Chlorophylls vegetables

Green coloration, present in many vegetable oils, poses a particular problem in oil extracted from immature or damaged soybeans. Chlorophyll is the compound responsible for this defect. StmcturaHy, chlorophyll is composed of a porphyrin ring system, in which magnesium is the central metal atom, and a phytol side chain which imparts a hydrophobic character to the stmcture. Conventional bleaching clays are not as effective for removal of chlorophylls as for red pigments, and specialized acid-activated adsorbents or carbon are required. 

Fungi Simple vegetative bodies from which reproductive structures are elaborated. The fungi contain no chlorophyll and therefore require sources of complex organic molecules. Many species grow on dead organic materials and others live as parasites. 

The influence of sunlight on vegetable growth, and the results of etiolation are, of course, well known to botanical students. There is no room for doubt that the production and evolution of the odour-bearing constituents of a plant are in direct relationship with the chlorophyll... 

The typical isocyclic ring E present in chlorophylls is susceptible to a number of different modifications such as epimerization, which produces stereoisomers by inversion of the configuration at C-13 of their parent pigments. These 13 -epichlorophylls, known as chlorophylls a and b, are minor pigments. They are considered artifacts produced in the course of handling plant extracts and sometimes are also found in small amounts in heated and deep-frozen vegetables, hi the old Fischer systan of nomenclature that can still be found in some literature, these epimers were named 10-epichlorophylls. 

Allomerized chlorophylls are oxidized compounds at C-13, forming theC-13 OH-chlorophyU catabolites. Other common positions for modifications and/or oxidation have been found at C-3, C-7, and C-8. Pyroderivatives of chlorophylls and their degradation products, usually found in heated and processed vegetables, lack the carbomethoxy group (-COOCH3) at C-13 of ring E, which is replaced by hydrogen. 

In a clinical trial performed in China, the administration of 300 mg/day of copper chlorophyllin to humans who had detectable levels of serum aflatoxin due to unavoidable food contamination resnlted in a 50% reduction of median urinary levels of aflatoxin-DNA adducts. If health benefits from consuming natural chlorophylls were confirmed, it wonld be easy to add green leafy vegetables to a daily diet to obtain the benefit. Since leafy vegetables contain usually up to 200 mg chloro-phylls/100 g fresh weight, the intake of approximately 1 to 2 cups of raw spinach/day... 

Diets high in red meat and low in green vegetables have been associated with increased colon cancer risk and the opposite has been postulated for diets rich in green vegetables. A plausible explanation for an increased colon cancer risk is that dietary haem is metabolized in the gut to a factor that increases colonic cytotoxicity and hyperproliferation, which are considered important risk factors in the development of cancer. In this sense, it has been shown that spinach and isolated natural chlorophyll, but not sodium-copper chlorophyUin, prevented the proliferation of colonic cells and may therefore reduce colon cancer risk. It has been speculated that haem and chlorophylls, due to their hydrophobicity, form a complex, thus preventing the metabolism of haem. ... 

Gross, J., Chlorophylls, in Pigments in Vegetables Chlorophylls and Carotenoids, Gross, J., Ed., Van Nostrand Reinhold, New York, 1991, 2. 

Tan, Y.A., Low, K.S., and Chong, C.L., Rapid determination of chlorophylls in vegetable oils by laser-based fluorometry, J. Sci. Food Agric., 66, 479, 1994. Bhattacharya, D. and Medlin, L., Algal phylogeny and the origin of land plants, Plant Physiol., 116, 9, 1998. 

De Vogel, J. et al.. Green vegetables, red meat and colon cancer Chlorophyll prevents the cytotoxic and hyperproliferative effects of haem in rat colon. Carcinogenesis, 26, 387, 2005. 

Despite the ubiquitous distribution of chlorophylls in all photosynthetic plants, quantitative information exists only for a few vegetables. The most common edible plants lack definitive data and consequently no information is available about chlorophyll distribution in current food composition tables. Still more difficult is to find analytical data in literature about the individual amounts of chlorophyll a and b and their respective derivatives. 

The wide distribution of chlorophylls throughout the plant kingdom facilitates the scrutiny of chlorophyll-rich vegetables for human nutrition with a view to their direct consumption. However, until now, little standardized information was available in the literature regarding the absolute total chlorophyll contents and the ratios of chlorophylls a and b in raw materials. The different analytical methods of extraction and quantification and the lack of data about moisture contents (that may vary considerably among varieties and preparations) can also influence the final contents of pigments. These factors have largely contributed to the discrepancies found in similar food samples. 

Total Chlorophyll Contents of Some Vegetables and Fruits... 

Leafy vegetables and some fruits in particular are rich sources of chlorophylls. However, they are ranked among the most perishable post-harvest products and must be consumed within a few days after harvest or subjected to preservation methods to extend their freshness. Their typical green color is, if not the most important sensory attribute, an extremely important parameter of quality. Any discoloration can lead to rejection by consumers as the bright green color is intuitively linked with freshness. 

Traditionally, dried or powdered plant material is used and extracts can be obtained by mixing the material with food-grade solvents like dichloromethane or acetone followed by washing, concentration, and solvent removal. The result is an oily product that may contain variable amounts of pheophytins and other chlorophyll degradation compounds usually accompanied by lipid-soluble substances like carotenoids (mainly lutein), carotenes, fats, waxes, and phospholipids, depending on the raw material and extraction techniques employed. This product is usually marketed as pheophytin after standardization with vegetable oils. 

Commercially available stable green metallo-chlorophyU colorants could be produced and in 1984 Segner et al. patented the process to preserve the green color in canned vegetables under the Veri-Green trade name. Some years later, the formation and stability of these complexes were found to be dependent on the type of metal, pH, ionic concentration, temperature, and chlorophyll species — which could explain the unpredictable color changes observed in the beginning. ... 

Lipid-soluble food grade copper chlorophyll is manufactured similarly by extraction of adequate plant material, followed by replacement of magnesium by copper, and purihcation steps to remove carotenoids, waxes, sterols, oils, and other minor components that are co-extracted. Commercial copper chlorophylls may vary physically, ranging from viscous resins to fluid dilutions in edible oils as well as granulated forms and emulsions standardized with edible vegetable oil. Colors may vary... 

Bohn, T. et al., Chlorophyll-bound magnesium in commonly consumed vegetables and fruits relevance to magnesium nutrition, J. Food Sci., 69, S347, 2004. 

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