Abstract:

Low methoxy pectin (LMP) was prepared from apple pomace through pectin extraction and alkali deesterification
in this study. The extraction and alkalization processes were optimized by using orthogonal array design and response surface
methodology, respectively. The extraction yield of high methoxy pectin (HMP) was 6.07% under the optimal experimental
conditions of 95 ℃, 120 min, 1:20 (g/mL) and 5 for temperature, extraction time, solid-to-solvent ratio and pH, respectively.
The significance of the four extraction parameters in affecting the extraction process was ranked in decreasing order as
follows: solid-to-solvent ratio ＞ pH ＞ temperature ＞ time. The optimal deesterification conditions that provided maximum
LMP yield (5.14%) were found to be alkalization at pH 9.87 for 25.33 min at 15 ℃, and the influence of the reaction
conditions on LMP yield was in decreasing order: pH ＞ time ＞ temperature. In contrast, the optimal alkalization temperature,
time and pH for achieving minimum degree of esterification (38.26%) for deesterified pectin were 15 ℃, 30.64 min
and 10.14, respectively, and the degree of esterification was affected in decreasing order by pH, temperature and time.

Key words: pectin, orthogonal array design, response surface methodology, extraction, alkalideesterification