Influence of Precipitation Conditions on Crystallinity of Amylose Nanoparticles

Abstract

Amylose nanoparticles are prepared via precipitation by dropping absolute ethanol into amylose paste. X‐ray diffraction analysis reveales that the amylose nanoparticles display V‐type crystalline structure, and crystallinity of the amylose nanoparticles is dependent upon precipitation conditions, that is, temperature of amylose paste, ethanol dropping rate, and length of amylose chains. Dropping ethanol of 20 °C into amylose paste of 90 °C at a rate of 5 mL min−1 promotes the molecular association of amylose and ethanol into a helical complex and forms more amylose single helices in the precipitated amylose nanoparticles, which results in a higher crystallinity (60.72%) after the amylose nanoparticles are dried at 4 °C for 12 h and then at 40 °C for 12 h under 11% relative humidity. Shorter amylose chains may be unfavorable to complex formation between amylose and ethanol. The findings of this study provide a guideline to prepare amylose nanoparticles with higher crystallinity via precipitation.

Encapsulation of Lutein into Starch Nanoparticles to Improve Its Dispersity in Water and Enhance Stability of Chemical Oxidation

“…Particle size distribution of the starch‐lutein nanoparticles was analyzed according to previously reported method . Dispersion (0.05% w/v) of starch‐lutein nanoparticles (after drying) in deionized water was prepared, the analysis was carried out by using a Malvern Zetasizer Nano‐ZS90 (Malvern Instruments Ltd., UK).…”

“…The X‐ray diffraction patterns were recorded over the 2 θ range of 4–35° with a speed of 2° min −1 . Crystallinity of the starch‐lutein nanoparticles was calculated by using previously described method …”

High‐Efficient Preparation of Cross‐Linked Cassava Starch by Microwave‐Ultrasound‐Assisted and its Physicochemical Properties

“…Chemical reagents are usually used to modify the performance of starch; however, homogeneously mixing these reagents with starch to permeate its internal structure is difficult. Therefore, more highly efficient methods by which starch can be modified have recently been the subject of attention and are showing great potential . To that end, microwaves, a type of electromagnetic wave, can heat reactants without conducting that heat, accelerate the reaction rate of the thermal effect from internal expansion, and improve the contact between the starch and the reagent.…”

Crystallization of Short‐Chain Amylose: Effect of the Precipitant

“…In addition, B‐type, A‐type, and V‐type amylose were obtained from pure water, 15% (v/v) ethanol and 40% (v/v) ethanol, respectively . On the other hand, crystallinity was often observed in the starch nanoparticles which were prepared by adding an excess of anhydrous ethanol into the starch solution …”

“…[9] On the other hand, crystallinity was often observed in the starch nanoparticles which were prepared by adding an excess of anhydrous ethanol into the starch solution. [13,14] It was found that polyethylene glycol (PEG) could precipitate dextrin like ethanol. [15,16] In addition, crystalline starch microspheres were successfully prepared in an aqueous two-phase system formed by starch and PEG.…”