Abstract:

Using one-factor-at-a-time method and response surface methodology (RSM), the optimal conditions for enzymatic
extraction of polysaccharides from loquat leaves with cellulase were determined as follows: temperature, 41 ℃; time, 2.95 h;
and cellulase amount, 15.6 mg/g. Under these optimal conditions, the extraction yield of polysaccharides was 8.03%.
The adsorption properties of loquat leaf polysaccharides (LLP) on the ion exchange adsorbent DEAE Sepharose CL-6B
were studied. Effects of pH and ion strength on isotherms were examined through static adsorption experiments. The
results showed that equilibrium sorption data could be described by the Langmuir isotherm equation with high correlation
coefficients, implying the existence of the monomolecular sorption in these systems. After fitting the experimental data
with Langmuir equation, several adsorption parameters, which directly reflected the influences of pH and ion strength, were
obtained. The adsorbent exhibited better adsorption performance for LLP at higher pH and lower ion strength of buffer
solution. The suitable conditions for ion chromatography were obtained with pH 8.0 of buffer solution without NaCl. Three
fractions named as LLPS-1, LLPS-2 and LLPS-3 were obtained through ion chromatography, and their yields were 32.66%,
1.22% and 3.12%, respectively.

Key words: loquat leaf polysaccharides, enzyme hydrolysis, extraction, ion exchange chromatography