Physicochemical Properties of Potato Starch Nanoparticles Produced by Anti‐Solvent Precipitation

Abstract

This work aims to understand the physicochemical properties of potato starch nanoparticles (SNPs) obtained by anti‐solvent precipitation. Moisture content, water activity, color, morphology, thermal behavior (differential scanning calorimetry), swelling factor, solubility in water, water sorption isotherms, rheological properties, and stability in water are analyzed and compared using native potato starch (PS) as control. The resulting SNPs after anti‐solvent precipitation have a particle size between 50 and 150 nm, smaller than those observed in PS (between 10 and 100 µm). SNPs behave as an amorphous material without gelatinization stage where the swelling factor is drastically reduced, while the solubility increased dramatically at low temperatures when compared with PS. The Guggenheim–Anderson–de Boer model from the isotherms data allows a calculation of the surface area, obtaining values of 105 and 211 m2 g−1 for PS and SNPs, respectively. The high surface area in SNPs is associated with an increase in the proportion of hydroxyl groups active for water adsorption throughout its structure. Both samples show Newtonian fluid behavior; however, SNPs solutions prove to be much more stable at room temperature than PS solution.

Physicochemical Properties of Modified Starches Obtained by Anti‐Solvent Precipitation Containing Anthocyanins from Jambolan (Syzygium cumini) Fruit

“…A reduction in RC value could be correlated with the amorphization of the starches during the anti‐solvent precipitation. [ 13,30 ] Similar results were informed by Ahmad et al. [ 12,14 ] in horse chestnut, water chestnut and lotus stem starches submitted to anti‐solvent precipitation.…”

“…Furthermore, a complete MCS‐ACN and MPS‐ACN solubilization in water can be credited to the reduction in the crystalline index of the native starches during the anti‐solvent precipitation (see Section 3.3). [ 30 ] Based on desorption results, modified starches containing ACNs could be used as natural colorants of food products with acid pH, being that these materials can be dissolved at room temperature.…”

“…[ 14 ] and Chacon et al. [ 13,30 ] Native starch granules (5% or 10% w/v) were dispersed in distilled water and then heated at 90 °C for 30 min, under constant agitation (290 rpm). In sequence, starch solutions were cooled to 25 °C, under constant agitation.…”

“…Modified cassava starch (MCS) and modified potato starch (MPS) were obtained after the precipitation of native cassava and potato starches with acidified ethanol (100:1 v/v, ethanol:HCl 37 wt%) or ACN extract in acidified ethanol, as proposed by Ahmad et al [14] and Chacon et al [13,30] Native starch granules (5% or 10% w/v) were dispersed in distilled water and then heated at 90°C for 30 min, under constant agitation (290 rpm). In sequence, starch solutions were cooled to 25°C, under constant agitation.…”

“…[28] Water activity (a w ) measurements of samples was carried out at 25°C using a water activity meter (Aqualab Model Series 3 instrument, Decagon Devices Inc., Pullman, WA, USA). [30]…”