SUPRAMOLECULAR STRUCTURE OF GEL-FORMING SYSTEMS OF PECTINS OF DIFFERENT ORIGIN

Two pectin preparations (citrus 'Copenhagen Pectin' and that derived f rom pumpkin) that formed opalescing suspensions in aqueous media were investigated. The values of concentration and mean size of supramolecu lar particles determined by a spectroturbidimetric method were used as indicators of the structural heterogeneity of the preparations. Accor ding to these criteria, the pumpkin pectin preparation had a higher de gree of structural heterogeneity than that of the citrus pectin. The p rocess of gel formation in the systems studied did not cause any signi ficant turbidimetric effects that could have pointed to the formation of particles of a new phase. Resuspended fractions of the supramolecul ar particles, which were obtained from the pumpkin preparations by cen trifugation, formed gels in acid solutions of sucrose. In this case, t he temperature of gel formation was close to that recorded for the ini tial preparations. However, it was about 10 degrees C below the temper ature of gel formation registered for the supernatants of pumpkin pect in preparations that remained after removal of the supramolecular part icles by centrifugation. (C) 1998 Published by Elsevier Science Ltd. A ll rights reserved.