| Abstract | Globalno, čaj je nakon vode jedan od najčešće konzumiranih napitaka. Prema aktualnim podacima, u svijetu se dnevno popije čak 18-20 milijardi šalica čaja. Popularnost ovog napitka prvenstveno se može povezati s brojnim blagodatima na ljudsko zdravlje, od antitumorskog i antioksidativnog djelovanja do regulacije metaboličkih procesa, a s obzirom na to da list biljke čajevac obiluje brojnim nutritivno značajnim fitokemikalijama (polifenoli, klorofili, organske kiseline, minerali i dr.). Prilikom standardne pripreme napitka čaja zaostaje 90 % krutog ostatka što uslijed neadekvatnog zbrinjavanja može predstavljati značajan problem za okoliš (onečišćenje tla i vode). Slijedom toga, cilj ovog diplomskog rada bio je utvrditi sadržaj specijaliziranih metabolita i nutritivni potencijal organskog ostatka nakon pripreme napitka čaja. Organski ostaci sakupljani su u periodu od tjedan dana u kućanstvima: organski ostatak 1 (zeleni čaj) i 2 (voćna infuzija) i u studenskoj kantini: organski ostatak 3 (mješavina voćnih i biljnih infuzija), a nakon čega je utvrđena količina generiranog organskog ostatka čaja za svaki od izvora. Analiziran je kemijski sastav i sadržaj specijaliziranih metabolita prikupljenih uzoraka organskog ostatka čaja i to: sadržaj suhe tvari, ukupna kiselost, sadržaj askorbinske kiseline, pigmentnih spojeva, polifenolnih spojeva te antioksidacijski kapacitet. Prema dobivenim rezultatima najviši sadržaj fenola (1038,18 mg GAE/100 g), flavonoida (587,06 mg GAE/100 g), neflavonoida (481,12 mg GAE/100 g) i ukupnih klorofila (0,7 μg/g) konstatiran je za organski ostatak od zelenog čaja. Najviši sadržaj vitamina C (31,04 mg/100 g) utvrđen je za organski ostatak voćne infuzije sakupljenog u kućanstvu, dok je za uzorak organskog ostatka utvrđen najviši sadržaj ukupnih karotenoida (0,09 μg/g). Iz rezultata ovog diplomskog rada može se zaključiti kako organski ostatak čaja i voćne infuzije sadrži nezanemarivu količinu specijaliziranih metabolita te time pokazuje i značajan nutritivni potencijal. Temeljem navedenog, organski ostatak čaja predstavlja vrijedan nusproizvod za uporabu i to na primjer u poljoprivredi za pripremu komposta ili biognojiva, kao poboljšivač tla, u farmaceutskoj industriji za izolaciju polifenolnih spojeva ili drugih metabolita. |
| Abstract (english) | Worldwide, tea is one of the most consumed beverages, right after water. According to current data, about 18-20 billion cups of tea are drunk worldwide every day. The popularity of this drink is mainly due to its numerous health benefits, ranging from antitumor and antioxidant effects to the regulation of metabolic processes. If we consider that the leaves of the tea plant are rich in various nutritionally significant phytochemicals (polyphenols, chlorophylls, organic acids, minerals, etc.), this becomes clear. During the normal preparation of tea, 90% of the solid residues remain, which, if not disposed of properly, can pose a significant environmental problem and contribute to the pollution of soil and water. Therefore, the objective of this Master's thesis was to determine the content of specific metabolites and the nutritional potential of organic residues after tea preparation. Organic residues were collected over a period of one week in households: organic residue 1 (green tea) and 2 (fruit tea) and in the student canteen: organic residue 3 (mixture of fruit and herbal tea), after which the amount of organic tea residues was determined for each of the sources. The chemical composition and content of specialized metabolites of the collected samples of organic tea residues were analyzed, including dry matter content, total acidity content, ascorbic acid content, pigment compounds, polyphenolic compounds, and antioxidant capacity. According to the results, the highest content of phenols (1038.18 mg GAE/100 g), flavonoids (587.06 mg GAE/100 g), non-flavonoids (481.12 mg GAE/100 g) and total chlorophylls (0.7 μg/g) was found in the organic residues of green tea. The highest vitamin C content (31.04 mg/100 g) was found in the organic residues of fruit teas collected from households. In contrast, the organic residue sample (a mixture of fruit and plant teas) had the highest content of total carotenoids (0.09 μg/g). The results of this work suggest that organic tea and fruit tea residues contain a considerable amount of specialized metabolites that have significant nutritional potential. Based on the above, organic tea residues represent a valuable by-product for reuse, for example, in agriculture for the production of compost or biofertilizers, as soil conditioners, and in the pharmaceutical industry for the isolation of polyphenolic compounds or other metabolites. |
