explants under influence of different concentrations of plant growth regulators such
as kinetin. The in vitro cultured plantlet exhibited more amounts of vanilla flavour
compounds in the cultured plantlets. It was found that enzymes of lignin biosynthesis (cinnomoyl CoA reductase and coniferyl alcohol dehydrogenase) as well as the
enzymes potentially involved in benzoate biosynthesis (O-methyl transferase and
glutamyl transferase) were induced by kinetin (Renuga and Saravana Kumar 2014).
The callus cultures of garlic (Allium sativum) and onion (Allium cepa) have been
used for the synthesis of the flavour precursor, alliin. Allyl thiol and allyl cysteine, at
a concentration of 10 mM, were incorporated into the callus medium for cultures of
garlic and onion callus (Hughes et al. 2005). Addition of S-alk(en)yl donors or
presumed biosynthetic intermediates aided in the synthesis of cysteine sulphoxide by
tissue culture method in both onion and garlic (Jones et al. 2004). Normal and cell
suspension cultures of flavour rich tuberous roots of Decalepis hamiltonii were used
for the enhanced production of metabolites through ferulic acid (FA) feeding to the
culture medium. Flavour metabolites such as 2-hydroxy-4-methoxy benzaldehyde
(2H4MB), vanillin, 4-Methoxy Cinnamic acid derivatives and aromatic alcohols
were produced as flavour metabolites (Matam et al. 2017). Using plant tissue culture
method, flavour molecules can also be produced following biotransformation. Cell
culture of Peganum harmala (African rue) converted geranyl acetate to geraniol and
linalyl acetate to linalool and α-terpineol (Zhu and Lockwood 2000). Controlledrelease polymer discs were made from poly-2-hydroxyethyl methacrylate containing
geranyl acetate or linalyl acetate, which produced higher concentrations of their
biotransformation products (Zhu et al. 2000). Geraniol is an essential oil constituent
commercially produced by Mitsui Chemicals Ltd. by culturing Geraminea spp.
(Ochoa-Villarreal et al. 2016). The commercial production of aromatic compounds
can be carried out by using stirred bioreactors, bubble column bioreactors, air-lift
bioreactors and wave-mixed bioreactors with one-dimensional (1-D) motion
(Ruffoni et al. 2010; Georgiev et al. 2013).
7.4
Sensory Evaluation of Flavour Compounds
The sensory evaluation has to be performed after the synthesis of aroma compounds.
The flavouring and fragrant components of compounds are detected by the headspace analysis. The volatile compounds can be measured by two methods: Gas
chromatograph-mass spectrometer (GC-MS) and a GC-MS coupled with an
olfactometric port or a sniff port (GC-O). Following the method of gas chromatography, the volatile components of a mixture are separated and then a massspectrometer is used to characterize each of the components individually. In
GC-O, this system is additionally equipped with a sniff port because of which it is
possible for a human to detect the components in the volatile mixture and thus
determines the sensory flavour of the sample (Chambers and Koppel 2013). Electronic nose can also carry out the analysis of aroma, which often consists of
non-selective sensors which interacts with volatile molecules so that if there is any
7 Biotechnological Interventions for Production of Flavour and Fragrance. . .
153
as kinetin. The in vitro cultured plantlet exhibited more amounts of vanilla flavour
compounds in the cultured plantlets. It was found that enzymes of lignin biosynthesis (cinnomoyl CoA reductase and coniferyl alcohol dehydrogenase) as well as the
enzymes potentially involved in benzoate biosynthesis (O-methyl transferase and
glutamyl transferase) were induced by kinetin (Renuga and Saravana Kumar 2014).
The callus cultures of garlic (Allium sativum) and onion (Allium cepa) have been
used for the synthesis of the flavour precursor, alliin. Allyl thiol and allyl cysteine, at
a concentration of 10 mM, were incorporated into the callus medium for cultures of
garlic and onion callus (Hughes et al. 2005). Addition of S-alk(en)yl donors or
presumed biosynthetic intermediates aided in the synthesis of cysteine sulphoxide by
tissue culture method in both onion and garlic (Jones et al. 2004). Normal and cell
suspension cultures of flavour rich tuberous roots of Decalepis hamiltonii were used
for the enhanced production of metabolites through ferulic acid (FA) feeding to the
culture medium. Flavour metabolites such as 2-hydroxy-4-methoxy benzaldehyde
(2H4MB), vanillin, 4-Methoxy Cinnamic acid derivatives and aromatic alcohols
were produced as flavour metabolites (Matam et al. 2017). Using plant tissue culture
method, flavour molecules can also be produced following biotransformation. Cell
culture of Peganum harmala (African rue) converted geranyl acetate to geraniol and
linalyl acetate to linalool and α-terpineol (Zhu and Lockwood 2000). Controlledrelease polymer discs were made from poly-2-hydroxyethyl methacrylate containing
geranyl acetate or linalyl acetate, which produced higher concentrations of their
biotransformation products (Zhu et al. 2000). Geraniol is an essential oil constituent
commercially produced by Mitsui Chemicals Ltd. by culturing Geraminea spp.
(Ochoa-Villarreal et al. 2016). The commercial production of aromatic compounds
can be carried out by using stirred bioreactors, bubble column bioreactors, air-lift
bioreactors and wave-mixed bioreactors with one-dimensional (1-D) motion
(Ruffoni et al. 2010; Georgiev et al. 2013).
7.4
Sensory Evaluation of Flavour Compounds
The sensory evaluation has to be performed after the synthesis of aroma compounds.
The flavouring and fragrant components of compounds are detected by the headspace analysis. The volatile compounds can be measured by two methods: Gas
chromatograph-mass spectrometer (GC-MS) and a GC-MS coupled with an
olfactometric port or a sniff port (GC-O). Following the method of gas chromatography, the volatile components of a mixture are separated and then a massspectrometer is used to characterize each of the components individually. In
GC-O, this system is additionally equipped with a sniff port because of which it is
possible for a human to detect the components in the volatile mixture and thus
determines the sensory flavour of the sample (Chambers and Koppel 2013). Electronic nose can also carry out the analysis of aroma, which often consists of
non-selective sensors which interacts with volatile molecules so that if there is any
7 Biotechnological Interventions for Production of Flavour and Fragrance. . .
153