Abraham Lifshitz

A comparative study of the carotenoid pigments in juice of Shamouti, Valencia and Washington oranges, three varieties of Citrus sinensis

Abstract The carotenoid composition of three varieties of Citrus sinensis grown in Israel was investigated. The pigment pattern was similar in all three varieties although some quantitative variation was observed. The differences in color between Valencia, Shamouti and Washington Navel varieties result from these quantitative differences in carotenoid composition. The ratio of the orange pigments (λ max 445 nm) to the yellow pigments (420 nm) decreased from Valencia through Shamouti to Washington. Carotenoids previously not reported in Citrus such as γ-carotene, rubixanthin, sintaxanthin and its OH-derivative and lutein 5,6-monoepoxide, were identified. Two new carbonyl pigments with unknown structure were also detected.

Water-insoluble derivatives of naringinase

Abstract 1. 1. Water-insoluble derivatives of naringinasc were prepared by covalent linking of the enzyme to copolymers of maleic anhydride with ethylene, methylvinyl ether, isobutyl-vinyl ether, or styrene. 2. 2. The enzymic activity, mechanical properties, and stability of the various water-insoluble naringinase derivatives were investigated. 3. 3. Some effects of the carrier polymer side chains on the properties of the insoluble enzyme-polymer conjugates were clarified.

Carotenoids in pulp, peel and leaves of Persea americana

Abstract A complex pattern of chloroplast pigments was found to be common to pulp, peel and leaves of avocado. This is explained by the presence of chlorophyll in the ripe fruit and its peel. Two chromoplast-specific pigments were found in ripe pulp and are tentatively identified as α-citraurin and mimulaxanthin. The identity of the latter and of neochrome, was established inter alia by the MS. The xanthophylls occur esterified to a major extent in pulp but entirely free in peel. The coexistence of chloroplast and chromoplast pigments in avocado fruit make this a suitable object for the ultrastructural studies of the origin of the chromoplasts.

Structural elucidation of some orange juice carotenoids

Abstract The structure of some carotenoids of Valencia orange juice were elucidated by chemical tests and MS of the free pigments and their derivatives. A new apocarotenal was shown to be 3-hydroxy-5,8-epoxy-5,8-dihydro-8′-apo-β-caroten-8′-al. Two UV-fluorescent apocarotenols found recently in avocado were also present. For the pigments previously designated trollixanthin and trollichrome, the new structures 5,6-dihydro-β,β-carotene-3-3′,5,6-tetrol and 5,8-epoxy-5,8,5′,6′-tetrahydro-β,β-carotene-3,3′,5′,6′-tetrol are assigned, both containing a trihydroxylated ring as in heteroxanthin.

Carotenoids of Eriobotrya japonica

Abstract The carotenoids of the loquat fruit Eriobotrya japonica Golden Nugget variety, were investigated. They were identified according to their chromatographic, spectrophotometric and chemical properties and compared with standard pigments. For some of the carotenoids, MS were determined. Pulp and peels were investigated separately. The main pattern of the pulp carotenoids was β-carotene (33%), γ-carotene (6%), cryptoxanthin (22%), lutein, violaxanthin and neoxanthin, each about 3–4%. The peel, with a carotenoid content 5 times as high, had a similar pattern, but the ratio between the main pigments differed: β-carotene (50%); γ-carotene (5%); cryptoxanthin (5%); lutein (13%); violaxanthin, neoxanthin, 3–4%. The carotenoids of the loquat (subfamily Maloideae) were very similar to those of the apricot ( Prunus armeniaca -subfamily Prunoideae) both of the family of Rosaceae . The intergeneric differences are more pronounced, which is of possible taxonomic significance. The lower concentration of cryptoxanthin and the high concentration of lutein in the peels is noteworthy and of biosynthetic interest.

Structures of some carotenoids from the pulp of Persea americana

Abstract The identity of chrysanthemaxanthin as a major pigment in avocado pulp has been confirmed by MS and the identity of neoxanthin similarly established. A carbonyl pigment was identified as 3-hydroxy-sintaxanthin. Two new UV fluorescent apocarotenoids were isolated. On the basis of spectrum, behaviour in acid and MS, one of these is assigned the structure 5,8-epoxy-5,8-dihydro- 10′-apo-β-caroten-3, 10′-diol. The other has an acid labile pentaene chromophore, and structure ( 1 ) has been tentatively assigned on similar evidence. These are the first natural allyic apocarotenols whose structures have been established.

Carotenoids of the invertebrates of the red sea (Eilat shore)—II Carotenoid pigments in the gonads of the sea urchin Tripneustes gratila (echinodermata)

Abstract 1. 1. The carotenoids of female and male gonads of the sea urchin Tripneustes gratila have been investigated and characterized. 2. 2. The predominant carotenoids in both sexes are echinenone (80%), β-carotene (8%), with various minor keto- and hydroxycarotenoids (12%). 3. 3. β-carotene is selectively ingested and metabolized to echinenone, both being stored in the gonadal tissue. 4. 4. The minor pigments are ingested from the food, being of both plant and animal origin. 5. 5. The carotenoid concentrations and the relative abundance of the carotenoid fractions in immature and mature gonads have been compared. 6. 6. The main change taking place during maturation is the increasing storage of echinenone at the expense of β-carotene in the gonads, preponderantly in the female.