Influence of composition on the internal diffusion mechanism of pectin–starch gel beads

Abstract

Pectin is a hydrocolloid commonly used as a wall material for encapsulation, meantime using a filler such as starch can improve the retention in the matrix and control the release in specific places. Formulations of pectin and starch were evaluated for bead production by ionic gelation technique using dripping and jet cutter methods. In addition, beads were dried in a fluidized bed and rotating drum at 50°C. The mean diameter, mechanical strength, yield, moisture content, the morphology of wet and dry beads, and rehydration behavior were evaluated. Furthermore, the pomegranate extract (PE) encapsulation efficiency and release in water were measured. The beads with 2.85% solids content of which 70% are pectin and 30%, waxy corn starch proved to be technologically viable and were satisfactorily dried in a fluidized bed, while on a rotating drum, drying was not efficient. Compared with pure pectin, the pectin–starch beads showed a spherical shape, smoother and more homogeneous with greater mechanical strength and greater water absorption capacity after drying in a fluidized bed. The conventional encapsulation of PE added to biopolymer solutions showed low efficiency (4.7%–43.7%) and the release velocity was higher for drip beads (~70%).

Stability of yerba mate extract, evaluation of its microencapsulation by ionic gelation and fluidized bed drying

“…[ Table 2 ]. Similar values of phenolic compounds (376.40 ± 23.80 to 408.08 ± 12.54 mg/100 g d.b) were found by Silveira et al [ 9 ] in the encapsulation of pomegranate extract using ionic gelation by dripping and subsequent drying. By reducing the moisture, the particles could be employed in drier products in which high moisture content would cause changes in their characteristics.…”

“…The encapsulation efficiency was 45%, equation [ 7 ]. In the encapsulation of pomegranate extract using ionic gelation by dripping and with pectin as wall material, EE values of phenolic compounds between 41.2 and 43.4% were found [ 9 ]. Since they are too sensitive, phenolic compounds tend to lose their properties of interest fast when compared to unprotected compounds as free extract.…”

“…The use of low-methoxy pectin promotes microparticles with soft structure and has application in products of a wide pH range [ 8 ]. Since the high moisture content of the particles obtained by ionic gelation can cause limited stability and lead to an incompatibility with the food matrix, the strategy of subsequent drying of these particles can be a viable alternative for greater stability and better possibility of commercialization of these particles [ 9 ]. The use of a commercial hydroalcoholic extract was chosen in order to facilitate a future industrial application of the microparticles, since the extract would be easily available and commercially standardized.…”