150
Microwave-Assisted Extraction (or MAE)
With respect to the pectin modifying effects of microwave assisted extraction, various works have been carried out as in case of pectin extracted from grapefruit by
(Bagherian et al. 2011). The workers reported that using microwave power of 0.45,
0.63, and 0.9 kW not only increased the yield of pectin but also the values for DE
increased generally with increasing microwave power and time (70.96–80.89%).
Similarly Galacturonic acid unit contents were also found to be higher with increasing power and time, thus showing the modifying effect of this novel technique.
Another notable feature of the microwave based extraction is that it takes less time
approximately 15 min to obtain satisfactory extraction (Fishman et al. 2000). Also
the yield efficiency and the quality of pectin obtained is better. In a study carried out
by Fishman et al. 2000, orange albedo were subjected to microwave heating under
high pressure for pectin extraction and it was observed that there was an increase in
molar mass, size and intrinsic viscosity as compared to conventional methods.
Modification of Pectin Macromolecules
The pectin modification techniques can be broadly classified and studied under the
subheadings including:
1. Enzymatic methods.
2. Physical methods such as ultrasonication, high pressure treatment, radiation,
photolysis and microfluidization.
3. Chemical methods such as alkylation, amidation, quaternization, thiolation, sulfating and oxidation.
Modification of Pectin with Physical Treatment
In case of physical treatment such as ultra sound, a number of studies reveal the
improved properties of pectin as a result of disaggregation of pectin polymers. For
instance Muñoz-Almagro et al. (2017) reported that with the increase in time and
intensity of ultrasound the depolymerisation of citrus and apple pectin increases
although there was a reduction in polydisparity. Also there may no alteration in the
primary structure of pectin, but this technique offers the advantages of transforming
the pectins and formulating the pectin products with anti-oxidant properties (Ogutu
and Mu 2017). Another study on physical modification of pectin, involving the
technique dynamic high pressure microfluidization (DHPM) for black-cherry
tomato pomace by was carried out by (Zhang et al. 2018). This treatment altered the
rheological and physiochemical properties of the test material by increasing the
average particle size which resulted in the formation of particles foamed filiform
microparticles. The study also reported that there was a decrease in the apparent
N. Noor et al.
Microwave-Assisted Extraction (or MAE)
With respect to the pectin modifying effects of microwave assisted extraction, various works have been carried out as in case of pectin extracted from grapefruit by
(Bagherian et al. 2011). The workers reported that using microwave power of 0.45,
0.63, and 0.9 kW not only increased the yield of pectin but also the values for DE
increased generally with increasing microwave power and time (70.96–80.89%).
Similarly Galacturonic acid unit contents were also found to be higher with increasing power and time, thus showing the modifying effect of this novel technique.
Another notable feature of the microwave based extraction is that it takes less time
approximately 15 min to obtain satisfactory extraction (Fishman et al. 2000). Also
the yield efficiency and the quality of pectin obtained is better. In a study carried out
by Fishman et al. 2000, orange albedo were subjected to microwave heating under
high pressure for pectin extraction and it was observed that there was an increase in
molar mass, size and intrinsic viscosity as compared to conventional methods.
Modification of Pectin Macromolecules
The pectin modification techniques can be broadly classified and studied under the
subheadings including:
1. Enzymatic methods.
2. Physical methods such as ultrasonication, high pressure treatment, radiation,
photolysis and microfluidization.
3. Chemical methods such as alkylation, amidation, quaternization, thiolation, sulfating and oxidation.
Modification of Pectin with Physical Treatment
In case of physical treatment such as ultra sound, a number of studies reveal the
improved properties of pectin as a result of disaggregation of pectin polymers. For
instance Muñoz-Almagro et al. (2017) reported that with the increase in time and
intensity of ultrasound the depolymerisation of citrus and apple pectin increases
although there was a reduction in polydisparity. Also there may no alteration in the
primary structure of pectin, but this technique offers the advantages of transforming
the pectins and formulating the pectin products with anti-oxidant properties (Ogutu
and Mu 2017). Another study on physical modification of pectin, involving the
technique dynamic high pressure microfluidization (DHPM) for black-cherry
tomato pomace by was carried out by (Zhang et al. 2018). This treatment altered the
rheological and physiochemical properties of the test material by increasing the
average particle size which resulted in the formation of particles foamed filiform
microparticles. The study also reported that there was a decrease in the apparent
N. Noor et al.