Amylopectin-Sodium Palmitate Complexes as Sustainable Nanohydrogels with Tunable Size and Fractal Dimensions

Abstract

Starch-based nanohydrogels with polyelectrolyte characteristics may find unique applications. Herein, the branch chains of amylopectin (AP) were elongated to different extents by amylosucrase, followed by complexation with sodium palmitate (SP) to produce nanohydrogels. Modified AP (mAP) with a longer chain length displayed a better ability to complex with SP, and the mixtures exhibited nanosized particles with an average diameter ranging from 153.5 to 1049.8 nm. The gel strength of bulk nanohydrogels was dependent on the chain length of mAP and SP content, and their fractal dimension was between 1.82 and 2.45. The crystalline structure of native AP was altered from A- to B-type after chain elongation and, subsequently, to B + V-type after complexing with SP. Diffraction peaks of the complexes at 2θ of 7.5°, 12.9°, and 19.8° implied that the AP side chains formed left-handed single helices and the hydrophobic SP was entrapped in the helix cavity.

Physicochemical Properties of the Rice Flour and Structural Features of the Isolated Starches from Saline-Tolerant Rice Grown at Different Levels of Soil Salinity

“…The microstructure of cooked rice flour can be resolved by rheological test. , For all samples, both storage modulus ( G ′) and loss modulus G ″ increased with the increase of ω, and the magnitude of G ′ was higher than that of G ″ at the range of frequency examined (Figure ). G ′ and G ″ indicate the elastic and viscous properties, respectively, and thus the cooked rice flour had a weak-gel behavior . The data of log G ′ and log G ″ versus log ω were subjected to linear regression as follows: log G ′ = K ′ + n ′ log ω log G ″ = K ″ + n ″ log ω …”

Effects of Pectin on the Physicochemical Properties and Freeze-Thaw Stability of Waxy Rice Starch

“…Dynamic modulus can be used to examine the interactions between the disperse phase and the continuous phase in some polymer solutions [21]. In general, G' represen the energy stored as mechanical energy, whereas G" measures the energy dissipated heat, and mostly represents the viscous portion [29]. As shown in Figure 3A,B, the G' an G" of all samples increased as the scanning frequency increased from 0.1 Hz to 10 H Moreover, the value of G' was slightly higher than that of G", indicating that both WR and the WRS-PEC blends had weak gel properties.…”

Structural Features, Physicochemical Properties, and In Vitro Digestibility of the Starch-Lipid Complexes Formed between High Amylose Starch and Stearic Acid or Potassium Stearate

“…The formation of starch gels involves the reassociation of starch chains, where the hydrogen bonding formed between adjacent starch chains determines the gel strength. According to previous studies [ 22 , 28 ], the addition of sodium palmitate decreased the viscosity of the amylose solution, and no visual or microscopic evidence of retrogradation was observed for amylose because the electrostatic repulsion restricted the amylose reassociation. In this study, the hydrophobic forces transferred the hydrophobic chain of PS into the amylose helix cavity, and the ionization of −COOK provided the polyelectrolyte characteristics of HAS-PS ( Figure 1 ).…”

“…Additionally, the magnitude of the negative ζ potential of HAS-PS dispersions gradually increased from −22.2 mV to −32.8 mV when the addition of PS increased from 0.5 mM to 2.0 mM ( Figure 1 ). In a previous study [ 22 ], the starch-lipid complexes prepared from chain-elongated amylopectin and sodium palmitate also showed polyelectrolyte characteristics, and structural analysis revealed that the hydrophobic hydrocarbon chain of sodium palmitate is trapped in the starch particles via a V-type helix formation, and the carboxylate group was present on the particle surface. Consequently, a higher magnitude of ζ potential might result from a greater inclusion of PS within the HAS-PS particles.…”

“…A 40 mm parallel plate geometry with a gap of 1000 μm was used for the test. [ 22 ]. Before the measurements, the HAS-SA/PS dispersions were stored in a 4 °C refrigerator for 48 h. The samples were transferred to the testing plate and equilibrated at 25 °C for 30 s. To prevent water evaporation of the samples, a layer of mineral oil was coated around the rim.…”