Carotenoids nature

Carrot oil—The Hquid or the soHd portion of the mixture, or the mixture itself obtained by the hexane extraction of edible carrots (Daucus carota L.) with subsequent removal of the hexane by vacuum distillation. The resultant mixture of soHd and Hquid extractives consists chiefly of oils, fats, waxes, and carotenoids naturally occurring in carrots. 

Chaudhry, Y., Carotenoids natural food colors and health benefits. Symposium 12 Interaction of Natural Colors with Other Ingredients, July 19, 2003, GNT USA Inc., Tarrytown, NY. 

Moore TA, Gust D and Moore AL (1994) Carotenoids Nature s unique pigments for light and energy processing. Pure Appl Chem 66 1033-1040... 

This Volume, as the previous volumes in this series, is highly recommended as a useful summary of important information which spans the diverse area of biological activity, medicinally important terpenes, alkaloids, steroidal lactones, carotenoids, natural colourants, peptides and the use of enzymes in the products of chiral synthons. 

Carotenoids Naturally occurring tetraterpenoid compounds found in plants and animals. 

SCHEME 6 Sequential Stille couplings of our unsymmetric hexatriene-l,6-distannane rrans,rrans, -19. " The reactivity order of the C-Sn bonds is such that the sterically least hindered C-Sn bond couples first. This was exploited in our laboratory for realizing the first total synthesis of the carotenoid natural product pyrrhoxanthin. ... 

FIGURE 18.2 Names and structures of the fat-soluble vitamins and pro-vitamins A carotenoid naturally occurring in foods, (a) Vitamins A and D (b) vitamins E and K.p... 

Carotenoids are natural pigments characterized by a tail to tail linkage between two C20 units and an extended conjugated system of double bonds They are the most widely dis tributed of the substances that give color to our world and occur m flowers fruits plants insects and animals It has been estimated that biosynthesis from acetate produces approximately a hundred million tons of carotenoids per year The most familiar carotenoids are lycopene and (3 carotene pigments found m numerous plants and easily isolable from npe tomatoes and carrots respectively... 

Carotenoids (Section 26 16) Naturally occurring tetrater penoid plant pigments... 

Flour Bleaching Agents and Bread Improvers. Freshly milled flour contains carotenoid pigments that cause the flour to have a yellow color. In addition, when the flour is made into dough the product is sticky and unmanageable. As the flour ages, a natural process takes place which turns the flour white and improves its baking qualities. Because the natural process takes quite a bit of time, additives are used to speed up the process. 

Tetraterpenes. Carotenoids make up the most important group of C q terpenes and terpenoids, although not all carotenoids contain 40 carbon atoms. They are widely distributed in plant, marine, and animal life. It has been estimated that nature produces about 100 million t/yr of carotenoids synthetic production amounts to several hundred tons per year (207,208). 

In nature, vitamin A aldehyde is produced by the oxidative cleavage of P-carotene by 15,15 - P-carotene dioxygenase. Alternatively, retinal is produced by oxidative cleavage of P-carotene to P-apo-S -carotenal followed by cleavage at the 15,15 -double bond to vitamin A aldehyde (47). Carotenoid biosynthesis and fermentation have been extensively studied both ia academic as well as ia iadustrial laboratories. On the commercial side, the focus of these iavestigations has been to iacrease fermentation titers by both classical and recombinant means. 

The chief coloring principle found ia the oil or fat extracts of annatto seeds is the carotenoid hixin (36, R = UH3) (Cl Natural Orange 4, Cl No. 

Although the carotenoids can be obtained from natural sources, it is far more economical to manufacture them for commercial use (130). Three have been manufactured for many years -carotene [7235-40-7] (42), canthaxanthin [514-78-3] (43), and P-apo-8 -carotenal [1107-26-2] (44) (131). Their stmctures are shown ia Figure 1. 

Carotenoids have two general characteristics of importance to the food iadustry they are not pH sensitive ia the normal 2—7 range found ia foods, and they are not affected by vitamin C, making them especially important for beverages. They are more expensive than synthetic food dyes and have a limited color range. In their natural environment they are quite stable, but they become more labile when heated or when they are ia solution. Under those conditions, there is a tendency for the trans-double bonds to isomerize to the cis-stmcture with a subsequent loss of color iatensity. The results of controlled tolerance and toxicity tests, usiag pure carotenoids, iadicate that they are perfecdy safe as food colors (132). 

Retinoids are alcohols and accordingly soluble in ethanol, isopropanol, and polyethylenglycol. Major sources of natural retinoids are animal fats, fish liver oil (retinylesters) and yellow and green vegetables (carotenoids). Ingested retinylesters (RE) are hydrolyzed to retinol by enteral hydrolases in the intestine. ROL and carotenoids are absorbed by intestinal mucosa cells. 

The absorption and transport processes of many of the phytochemicals present in food are complex and not fully understood, and prediction of their bioavailability is problematic. This is particularly true of the lipid-soluble phytochemicals. In this chapter the measurement of carotenoid bioavailability will be discussed. The carotenoids serve as an excellent example of where too little understanding of food structure, the complexity of their behaviour in foods and human tissues, and the nature and cause of widely different individual response to similar intakes, can lead to misinterpretation of study results and confusion in our understanding of the relevance of these (and other) compounds to human health. 

The complex nature of the mass transfer of carotenoids to absorbable lipid species, the diversity of raw and processed foods consumed, and individual variations in the degree of mastication, will lead to differences in the amount of carotenoid that becomes bioaccessible and potentially available for absorption. By understanding the underlying mechanisms of these processes, for a wider range of fruit and vegetable constituents, it will become possible... 

Classically, to measure absolute absorption the plasma area imder the curve from an intravenous dose would be compared to that caused by the feeding of an oral dose. However, the carotenoids are lipid-soluble and are normally incorporated in chylomicrons synthesised in the enterocytes, a situation that cannot be replicated and applied to studies in humans because an intravenous preparation that would behave naturally is not possible. 

One of the few phytochemicals that has been subjected to the rigorous testing procedures required by food safety authorities is P-carotene, a naturally-occurring carotenoid that is also a pre-cursor of vitamin A in humans. It is increasingly used as a food colour since the food product can be claimed to contain all natural ingredients. For this reason, detailed toxicological studies were undertaken that enabled the Joint FAO/WHO Expert Committee for Food Additives (JECFA) to set an ADI of 0-5 mg/kg/bw/day based on a NOAEL of 50 mg/day and the application of an uncertainty factor of 10 (JECFA, 1974). This low factor was used because it was argued that the compound occurred naturally in food, that its use as a food additive would not lead to a substantial increase in the total amount normally consumed, and that there had been no reports of adverse effects in humans. The ADI would correspond to an acceptable intake in humans of up to 350 mg/day. 

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