BOD/COD – Biological / Chemical Oxygen Demand, indicators of the impact of wastewater on the environment.
References_____________________________________________________________________
(1) EFSA Scientific Opinion on the re-evaluation of β-apo-8’-carotenal (E 160e) as a food additive EFSA Journal 2012;10(3):2499 doi 10.2903/j.efsa.2012.2499
Abstract. The Panel on Food Additives and Nutrient Sources added to Food provides a scientific opinion re-evaluating the safety of β-apo-8’-carotenal (E 160e) as a food additive in the EU. β-Apo-8’-carotenal was previously evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1974 and the EU Scientific Committee for Food (SCF) in 1975 and 2000. Both committees established an Acceptable Daily Intake (ADI) of 0–5 mg/kg bw/day, which was withdrawn by the SCF in 2000. The Panel concluded that the available in vitro and in vivo genotoxicity studies do not give reason for concern with respect to genotoxicity. Upon a public call for data two subchronic toxicity studies in rats performed according to OECD guidelines and under GLP became available for evaluation. Based on the 13-week study the Panel established that based on increased incidence of eosinophilic droplets in the kidneys the LOAEL was 10 mg β-apo-8’-carotenal active ingredient/kg bw/day. Upon a public call for data two additional studies on reproductive and developmental toxicity became available revealing a NOAEL of 500 mg/kg bw/day, the highest dose level tested. Overall, the Panel concluded that the present database on β-apo-8′-carotenal provides a basis to revise the ADI. The Panel concluded that based on the LOAEL of 10 mg/kg bw/day from the 13 week study in rats and an uncertainty factor of 200, an ADI for β-apo-8’-carotenal of 0.05 mg/kg bw/day can be established. Exposure estimates at Tier 3 indicate that the newly set ADI is reached for adults on average and exceeded by adults at the 95th percentile and by children on average and at the 95th/97.5th percentile.
Ragnoni E, Di Donato M, Iagatti A, Lapini A, Righini R. Mechanism of the intramolecular charge transfer state formation in all-trans-β-apo-8'-carotenal: influence of solvent polarity and polarizability. J Phys Chem B. 2015 Jan 15;119(2):420-32. doi: 10.1021/jp5093288.
Abstract. In this work we analyzed the infrared and visible transient absorption spectra of all-trans-β-apo-8'-carotenal in several solvents, differing in both polarity and polarizability at different excitation wavelengths. We correlate the solvent dependence of the kinetics and the band shape changes in the infrared with that of the excited state absorption bands in the visible, and we show that the information obtained in the two spectral regions is complementary. All the collected time-resolved data can be interpreted in the frame of a recently proposed relaxation scheme, according to which the major contributor to the intramolecular charge transfer (ICT) state is the bright 1Bu(+) state, which, in polar solvents, is dynamically stabilized through molecular distortions and solvent relaxation. A careful investigation of the solvent effects on the visible and infrared excited state bands demonstrates that both solvent polarity and polarizability have to be considered in order to rationalize the excited state relaxation of trans-8'-apo-β-carotenal and clarify the role and the nature of the ICT state in this molecule. The experimental observations reported in this work can be interpreted by considering that at the Franck-Condon geometry the wave functions of the S1 and S2 excited states have a mixed ionic/covalent character. The degree of mixing depends on solvent polarity, but it can be dynamically modified by the effect of polarizability. Finally, the effect of different excitation wavelengths on the kinetics and spectral dynamics can be interpreted in terms of photoselection of a subpopulation of partially distorted molecules.
Harrison EH. Carotenoids, β-Apocarotenoids, and Retinoids: The Long and the Short of It. Nutrients. 2022 Mar 28;14(7):1411. doi: 10.3390/nu14071411.
Abstract. Naturally occurring retinoids (retinol, retinal, retinoic acid, retinyl esters) are a subclass of β-apocarotenoids, defined by the length of the polyene side chain. Provitamin A carotenoids are metabolically converted to retinal (β-apo-15-carotenal) by the enzyme β-carotene-15,15'-dioxygenase (BCO1) that catalyzes the oxidative cleavage of the central C=C double bond. A second enzyme β-carotene-9'-10'-dioxygenase cleaves the 9',10' bond to yield β-apo-10'-carotenal and β-ionone. Chemical oxidation of the other double bonds leads to the generation of other β-apocarotenals. Like retinal, some of these β-apocarotenals are metabolically oxidized to the corresponding β-apocarotenoic acids or reduced to the β-apocarotenols, which in turn are esterified to β-apocarotenyl esters. Other metabolic fates such as 5,6-epoxidation also occur as for retinoids. Whether the same enzymes are involved remains to be understood. β-Apocarotenoids occur naturally in plant-derived foods and, therefore, are present in the diet of animals and humans. However, the levels of apocarotenoids are relatively low, compared with those of the parent carotenoids. Moreover, human studies show that there is little intestinal absorption of intact β-apocarotenoids. It is possible that they are generated in vivo under conditions of oxidative stress. The β-apocarotenoids are structural analogs of the naturally occurring retinoids. As such, they may modulate retinoid metabolism and signaling. In deed, those closest in size to the C-20 retinoids-namely, β-apo-14'-carotenoids (C-22) and β-apo-13-carotenone (C-18) bind with high affinity to purified retinoid receptors and function as retinoic acid antagonists in transactivation assays and in retinoic acid induction of target genes. The possible pathophysiologic relevance in human health remains to be determined.
Gordon HT, Bauernfeind JC. Carotenoids as food colorants. Crit Rev Food Sci Nutr. 1982;18(1):59-97. doi: 10.1080/10408398209527357.
Abstract. The carotenoids are a chemically related group of pigments which occur widely and abundantly in nature. Fruits, vegetables and vegetable oils, dairy products, leaves, shrimp, lobster, the plumage of exotic birds, all contain carotenoids. Chemically, the carotenoids may be divided into carotenes, made up of carbon and hydrogen only, and oxycarotenoids containing oxygen in addition to carbon and hydrogen. The use of carotenoid-containing plant extracts for coloring foods has been practiced for centuries and continues today. Advances in chemical synthesis resulted in the complete laboratory synthesis of beta carotene in 1950. Since then the commercial synthesis of several carotenoids has been accomplished. In the U.S. three of these commercially synthesized carotenoids, beta-carotene, beta-apo-8'-carotenal, and canthaxanthin, are accepted color additives for use in foods and are exempt from certification. These three carotenoids are also widely accepted for food use in other countries. This paper deals with the chemistry and synthesis of these three carotenoids, with special emphasis on their numerous commercially available market forms and their characteristics, and on the application of these carotenoids in the coloring of food products.
Šebelík V, Kuznetsova V, Šímová I, Polívka T. Carotenoid radical formation after multi-photon excitation of 8'-apo-β-carotenal. Phys Chem Chem Phys. 2025 Mar 6;27(10):5080-5086. doi: 10.1039/d4cp04373a.
Abstract. Carotenoids containing a conjugated CO group exhibit complex excited-state dynamics that are influenced by solvent polarity due to the involvement of an intramolecular charge transfer (ICT) state. Our study explores the excited-state behavior of 8'-apo-β-carotenal under multi-photon excitation conditions. Using near-infrared (1300 nm) multi-photon excitation, we observe the formation of a cation radical of 8'-apo-β-carotenal, a process distinct from those following one-photon visible or UV excitation. Our findings suggest that this radical formation results from multi-photon excitation involving a higher-lying dark state, supported by intensity-dependent experiments. This work demonstrates that radical generation is a characteristic of this higher excited state and is not produced during relaxation from the S1/ICT state. The results open new pathways for understanding carotenoid radical formation mechanisms under intense multi-photon excitation.
E160e 
