A-Cryptoxanthin

It is assumed that in order to have vitamin A activity a molecule must have essentially one-half of its structure similar to that of (i-carotene with an added molecule of water at the end of the lateral polyene chain. Thus, P-carotene is a potent provitamin A to which 100% activity is assigned. An unsubstituted p ring with a Cii polyene chain is the minimum requirement for vitamin A activity. y-Car-otene, a-carotene, P-cryptoxanthin, a-cryptoxanthin, and P-carotene-5,6-epoxide aU have single unsubstimted rings. Recently it has been shown that astaxanthin can be converted to zeaxanthin in trout if the fish has sufficient vitamin A. Vitiated astaxanthin was converted to retinol in strips of duodenum or inverted sacks of trout intestines. Astaxanthin, canthaxanthin, and zeaxanthin can be converted to vitamin A and A2 in guppies. ... 

Auroxanthin, antheraxanthin, violaxanthin, mutatoxanthin, lutein, zeaxanthin, a-cryptoxanthin or zeinoxanthin, P-cryptoxanthin, -carotene, a-carotene, P-carotene... 

Mercadante, A.Z. and Rodriguez-Amaya, D.B., Confirmation of the identity of a-cryptoxanthin and incidence of minor provitamin A carotenoids in green leafy vegetables, Cienc. Tecnol. Alim., 21, 216, 2001. 

The absorption efficiency of the different carotenoids is variable. For example, (3-cryptoxanthin has been reported to have higher absorption efficiency than a-cryptoxanthin in rats (Breithaupt and others 2007). Carotenoids must be liberated from the food before they can be absorbed by intestinal cells (Faulks and Southon 2005). Mechanical disruption of the food by mastication, ingestion, and mixing leads to carotenoid liberation (Guyton and Hall 2001). The enzymatic and acid-mediated hydrolysis of carbohydrates, lipids, and proteins (chemical breaking of the food) also contributes to carotenoids liberation from the food matrix (Faulks and Southon 2005). Once released, carotenoids must be dissolved in oil droplets, which are emulsified with the aqueous components of the chyme. When these oil droplets are mixed with bile in the small intestine, their size is reduced, facilitating the hydrolytic processing of lipids by the pancreatic enzymes (Pasquier and others 1996 Furr and Clark 1997 ... 

Fig. 2.3. Characteristic chromatogram of paprika paste. Detection at 450 nm. Peak identification 1 = Capsorubin 2 = 5,6-Diepikarpoxanthin 3 = Capsanthin-5,6-epoxide 4 = Capsanthin-3,6-epox-ide 5 = Violaxanthin 6 = Luteoxanthin 2 7 = Luteoxanthin 1 8 = Capsanthin 9 = Antheraxanthin 10 = Mutatoxanthin 11 = Cucurbitaxanthin A 12 = (9/9 Z)-Capsanthins 13 = (13/13 Z)-Capsanthins 14 = Zeaxanthin 15 = Nigroxanthin 16 = (9Z)-Zeaxanthin 17 = (13Z)-Zeaxanthin 18 = Cryptocapsin 19 = a-Cryptoxanthin 20 = /TCryptoxanthin 21 = (Z)-Cryptoxanthin 22 = /1-Carotene 23 = (Z)-jS-Carotene. Reprinted with permission from J. Deli et al. [27].

Fig. 2.17. Saponified carotenoids in orange juice. Chromatographic conditions are given in text. Chromatograms from absorbance monitoring at 430, 486 and 350 nm, respectively, are shown, all at identical attenuation. Peak identification 1, 3, 5, 8, 26 and 29 = unidentified peaks 4 = valen-ciaxanthin 6 = neochrome 7 = trollichrome 9 = antherxanthin 11 = c/s-anthexanthin 12 = neoxanthin 19 = auoxanthin B 20 = c/s-violaxanthin 22 = leutoxanthin 23 = mutatoxan-thin A 24 = mutatoxanthin B 25 = lutein 27 = zeaxanthin 28 = isolutein 31 = a-cryptoxanthin 33 = /J-cryptoxanthin 34 = phytofluene 35 = a-carotene 36 = ae-carotene 37 = / -carotene. Reprinted with permission from R. Rouseff et al. [41].

Fig. 3 Normal-phase HPLC separation of Valencia orange peel carotenoids. Peaks 2 — a-cryptoxanthin esters 5 = lutein diesters 6 and 7 = violaxanthin diesters 8 = luteoxanthin diesters 15 and 16 = violaxanthin monoesters 17 = luteoxanthin monoesters. The other peaks are not identified. (From Ref. 46.)...

In a 1997 publication, we reported the relative distribution of 13 major dietary carotenoids in the serum of 10 healthy human subjects with a high intake of fruits and vegetables." The concentrations of the 12 dietary cii-carotenoids were combined and reported together with 13 of their corresponding all-trani-compounds. The average distribution of serum carotenoids for these subjects were lutein (20%), lycopene (20%), P-carotene (10%), -carotene (10%), P-cryptoxanthin (8%), phyto-fluene (8%), a-carotene (6%), a-cryptoxanthin (4%), phytoene (4%), zeaxanthin... 

Carotenoids a-carotene, 13-carotene, a-cryptoxanthin, P-cryptoxanthin, lutein, lycopene, zeaxanthin Most red to yellow fruits and vegetables Color... 

The photosynthetic pigments of higher plants comprise not only the chlorophylls (a and b) but also a range of carotenoids. The main ones of these are B-carotene (usually 25-30% of the total carotenoids) and the xanthophylls lutein (45-50%), violaxanthin (ca. 15%) and neoxanthin (ca. 15%), though small amounts of others, e.g. a-carotene, zeaxanthin, antheraxanthin, lutein-5,6-epoxide and a-cryptoxanthin, may also be detected. The... 

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