Isolation and Characterization of Pectin from Pumpkin (Cucurbita maxima) Waste and Its Food Application

Pectin was extracted using the method of acid hydrolysis followed by ethanol precipitation at various reaction conditions. Effect of blanching prior to acid hydrolysis, acid types (hydrochloric and citric) and extraction time and temperature combinations were tested to maximize the yield of pectin and they were characterized by assessing physiochemical and functional properties. The feasibility of utilizing extracted pectin in food applications was evaluated. The yield of pectin ranged from 7.30 ± 0.07- 11.04 ±0.01% on a dry weight basis. The results suggested that the highest pectin content is in the fresh pumpkin peel extracted using 0.1 N hydrochloric acid at 80±5℃, 1.25 pH for 1 hour. Water holding capacity, oil holding capacity and emulsifying activity index of pumpkin pectin were 2.5 g/g of pectin (SD 0.46), 1.76 g/g of pectin (SD 0.10) and 0.29 (SD 0.01) respectively. In addition, the degree of esterification, equivalent weight, methoxy content and galacturonic acid content of extracted pectin were 67.64% (SD 0.89%), 978.35 (SD 69.88), 6.55% (SD 0.37%) and 66.46% (SD 1.19%) respectively. Sensory analysis revealed that there is no significant difference in spreadability, surface texture and chewiness of two types of jam prepared using pumpkin and commercial pectin. In conclusion, pumpkin pectin can be categorized as high methoxy pectin.