Terpenoid Pigments

Solvent extraction removes chlorophyll and other pigments to give a light-colored product but increases processing costs. Furthermore, solvent extraction removes p-carotene and reduces vitamin A activity (89) (see Terpenoids Vitamins). Supercritical CO2 extraction at 30 and 70 MPa (4,350 and 10,150 psi) and 40°C removed 90 and 70% carotene and lutein, respectively, from alfalfa LPC (96). This process avoids organic solvent residues and recovers valuable by-products. 

Lipids have been dehned on the basis of their stmctnre and solnbility. Lipids are natnrally occnrring componnds consisting of fatty acids and their derivatives, bile acids, pigments, vitamins, and steroids, as well as terpenoids, which are usually soluble in organic solvents such as benzene, chloroform, ether, and alcohol, etc., with variable solubility depending on the stmctnre of the lipid compound. 

T. Cserhati and E. Forgacs, Liquid chromatographic separation of terpenoid pigments in foods and food products. J. Chromatogr.A 936 (2001) 119-137. 

Structure of various terpenoid piant pigments (a) fucoxanthin, (b) (i-carotene, and (c) xanthophyll. OAc = acetate. 

Carotenoids Organic compounds that are 40-carbon terpenoids. They serve as photosynthetic pigments in algae, photosynthetic bacteria, and higher plants. They are also present in some nonphotosynthetic bacteria. 

Lipids is a broad term that includes all oil-soluble, water-insoluble organic substances such as fats, waxes, fatty acids, sterols, pigments and terpenoids synthesized by contemporary biota. 

Table IV. Percentages of Methylation of Total Terpenoid Aldehydes in Pigment Glands of Various Gossypium Species and Hybrids with hirsutum...

Table V. Percentages of Raimondar in the Total Terpenoid Aldehydes from Pigment Glands of Gossypium Species and Their Hybrids with G.. raimondii...

The berry or the small fruits consist of strawberry, raspberry, blackberry, black currant, blueberry, cranberry and elderberry. The volatiles responsible for the flavour of small fruits are esters, alcohols, ketones, aldehydes, terpenoids, furanones and sulfur compounds (Table 7.3, Figs. 7.1-7.7). As fruit ripen, the concentration of aroma volatiles rapidly increases, closely following pigment formation [43]. 

Over 20,000 terpenoids have been identihed (1), and more are being discovered continuously. Plant terpenoids are important in both primary and secondary (speciahzed) metabolism. Their importance in primary metabolism includes physiological, metabolic, and stmctural roles such as plant hormones, chloro-plast pigments, roles in electron transport systems, and roles in the posttranslational modihcation of proteins. In secondary metabolism, the roles of plant terpenoids are incredibly diverse but are associated most often with defense and communication of sessile plants interacting with other organisms. Examples include terpenoid chemicals that form physical and chemical barriers, antibiotics, phytoalexins, repellents and antifeedants against insects and other herbivores, toxins, attractants for pollinators or fruit-dispersing animals, host/nonhost selection cues for herbivores, and mediators of plant-plant and mycorrhiza interactions (2, 3). 

Other classes of organic materials, such as alkaloids, pigments, resins, sterols, terpenes, terpenoids, and waxes, and many simple organic compounds are often present in various biomass species, but are not discussed here because they are usually present in very small amounts. The peptides present in herbaceous biomass are also not discussed here because, although the nitrogen and sulfur contents of the biomass should be assessed for certain microbiological processes, the amino acids that make up the proteins are generally not important factors in conversion processes. 

Apart from the carotenoids relatively few terpenoids have sufficient conjugated unsaturation to contribute to fungal pigments. Exceptions are the sesquiterpe-noid lactarazulenes, e.g. lactaroviolin (7.42), which are obtained from several Lactarius species of milk cap. These are discussed in Chapter 5. 

Pigment glands in resistant cultivars are reported to rupture more readily in resistant than susceptible cultivars (8), but the toxicity of compounds released from the glands has not Been tested against X. campestris. Thus, the role of constitutive terpenoids in resistance Is uncertain. 

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