16 Chlorophylls as Food Additives
399
However, due to outstanding beneficial biological effects of these molecules in
addition to their potential action dyes, these compounds can be used as additives
in functional or nutraceuticals foods, aiming at promoting health (Humphrey 2004;
Christaki et al. 2015; Janiszewska-Turak et al. 2016; Kang et al. 2018; Martins et al.
2019).
Predominantly, liposoluble chlorophyll a and b as well as their pheophytins
directly extracted from natural sources are widely used in the food industry as a
basis for obtaining green dyes (Rodriguez-Amaya 2019; Vieira et al. 2019). At the
same time, it is known that these compounds have an inherent instability and want
greater care as the physical and chemical changes during the processing (DelgadoVargas and Paredes-López 2002; Lanfer-Marquez and Borrmann 2009). There are
two key structural characteristics of chlorophyll pigments responsible for their properties, especially as it relates to their solubility and colour (Wrolstad and Culver
2012). More intense changes in the colour of chlorophylls are closely linked to the
pH of the medium or enzymatic activity and can be observed when the central Mg
2+
ion is replaced. On the other hand, the solubility of chlorophyll molecules is totally
dependent on the phytol isoprenoid alcohol, since this when present in the structures
gives confer the characteristic molecules more nonpolar (Galaffu et al. 2015; Pareek
et al. 2017).
Consequently, to expand the applicability and reach successful application of
natural chlorophylls extracted for commercial applications, some modifications are
induced out in their structures and derivative compounds are formed as a strategy
to increase their chemical stability and colour potential (Fig. 16.5) (Solymosi and
Mysliwa-Kurdziel 2016).
Among these modifications, the copper complexes (Cu-chlorophyll), replacing the
central magnesium, are frequently marketed as the green dye for the food industry,
because it maintains the bright green colour and chemical stability of the molecules
formed. These compounds are basically obtained by the addition of copper sulfate in
acidic medium soon after extracting chlorophyll extracts (Vieira et al. 2019). More
rarely, divalent cations such as Fe
2+ and Zn
2+ can be also used to replace the central
Mg
2+ ion during food processing (Canjura et al. 1999; Kang et al. 2018).
As well as, modifications in the hydrophobicity of the pigment molecule conferred
by its long hydrophobic phytol chain and by a fifth ring (cyclopentanone) in the
macrocycle are carried out starts with the alkaline hydrolization (saponification),
and subsequent neutralization by K and/or Na salts, or enzymatic action. With this,
are obtained chlorophyll derivatives with greater solubility in water and with similar
spectral properties to those of chlorophyll, called chlorophyllins by scientists and
the food colour industry. For this purpose, the term chlorophyllins refer to a complex
mixture of various chlorine compounds (mainly chlorin e 6 and rhodin g 7 ), chlorophyllides, and pheophorbides, however its composition is not clearly defined because
it is highly variable (Pérez-Gálvez et al. 2017).
Moreover, both processes of chemical transformations mentioned above (replacement of central magnesium by copper, and phytyl group removal) can be induced
simultaneously in order to obtain Cu-Chlorophyllin. Several purification steps are
necessary to remove interferents (Lanfer-Marquez and Sinnecker 2008). However,
399
However, due to outstanding beneficial biological effects of these molecules in
addition to their potential action dyes, these compounds can be used as additives
in functional or nutraceuticals foods, aiming at promoting health (Humphrey 2004;
Christaki et al. 2015; Janiszewska-Turak et al. 2016; Kang et al. 2018; Martins et al.
2019).
Predominantly, liposoluble chlorophyll a and b as well as their pheophytins
directly extracted from natural sources are widely used in the food industry as a
basis for obtaining green dyes (Rodriguez-Amaya 2019; Vieira et al. 2019). At the
same time, it is known that these compounds have an inherent instability and want
greater care as the physical and chemical changes during the processing (DelgadoVargas and Paredes-López 2002; Lanfer-Marquez and Borrmann 2009). There are
two key structural characteristics of chlorophyll pigments responsible for their properties, especially as it relates to their solubility and colour (Wrolstad and Culver
2012). More intense changes in the colour of chlorophylls are closely linked to the
pH of the medium or enzymatic activity and can be observed when the central Mg
2+
ion is replaced. On the other hand, the solubility of chlorophyll molecules is totally
dependent on the phytol isoprenoid alcohol, since this when present in the structures
gives confer the characteristic molecules more nonpolar (Galaffu et al. 2015; Pareek
et al. 2017).
Consequently, to expand the applicability and reach successful application of
natural chlorophylls extracted for commercial applications, some modifications are
induced out in their structures and derivative compounds are formed as a strategy
to increase their chemical stability and colour potential (Fig. 16.5) (Solymosi and
Mysliwa-Kurdziel 2016).
Among these modifications, the copper complexes (Cu-chlorophyll), replacing the
central magnesium, are frequently marketed as the green dye for the food industry,
because it maintains the bright green colour and chemical stability of the molecules
formed. These compounds are basically obtained by the addition of copper sulfate in
acidic medium soon after extracting chlorophyll extracts (Vieira et al. 2019). More
rarely, divalent cations such as Fe
2+ and Zn
2+ can be also used to replace the central
Mg
2+ ion during food processing (Canjura et al. 1999; Kang et al. 2018).
As well as, modifications in the hydrophobicity of the pigment molecule conferred
by its long hydrophobic phytol chain and by a fifth ring (cyclopentanone) in the
macrocycle are carried out starts with the alkaline hydrolization (saponification),
and subsequent neutralization by K and/or Na salts, or enzymatic action. With this,
are obtained chlorophyll derivatives with greater solubility in water and with similar
spectral properties to those of chlorophyll, called chlorophyllins by scientists and
the food colour industry. For this purpose, the term chlorophyllins refer to a complex
mixture of various chlorine compounds (mainly chlorin e 6 and rhodin g 7 ), chlorophyllides, and pheophorbides, however its composition is not clearly defined because
it is highly variable (Pérez-Gálvez et al. 2017).
Moreover, both processes of chemical transformations mentioned above (replacement of central magnesium by copper, and phytyl group removal) can be induced
simultaneously in order to obtain Cu-Chlorophyllin. Several purification steps are
necessary to remove interferents (Lanfer-Marquez and Sinnecker 2008). However,