Antioxidative activity of sinapic acid and its derivatives in model lipid systemsMartinović, Neda (Avtor) Abramovič, Helena (Mentor) Poklar Ulrih, Nataša (Komentor) sinapic acidsinapinesyringic acidsyringaldehyde4-vinylsyringolethyl sinapatepropyl sinapatebutyl sinapateantioxidantsfree radical scavenginglipid peroxidationemulsionoiloleoelliposomesThe effectiveness of sinapic acid and its derivatives varied with the test system, the type of free radicals and the mechanism of antioxidant activity. It was shown that early response parameters of free radical scavenging are adequate to evaluate differences between antioxidants with comparable endpoint (steady-state) activity. Among selected compounds syringic acid and sinapic acid showed the highest DPPH˙ and O2˙– scavenging activities (determined at steady-state) and the highest ability to inhibit lipid peroxidation in oil. Sinapic acid esters had the highest activities in oil-in-water emulsion and liposome suspension, and ethyl sinapate and propyl sinapate, furthermore, proved to be excellent ˙OH-scavengers. These esters, which were the most lipophilic, had the greatest effects on liposome bilayer thermal and enthalpic destabilisation of the gel state and increased the ordering of the liquid state of the lipids. This dual effect on the lipid bilayer might suggest that the esters initiate the formation of nanodomains with reduced fluidity that can capture hydroperoxides and thus inhibit lipid peroxidation. In the oleogel, the level of inhibition for the more polar compounds, sinapic acid, syringic acid and syringaldehyde, and less polar, 4-vinylsyringol and butyl sinapate, was at the same level, indicating the possible interactions of these less polar compounds with the oil structuring agent in oleogel. This research thus opened a new approach: the possibility of incorporating lipophilic antioxidants to prolong the oxidative stability of oleogel based products. It was shown that white mustard seeds provide excellent source of raw material for the recovery of value-added antioxidant compounds that are effective in preventing lipid peroxidation in systems such as oil and oleogel.[N. Martinović]20202020-04-11 07:15:04Doktorsko delo/naloga115068UDK: 577.1:547.587.53:66.964.3.097.8VisID: 175758COBISS_ID: 5181304sl