Extraction of highly gelling pectic substances from sugar beet pulp and potato pulp: influence of extrinsic parameters on their gelling properties

Sugar beet and potato pulps were considered as potential new sources of pectins because of their high pectin content, from 15 to 30% on a dry matter basis, and their availability in large quantities. Up to now, no pectins with gel forming properties comparable to the pectins extracted from apple pomace and citrus peels have ever been extracted from these by-products. Ln the present work, an extraction process for each by-product has been developed which maintains the structural integrity of the pectins as much as possible. These procedures yielded products which possessed both a high pectic substance content with a low degree of esterification and a high gelling ability in the presence of calcium. The composition of the extracted products was determined and the effect of extrinsic factors such as concentration of the extracted product, calcium content, sequestrant content and hydration temperature, on gel properties was evaluated by rheological measurements. (C) 1999 Elsevier Science Ltd. All rights reserved.