Rheological behavior of soluble dietary fiber fractions isolated from artichoke residues

ZUKOWSKI, ENZO; SANTO DOMINGO CINTHIA; ROJAS ANA M; FISSORE ELIANA N; GERSCHENSON LÍA N

Conferencia; e-Conference on Food Texture and Rheology; 2019

Globe artichoke (Cynara cardunculus var. scolymus) by-products (stems, outer bracts, leaves) constitute an 80% of the plant. Artichoke agroindustrial by-products can be applied to the extraction of soluble dietary fibers. In this work, the rheological behavior of fractions isolated from bracts and stems of artichoke was studied. Soluble dietary fiber fractions isolated from stem (S) and bracts (B) by means of a heat treatment followed by processing with sodium citrate buffer (S1, B1) or buffer/protease (S2, B2) or hemicellulase (S3, B3) or both enzymes (S4, B4) were composed, mainly, by pectin (degree of methylation, DM  53%) and inulin. When dissolved in water (2.00% w/v) with Ca2+ (40 mg/g pectin), fiber fractions were sensitive to calcium showing shear thinning flow, with initial yield stress in the case of B2, B3 or S3. Citrate buffer extracted fractions showed the highest viscosities (B1, S1) whereas extraction with buffer and both enzymes (B4, S4) produced the least viscous fiber fractions. Rest assays performed under dynamic conditions, revealed the formation of gel-like networks with varying lifetimes of the calcium junction zones. Networks formed by fibers were favored, in general, by higher pectin and inulin content, homogalacturonan proportion, and low DM. Leftovers of artichoke can be used to extract soluble dietary fiber fractions that might be utilized as natural thickeners and gelling agents in foods, pharmaceutical and cosmetics, helping to add value to raw materials and to close the bioeconomy loop in relation to this plant.