Lutein

In this research, carrot pulp was added to traditional snack made from corn-grit. As the biological activity of carotenoids in the body depends on their bioaccessibility, change in carotenoid bioaccessibility during extrusion processing was investigated. In addition, phenolic content, antioxidant activity, β-carotene and lutein contents were investigated before and after the extrusion process. Two different temperature profiles were used for extrusion process. In-vitro bioaccessibilities of β-carotene and lutein increased by extrusion, β-carotene at both temperature profiles while lutein only at higher temperature profile. Extrusion decreased the antioxidant activity, total phenolic, β-carotene and lutein contents. Results suggest that even though amount of functional components decrease, in vitro bioaccessibility could be enhanced by extrusion. Therefore, carrot pulp can successfully be added as a functional ingredient to extrudated.

Photosynthesis is known to produce reactive oxygen species together with the transformation of light into biochemical energy. To fill the gap of the knowledge on the protective antioxidant network of microalgae, a series of experiments to explore the role of spectral composition and intensity of light in the modulation of the photodefence mechanisms developed by the coastal diatom Skeletonema marinoi were performed. The modulation of the total phenolic content, ascorbic acid and the enzymes glutathione reductase, catalase, ascorbate peroxidase and superoxide dismutase together with xanthophyll cycle and non-photochemical quenching in response to variations in the light environment were analysed. Most of the enzymes' activity was promptly affected by the red light. Yet, the monochromatic high intensity blue light enhanced the synthesis of total phenolic content and ascorbic acid in parallel to the xanthophyll cycle activity. This study reveals the dual effects of spectral composition and intensity of light on the modulation of photoprotective mechanisms. Diatoms developed a complementary and/or alternative tuning processes to cope with the variable light environment they experience in the water column.

The ultrafast internal conversion (IC) dynamics of seven C(40) carotenoids have been investigated at room temperature in a variety of solvents using two-color transient lens (TL) pump-probe spectroscopy. We provide comprehensive data sets for the carbonyl carotenoids canthaxanthin, astaxanthin, and-for the first time-echinenone, as well as new data for lycopene, beta-carotene, (3R,3'R)-zeaxanthin and (3R,3'R,6'R)-lutein in solvents which have not yet been investigated in the literature. Measurements were carried out to determine, how the IC processes are influenced by the conjugation length of the carotenoids, additional substituents and the polarity of the solvent. TL signals were recorded at 800 nm following excitation into the high energy edge of the carotenoid S2 band at 400 nm. For the S2 lifetime solvent-independent upper limits on the order of 100-200 fs are estimated for all carotenoids studied. The S1 lifetimes are in the picosecond range and increase systematically with decreasing conjugation length. For instance, in the sequence canthaxanthin/echinenone/beta-carotene (13/12/11 double bonds) one finds tau1 approximately 5, 7.7 and 9 ps for the S1-->S0 IC process, respectively.