This research aims to evaluate the effects of varying stearic acid (SA) concentrations (2%, 4%, and 6%), followed by an ultrasound treatment with SA, on the morphology, structure, functionality, and rheological behavior of starch extracted from khesari peas. The ultrasonically treated samples showed higher complexing index (CI) values (23.65%-92.86%) than starch-SA complexes, decreased amylose content (30.22%-18.11%), and increased water-holding capacity (175.18%-306.65%). FTIR spectra suggested the formation of starch-SA complexes, indicated by additional peaks at 2849 and 1704 cm- 1, along with a new band near 684 cm- 1 in SA-treated samples, absent in native starch. Ultrasonically treated samples retained characteristic bands but showed reduced peak intensities, implying structural degradation. Rheological analysis revealed a viscosity reduction in samples with higher SA levels. Ultrasonicated samples displayed non-Newtonian flow behavior, with shear stress and shear rate showing a nonlinear relationship, especially at low shear rates. In summary, this study highlights the novelty of sequential SA complexation and ultrasonication in tailoring the functional, structural, and rheological characteristics of khesari pea starch, offering a potential approach to developing starch ingredients for food packaging, nutritional, and pharmaceutical applications.
The transition to a more environmentally friendly production has motivated the development of new food ingredients and processing. This research investigated the development of snack products based on sweet potato starch modified by heat-moisture treatment (HMT) and processed through compression molding. Native and modified starches were characterized by scanning electron microscopy, particle size analysis, color measurement, x-ray diffraction, Fourier transform infrared spectroscopy, moisture content, and water activity analyses. Snacks were formulated with starch (82.64%), honey (8.26%), curcumin (4.13%), and cinnamon (4.96%) and produced under different compression forces (1-5 t). Structural and physicochemical properties, mechanical behavior, and sensory acceptance were evaluated. HMT disrupted starch granules, producing larger amorphous aggregates and significantly reducing crystallinity. Snacks prepared with modified starch exhibited a more compact and homogeneous microstructure, lower thickness, and significantly higher shear strength (25-33 N) compared with those produced with native starch (5-10 N). Water activity values remained below 0.33, indicating good microbiological stability. Sensory evaluation demonstrated superior texture and overall acceptance for modified starch snacks. These results highlight HMT-modified sweet potato starch as a promising ingredient for developing compressed snack products with acceptable structural and sensory properties. Furthermore, the product was obtained through mechanical processing alone, without the use of synthetic additives, water, oils, or the generation of waste.
This study aimed to investigate the effects of microwave treatment on the functional, structural, thermal, and color properties of sweet potato starch to enhance its industrial applicability. Sweet potato starch was extracted using an alkali method and modified at microwave powers of 100, 300, 450, 600, and 900 W for 3 min at 50% moisture content, with native starch (T0) as the control. The modified starches were analyzed for color (L, a, b*), bulk density, tapped density, Hausner ratio, Carr's index, water absorption capacity (WAC), water solubility index (WSI), turbidity, FTIR, XRD, TGA, DSC, and SEM. Results showed that bulk density (0.46-0.54 g/ml) and tapped density (0.61-0.79 g/ml) remained nearly unchanged, while Hausner ratio decreased from 1.49 (T0) to 1.25 (T3), and Carr's index improved from 32.08% to 17.54% (T4), indicating better flowability. WAC increased from 1.64 g/g (T0) to 2.46 g/g (T5), and WSI rose from 0.82 to 0.94 g/g, reflecting enhanced porosity. Lightness (L*) declined from 91.78 to 78.09, redness (a*) shifted from negative (-0.22) to positive (4.15), and yellowness (b*) increased from 5.02 to 18.22. FTIR revealed broadened O-H peaks indicating structural disruption, TGA showed decreased thermal stability, DSC exhibited increased gelatinization enthalpy, and SEM revealed rough, pitted, and aggregated granule morphology. Microwave treatment significantly alters sweet potato starch properties, improving water interaction and flowability while reducing lightness and thermal stability, thereby broadening its potential in food and biodegradable material industries.
Type V resistant starch (RS5), produced through amylose-lipid complexation, provides important functional and nutritional benefits. However, its formation in rice cooked with coconut milk, a key component of Malaysia's nasi lemak, remains poorly understood. This study examined RS5 formation in three rice varieties of differing amylose levels (Commercial variety, UPM Putra 2, and NMR 152) cooked with and without coconut milk using steaming and boiling. The most significant findings show that amylose level and cooking method strongly influenced complex formation. Although Commercial variety contained 26.38 +/- 1.52a highest amylose content, the medium-amylose UPM Putra 2 with amylose 21.50 +/- 0.62b unexpectedly exhibited the highest complexing index under both steaming (30.39% +/- 0.45%) and boiling (26.01% +/- 0.19%). Steaming consistently produced higher complexing indices than boiling across all rice types, demonstrating its superior efficiency in promoting amylose-lipid interactions. Thermal analysis showed that samples cooked with coconut milk displayed a characteristic high-temperature dissociation peak (118 degrees C-131 degrees C), demonstrating amylose-lipid complex presence. Commercial variety exhibited the highest enthalpy values during complex dissociation in both steaming (104.05 +/- 1.87 J/g) and boiling (38.20 +/- 1.39 J/g), indicating greater thermal stability and suggesting that, despite its lower complexing index, it formed more stable complexes structurally. Notably, steamed samples with lipid consistently showed higher enthalpy changes than boiled samples. X-ray diffraction data revealed increased intensity at the 19.8 degrees peak in all rice samples cooked with coconut milk, suggesting RS5 formation. Commercial variety demonstrated the sharpest and most defined peak, reflecting higher crystallinity and a more ordered starch-lipid structure. Overall, the study demonstrates that coconut milk enhances RS5 formation in white rice, with steaming outperforming boiling in promoting amylose-lipid complex development. While medium-amylose rice showed the highest complexing index, high-amylose rice produced the most thermally and structurally stable complexes. These findings offer practical implications for optimizing rice preparation to improve functional and nutritional qualities in traditional and modern food applications.
Potato peels were valorized as a sustainable starch source for the development of functional materials such as bioplastics. Starch was extracted from potato peels (18.75% yield), and subsequently modified via dodecenyl succinylation and acetylation to obtain dodecenyl succinylated starch (degree of substitution (DS) 0.021), acetylated starch (DS 0.67), and two dual-modified starches with a fixed dodecenyl succinate DS of 0.021 and acetyl degrees of substitution of 0.52 and 1.94. Morphology of derivatives differed structurally relative to native starch with FTIR spectra showing new peaks at 1735, 1435, 1370, and 1215 cm-1, indicating successful esterification reactions. Furthermore, x-ray diffraction showed a shift of the typical B-type crystallinity toward amorphism with increasing degree of acetylation. Thermogravimetric analysis revealed the dual-modified starch with acetyl DS of 1.94 as the most thermally stable with thermal degradation temperature of 325 degrees C, while differential scanning calorimetry (DSC) revealed it as the only derivative with glass transition temperature (152.5 degrees C). Pasting properties were recorded to change significantly with increasing degree of acetylation, with the dual-modified starch with high degree of acetylation exhibiting a complete loss of pasting behavior. These findings demonstrate that esterification reactions could impart distinct functionalities to potato residues which could be further utilized for tailored applications in biobased material development.
