Rheological Properties Of Pectin Enriched Products Isolated From Butternut (Cucurbita Moschata Duch Ex Poiret)

FISSORE ELIANA N; MATKOVIC LAURA B; WIDER EVA A; ROJAS ANA M; GERSCHENSON LÍA N

LEBENSMITTEL-WISSENSCHAFT UND-TECHNOLOGIE-FOOD SCIENCE AND TECHNOLOGY

ELSEVIER SCIENCE BV

Año: 2009 vol. 42 p. 1413 - 1421

0023-6438

Rheological behavior of five different pectin enriched products obtained from a cell wall enriched powder of butternut (Cucurbita moschata Duch ex Poiret) was evaluated through flow and oscillatory assays. The product SE was obtained through treatment with citrate buffer; C1 and C2 were obtained using cellulase and different enzyme-substrate ratios while H1 and H2 resulted from hemicellulase treatment at different levels. SE- and H1-pectin enriched fractions showed the best performance as thickeners as indicated by their highest Newtonian viscosities and time constants on shear-thinning along the flow. These fractions showed a structure with the highest density of interactions between the hydrated macromolecules when solutions were evaluated at rest. Fractions obtained with a higher activity of hemicellulase (H2) or with the lowest activity of cellulase assayed (C1) showed the same degree of structure when evaluated at rest, while C2-fraction presented the lowest density of macromolecular interactions in water, behaving as a diluted hydrocolloid solution as confirmed by its fitting to the Cox-Merz rule. Molecular weight distribution of polysaccharide fractions along with chemical composition helped to explain the rheological behavior of these isolated fractions which contained between 39 and 78 g of galacturonic acid per 100 g of product. With the exception of C2 fraction, pectin enriched products isolated from butternut showed an interesting range of thickening properties and can be used as thickeners in the food industry.