Thermal characterization of partially hydrolyzed cassava (Manihot esculenta) starch granules (original) (raw)
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Agronomia colombiana, 2022
Cassava starch is modified to increase porosity and lacerations that are limited when only enzymatic treatments are used. This study proposes to improve enzymatic activity of α-amylase and amyloglucosidase on the polymer chains of cassava starch by implementing physical and thermal pretreatments below the gelatinization temperature and before the hydrolytic process. The pretreatments increased the biocatalytic action of the enzymes, causing significant changes in the morphology of the granules, and superficial lacerations were found in samples of starches pretreated with ultrasound (UTS) or annealing and ultra-rapid freezing (ANN-C). At the structural level, the modified starches revealed substantial changes as the infrared spectra reflected a displacement of the absorption bands in the region from 900 to 1100 cm-1. This is associated with an alteration and reorganization of the amorphous and crystalline zones of the granules and is consistent with a decrease in amylose content (from 19.53% to 17.64%) and an increase in the crystallinity index. The thermal behavior of the starches was also modified by increasing the peak temperature (from 68.22°C to 75.38°C) and reducing the gelatinization enthalpy (from 19.34 to 15.79 J/g). UTS and ANN-C pretreatments significantly improved the mesoporous and hydrophilic properties of the modified cassava starches.
Thermal behaviour of corn starch granules under action of fungal α-amylase
Journal of Thermal Analysis and Calorimetry, 2008
Corn starch, partially hydrolyzed by fungal a-amylase was investigated by using thermal analysis, microscopy and X-ray diffraction. After enzymatic treatment lower degradation onset temperatures were observed. DSC analysis showed almost similar range of gelatinization temperature, however, the enthalpies of gelatinization increased for the partially hydrolyzed starch granules. According to the X-ray diffraction analysis, stronger cereal pattern peaks were recognized after enzymatic digestion. The results suggested that the hydrolysis was more pronounced in the amorphous part of the starch granules.
Starch extracted from cassava was subjected to chemical and enzymatic modification. Extracted native starch and modified starches were evaluated for proximate analysis and then assessed for different functional properties such as water-binding capacity, swelling power and solubility. Chemically and enzymatic modified starches recorded higher water-binding capacity i.e. 89.69% and 96.10% respectively and higher solubility 80.33% and 79.66% respectively as compared to native starch having the water-binding capacity 70.63% and solubility 25.18%. Scanning electron microscopy revealed round to polygonal in shapes with smooth surface for native starch and spherical to oval shaped granules for chemically modified starch. Enzymatic modified starch showed relatively rough surface, pores and cracks on surface fissures. X-ray diffractograms showed typical ‘B’ for pattern native starch but in modified starches showed typical ‘A’ pattern comparatively reduced peak and covers a larger area. FT-IR Image of starch and modified starch showed the typical peaks for the starch backbone. The O-H (alcohol) stretching band in the region 3500–3000 cm-1 was found to be broadened and became less sharp, strong and broad in the spectra of the native and chemical modified starch, in comparison to that of the enzyme modified starch. Functional properties of starch such as water-binding capacity and solubility of starch granules increased by chemical and enzymatic modification.
Characterization of Fermented Cassava Starches
Journal of Food Biochemistry, 1993
Fermented and nonfermented cassava (Manihot utilissima Pohl) starchesfrom Colombia and Brazil were studied. l3e DSC themgrams obtained at high water contents (watecstarch 3.1 to 4.2) showed that starch fermentation decreased both the temperature of gelatinization (T m) and that offinal gelatinizm'on. No sign@cant differences were found between the enthalpies of gelatinization of fermented and non-fermented starches. Differences in AH corresponding to the first endothermic transition of fermented and nonfermented samples were detected at low water contents (water:starch 1.0 to 0.4). Pastes obtained with nonfermented starches were more viscous than those corresponding to fermented samples. l%is behavior could be related to the greater solubility of the femented samples, leading to a smaller size of hydrated granules.
Impact of Annealing on the Physicochemical Properties of Unfermented Cassava Starch (“Polvilho Doce
Starch-starke, 2004
Unfermented cassava starch (“polvilho doce”) was subject to annealing treatment at 50°C for 24, 48, 96, 120, 168 and 192 h, in 1:5 starch to water ratio. The annealing treatment changed the internal structure of “polvilho doce” at increasing treatment time. Peak viscosities decreased significantly, denoting that there was a decrease in leaching of amylose from the granules. The pasting temperatures were increased, setback and breakdown were reduced while hold and final viscosities increased, showing an improvement of the stability of the paste. Swelling power and solubility were reduced at all temperatures and the solubility at 55°C was zero after 120 h of treatment. The DSC data for To, Tp, Tc and ΔH increased and the gelatinization range was narrowed. The X-ray diffractograms changed from CA to A pattern (samples annealed for 48, 96, 120, 168 and 192 h), denoting an increase in organization of double helices of amylopectin. Annealing imparts to the samples some waxy starches characteristics which can be very useful in the food industry.
Cassava starches modified by enzymatic biocatalysis: effect of reaction time and drying method
Dyna-colombia, 2019
Currently, comes up the need to develop and produce modified starches that allow enhancing their applicability as additives in food industry. In this, the effect of biocatalysis time and type of drying (forced convection and vacuum drying) on the morphological, structural and pasting properties of enzymatically modified cassava starch granules was evaluated. The application of amyloglucosidase generated a degree of hydrolysis ranging between 35.87 and 41.02% dextrose equivalents (ED), in addition, it caused significant changes in starch granules morphology. At structural level, modified starch reveals substantial changes with respect to control, where FT-IR spectra show the displacement of absorption bands by tension or bending in the region between 900 and 1100 cm-1 due to the breakdown of α-Dglucosidic bonds α-D-(1,4) or α-D-(1,6), increasing swelling, absorption and solubility in water properties. Likewise, significant changes are reported in pasting properties together with an increase in stability in techno-functional properties of hydrolyzed starches dried by vacuum.
Carbohydrate polymers, 2017
The aim of this study was to determine and compare the melting (Tm), glass transition (Tg) and mechanical relaxation (Tα) temperatures of a new waxy cassava starch. Thermal transitions measurements were obtained by Differential Scanning Calorimetry (DSC) and Dynamical Mechanical Thermal Analysis (DMTA). The experimental data showed a high correlation between water volume fraction and melting temperature (Tm) indicating that the Flory-Huggins theory can be used to describe the thermal behavior of this starch. The Tm of waxy cassava starch-water mixes were lower than a waxy corn starch-water reference system, but differences were not statistically significant. The mechanical relaxation temperatures taken at tan δ peaks were found 29-38°C larger than Tg. The Tα and Tg measured for waxy cassava starch exhibited similar properties to the ones of waxy corn starch, implying that waxy cassava starch can be used in food and materials industry.
Effect of Physical and Chemical Modification on Characterization of Cassava Starch
A naturally occurring, inexpensive, renewable, and widely accessible polysaccharide molecule is starch. Native cassava (NCAS) was altered using conventional techniques (autoclaving and autoclaving/sonication/cross-linking). The treatments were designated as T1 (5% CC, 20 min ST), T2 (5% CC, 30 min ST), T3 (10% CC, 20 min ST), and T4 (10% CC, 30 min ST) based on the cross-linking agent concentration (CC) and sonication time (ST). Standard methods were used to examine the chemical, functional, starch digestibility, colour, and morphological aspects of modified starches. In comparison to native starches, modified cassava starches included less moisture, protein, and fat. In comparison to native starches, modified starches contained more ash, amylose, and resistant starch. Amylose and resistant starch levels were higher in T4 than in native and other treated samples in both cassava (51.34%). Native starch swelling power grew progressively from 40 to 90°C, whereas it increased for all modified starches up to 70°C before declining at 80 to 90°C. While modified starches became less soluble as the temperature rose, native starch became more soluble as the mercury rose. Native cassava starches were made up of granules that were rounded and uneven in shape. Furthermore, as shown in NCAS there were no glaring flaws or indications of damage on the surface of the native starch granule. After being autoclaved and dual modified, the starch's granular structure vanished. In modified starches, starch with rough surfaces, larger, and irregularly shaped structures were discovered. The L* value of native cassava starches was higher than that of modified starches. The resistant starch and amylose contents of T4 were higher than those of the other samples.
International Journal of Biological Macromolecules, 2020
This study evaluated the effect of amylases on the formation, and characteristics of retrograded starches using sweet potato (SPS), cassava (CAS) and high amylose maize (HAS) starches. The starches were gelatinized, hydrolyzed with fungal or maltogenic α-amylase, de-branched and retrograded. The modified starches were then analyzed for digestibility, chain size distribution, relative crystallinity and crystallite size, thermal properties and the proportion of double helices. CAS was the most susceptible and HAS the most resistant to the action of both enzymes. Amylolysis was efficient in forming resistant starch type 3 (RS3) and high levels (> 60%) were found for all starches. RS3 content was highly correlated with the proportion of chains with degrees of polymerization between 13 and 30 for all starches, especially for the root starches, while for HAS, the high amylose content and reduction in the size of amylose chains and very long amylopectin chains also deeply contributed for the RS3 formation. These sizes (DP 13-30) are best suited for the formation of a more crystalline, more perfect, and more strongly bonded structure, composed of larger crystallites, and with a higher concentration of double helices. High correlation coefficients were found between RS3, relative crystallinity, crystallites size, and enthalpy change.
Thermochimica Acta, 2013
Starch is arguably one of the most actively investigated biopolymer in the world. In this study, the native (untreated) cassava starch granules (Manihot esculenta, Crantz) were hydrolyzed by standard hydrochloric acid solution at different temperatures (30 • C and 50 • C) and the hydrolytic transformations were investigated by the following techniques: simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), as well as non-contact atomic force microscopy (NC-AFM), X-ray diffraction (XRD) powder patterns, and rapid viscoamylographic analysis (RVA). After the treatment with hydrochloric acid at different temperatures, the thermal stability, a gradual loss of pasting properties (viscosity), alterations in the gelatinization enthalpy (H gel), were observed. The use of NC-AFM and XRD allowed the observation of the surface morphology and topography of the starch granules and changes in crystallinity of the granules, respectively.