Vpliv resveratrola na obstojnost olj

Mršnik, Urša (author), Pogačnik, Lea (mentor), Cigić, Blaž (co-mentor)

Trans-resveratrol (RES) v etanolni raztopini na svetlobi ni stabilen, saj zelo hitro začne prehajati iz trans- v cis-izomer. V raziskavi smo preučevali topnost in stabilnost trans-RES v oljih ter njegov vpliv na obstojnost olj. Ugotovili smo, da je trans-RES v gliceril trioktanoatu (TAG) dobro topen, v sončničnem olju (SON) pa nekoliko manj. Njegova temperaturna stabilnost v izbranih oljih je dobra, saj se v lanenem olju (LAN) pri temperaturi 60 °C ohrani pet dni, v SON pa vsaj deset dni. V TAG z dodatkom metil-linolenata (M-L) in trans-RES se je slednji izkazal kot učinkovit antioksidant, saj je raztopina brez dodanega trans-RES bistveno hitreje oksidirala. V TAG smo ugotavljali tudi antioksidativno učinkovitost (AOU) dodanega α-tokoferola (TOKO) in njegove kombinacije z trans-RES. α-TOKO je boljši antioksidant kot trans-RES, sinergističnega učinka med omenjenima antioksidantoma pa nismo opazili. Podobno tudi v SON in LAN ni bilo zaznanega sinergističniga učinka trans-RES z naravno prisotnimi antioksidanti - peroksidacija v oljih z dodatkom trans-RES in brez njega je potekala skoraj enako hitro (dan 10 – peroksidno število; SON in SON z dodatkom RES – 58, LAN – 310 ter LAN z dodatkom RES – 277). Pri raztapljanju ekstrakta olupka korenine japonskega dresnika v oljih in TAG smo ugotovili, da so se poleg trans-RES raztopili tudi nekateri drugi antioksidanti, ki pomembno prispevajo k AOU, določeni z radikalom DPPH.

• Language: Slovenian
• Keywords: antioksidanti, resveratrol, sončnično olje, laneno olje, modelni lipidni sistemi, peroksidacija
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [U. Mršnik]
• Year: 2018
• PID: 20.500.12556/RUL-104966
• UDC: 664.3.094.3.097.8:577.115
• COBISS.SI-ID: 4974456
• Publication date in RUL: 19.10.2018

Secondary language

• Language: English
• Title: Impact of resveratrol on oil stability

Abstract

When exposed to light, trans- resveratrol (RES) dissolved in ethanol is not stable as it isomerises into cis- isomer. In this research, we examined the solubility and stability of trans-RES in oils and its influence on lipid stability. Trans-RES was better soluble in glyceril trioctanoate (TAG) than in sunflower oil (SON). Temperature stability of trans-RES in edible oils was good; in flaxseed oil (LAN) it was preserved for 5 days and in SON at least 10 days upon incubation at 60 °C. In TAG with added methyl-linolenate (M-L) trans-RES was an efficient antioxidant – the solution with only TAG and M-L peroxidised faster. We also examined antioxidant capacity (AOC) of TAG with α-tocopherol (TOKO) and its combination with trans-RES. α-TOKO was better antioxidant, while the synergistic effect between α-TOKO and RES was not observed. Likewise, the synergistic effect among trans-RES and other antioxidants already present in LAN and SON was not observed. Peroxidation rate of oils with or without trans-RES was similar (day 10 – peroxide value; SON and SON with addition of RES – 58, LAN – 310 and LAN with addition of RES – 277). When root peel extract of Fallopia japonica was dissolved in oils and TAG, other antioxidants apart from trans-RES were also dissolved. They significantly contributed to the AOC determined with DPPH radical.

• Keywords: antioxidants, resveratrol, sunflower oil, flaxseed oil, model lipid systems, peroxidation