Properties and Structure of Modified Taro Starch: Comparison of Ultrasound and Malic Acid Treatments

Abstract

The properties and structure of native taro starch and three modified starches (ultrasonically modified starch, malic acid modified starch, and ultrasound-malic acid modified starch) are compared and analyzed in this work. Experimental results demonstrate that ultrasound and malic acid change the properties and structure of taro starch. Compared with the native starch, the combination of ultrasound and malic acid (UM) leads to the decrease of the viscosity values and H, as well as the improvement of swelling power, water holding capacity, and oil absorption rate. In addition, scanning electron microscopy (SEM) microgram shows that UM results in the damage and degradation of starch granules. Laser diffraction analysis indicates that native starch and modified starches all exhibit bimodal distribution, and ultrasound leads to the decrease of starch particle size, while malic acid results in the increase. The FT-IR spectra suggest that UM changes the peak intensity and width of starch molecules and produces a new characteristic peak at 1741 cm −1 . In conclusion, UM is effective for modifying starch, and it can promote the taro starch process.

Study on Structural and Physicochemical Properties of Modified Corn Starch: Comparison of Ultrasound, Stirring, and Lactic Acid Treatments

“…[ 2,20 ] In DSC analysis, the enthalpy of gelatinization (Δ H ) indicates the energy needed for the separation of double helix structure as well as the loss of the starch molecular order during gelatinization process, and gelatinization temperatures are indicator of the changes in crystalline structure. [ 2,20 ]…”

“…The reduction of gelatinization parameters could be attributed to the incorporation of functional groups on starch chains and the destruction of inter‐helices interactions (crystalline and amorphous areas) present in starch granules under acid hydrolysis and ultrasound treatments. [ 20,17,21 ] The greatest decrease in enthalpy was observed for USA‐CS sample (5.23 J g −1 ) which showed that it needed the lowest energy for gelatinization in comparison with the native and other treated starches. The ultrasound treatment resulted in more loss of ordered structure compared to lactic acid hydrolysis, thereby more reduction of gelatinization parameters.…”

“…By comparing the samples of UA‐CS and SA‐CS could be concluded that ultrasonication treatment was more effective in the esterification process than stirring due to the mechanical effects of ultrasound cavitation on starch granules. Consequently, the shock wave of ultrasound and stirring on the USA‐CS sample could promote substitution reaction in starch chains by homogenizing the reaction medium [ 20 ] and increasing the diffusion of lactic acid into the granules. [ 9 ] The obtained results were in accordance with FT‐IR examinations.…”

“…The water holding capacity and water absorption index express the capability of starch to absorb and retain water molecules inside the starch network. [ 20 ] Table 2 displayed the determination results of both factors for eight starch samples. A noticeable difference in the values of both factors between native and modified starches was observed.…”

“…The removed water from the starch sample (supernatant) and the wet sediment was weighed. The water holding capacity (g g −1 ) and water absorption index (g g −1 ) of all starch samples were obtained according to the following equations [ 20 ] : $$$$\begin{equation}Water\;holding\;capacity\;\left( {\frac{g}{g}} \right) = \frac{{({m_{1 }} - {m_2})}}{{{m_3}}}\end{equation}$$$$ $$$$\begin{equation}Water\;absorption\;index\;\left( {\frac{g}{g}} \right) = \frac{{{m_4}}}{{{m_3}}}\end{equation}$$$$here, m 1 was the weight of water added to the starch sample (g); m 2 was the weight of supernatant (g); m 3 was the weight of the starch sample (g); m 4 was the weight of the obtained wet sediment after centrifugation.…”