Chlorophyll, the green pigment found in almost all plants, algae and cyanobacteria is the vital pigment for photosynthesis. Chlorophyll molecules are arranged in and around the photosystems in the thylakoid membranes of chloroplasts. The function of chlorophyll in plants is to absorb sunlight, which is an essential requirement for plants to carry out photosynthesis.
Sources of Chlorophyll
Chlorophyll is present in all plants, most of the algae and cyanobacteria. Chlorophyll is abundant in leafy vegetables and generally to a lesser extent in fruits. For example in spinach, chlorophyll can be as high as 1% on a dry weight basis. Chlorophyll a, due to its stability properties, has been widely used as a coloring substance and is conventionally obtained from higher plants.
Chlorophyll a is abundantly found in Chlorella and Spirulina. Chlorella is called ‘Emerald food’ due to its amazingly high content of chlorophyll.
Chlorella contains five times the amount of chlorophyll than Sprirulina. The chlorophyll content of Chlorella is about 7% of the biomass.
Types of Chlorophyll
Chlorophyll itself is actually not a single molecule but a family of related molecules, designated chlorophyll a, b, c, and d. Chlorophyll a is the molecule found in all plant cells. Chlorophyll d is found only in marine red algae, but chlorophylls b and c are common in fresh water algae.
Pigment Composition of Several Algal Groups
MAJOR ACCESSORY PIGMENT
Chlorophyll c1 + c2, fucoxanthin
Yellow-brown or golden-brown algae
Chlorophyll c1 + c2, fucoxanthin
Chlorophyll c2, peridinin
Chlorophyll c2, phycobilins
Chlorophyll a, Phycocyanin, phycoerythrin
Production of Chlorophyll Using Algae
The cyanobacterium Spirulina platensis is an attractive alternative source of the pigment chlorophyll, which is used as a natural color in food, cosmetic, and pharmaceutical products. S platensis, on the contrary, presents only chlorophyll a on its composition. In addition, this micro alga presents one of the highest chlorophyll contents found in nature, corresponding to 1.15% of its biomass. The use of the Spirulina sp for pigments as colorant has already been explored by the cosmetic, pharmaceutical and food industries.
In Brazil, the chlorophyll used as natural green colorant is obtained from spinach, which contains approximately 0.06 mg g−1, whereas the Spirulina sp biomass contains 1.15 mg g−1 of chlorophyll.
Chlorophyll is generally produced by Spirulina using fermentation process. It has been shown that the composition of the cultivation medium, cellular age, and light intensity are the main factors influencing chlorophyll content in S platensis biomass. Research studies have shown that Spirulina cultivated under poor light intensity present higher chlorophyll concentration in the biomass than that cultivated under highly illuminated conditions. This suggests an inverse relationship between light intensity and chlorophyll content. The concentration of chlorophyll in S platensis also increases with the increase in nitrogen concentration of the medium. Chlorophyll can be extracted from the algal cells using dimethyl sulfoxide.
Chlorophyll production from Chlorella can be carried out in open ponds as well as fermenters.
Chlorella cultivation is also carried out in open ponds, but concrete ponds are not economical. One company in Taiwan has developed an inexpensive 'red mud plastic' which is resistant to sun's UV rays.
Lack of sunlight is a major problem with chlorophyll production in closed Fermentation systems. In a Taiwan company, Chlorella is produced in completely closed systems from test tubes to small tanks to large fermenters. The concentrated stream of Chlorella is produced from large fermenter onto the roof of the factory, where it then flows down through translucent plastic tubes while exposing the algae to sunlight and then returns to the fermenter. The sunlight transmitted into the medium through the plastic tubes produces a chlorophyll concentration that compares favorably with that of Chlorella grown in open ponds.
Source: Chlorella: the emerald food
Health Benefits of Chlorophyll
- Chlorophyll and its derivatives are known to have antioxidant activity.
- Consumption of vegetables rich in chlorophyll and chlorophyll derivatives such as chlorophyllin, is associated with reduced risks of certain types of cancers.
- Consumption of chlorophyll-rich diet could prevent or delay the onset of certain diseases such as cancer that manifest with aging and are induced by free radicals.
- The function of chlorophyll in animals is suggested to be inhibition of lipid peroxidation and protection of mitochondria from oxidative damage induced by various free-radicals and other reactive oxygen species.
- Chlorophyllin has also been reported to inhibit radiation-induced DNA and mitochondrial membrane damage and it would also appear to be a potent protector of DNA with regard to oxidative damage.
- Chlorophyll is sometimes called `green blood" because of its similarity to the hemoglobin molecule found in human blood cells.
- Chlorophyll increases peristaltic action and thus relieves constipation, and also normalizes the secretion of digestive acids. It soothes the inflammation and reduces the excess pepsin secretion associated with gastric ulcers.
- Chlorophyll actually helps remove heavy metals from the body that have accumulated due to the ingestion of contaminated food products.
- During World War II, the drying action of chlorophyll and its antiseptic qualities made it a common first-aid measure to prevent festering of wounds. In addition, chlorophyll soothes swelling and promotes granulation, the process that regenerates new tissue over injuries.
- Chlorophyll appears to promote regeneration of damaged liver cells, and also increases circulation to all the organs by dilating blood vessels.
- It is believed that if chlorophyll is ingested with sufficient iron, the magnesium can be displaced to yield a hemoglobin molecule. Experiments in Japan have demonstrated that Spirulina has a marked positive effect on anemia, possibly due to the conversion of chlorophyll into hemoglobin.
Industrial Uses of Chlorophyll
In the food industry, chlorophyll is used as a natural pigment ingredient in processed foods.
Because of its strong green pigment and consumers growing preference for natural foods, chlorophyll is gaining importance as food additive. Increasing number of researches are also reporting health benefits from consumption of high chlorophyll diet. This in turn is encouraging food processors to switch from artificial pigments to chlorophyll-based natural coloring.
In the cosmetics industry, chlorophyll a (known as Natural Green 3) is used in soaps and cosmetics products.
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