Background: Pectin is a natural polysaccharide that has been used widely as a stabilizer
in food emulsion system.
Objective: This study aimed to optimize the yield of pectin extracted from sweet potato residue and
investigate its emulsifying properties.
Methods: Response surface methodology (RSM) has been utilized to investigate the pectin extracted
from sweet potato peels using citric acid as the extracting solvent. Investigation of the effect
of different extraction conditions namely temperature (°C), time (min) and solution pH on pectin
yield (%) were conducted. A Box-Benhken design with three levels of variation was used to optimize
the extraction conditions.
Results: The optimal conditions determined were temperature 76°C, time 64 min and pH 1.2 with
65.2% yield of pectin. The degree of esterification (DE) of the sweet potato pectin was determined
using Fourier Transform Infrared (FTIR) Spectroscopy. The pectin is high-methoxyl pectin with
DE of 58.5%. Emulsifying properties of sweet potato pectin were investigated by measuring the
zeta-potential, particle size and creaming index with addition of 0.4 and 1.0 wt % pectin to the
Conclusion: Extraction using citric acid could improve the pectin yield. Improved emulsion stability
was observed with the addition of the sweet potato pectin.