Dietary fiber, fructooligosaccharides, and physicochemical properties of homogenized aqueous suspensions of yacon (Smallanthus sonchifolius)

• Yacon roots are a promising source of inulin­type fructans (35 g/100 g dry matter) with a total amount of dietary fiber of about 45 g/100 g dry matter. The polydispersity of the particle size distribution of yacon aqueous suspension was reduced with increasing the degree of homogenization due to two phenomena: aggregation of particles, and disruption of large particles. Non­homogenized yacon suspensions exhibited large cell clusters that were disrupted into small cell clusters, single cells, and aggregates. The most concentrated suspension exhibited mainly aggregates. The reducing effect of homogenization and the absence of a concentration effect on volume fraction were attributed to the dense packing of small particles and aggregates in between large particles thus allowing the water within the structure to be released. Yacon suspensions exhibited high elastic modulus (750 Pa) at low water insoluble solids content (0.9 % WIS). The results suggested that inulin­type fructans contributed to the elastic properties of yacon suspensions. Yacon suspensions exhibited brittle flow behavior and they can be considered as semi­concentrated i.e. the yacon suspensions studied in this work represented a region immediately after the transition region where the rheological properties of yacon suspensions are dependent on concentration, particle interaction, and particle properties. Particle interactions seem to be of great importance as the elastic modulus (G’) reached 750 Pa at low water insoluble solids content (<1%).

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Annan teknik -- Livsmedelsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Other Engineering and Technologies -- Food Engineering (hsv//eng)

Nyckelord

yacon

dietary fiber

fructooligosaccharides

physicochemical properties

particle size distribution

viscoelastic properties

homogenization

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