Comparison of Three Methods to Determine the Degree of Substitution of Quinoa and Rice Starch Acetates, Propionates, and Butyrates: Direct Stoichiometry, FTIR, and 1H-NMR

Abstract

Rice and quinoa starch esters were prepared by acylation using short-chain fatty acid anhydrides with different chain lengths (acetic, propionic, and butyric anhydride). A direct stoichiometric method based on the acylation reaction was used to determine the degree of substitution (DS) and acyl content (AC). In addition, Fourier-transform infrared spectroscopy (FTIR) was used to validate the conformational changes of acylated starch and 1 H-NMR was used as a DS reference method. DS by stoichiometric calculation was shown to be in agreement with FTIR and was comparable with DS obtained from Proton nuclear magnetic resonance ( 1 H-NMR). Based on this study, stoichiometric calculation allows rapid and direct determination of substitution levels and acyl content without the loss of samples, which provides efficiency and optimization of manufacturing procedures in producing the desired level of esterified starches.

Thermally Induced Silane Dehydrocoupling: Hydrophobic and Oleophilic Filter Paper Preparation for Water Separation and Removal from Organic Solvents

“…After the reaction between CFP and ODS, the absorption band at 2100 cm −1 , corresponding to Si–H groups, confirmed the successful conjugation of ODS with CFP [ 42 ]. For calculating the degree of substitution of OCFP, we normalized the intensity of the ν(Si–H) peak and weighed the CFP and OCFP [ 47 ]. The weight of CFP (0.346 g) increased to 0.464 g after the reaction.…”

Dysphagia management in Parkinson's disease: Comparison of the effect of thickening agents on taste, aroma, and texture

“…Differences in taste retention or mouthfeel between PS and QF could be explained by their structural differences. Quinoa starch has extremely small granules (0.3 to 2 µm) and A‐type polymorph crystallinity, whereas PS has large granules (30 to 100 µm) and B‐type polymorph crystallinity (Abdul Hadi, Wiege, Stabenau, Marefati, & Rayner, 2020; Kong, Lee, Kim, & Ziegler, 2014).…”

The effect of natural modifiers for starch hydrophobization on performance of composite based on ethylene acrylic acid copolymer

“…[ 10 ] In addition, it was concluded that for the achievement of high DS for the starch esterification by acetic, propionic or butyric acid it is necessary to follow reaction in water solution under controlled pH value. [ 14 ] On this manner, the values of DS obtained were in the range 0.0305–0.1361. For obtaining higher DS it is necessary to be used different catalysts such as alkaline, triethylamine or using pyridine as reaction medium.…”