BOOK OF ABSTRACTS startpage: 76 endpage: 77 Different food industry sectors generate substantial amounts of waste, posing a serious problem if not properly managed. The herbal tea industry by-products that remain after drying and cutting are rich in bioactive compounds such as polyphenols, flavonoids, phenolic acids, etc. however, they are underutilized. Approximately 10–40% (depending on plant species) of the total processed raw material in the herbal filter tea production is byproducts in the form of pulvis. The common nettle (Urtica dioica L.) is an important part of human diet and it is commonly used for treating prostatic hyperplasia, hyperglycemia, allergies, anemia, etc., because of its diverse chemical profile. Since nettle is rich in polyphenols including flavonoids and phenolic acids, vitamins, minerals, etc. it is expected that it can be a good substrate for biotransformation by lactic acid bacteria. The optimized processing, including extraction and biotransformation, can convert these by-products into valuable sources of biologically active compounds for functional food applications. This study compares innovative strategies for the valorization of nettle by-products in accordance to the circular bioeconomy principles. Green techniques, including ultrasound-assisted and non-thermal plasma-assisted extraction were employed for the efficient recovery of bioactive compounds from nettle by-products. Studied treatments and solvents (water and water/ethanol mixtures) were compared in order to examine their selectivity towards the antioxidant compounds which are suitable substrates for biotransformations. Extracts were used as substrates for the growth of Ligilactibacillus salivarius ATCC 11741, lactic acid bacteria strain with probiotic potential. Extracts were first lyophilized and later reconstituted with water, to obtain water-based media for L. salivarius growth. The antioxidant activity assays, ABTS, DPPH and total phenolic content as well as viability of L. salivarius were assessed. Further, biotransformation of aqueous extracts by fermentation with L. salivarius was confirmed by HPLC analysis. Fermentation improved the quality of the extract by increasing the concentration of phenolic compounds, namely, caffeic acid (44%), chlorogenic acid (35%) and caffeic acid derivates (44%), while maintaining a high growth rate of tested microorganism. DPPH assay showed high activity of 234 trolox eq/g dm in non-thermal plasma extracted fermented extracts. Although non-thermal plasma is used for its sterilization and antimicrobial properties in some cases, L. salivarius showed high viability in both non-thermal plasma and ultrasound treated extracts. The fermentation with L. salivarius was directly associated with an increase in the concentration of biologically active compounds, which opens new opportunities for biotransformation of extracts, potentially also with other lactic acid bacteria to obtain new specific fermentation products. The fermented aqueous extracts showed significant potential as symbiotics with antioxidant and postbiotic properties. The stability of fermented extracts should be further examined in order to propose best route for their exploitation, but increased biological activity suggests that their applications could span from functional food to dietary supplements and cosmetic ingredients. info:eu-repo/semantics/conferenceProceedings VALORIZATION OF NETTLE TEA INDUSTRY BY-PRODUCTS THROUGH INNOVATIVE GREEN EXTRACTION AND FERMENTATION FOR FUNCTIONAL FOOD APPLICATIONS All rights reserved https://unilib.phaidrabg.rs/o:7479 ISBN: 978-86-7520-629-3 Bogdanović, Mihajlo Grbić, Jovana Mladenović, Dragana Žugić, Ana Tadić, Vanja Petrović, Predrag Đukić-Vuković, Aleksandra common nettle, non-thermal plasma, ultrasound extraction, Ligilactibacillus salivarius, biotransformation, green extraction eng application/pdf 1198280 bytes 2025