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Chlorophylls are ubiquitous pigments in the plant kingdom that play a key role in photosynthesis, a vital function for life on Earth. This chapter covers the main issues needed to recognize the value of chlorophylls and their derivatives in food technology, including aspects related to the structures naturally present in foods, arising from biosynthetic and catabolic processes, food processing, and cooking operations. In addition, common analytical procedures to isolate chlorophyll standards and available methods to identify and characterize the chlorophyll profile of food products and extracts will be presented. The intricate structural arrangements of the basic tetrapyrrole structure responsible for a wide range of chlorophyll-related derivatives and their susceptibility to undergo oxidation processes when out of their genuine cellular organelles are challenges for the development of analytical methodologies and industrial applications as coloring matter. A review of the existing chlorophyll formulations produced to give or reinforce green hues in foods is issued with special emphasis on their composition and current legal regulations.

Attempts have been made to develop dye-sensitized solar cells based on the principles and materials of photosynthesis: We first tested photosynthetic pigments, carotenoids (Cars), chlorophylls (Chls) and their derivatives, to find sensitizers showing reasonable performance (photocurrent and conversion efficiency). We then tried to introduce the principles of photosynthesis, including electron transfer and energy transfer from Car to Phe a. Also, we tried co-sensitization using the pheophorbide (Phe) a and Chl c(2) pair which further enhanced the performance of the component sensitizers as follows: J(sc) = 9.0 + 13.8 --14.0 mA cm(-2) and eta = 3.4 + 4.6 --5.4%.

As clorofilas são pigmentos verdes, comuns em todas as células fotossintéticas. Por sua estrutura química ser instável, são facilmente degradadas, resultando em produtos de decomposição que modificam a percepção e qualidade dos alimentos. Esta revisão trata dos vários fatores que interferem na degradação das clorofilas, como a luz, radiação, calor, ácidos, oxigênio, alteração enzimática e interação com outros pigmentos. Também, outro aspecto a ser abordado é a utilização das clorofilas como corantes, através da formação de complexos que tornam esses pigmentos mais estáveis à decomposição.The Chlorophylls are a common green pigment to all photosynthetic cells. They are easily degraded, because of their unstable chemical structure. Degradation results in products alter the perception and quality of foods. This review discusses the various factors, that interfere on chlorophyll degradation such as light, irradiation, heat, acids, oxygen, enzymatical alteration and the interaction with other pigments. Also, the other topic that was mentioned the utilization of the chlorophylls as dyes through a complex formation that make this pigment more stable to degradation.

As clorofilas são pigmentos verdes, comuns em todas as células fotossintéticas. Por sua estrutura química ser instável, são facilmente degradadas, resultando em produtos de decomposição que modificam a percepção e qualidade dos alimentos. Esta revisão trata dos vários fatores que interferem na degradação das clorofilas, como a luz, radiação, calor, ácidos, oxigênio, alteração enzimática e interação com outros pigmentos. Também, outro aspecto a ser abordado é a utilização das clorofilas como corantes, através da formação de complexos que tornam esses pigmentos mais estáveis à decomposição. The Chlorophylls are a common green pigment to all photosynthetic cells. They are easily degraded, because of their unstable chemical structure. Degradation results in products alter the perception and quality of foods. This review discusses the various factors, that interfere on chlorophyll degradation such as light, irradiation, heat, acids, oxygen, enzymatical alteration and the interaction with other pigments. Also, the other topic that was mentioned the utilization of the chlorophylls as dyes through a complex formation that make this pigment more stable to degradation.

8 páginas, 5 figuras, A monolithic C18-bonded silica rod column (Merck Chromolith) was applied to the separation of mixtures of chlorophylls a and b and their derivatives originated by hydrolysis of the phytyl ester linkage (chlorophyllides), loss of the central Mg atom (pheophytins), or both processes (pheophorbides). Mobile phases containing two different ion-pair reagents, ammonium acetate and buffered pyridine, were tested. Both eluents achieved the resolution of the eight pigments in less than 5 min. The method based on the pyridine-containing mobile phase was applied to the separation of chlorophylls and their green coloured degradation products in senescing leaves of deciduous trees, green fruits and a marine microalga., This work was supported by Xunta de Galicia through project PGIDT99MAR50102.