Abstract:

This study was intended to optimize the process conditions for ultrasonic-assisted extraction of pectin from
muskmelon rind by the combined use of one-factor-at-a-time method and response surface methodology. For this purpose,
a quadratic regression model was developed indicating the effects of extraction parameters on pectin yield, and the main
effects and interactions of ultrasonic irradiation time, ultrasonic power and solid-to-solvent ratio on extraction efficiency
were examined. The results showed the model was highly statistically significant and had a good prediction performance.
The decreasing order of the effects of the studied variables on pectin yield was as follows: solid-to-solvent ratio >
ultrasonic irradiation time > ultrasonic power. The optimum extraction conditions that provided the maximum pectin yield
(1.76%) were obtained as 41 min; 300 W and 1:21 (g/mL) for ultrasonic irradiation time, power and solid-to-solvent ratio,
respectively. Physicochemical analyses and Fourier transform infrared spectroscopic (FTIR) studies revealed that the
extracted pectin had a galacturonic acid content of 76.24% and an esterification degree of 67.31% as a high-ester pectin
which was in line with the requirements of the national standard. By adding the pectin, the gel strength of gel products could
be enhanced by up to 140%, in turn resulting in improved physical characteristics.

Key words: response surface methodology, muskmelon rind pectin, ultrasonic-assisted extraction, physical characteristics, gel strength