Starch Modification and Characterizatıon with Atmospheric Plasma and Ultrasound Applications
Project no. 29651 · Status: Kapanmış · 2023
Summary
<p>Starches are one of the most promising raw materials for the edible film industry due to their abundance in nature, colorless, odorless, inexpensive and biodegradable properties. However, natural starches may be unsuitable for production processes due to certain undesirable characteristics, such as their hydrophilic nature, poor mechanical properties, and low gas permeability. In order to eliminate such negative effects, chemical, enzymatic or physical modifications to starch are recommended.</p><p>In this study, starch was isolated from newly registered dry pea seeds (<em>P. sativum L.</em>) in Turkey, and production yields were calculated. The obtained starches were modified using physical (plasma and ultrasound) and chemical methods (acid and cross-linking). The technological, morphological, structural, pasting, thermal, and digestibility properties of the native and modified starches were determined. Edible starch-based films were produced using these starches, and the morphological, mechanical, and permeability properties of the starch-based film samples were revealed.</p><p>In general, solubility, syneresis, and water-binding capacity values increased for all modified starches, but viscosity values decreased. Amylose amounts increased in ultrasound- and acid-modified starches, while apparent amylose amounts decreased in plasma- and cross-linked modified starches. Swelling force data showed an increase for plasma- and cross-linked starches, while it decreased in ultrasound- and acid-modified starches. While the C-type crystal structure did not change for all modified starches in X-ray diffraction patterns, the relative crystallinity values decreased in ultrasound, acid and cross-linked starches and increased in plasma modified starches. It was determined that the Fourier transform infrared spectroscopy spectra for all modified starches were similar and the bond structure was not affected much after the modifications. Compared to native starch, starches modified with ultrasound, acid, and cross-linking exhibited higher turbidity, while plasma-modified starches exhibited lower turbidity. While the enzyme-resistant starch (RS) content of native starch was 3.36%, the amount of enzyme-resistant starch decreased with ultrasound modification, with the lowest value being 0.45% in the 30%60US sample. The RS amounts of starch samples obtained with other modification methods increased and the highest values were determined as 20.88% (30% 15PS), 8.09% (24h HCl) and 22.82% (2%CB) for the samples modified with plasma, acid and cross-linking, respectively. When the morphological properties of the starches were examined, SEM images revealed that starch granules were affected by the modifications, and this effect worsened with increasing modification time.</p><p>The bursting strength of the starch-based film prepared with native starch was determined 2379.11 <em>g</em>. It was determined that the bursting strengths of all edible films produced using modified starch were higher than those of the film samples containing native starch. The highest bursting strengths of starch-based films modified by ultrasound, plasma, acid, and crosslinking were determined as 4188.32 <em>g</em> (10% 45US), 3429.96 <em>g</em> (10% 15PS), 4330.72 <em>g</em> (24h HCl), and 3036.95 <em>g</em> (% 2CB), respectively. The thicknesses of films prepared with starches modified by plasma and crosslinking decreased compared to the film sample containing native starch, while they increased in films prepared with ultrasound and acid modified starches. It was determined that modified starch-based films were more brittle than native starch-based films. It was observed that plasma and crosslinking modifications contributed to reducing the water vapor permeability of the films.</p>