160
is favourable for this purpose because the juices to be treated with the enzyme are
quite acidic (Puri et al. 2005). Lei et al. (2011) reported another example of improved
enzyme activity due to an immobilization method. They demonstrated the immobilization of naringinase obtained from P. decumbens on mesoporous silica MCM-41
activated with glutaraldehyde used to debitter white grapefruit, which yielded a
naringin conversion on the juice of up to 95%.
β-Glucosidase β-Glucosidases (EC 3.2.1.21) are enzymes that catalyse the hydrolysis of the glycosidic bonds to terminal non-reducing residues in beta-D-glucosides
and oligosaccharides, converting them to glucose. Increasing aroma represents the
most valuable application of glucosidases (Romo-Sánchez et al. 2014).
β-Glucosidases are generally used to enhance the aroma of tea. Among more than
500 kinds of tea aroma constituents, the floral aroma of tea is largely contributed by
monoterpene alcohols (i.e. linalool and geraniol) and aromatic alcohols (i.e. benzyl
alcohol and 2-phenylethanol) (Wang et al. 2001). These aroma compounds are present in fresh leaves of tea plants as flavourless monosaccharide or disaccharide glycoside precursors (β-D-glucopyranosides), which can be hydrolysed by endogenous
enzymes, such as β-D-glycosidase to release free aroma constituents (Ogawa et al.
1995; Su et al. 2010). However, the limitations of glycosidases from tea plant exhibit
low activity under natural conditions, and they can be destroyed to a huge degree
during the tea manufacturing process. Hence, most of the glycoside precursors will
remain in the final tea products, and there are big potentialities to improve the aroma
quality of tea by exogenous glycosidases. The cross-linking–entrapment–crosslinking immobilization on an alginate of a commercial β-glucosidase resulted in a
stable enzyme preparation, which was successfully used to treat the total amount of
essential oil in green tea, oolong tea, and black tea increasing it by 20.7%, 10.3%,
and 6.8%, respectively. This engineered biocatalyst has been repeatedly used 50
times, maintaining a final residual activity of about 93.6% compared to its initial
activity (Su et al. 2010).
Lipases Lipases (EC 3.1.1.-) are enzymes that catalyse the hydrolysis of fats and
lipids. Lipases are extensively employed for a plethora of applications in food and
feed industries (Hasan et al. 2006; Jaeger and Eggert 2002). Among them, two of
the most valuable examples include the preparation of functional ingredients in general and omega-3 fatty acids in particular. The omega-3 fatty acids derived from fish
oils, mainly consisting of docosahexaenoic acid (DHA) and eicosapentaenoic acid
(EPA), are highly beneficial to health (Swanson et al. 2012). DHA is required in
large amounts in the brain and retina, in the early stages of life, as a physiologically
essential nutrient to provide optimal neuronal functioning (learning ability and
mental development) and visual acuity (Heird 2001), while EPA is considered to
have beneficial effects in the prevention of cardiovascular diseases in adults (Saremi
and Arora 2009). Considering these facts, the preparation of triglycerides enriched
in both of the omega-3 acids (DHA and EPA) or even in only one of them could be
very attractive. The first crucial step for the production of triglycerides of omega-3
is the rapid and selective release of PUFAs from fish oils. Lipases immobilized on
porous supports have been extensively described for the hydrolysis of fish oils
S.M. Basheer and S. Chellappan
is favourable for this purpose because the juices to be treated with the enzyme are
quite acidic (Puri et al. 2005). Lei et al. (2011) reported another example of improved
enzyme activity due to an immobilization method. They demonstrated the immobilization of naringinase obtained from P. decumbens on mesoporous silica MCM-41
activated with glutaraldehyde used to debitter white grapefruit, which yielded a
naringin conversion on the juice of up to 95%.
β-Glucosidase β-Glucosidases (EC 3.2.1.21) are enzymes that catalyse the hydrolysis of the glycosidic bonds to terminal non-reducing residues in beta-D-glucosides
and oligosaccharides, converting them to glucose. Increasing aroma represents the
most valuable application of glucosidases (Romo-Sánchez et al. 2014).
β-Glucosidases are generally used to enhance the aroma of tea. Among more than
500 kinds of tea aroma constituents, the floral aroma of tea is largely contributed by
monoterpene alcohols (i.e. linalool and geraniol) and aromatic alcohols (i.e. benzyl
alcohol and 2-phenylethanol) (Wang et al. 2001). These aroma compounds are present in fresh leaves of tea plants as flavourless monosaccharide or disaccharide glycoside precursors (β-D-glucopyranosides), which can be hydrolysed by endogenous
enzymes, such as β-D-glycosidase to release free aroma constituents (Ogawa et al.
1995; Su et al. 2010). However, the limitations of glycosidases from tea plant exhibit
low activity under natural conditions, and they can be destroyed to a huge degree
during the tea manufacturing process. Hence, most of the glycoside precursors will
remain in the final tea products, and there are big potentialities to improve the aroma
quality of tea by exogenous glycosidases. The cross-linking–entrapment–crosslinking immobilization on an alginate of a commercial β-glucosidase resulted in a
stable enzyme preparation, which was successfully used to treat the total amount of
essential oil in green tea, oolong tea, and black tea increasing it by 20.7%, 10.3%,
and 6.8%, respectively. This engineered biocatalyst has been repeatedly used 50
times, maintaining a final residual activity of about 93.6% compared to its initial
activity (Su et al. 2010).
Lipases Lipases (EC 3.1.1.-) are enzymes that catalyse the hydrolysis of fats and
lipids. Lipases are extensively employed for a plethora of applications in food and
feed industries (Hasan et al. 2006; Jaeger and Eggert 2002). Among them, two of
the most valuable examples include the preparation of functional ingredients in general and omega-3 fatty acids in particular. The omega-3 fatty acids derived from fish
oils, mainly consisting of docosahexaenoic acid (DHA) and eicosapentaenoic acid
(EPA), are highly beneficial to health (Swanson et al. 2012). DHA is required in
large amounts in the brain and retina, in the early stages of life, as a physiologically
essential nutrient to provide optimal neuronal functioning (learning ability and
mental development) and visual acuity (Heird 2001), while EPA is considered to
have beneficial effects in the prevention of cardiovascular diseases in adults (Saremi
and Arora 2009). Considering these facts, the preparation of triglycerides enriched
in both of the omega-3 acids (DHA and EPA) or even in only one of them could be
very attractive. The first crucial step for the production of triglycerides of omega-3
is the rapid and selective release of PUFAs from fish oils. Lipases immobilized on
porous supports have been extensively described for the hydrolysis of fish oils
S.M. Basheer and S. Chellappan