Enzyme Assisted Extraction, Purification and Structure Analysis of the Polysaccharides from Naked Pumpkin Seeds

Abstract

Enzyme assisted extraction was used to extract the polysaccharides from pumpkin seeds (PSP) and the extraction parameters were optimized by response surface methodology (RSM). Under the optimum experimental parameters: Extraction temperature of 60 °C, extraction time of 43 min, enzyme concentration of 2.5%, and pH of 6.0, the yield of PSP was 3.22 ± 0.04%, which was in close agreement with the predicted value (3.24%). After further purification on anion exchange column and gelfiltration column, a novel purified polysaccharide (PSPE) with molecular weight of 16,700 g/mol was obtained. PSPE was mainly composed of mannose, galactose and glucose in the molar ratio of 1.00:3.84:1.62. NMR spectra analysis showed that the major backbone of PSPE consisted of →4)-α-d-Glcp-(1→, →4)-β-d-Manp-(1→, →3,6)-β-d-Glap-(1→, and β-d-galactose.

Utilization of Response Surface Methodology in Optimization of Polysaccharides Extraction from Vietnamese Red Ganoderma lucidum by Ultrasound-Assisted Enzymatic Method and Examination of Bioactivities of the Extract

“…However, when the ultrasonic power was higher than 400 W, enzyme could be inactivated and the cavitation effect could be weakened [ 28 , 29 ]. This result is in agreement with the result reported in previous research [ 23 , 24 , 26 ].…”

“…It is stated that although longer extraction time could facilitate the extraction process, this could lead to processes of oxidation and degradation of polysaccharide [ 25 , 26 ]. This result, therefore, can be found similar to the other studies [ 23 , 24 , 27 ].…”

“…Nevertheless, when extraction temperature was over 48 o C and extraction time longer than 120 min, the content of polysaccharides decreased gradually. This could be explained by the fact that when extraction time and extraction temperature exceed the values, the hydrolysis of polysaccharides tends to happen vigorously, leading to a decrease in the content of polysaccharides according to reported experiments [ 20 , 23 , 27 ].…”

“…This could be explained that when the pH and the extraction temperature were not too high, the impact of enzyme and high ultrasonic power efficiently broke the structure of the cell wall, leading to the diffusion of content of polysaccharides into solvent. However, at high pH (>8.2) and high temperature (>52 o C), the yield of polysaccharides experienced a decrease because polysaccharides were reported to be more likely to be hydrolyzed under these conditions [ 22 , 23 ]. This result is suitable with a previous study [ 24 ].…”

“…Figure 6 describes the simultaneous effects of extraction temperature and ultrasonic power on content of polysaccharides. The content of polysaccharides increased considerably in the extraction temperature which ranged from 45 to 55°C and ultrasonic power which ranged between 220 W and 400 W. Earlier reports indicated that wave could improve mass transfer, enhancing the efficiency of substrate delivery to the active sites of the enzymes [ 23 , 27 , 30 – 32 ].…”