258
H. Schulz
9.2.3 Carbohydrates
Already in 1990 the special advantages of Ft-Raman spectroscopy for studies of
various carbohydrates have been described [30]. the author measured several pure
mono- and disaccharides but also polysaccharides such as woody cotton wool and
cypressus wood tissues which show the characteristic signals of cellulose, lignin
and hemicelluloses with little fluorescence. Based on the hierarchical cluster analysis of Raman spectra obtained from various species of the Apiaceae family, a taxonomical discrimination of different genbank accessions could be achieved [31].
main spectral influences of the analysed single seeds were assigned to fatty acids,
polysaccharides, proteins, and lignin.
9.3 Secondary Substances
Secondary plant metabolites are organic compounds that are not directly involved
in the biochemical processes related to growth, development, or reproduction of
the organism. Frequently, they play an important role in prevention of cancer, antiinflammatory and antiviral effects, decreasing cholesterol levels and blood pressure
regulation. Specific types of fruits and vegetables are credited with a variety of
various health benefits.
9.3.1 Phenolic Substances
the chemical group of phenolic compounds comprises a considerable range of plant
substances possessing an aromatic ring bearing one or more hydroxyl substituents.
they play an important role in the broad field of resistance against various plant
diseases. Furthermore, phenolic substances contribute to antioxidative properties
as well as to the individual flavour of plant species. most common (poly)phenolic
substances occurring in various plants are represented by flavones, flavonols, flavonol glycosides, flavanon glycosides, anthocyanins, catechins and chalcones. the
chemical structure of these flavonoids can be modified by hydroxylation, methylation, acylation and glycosylation resulting in a huge number of different chemical
substances which may occur in the individual plant tissue. other phenolic compounds are biosynthesized in the phenylpropane pathway such as anethole, eugenol,
carvacrol and thymol which represent important components of various essential
oils. Several of them are widely used in the fragrance & flavour industry or as additives for food or feed products relating to their antibiotic properties. generally,
phenolic substances show intense Raman bands due to ring deformation vibrations
occurring between 740 and 760 cm
−1
[32–34]. Furthermore, medium to strong signals are registered between 1,180 and 1,260 cm
−1
which are related to out-of phase
C-C-o stretching modes [35].
H. Schulz
9.2.3 Carbohydrates
Already in 1990 the special advantages of Ft-Raman spectroscopy for studies of
various carbohydrates have been described [30]. the author measured several pure
mono- and disaccharides but also polysaccharides such as woody cotton wool and
cypressus wood tissues which show the characteristic signals of cellulose, lignin
and hemicelluloses with little fluorescence. Based on the hierarchical cluster analysis of Raman spectra obtained from various species of the Apiaceae family, a taxonomical discrimination of different genbank accessions could be achieved [31].
main spectral influences of the analysed single seeds were assigned to fatty acids,
polysaccharides, proteins, and lignin.
9.3 Secondary Substances
Secondary plant metabolites are organic compounds that are not directly involved
in the biochemical processes related to growth, development, or reproduction of
the organism. Frequently, they play an important role in prevention of cancer, antiinflammatory and antiviral effects, decreasing cholesterol levels and blood pressure
regulation. Specific types of fruits and vegetables are credited with a variety of
various health benefits.
9.3.1 Phenolic Substances
the chemical group of phenolic compounds comprises a considerable range of plant
substances possessing an aromatic ring bearing one or more hydroxyl substituents.
they play an important role in the broad field of resistance against various plant
diseases. Furthermore, phenolic substances contribute to antioxidative properties
as well as to the individual flavour of plant species. most common (poly)phenolic
substances occurring in various plants are represented by flavones, flavonols, flavonol glycosides, flavanon glycosides, anthocyanins, catechins and chalcones. the
chemical structure of these flavonoids can be modified by hydroxylation, methylation, acylation and glycosylation resulting in a huge number of different chemical
substances which may occur in the individual plant tissue. other phenolic compounds are biosynthesized in the phenylpropane pathway such as anethole, eugenol,
carvacrol and thymol which represent important components of various essential
oils. Several of them are widely used in the fragrance & flavour industry or as additives for food or feed products relating to their antibiotic properties. generally,
phenolic substances show intense Raman bands due to ring deformation vibrations
occurring between 740 and 760 cm
−1
[32–34]. Furthermore, medium to strong signals are registered between 1,180 and 1,260 cm
−1
which are related to out-of phase
C-C-o stretching modes [35].