Effect of phosphoric acid treatment on physicochemical, functional, and structural properties of starch extracted from yam (Dioscorea rotundata)

Abstract

This work was designed to elucidate selected physicochemical, functional, and structural properties of native and modified yam (Dioscorea rotundata) starch. The isolated starch was chemically modified using 5, 10, 15, 20, and 25% phosphoric acid solution at 50°C for 1 h, and yield, swelling power, gelation, water holding capacity, paste clarity, blue value, and amylose and amylopectin content of the native and modified yam starch were determined. Structural changes in the native and starch modified with 25% phosphoric acid were evaluated using Fourier transform infrared spectroscopy and optical microscopy. The result showed that the yield, swelling power, water holding capacity, paste clarity, blue value and amylose and amylopectin content of native yam starch was 33.38% (217 g), 3.84 g/g, 1.0 v/g, 10%, 0.52 and 25.96, respectively, whereas gelation study of the native and modified starch indicated that native starch was viscous and modified starch firm. However, yield, swelling power, water holding capacity, paste clarity, blue value, and amylose content of modified yam starch reduced in a dose dependent manner with phosphoric acid. The reduction in the values of the various functional properties could be associated with the effect of phosphoric acid on the starch granular structure. The result of Fourier transform infrared spectroscopy and optical microscopy revealed that the yam starch was modified by phosphoric acid with changes in functional groups spectra such as-OH stretch (3177 cm −1), H 2 O absorbed (1644 cm −1) (amorphous region), C-H stretch (2923 cm −1), CH 2 O (1253 cm −1), and CO -C (1078 cm −1) when compared to native starch. The morphology of native and modified yam starch granules ranged from oval to eliptical. However, modified starch granules were rough in surface. In conclusion, the characterized physicochemical and functional properties and structure exhibited by native and modified yam starch indicated that, yam could be a cheap and valuable source of starch for industrial application.

Effects of Lintnerization, Autoclaving, and Freeze-Thaw Treatments on Resistant Starch Formation and Functional Properties of Pathumthani 80 Rice Starch

“…The water holding capacity of the RD 31 flour and native starch was observed to increase up to 8.77 ± 0.48 and 12.37 ± 0.32 g/g, respectively, at 90 °C, while the lintnerized starch exhibited the lower water holding capacity as compared to that of RD 31 rice flour and native starch. Low water holding capacity of acid treated starch could be attributed to reducing the amorphous region in the starch granule, which, in turn, reduces the number of available binding sites for water in starch granules [46]. However, the water holding capacity was observed to increase with the rise in acid concentration, which might be due to the rise in the low molecular weight starch with hydroxyl groups that can hold water molecules [47].…”

Optimization of Porous Phosphorylated Chestnut Starch Synthesis by Response Surface Methodology and Characterization of its Properties

“…These three bands represent the characteristic bands of starch. [ 39,40 ] The IR spectrum curves of P‐PCS differed from those of CS. New diffraction absorption peaks appeared at 1058 cm −1 , which reflected the antisymmetric stretching vibration of C─O─P bonds.…”

Synthesis of reticular long-carbon-chain polysiloxane and its hydrophobic modification of phosphogypsum-based materials

“…The peaks at 1258 and 785 cm −1 were attributed to the symmetric deformation vibration of –CH 3 in polysiloxane and the Si–O vibration, respectively. The peak at 1078 cm −1 corresponds to the C–O–C asymmetric stretching vibration, 25 while those centered at 1462 cm −1 and 1380 cm −1 are the characteristic peaks of the C–H asymmetric bending vibration of the –CH 3 group. The FTIR analysis indicates that PVD-C has the molecular structure shown in Fig.…”