strength of the solution, protein-protein and protein-membrane interactions, and flux
and mass transfer across the membrane.
The protein purification and concentration are carried out in the above mentioned
steps by using membrane separation processes. The major advantages of using
membranes in protein purification and concentration are that they are efficient,
effective, economical, and consume low energy.
4.2 Fruit Juice Clarification
Fruit juices are rich in cellulose, protein, fibers, pectin, polysaccharides, lignin, gum,
and starch including many other constituents. The fruit juice is very cloudy and
viscous due to the presence of these compositions. The processed fruit juices should
have the following requirements for consumer satisfactoriness: (1) fruit juice with
low viscosity and higher clarity, (2) should have natural flavor, (3) and long shelf life
of the juice. Several separation and conservation methods have been in use to make
the treated fruit juice more concentrative for the consumers [1].
Membrane separation techniques are one of the most profitable methods, as they
do not require addition of any chemical agents and it is a room temperature process.
Additionally, they need low maintenance to maintain the original flavor, taste, smell,
and nutritional parameters of the fruit juice. However, they have a limitation of
fouling, as the accumulation of fouling layer on the membrane surface reduces the
permeability flux [15]. Consider that pectin is one of the key gel forming agent in the
presence of Ca
2+ ions at low pH, which is present in fruits. Pectin is mostly found in
citrus fruits and enzymatic treatment of guava juice at 45
C with various enzyme
concentrations [16]. Among these bananas has high content of pectin. Pectins are
polysaccharides which are rich in galacturonic acid. The molecular weight of pectin
is in the range of 30,000–130,000 Da, based on separation conditions. In the
extraction process, the juices are viscous because of the presence of pectin, thus
affecting the flux of the filtration process. Therefore, it needs depectinization to give
long shelf life to the fruit juice as well as the membranes.
Clarification/Depectinization
Amylase and pectinase enzymes are used for the clarification of fruit juices conventionally to reduce the high pectin concentrations as shown in Table 2. Membranebased separation processes are used for clarification of fruit juices because they are
high-pressure resistant, operated at high temperatures, and resistant to highly corrosive fluids. In 1991, Chamchang et al. reported that by using pectinase enzyme at
constant temperature tangerine juice had been depectinized [18]. Rai et al. (2004)
stated that mosambi fruit juice clarification varies with concentration of enzyme
(pectinase) and temperature [19]. Apple juice clarification is reported by
Onsekizoglu et al. (2010) that a series of membrane processes ultrafiltration, membrane distillation, and osmotic distillation were employed, with combined application of bentonite and gelatin (fining agents) that gives high permeability flux,
14
R. Singh et al.
and mass transfer across the membrane.
The protein purification and concentration are carried out in the above mentioned
steps by using membrane separation processes. The major advantages of using
membranes in protein purification and concentration are that they are efficient,
effective, economical, and consume low energy.
4.2 Fruit Juice Clarification
Fruit juices are rich in cellulose, protein, fibers, pectin, polysaccharides, lignin, gum,
and starch including many other constituents. The fruit juice is very cloudy and
viscous due to the presence of these compositions. The processed fruit juices should
have the following requirements for consumer satisfactoriness: (1) fruit juice with
low viscosity and higher clarity, (2) should have natural flavor, (3) and long shelf life
of the juice. Several separation and conservation methods have been in use to make
the treated fruit juice more concentrative for the consumers [1].
Membrane separation techniques are one of the most profitable methods, as they
do not require addition of any chemical agents and it is a room temperature process.
Additionally, they need low maintenance to maintain the original flavor, taste, smell,
and nutritional parameters of the fruit juice. However, they have a limitation of
fouling, as the accumulation of fouling layer on the membrane surface reduces the
permeability flux [15]. Consider that pectin is one of the key gel forming agent in the
presence of Ca
2+ ions at low pH, which is present in fruits. Pectin is mostly found in
citrus fruits and enzymatic treatment of guava juice at 45
C with various enzyme
concentrations [16]. Among these bananas has high content of pectin. Pectins are
polysaccharides which are rich in galacturonic acid. The molecular weight of pectin
is in the range of 30,000–130,000 Da, based on separation conditions. In the
extraction process, the juices are viscous because of the presence of pectin, thus
affecting the flux of the filtration process. Therefore, it needs depectinization to give
long shelf life to the fruit juice as well as the membranes.
Clarification/Depectinization
Amylase and pectinase enzymes are used for the clarification of fruit juices conventionally to reduce the high pectin concentrations as shown in Table 2. Membranebased separation processes are used for clarification of fruit juices because they are
high-pressure resistant, operated at high temperatures, and resistant to highly corrosive fluids. In 1991, Chamchang et al. reported that by using pectinase enzyme at
constant temperature tangerine juice had been depectinized [18]. Rai et al. (2004)
stated that mosambi fruit juice clarification varies with concentration of enzyme
(pectinase) and temperature [19]. Apple juice clarification is reported by
Onsekizoglu et al. (2010) that a series of membrane processes ultrafiltration, membrane distillation, and osmotic distillation were employed, with combined application of bentonite and gelatin (fining agents) that gives high permeability flux,
14
R. Singh et al.