Carotenoids breakdown

As there is great interest from the detergent, food and perfume industry in the potent aroma compounds formed by carotenoid breakdown, and as the fi-ionone obtained can be labelled as natural aroma—if natural carotenoids are used—this cleavage reaction might have a high potential. 

Carotenoid breakdown Lipoxygenase, unsaturated lipids, O2 Carotenoids Autooxidation, O2 Carotenoid breakdown... 

The subsequent conversion of the accessible primary carotenoid breakdown products h already been carried out by using (i) plant cell cultures and (ii) microorganisms. 

A large number of carotenoid compounds have been isolated from saffron. Crocins and crocetin have been already mentioned above and are listed in Table 2. a-Carotene (V), p-carotene (VI), lycopene (VII), zeaxanthin (VIII), phytoene (IX), phytofluene (X) are the minor ones [22]. Straubinger et al [23] have reported the identification of four novel glycoconjugated carotenoid breakdown products of saffron that are the P D-glucosides of (4R)-4-hydroxy-3,5,5-trimethylcyclohex-2-enone, (4S)-4-hydroxy-3,5,5-trimethylcyclohex-2-enone and (4S)-4-(hydroxymethyl)-3,5,5-trimethylcyclohex-2-enone as well as the P-D-gentiobiosyl ester of 2-methyl-6-oxohepta-2,4-dienoic acid. 

Lycopene is a bright red pigment that colors several ripe fruits, vegetables, and flowers. Tomato and tomato products are the main dietary sources of this carotenoid, although it is also found in watermelons, guavas, pink grapefruits, and in small quantities in at least 40 plants. - The absorption of lycopene in the human gut is increased by heat treatment, probably because the breakdown of the plant cells makes the pigment more accessible. ... 

Mantoura, R.F.C. and Llewellyn, C.A., The rapid determination of algal chlorophyll and carotenoid pigments and their breakdown products in natural waters by reversed-phase high-performance liquid chromatography, A a/. Chim. Acta, 151, 297, 1983. 

Unfortunately, the above analysis can never be widely applicable to the determination of excited-state geometries since so few molecules and ions exhibit vibronically structured absorption bands and excitation profiles, even at low temperatures. Moreover, some questions arise as to the possible breakdown of the Condon approximation. Other types of molecule for which similar analyses have been carried out include 3-carotene, carotenoids (9) and certain carotenoproteins such as ovorubin (10). In these cases the excitation profiles of three skeletal a bands are monitored, and estimates for the change in C-C and C=C bonds lengths ( 0.02 A) have been made. 

Queensland mango, Mangifera indica, fruit irradiated postharvest, single dose, 250 or 750 Gy At 250 Gy, skin and pulp color inhibited 50% due to irradiation-induced suppression of chlorophyll breakdown and reduction in carotenoid production. At 750 Gy, fruit respiration increased for 3-5 days, but no effect on fruit firmness 5... 

Common unit operations of food processing are reported to have only minor effects on the carotenoids (Borenstein and Bunnell 1967). The carotenoid-protein complexes are generally more stable than the free carotenoids. Because carotenoids are highly unsaturated, oxygen and light are major factors in their breakdown. Blanching destroys enzymes that cause carotenoid destruction. Carotenoids in frozen or heat-sterilized foods are quite stable. The stability of carotenoids in dehydrated foods is poor, unless the food is packaged in inert gas. A notable exception is dried apricots, which keep their color well. Dehydrated carrots fade rapidly. 

In some species of green algae keto-carotenoids were synthesized when growth was halted by environmental conditions and these compounds may be formed either by the catabolism of chlorophyll or by the result of de novo synthesis. The profile of incorporation of tracer from [2acetate by Haematococcus lacustris into carotenoid and keto-carotenoids indicated that the latter was the major pathway to the keto-compounds, but some breakdown of chlorophyll did occur and the relative contributions of these two pathways varied with the external conditions. In the marine isopod Idotea resecata incorporation of [ Cj-zS-carotene into hydroxy-carotenoids was very low and it was not possible to decide whether the keto-carotenoids present were formed by direct oxidation of jS-carotene to canthaxanthin via echinenone or via hydroxy-compounds. ... 

Since carotenoids and several of their enzymatic and non-enzymatic breakdown products exert a multitude of biological effects, including the regulation of gene expression, it is very often difficult to discriminate between antioxidant effects and other mechanisms of carotenoid action. 

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