**5. Quality of pectin molecules from enzymatic extraction**

"Studies show that the highest efficiency and quality of pectin extraction is obtained by enzymatic method with simultaneous use of cellulase and xylanase enzymes. For more information, see the following data: All spectra showed the characteristics peaks for pectic rich polysaccharide as follows: stretching vibration of OH groups of carboxylic acid and alcohol at ~3432 cm − 1, stretching vibration ofC-H groups of methyl, methylene groups at ~2900 and 2925 cm − 1, stretching vibration of CO of ester groups at ~1744 cm − 1, symmetric and asymmetric stretching vibration of CO of carboxylate groups at ~1621 cm − 1 and 1433 cm − 1, amide groups of protein linked to pectin at ~1544 cm − 1, stretching vibration of C-N groups (present in protein) and also C-O bending at 1270, 1100 & 1026 cm − 1 for the C-O bonds in glycosidic linkage and alcoholic OH groups of sugars. Quantification the ratio of the intensities of carboxylic group at 1632 cm − 1 or ester group at 1744 cm − 1 to that of methylene C-H group of the backbone at 2925 cm − 1 showed that A1632/ A2925 ratios were 1.49, 1.63, and 1.50 for pectin sample extracted using 1:1, 1:1.5, and 1:2 xylanase to cellulase enzymes, respectively, while A1744/A2925 ratios were 0.88, 1.0, and 0.97 for the same samples, respectively.

The results showed noticeably higher ratios of A1632/A2925 and A1744/A2925 in case of using 1:1.5 xylanase to cellulase ratio. The study of sugars in **Table 2** shows the highest galacturonic acid content in this sample. It is also shown that the highest extraction performance is obtained at this enzymatic ratio. Ester or carboxylic acid groups are another important factor in the emulsification properties of pectin" [4].

"**Table 2** shows galacturonic acid, neutral sugars, protein, ferulic acid contents, degree of esterification, and molecular weight of the extracted pectin samples using different xylanase to cellulase enzymes doses. Examination of the table shows that increasing the ratio of xylanase to cellulase from 1: 1 to 1.5: 1 in the extraction solution does not cause significant changes in the galacturonic acid content of the resulting pectins. While increasing the concentration of cellulase enzyme in a ratio of 2: 1, reduces the amount of galacturonic acid in pectin polymers. Analyzes show that the highest content of neutral sugars is related to glucose and the concentrations of rhamnose, galactose, xylose and arabinose are less than 5%. Enzymatic extraction of pectin with the treatment of xylanase to cellulase ratio of 1.5: 1, releases the highest concentration of neutral sugar. High concentrations of neutral sugar have been reported for the enzymatic-ultrasonic extraction of pectin from sisal lesions as well as for the hydrothermal extraction of pectin from sugar beet. High glucose concentrations are mostly related to pectin-bound hydrolyzed cellulose oligomers. As described, cellulose, pectin and hemicellulose are bound together in the cell wall. In addition, previous studies have shown the concentration of glucose or cellobiose in products obtained from the extraction of pectin by acidic method, also the relationship between the concentration of free sugar and the galacturonic column. In general, the optimal purity of the extracted pectin is related to the concentration of galacturonic acid; However, other sugars are also extracted in the process. In fact, proteins ad esterified carboxylic groups in galactron chains have an important


**Table 2.** *Effect of different doses of cellulase and xylanase enzymes on composition of isolated pectin.*

#### *Biotechnology Applications in the Pectin Industry DOI: http://dx.doi.org/10.5772/intechopen.100470*

effect on the emulsification properties of pectin. In addition, presence of ferulic acid groups, which are attached to the O-2 position of (1 → 5)-linked arabinose residues in the arabinan side-chains as well as to the O-6 position of galactose residues in (1 → 4)-linked galactans, contributes also to the emulsification efficiency of pectin. **Table 2** shows that enzymatic extraction of pectin from SBP results in pectins with a high degree of esterification (>50%). The different samples of pectin extracted by this method do not show much difference in the ester content. The content of galacturonic acid and ester in this table – continuously – are at a very good level. But the protein content in different samples varied from 5.6% to 6.7%. According to FAO standards, the nitrogen content of pectin should not exceed 2.5%, which refers to 15.6% of protein. The concentration of ferulic acid varies in the range of 0.19% to 0.27% between different samples with a maximum solution of xylanase to cellulase 1: 1.5. Increasing the concentration of cellulase enzyme relative to xylanase from 1: 1 to 1: 1.5 reduces the molecular weight of pectin in the extraction process, while increasing the concentration of cellulase in the extraction solution will not further reduce the weight of pectin molecules. The molecular weight loss of pectin in this case may be due to the presence of pectinase in commercial cellulase enzymes, as these enzymes have the ability to hydrolysis pectin.

Comparison of the chemical composition of pectin obtained from acid extraction in the best conditions (temperature 85°C, 2 h, ph 2) with pectin obtained from enzymatic extraction using a combination treatment with cellulase and xylanase shows a higher concentration of galacturonic acid in the acidic method (72.56%). Also lower glucose content (3.52%), lower ester content (60.6%), lower ferulic acid concentration (0.49%), near arabinose (3.01%), galactose + rhamnose + xylose (4.11%) and protein (5.01%) it shows. The molecular weight of pectin in this case was measured as 1.85E + 05, which shows a higher proportion of pectins from enzymatic extraction in the Abou Elseoud study" [4].
