Paula Mapelli-Brahm

A comprehensive review on the colorless carotenoids phytoene and phytofluene.

Carotenoids and their derivatives are versatile isoprenoids involved in many varied actions, hence their importance in the agri-food industry, nutrition, health and other fields. All carotenoids are derived from the colorless carotenes phytoene and phytofluene, which are oddities among carotenoids due to their distinct chemical structure. They occur together with lycopene in tomato and other lycopene-containing foods. Furthermore, they are also present in frequently consumed products like oranges and carrots, among others. The intake of phytoene plus phytofluene has been shown to be higher than that of lycopene and other carotenoids in Luxembourg. This is likely to be common in other countries. However, they are not included in food carotenoid databases, hence they have not been linked to health benefits in epidemiological studies. Interestingly, there are evidences in vitro, animal models and humans indicating that they may provide health benefits. In this sense, the study of these colorless carotenes in the context of food science, nutrition and health should be further encouraged. In this work, we review much of the existing knowledge concerning their chemical characteristics, physico-chemical properties, analysis, distribution in foods, bioavailability and likely biological activities.

Study of the time-course of cis/trans (Z/E) isomerization of lycopene, phytoene, and phytofluene from tomato.

In this study we investigated the formation of isomers of lycopene, phytoene, and phytofluene from tomato and their theoretical energy. The results indicated that certain (Z)-isomers are favored thermodynamically and/or kinetically over their (all-E)-counterparts. The relative percentages of (5Z)-lycopene in either thermodynamic or kinetic equilibria were approximately 33%, and those of (all-E)-lycopene were only approximately 22%. Most strikingly (15Z)-phytoene was the major isomer (>90%) when the thermodynamic or the kinetic equilibria were reached. These observations can explain the high levels of lycopene (Z)-isomers found in humans and their rapid formations upon additions of oil to tomato products. In addition, the results can be useful to predict the isomeric forms of lycopene, phytoene, and phytofluene expected in foods as well as in plasma and tissues upon ingestion. In light of the data in the present study, the use of certain geometrical isomers of phytoene, phytofluene and lycopene on their own or as mixtures is recommended in future studies aimed at assessing their possible bioactivity.

Bioaccessibility of phytoene and phytofluene is superior to other carotenoids from selected fruit and vegetable juices

Phytoene and phytofluene are major abundant dietary carotenoids largely ignored in the context of agro-food and health. The bioaccessibility of phytoene and phytofluene in tomato, carrot, blood orange (sanguinello cultivar), and apricot juices was analysed following simulated gastro-intestinal digestion with coffee cream as a lipid source, and compared with that of other main carotenoids from these matrices. The bioaccessibility of phytoene and phytofluene, and also total carotenoid bioaccessibility, followed the order: sanguinello>apricot>tomato>carrot. Phytoene was consistently the carotenoid with the highest bioaccessibility, up to 97%, generally followed by phytofluene. The higher bioaccessibility of these carotenoids could mainly be due to their marked difference in chemical structure and matrix distribution. For most juices, cis-isomers presented a higher bioaccessibility than their all-trans counterparts (P<0.05). The dietary source that provided highest amounts of potentially absorbable phytoene/phytofluene was by far tomato juice (5mg/250mL juice).

Extraction of carotenoids from cantaloupe waste and determination of its mineral composition

The carotenoid and mineral levels as well as the in vitro antioxidant capacity, using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, of waste from cantaloupe was assessed. Then the matrix was subjected to ultrasound-assisted extraction (UAE) and response surface methodology (RSM) was used for the optimization of the extraction of carotenoids. The effect of the extraction procedure on the microstructure of the powder was assessed by scanning electron microscopy (SEM) analysis. The major carotenoids identified were lutein (63.24 ± 0.73 μg βCE/g dw) and β-carotene (56.43 ± 0.11 μg βCE/g dw). Several mineral elements (K, Na, P, Mg, Ca, Fe, Cu, Mn and Zn) were identified, potassium being the major one.The extract exhibited in vitro antioxidant activity (IC50 = 7.33 ± 0.22 μg/mL). The RSM results showed that an amplitude of 100%, extraction time of 10 min, hexane percentage of 80% in hexane/acetone solvent, and solvent-to-solid ratio of 55 mL/g were the optimal conditions for the extraction of carotenoids. Under these conditions, the carotenoid content of the extract was 124.61 ± 3.82 μg/g.The microscopic analysis revealed the effectiveness of the ultrasound treatment that results in noticeable physical changes, like microscopic perforations and breakages.