Structural Characterization of Controlled Decrystallization of Cassava Starch

Abstract

Native starch granule has a complex crystalline structure. Controlled decrystallization cassava starch (CDCS) was prepared by the alcohol–alkali method. Polarized microscopy, scanning electron microscopy (SEM), X‐ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analysis of the CDCS are carried out to investigate its structural information. The results show that the relative crystallinity (RC) of the processed cassava starches can be reduced from 25.56% to 17.90% by adjusting the concentration of sodium hydroxide while keeping the integrity of the starch granule. During the decrystallization process, as the sodium hydroxide concentration is increased from 0.25 to 1.25 mol L−1, the polarized light of the starch granules disappear from the inside to the outside, and the X‐ray diffraction peaks of native cassava starch (NCS) disappear sequentially from 17.16°, 23.04°, 15.08°, to 17.83°. On the other hand, the FTIR peaks of the NCS centered at 1645 cm−1 is shifted to about 1600 cm−1, and the intensity of the peaks at 3424, 2929, 1645, and 1017 cm−1 become weaker with decrystallization process. This study provides valuable data and a theoretical basis to understand the mechanism of the controlled decrystallization of cassava starch.

Cassava Starch-Based Thermo-Responsive Pb(II)-Imprinted Material: Preparation and Adsorption Performance on Pb(II)

“…For CS, the broad peak around 3421 cm −1 is the O–H stretching vibration of hydroxyl groups. The adsorption peaks at 2929 cm −1 and 1653 cm −1 are attributed to the C–H and C=O stretching vibrations from glucosl units in CS, respectively [ 21 , 22 ]. Regarding NIPAM, a characteristic absorption peak at 3298 cm −1 refers to the N–H stretching vibration of amino groups and the absorption of C–H stretching vibration at 2975 cm −1 originates from the methyl groups.…”

Synthesis of Selenium‐Enriched Cassava Starch with Immediate Antioxidant Activity and Its Antioxidant Catalytic Mechanism

“…This decrease may be due to the erosion of the strong alkaline media during the modification. [ 32 ]…”

Preparation and catalytic behavior of antioxidant cassava starch with selenium active sites and hydrophobic microenvironments

“…Due to the nucleophilic addition occurring in the OSA molecular chain, which did not affect the crystallinity of starch, the mild reduction of the crystallinity degree might be caused by the strong alkaline environment. 40 In order to further study the changes in starch during the modication, thermogravimetric analysis (TGA) was used to analyze the thermal decomposition behavior of starch. The curves of TGA and the corresponding derivative thermogravimetric analysis (DTG) for the cassava starch, OSA-ca-starch, and AO-ca-starch are presented in Fig.…”

“…Due to the nucleophilic addition occurring in the OSA molecular chain, which did not affect the crystallinity of starch, the mild reduction of the crystallinity degree might be caused by the strong alkaline environment. 40 …”

“…Our group and other researchers have devoted considerable efforts to produce a series of biomimetic GPx using small molecules, 20,21 polymers, 22,23 proteins, 24,25 and nanomaterials, 26,27 and to expose the relationship between the structure and the function of biomimetic GPx. The previous results indicated that the three important catalytic factors for maintaining the high catalytic activity of GPx are the selenium element as the catalytic center on GPx, the hydrophobic microenvironment composed of hydrophobic amino acid residues such as 150 Phe, 148 Trp, and 34 Leu, and the recognition site for binding substrates via hydrogen bonds between substrates and arginine-based 40 Arg, 130 Arg, and 167 Arg. 28,29 In order to construct a biodegradable biomimetic GPx with high catalytic activity, we intended to prepare the biomimetic GPx with modied starch (OSA-starch), resulting in a new antioxidant starch.…”