. Irradiation was applied up to 25kGy (5kGy intervals) to powdered and intact samples. Total aerobic bacteria, yeast and mold, and lactic acid bacteria were counted after gamma irradiation. Decontamination was obtained at 20kGy. The radioresistance of microbial population was high with D10 values between 9.74 and 25.12kGy. Besides, gamma irradiation up to 25kGy was found to maintain the antioxidant capacity, molecular mass distribution of polyphenolics, total phenolics, ortho-diphenols, flavonoids, oleuropein, verbascoside and rutin contents. To conclude, the improvement of the microbial quality of air-dried olive leaves, without affecting phenolic composition and antioxidative properties, can be successively achieved by the application of gamma irradiation treatment.

Effect of Acclimatization on Earthworm’s (Eisenia Andrei) Potential on Olive Mill Wastewaters Detoxification

A laboratory vermicomposting (two months duration) was conducted to evaluate the effect of earthworm acclimatization (epigeic—Eisenia andrei) on decomposition and detoxification of olive mill wastewaters. The Earthworm growth rate and phenols reduction were superior in the mixture with acclimated earthworms (21.83 ± 0.01 mg worm−1 day−1 and 72% respectively), than mixture with unacclimated earthworms (4.67 ± 0.01 mg worm−1 day−1 and 41% respectively). The data reveal that acclimatization of earthworms is a promising alternative for OMWW detoxification and vermicomposting (using E. andrei) is a suitable technology for olive by-products conversion into value-added materials.