Chlorophyll pigment

Chlorophylls are key pigments participating in the absorption of light in photosynthesis. They consist of a magnesium porphyrin derivative in which one pyrrol ring is partially reduced. An isocyclic ring is also present Although no SERRS 

Garside and Riley [8] applied high performance liquid chromatography to the determination of a range of algal pigments. 

Tests carried out with the high performance liquid chromatographic technique endorsed the claim that it causes negligible degradation of both the chlorophylls and the xanthophylls. Amore efficient separation of 

Source Reproduced by permission from Elsevier Science, UK [8] 

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CFP-YFP donor-acceptor pair, YFP is several times brighter than CFP [62]. Lastly, for studying dynamic protein associations in plants, the presence of chlorophyll pigments in leaf and stem cells is an additional limitation. These pigments directly absorb the fluorescence, which decreases blue fluorescence intensity for BFP and CFP donors that can be erroneously interpreted as reduced donor fluorescence quantum yield caused by FRET [18]. If sensitized emission or FSPIM is the only available method for quantifying FRET, then it is very important to restrict measurements to chlorophyll free areas within the cells. 

Chlorophylls are macrocyclic tetrapyrrole derivatives containing in their natural form a chelated magnesium ion. The basic structure of chlorophyll pigments is shown in Fig. 2.122. 

Fig. 2.137. Left electrophoregram of chlorophyll pigments in fresh extra virgin olive oil, added with copper chlorophyllin (1) chlorophyllin B (2) pheophytin B (3) pheophytin B(4) chlorophyllin A (5) pheophytin A (6) pheophytin A (7) copper chlorophyllin. Right electrophoregram of chlorophyll pigments in extra virgin olive oil, with a long shelf-life, added with copper chlorophyllin (1) chlorophyllin B (2) chlorophyllin derivatives (3) chlorophyllin A (4) copper chlorophyllin. Reprinted with permission from L. Del Giovine et al. [308].

There have been only a few citations in the literature concerning the extraction and recovery of natural chlorophyll pigments. Chlorophylls, despite their high molecular weights, are soluble in pure CO2 (like pheophytin a at 500 bar and 55°C), or in the presence of an entrainer (like copper chlorophyllin at 60 bar and 20°C with 5% ethanol entrainer). The extraction of dried grass resulted in 1.56 wt.% yield of green components [79]. 

T. Goodwin, Biocbem. J. 68, 503-511 (1958), Studies in Carotenogenesis 24. The Changes in Carotenoid and Chlorophyll Pigments in the Leaves of Deciduous Trees During Autumn Necrosis. ... 

Although LOX activity is important to the plant s defense against pathogens, there are negative aspects of the enzyme in foods. LOX activity and the resulting fatty acid hydroperoxide products initiate free radical chains that modify proteins (particularly residues of Trp, His, Cys, Tyr, Met, and Lys) as well as vitamins or their precursors (e.g., carotene and tocopherol). Evidence of such free radical reactions is often visibly observed as loss of carotenoid/chlorophyll pigments in improperly blanched frozen foods. Another consequence of these free radical reactions is the development of potent off-flavors, many of which originate from decomposition of the fatty acid hydroperoxide products. 

Tetrapyrroles The red heme and green chlorophyll pigments, so important in the energy-... 

Chlorophyll concentrations were estimated from 40 ml subsamples following Suzuki and Ishimaru (1990). Samples were filtered on Whatman GF/F glass-fibre filters (pore size 0.45 pm). Chlorophyllous pigments were extracted by direct immersion of the filters in 5 ml of N,N-dimethylformamide, and actual extractions were made in the dark at 20°C. Concentrations of chlorophyll a in the extracts were determined following Strickland and Parsons (1972) using a Turner 450 fluorometer previously calibrated with chlorophyll a extracted from Anacystis nidulans (Sigma Chemicals, St Louis). 

In addition to chlorophyll pigments, carotenoids are also present in canola oil. In crude canola oil, carotenoids were present at around 130 mg/kg, composed mainly of xanthophylls (90%) and carotenes (10%). During refining and bleaching, the amount of carotenoids was reduced to 10 mg/kg (46). 

TABLE 9. Chlorophyll Pigments in Canola Oil During Processing (mg/kg). 

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