Chlorophyll pigments from

Pigments from cells or thylakoid membranes were extracted in 80 % acetone and debris was removed by centrifugation at 10,000 g for 5 min. The absorbance of the supernatant at 652 nm was measured by a Shimadzu UV-visible spectrophotometer. The chlorophyll (a and b) concentration of the samples was determined according to Amon [1949], with equations corrected as in Melis et al. [2000],... 

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].

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. 

Figure 2.12 Absorption spectra of various pigments from algae and plants chlorophyll a (—),...

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). 

Isolation of Chlorophyll and Carotenoid Pigments from Spinach... 

Zooplanicton pristane In copepods, HEH In zooplanicton-eating diatoms pristane Is derived from the phytol side chain of chlorophyll pigments... 

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