Study on extraction of low methoxyl pectin from silkworm excrement

Pectins were extracted from silkworm excrement by means of acid extraction and then molysite precipitation. A single-factor experiment and an orthogonal test were used to optimize the production conditions. The optimal conditions for pectin production were determined to include extraction at p H1.7 and a solid-liquid ratio of 1∶20(g/m L) in oxalic acid solution for 60 min at 85 ℃,and precipitation with 0.5% molysite solution at p H3.5. Under optimal conditions,the extraction rate of the pectin was 5.21%,the methoxy content and the degree of esterification(DE) was 5.62% and 34.46%,respectively,and the total galacturonic acid content of the pectin was 69.58%. Thus,the quality of the pectin was absolutely acceptable.