Virgin Olive Oil Enriched with Lutein-Zeaxanthin from Spinacia oleracea

A lutein and zeaxanthin enriched extra virgin olive oil as a potential nutraceutical agent: A pilot study

Xanthophylls lutein and zeaxanthin are carotenoids with important antioxidant capacities and relevant roles against the prevention of eye diseases. In this study a valorization of non-commercial spinach to obtain lutein and zeaxanthin as raw materials to develop nutraceuticals was carried out. Three oil matrixes were analyzed: extra virgin olive oil (EVOO), lutein and zeaxanthin enriched EVOO (EVOO+LZ), and EVOO enriched with 25 % of EVOO+LZ (namely EVOO+D) to evaluate their biological potential as antioxidants. Urinary antioxidant total capacity, and circulatory blood levels of lutein and zeaxanthin were determined (in vivo analysis). Also, a simulation of gastrointestinal simulation (in vitro analysis) was performed. The results showed an increase in the circulatory levels of lutein-zeaxanthin after the ingestion of EVOO+LZ during 45 and 60 days, and an increase in the urinary antioxidant levels after the intake of EVOO+LZ and EVOO+D. In vitro assay revealed that both xanthophylls showed bioavailability to be assimilated in the intestinal tract. Therefore, these EVOO enriched with lutein-zeaxanthin might be considered as powerful antioxidant tools with potential properties in the management/prevention of eye diseases.

Zeaxanthin Combined with Tocopherol to Improve the Oxidative Stability of Chicken Oil

Chicken oil is prone to oxidation due to the high content of unsaturated fatty acids. The interaction of antioxidants was affected by their concentration, ratio, and reaction system. In this article, mixtures of zeaxanthin and tocopherols (α-tocopherol and γ-tocopherol) were chosen to enhance the oxidative stability of chicken oil. The antioxidation of zeaxanthin with tocopherols was analyzed using the Rancimat test, the free radical scavenging capacity and the Schaal oven test (the variation of antioxidant content, PV and shelf life prediction). The optimal concentration of zeaxanthin determined by Rancimat in chicken oil was 20 mg/kg. The binary mixtures have a strong synergistic effect in the ABTS experiment, and the clearance rate was up to 99%, but antagonistic effect in ORAC. The degree of synergism between zeaxanthin and tocopherols was determined by ratio. The interaction between zeaxanthin and α-tocopherol was synergistic, while the types of interaction between zeaxanthin and γ-tocopherol were affected by concentration. The main synergistic interaction mechanism was the regeneration of tocopherol by zeaxanthin. Synergistic combinations of zeaxanthin with α-tocopherol and γ-tocopherol played a key role in the primary oxidation stage of the lipid. The best synergistic combination was A3 (zeaxanthin+α-tocopherol: 15+50 23 mg/kg), which could extend the shelf life of chicken oil (92.46 d) to 146.93 days. This work provides a reference for zeaxanthin and tocopherol to improve the oxidative stability of animal fat.

Zeaxanthin in Soybean Oil: Impact of Oxidative Stability, Degradation Pattern, and Product Analysis

In this study, the antioxidant capacity and oxidative stability of zeaxanthin with different concentrations in soybean oil were evaluated. The oxidative or isomerization products of zeaxanthin were monitored during oxidation for 12 h at 110 °C. It was found that the ability to scavenge the free radicals (DPPH, FRAP, and ABTS) was dependent upon the concentration of zeaxanthin. However, antioxidation of zeaxanthin was observed when the concentration was less than 50 μg/g. When the concentration exceeded 50 μg/g, zeaxanthin acted as a pro-oxidant. There were three kinds of non-volatile products of zeaxanthin that were detected: (a) Z-violaxanthin, (b) 9-Z-zeaxanthin, and (c) 13-Z-zeaxanthin, and it was found that the content of 13-Z-zeaxanthin formed by isomerization was the highest. In addition, the linear ketone (6-methyl-3,5-heptadien-2-one) and cyclic volatile products (3-hydroxy-β-cyclocitral, 3-hydroxy-5,6-epoxy-7,8-dihydro-β-ionone, and 3-hydroxy-β-ionone) formed by in situ oxidative cleavage were identified.

Untargeted Metabolomics to Evaluate the Stability of Extra-Virgin Olive Oil with Added Lycium barbarum Carotenoids during Storage

A carotenoid-rich extract from Lycium barbarum L. was added to extra virgin olive oil (EVOO), obtaining a carotenoid-enriched oil (EVOOCar). The oxidative stability of EVOO and EVOOCar was evaluated during long-term storage of 28 weeks at room temperature, by measuring some classical parameters (acidity and peroxide values, spectrophotometric coefficients, fatty acid composition) and the content of minor compounds (i.e., α-tocopherol and lutein). At the end of the storage, higher content (p < 0.01) of α-tocopherol in EVOOCar in respect to EVOO were observed. Zeaxanthin dipalmitate, the most abundant carotenoid compound of Goji berries, decreased slightly (p < 0.05) in EVOOCar until the end of the storage. In regard to polyphenols, an ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC/QTOF-MS) using untargeted metabolomics was carried out. This latter approach discriminated the two oil samples during long-term storage, allowing to identify also the phenolic classes most exposed to significant variations during storage (i.e., mainly lignans and flavones). Besides, the addition of Goji carotenoids preserved the stability of tyrosol equivalents in EVOOCar during long-term storage. These results highlighted that the enrichment of EVOO with a carotenoid-rich extract can improve the shelf-life and nutritional value of added-oil, protecting EVOO natural antioxidants during long-term storage.

Monitoring of acrylamide and phenolic compounds in table olive after high hydrostatic pressure and cooking treatments

Acrylamide and phenolic compounds on both fresh and cooked olives were monitored by HPLC/MS-MS and reversed-phase-HPLC methods along different procedures: elaboration process, high hydrostatic pressure (HHP), cooking treatment and bioavailability evaluation. Acrylamide was not detected during the elaboration process and after HHP treatment. Hydroxytyrosol, tyrosol, oleuropein and verbascoside were the most important phenols after HHP treatment. The frying and baking processes on olives enhanced the formation of acrylamide and a significant reduction in the phenolic compounds. The frying process produced lower acrylamide concentration and less reduction of phenolic compounds than the baking process, while in the gastrointestinal digestion these compounds were slightly reduced if compared to the initial stage. As a conclusion, the best way to ingest high quantities of phenols and reduce acrylamide consumption is by ingesting the olives when they are fresh. In case the olives need to be cooked, specific time and temperature conditions shall be applied.