Pectin from carrot pomace: Optimization of extraction and physicochemical properties

In this study, the central composite design for four variables in five levels was applied to determine the effects of pH (0.5-2.5), temperature (50-90°C), heating time (30-150min) and liquid/solid ratio (10-50v/w) on the yield and degree of esterification (DE) of carrot pomace pectin. The results showed that the pectin yield ranged from 5.0 to 15.2% and also, this pectin is classified as low methoxyl pectin (DE of 22.1-51.8%). The pH of 1.3, temperature of 90°C, time of 79.8min and liquid/solid ratio of 23.3v/w were determined as optimal conditions with a maximum yield of 15.6±0.5%, which was close to the predicted values (16.0%). Under the optimal extraction conditions, the galacturonic acid content and emulsifying activity were 75.5 and 60.3% respectively; moreover, the emulsions had a high stability at two different storage temperatures (4 and 23°C). Furthermore, carrot pectin solutions exhibited viscous and pseudoplastic behavior at 1% w/v.