Decrease In Relative Crystallinity Research Articles

Synthesis, optimization, and characterization of precipitation derived starch nanoparticles from guinea seeds

Guinea starch nanoparticles (GS-SNP) were developed using ultrasound and nanoprecipitation techniques. The physicochemical, thermal, structural, morphological, pasting, and rheological properties of GS-SNP were examined and compared with native starch. The particle size of GS-SNP was 391.50–206.00 nm, with a PDI of 0.35–0.23 and a zeta potential of −37.5 to −13 mV. The amylose content of GS-SNP increased with a decrease in relative crystallinity, and a VH-type crystalline structure was observed. The GS-SNP were in round shape with some self-aggregated granules. The water and oil absorption capacity, solubility, and gelatinization temperature of GS-SNP increased, but the swelling power was restricted. The viscosity of the GS-SNP dispersion remained almost constant throughout the heating but slightly increased after cooling. A higher degree of shear thinning was observed due to a fluid-like gel network and weak gel structure. The optimum conditions were: 50 % amplitude, 30 min time, and a starch to ethanol ratio (1:4) with 85 % maximum desirability. Overall, the findings suggest that GS-SNP have promising potential for application in a liquid system where viscosity of the system cannot be significantly influenced by temperature.

The impact of parboiling on physical structure, physicochemical properties and zinc status of Zn-fortified germinated brown rice

The structural and physicochemical properties, cooking quality and zinc retention ratio of Zn-fortified germinated brown rice were investigated with different parboiling times (4–20 min). The brown rice grains exhibited visually more yellowish-brown colour and cracks on the surface with the germination and longer parboiling, and the micrographs clearly displayed wrinkles after these processes. Germination and the increase of parboiling time exacerbated the disruption of microstructure and the decrease in relative crystallinity and enthalpy change. The relaxation time (T2) increased in Zn-fortified germinated brown rice and parboiled samples compared to brown rice. Cooking time of Zn-fortified germinated brown rice was reduced from 36 min to 27 min with longer parboiling. Parboiling treatment longer than 4 min improved the palatability. There was no significant difference of Zinc retention ratio at different parboiling times. Sixteen min parboiling was recommended to obtain the brown rice product, which requires a short cooking time with desired palatability, as well as acceptable colour and zinc content. Overall, parboiling is an effective technique to modify the physical structure and physicochemical properties and improve cooking quality of Zn-fortified germinated brown rice.

Impact of cyclic and continuous dry heat modification on the structural, thermal, technological, and in vitro digestibility properties of potato starch (Solanum tuberosum L.): A comparative study

Dry heat treatment (DHT) has been demonstrated as a viable method for starch modification, offering benefits due to its environmentally friendly process and low operational costs. This research modified potato starch using different DHT conditions (continuous-CDHT and cyclic-RDHT), with durations ranging from 3 to 15 h and 1 to 5 cycles, at 120 °C. The study investigated and compared the structural, thermal, pasting, and morphological properties of the treated samples to those of untreated potato starch, including in vitro digestibility post-modification. DHT altered the amylose content of the biopolymer. X-ray diffraction patterns transitioned from type B to type C, and a decrease in relative crystallinity (RC%) was observed. Morphological changes were more pronounced in starches modified by RDHT. Paste viscosities of both CDHT and RDHT-treated starches decreased significantly, by 61.7 % and 58.1 % respectively, compared to native starch. The gelatinization enthalpy of RDHT-treated starches reduced notably, from 17.60 to 16.10 J g−1. Additionally, starch digestibility was impacted, with cyclic treatments yielding a significant increase in resistant starch content, notably an 18.26 % rise. These findings underscore the efficacy of dry heat in enhancing the functional properties of potato starch.

Industrial crude bioethanol dehydration to ethylene: Doping ZSM-5 to enhance selectivity and stability

Although the conversion of bioethanol into light olefins is one of the most studied processes in biorefinery schemes, there is a need to develop materials more capable of operating at industrial conditions (WHSV > 20 h−1 crude bioethanol feed). Hence, in this study, we dehydrated crude bioethanol samples derived from sugarcane fermentation to produce ethylene over a series of H-ZSM-5 zeolites. Among them, H-ZSM-5 with different Si/Al ratios (26, 280, and 371) and doped with Ce and Cu were tested on the catalytic activity and stability. Accordingly, a 26 Si/Al ratio showed full conversion and ethylene selectivity at 300 °C with a WHSV of 30.2 h−1. When doping the zeolites, a decrease in relative crystallinity and a higher amount of acid sites were observed, which affected the interaction with reactants. This interaction was deeply analyzed by the in-situ DRIFTS, which showed that ethanol adsorption is lower for doped zeolites, but the desorption rate is higher, showing higher stability over longer reaction times. Therefore, the H-ZSM-5 with a Si/Al ratio of 26 and doped with Ce maintained its activity and improved its selectivity over 140 h under more drastic conditions of WHSV (42.3 h−1). These results elucidate that Ce-doped H-ZSM-5 zeolites can improve stability and represent a starting point for large-scale crude bioethanol conversion.

The structural and functional properties of a novel enzyme-modified starch as an alternative to hydroxypropyl starch ether

To expectedly replace chemically modified starch, β-amylase (BA) combined with hexose oxidase (HOX) were used to modify sweet potato starch by oxidizing starch chains. The results showed that BAHOX-treated starch had an increase in A chain and a decrease in relative crystallinity as compared to native starch. Peak viscosities of BAHOX6 (4433 mPa s) and BAHOX12 (4303 mPa s) were higher than that (4118 mPa s) of hydroxypropyl starch ether (HPS). With increasing shear rate, shear viscosity of BAHOX12 showed a slower decrease as compared to HPS at 90 °C, indicating BAHOX12 had a stronger heat and shearing resistance. With decreasing from 90 to 20 °C, the viscosity change (1069.9 mPa s) of BAHOX12 was smaller than that (1427.2 mPa s) of HPS at a constant shear rate (150 s−1), indicating BAHOX12 had a higher viscosity stability in the alternating heat and cold. Compared to HPS, all the BAHOX-treated starches had higher freeze-thaw stability and transparency. The outcome would provide a foundation of theory and application for exploring a novel and green enzyme-modified starch with higher added value, higher performance, higher stability and environmental protection.

Effect of microwave and hot air radiofrequency treatments on physicochemical and functional properties of foxtail millet flour and its protein isolate

The current study investigated the impact of microwave (MW) and hot-air assisted radiofrequency (HARF) technologies on physicochemical characteristics of foxtail millet (FM) flour. Besides, the physicochemical characteristics of foxtail millet protein (FMP) from MW and HARF treated FM flour were also evaluated. Residual relative lipase activity (LA) (10.86%) was least at 15% moisture (w.b.) for two passes-28 min treatment in HARF, while the MW heating showed lower LA at 786.80W power level for 6 min (0.27%) and 4 min (8.17%). Peak viscosities of MW and HARF treated FM flour exhibited a decreasing trend compared to untreated. An increase was observed in emulsifying, and oil/water absorption properties of MW and HARF treated FMP in comparison with the untreated sample, while it was vice versa with the foaming properties, and protein purity. This changes can be attributed to the decrease in relative crystallinity and modifications in the secondary structural elements (i.e., increase in β-turn, and decrease in α-helix, β-sheets), as confirmed by FTIR and XRD analyses performed.

Effect of Citric Acid Modification on Physio‐Chemical, Structural, Rheological, Thermal Properties, and In Vitro Digestibility of Amaranthus paniculatus (Rajgeera) Starch

AbstractIn this study, starch is treated with different concentrations of citric acid (CA, 5, 10, 20, and 30 g/100 g dry basis) which leads to the production of citrate starch. The effect of CA concentration on physio‐chemical, structural, rheological, thermal properties, and digestibility is analyzed. A Fourier transform infrared (FTIR) spectroscopy Stands for FTIR peak at 1728 cm−1 is observed, indicating ester bond formation between CA and starch molecules. A nonsignificant change in the crystalline pattern is observed between native and citrate starch, whereas a decrease in relative crystallinity from 15.75% to 6.91% is observed. With the increase in the degree of substitution, gelatinization decreases, and gelatinization's enthalpy (ΔH) decreases from 13.72 to 9.63 J g−1. The rapid digestible starch (RDS) decreases by CA treatment, whereas slow digestible starch (SDS) and resistant starch (RS) increase significantly from 32.81 g/100 g dry basis to 39.45 g/100 g dry basis and 9.87 g/100 g dry basis to 25.26 g/100 g dry basis, respectively.

Mechanism of feed moisture levels in extrusion treatment to improve the instant properties of Chinese yam (Dioscorea opposita Thunb.) flour

Extruded yam flour was prepared at different feed moisture to improve its instant properties. The water solubility index (WSI) and water absorption index (WAI) were used to compare the instant properties of yam flour. Their chemical compositions, particle size distribution, crystalline structure, and microscopic forms were also analyzed to assess the effects of feed moisture on the instant properties of yam flour. We found that extrusion significantly improved the instant properties of yam flour, while the WSI value increased from 29.50% to 71.86% and the WAI value decreased from 387.88% to 228.06% with decreased feed moisture. Extrusion led to the degradation of total starch and amylopectin, and the contents of soluble substances increased markedly. Extrusion destroyed the granular and crystalline structures, which were reconstituted as amylose–lipid complexes with a significant decrease in relative crystallinity. Increasing the feed moisture was beneficial to the flow and color retention, while lower feed moisture was more favorable to enhance the instant properties.

Impact of microwave and germination on physicochemical, functional properties, and solubility of black rice powder

AbstractBackground and ObjectivesBlack rice is limited due to factors such as low solubility, difficulty to disperse, and high viscosity. The aim of the study is to overcome these shortcomings and improve their practicability in various industrial applications. The effects of germination and microwave on the physicochemical, functional properties, and solubility of black rice powder were compared.FindingsThe effect of germination improved the GABA contents, increased the solubility and starch digestibility, which was consistent with the decrease in relative crystallinity and porous surface structure, and the increase in the gelatinization enthalpy. Microwave increased the solubility and starch digestibility of black rice powder. Total polyphenol content was increased by microwave compared to untreated and germinated black rice. The type of starch showed no significant effect in single and dual treatment. The combined treatment enhanced the GABA content, reduced the loss of polyphenols, anthocyanins and improved its solubility, physicochemical characteristics.ConclusionThe results might help understand the mechanism of germination and microwave treatments influencing the structural properties of starches and contribute to better‐developing products based on black rice flour.Significance and NoveltyThe association treatment increased GABA content, the solubility, and nutrition of black rice flour, but reduced the digestibility of black rice flour.

Comparative study on bread quality and starch digestibility of normal and waxy wheat (Triticum aestivum L.) modified by maltohexaose producing α-amylases

It is highly desirable to produce bread with both acceptable texture and health benefits. In this study, maltohexaose (G6) producing amylase AmyM and its truncation AmyM-TR2 from Corallococcus sp. strain EGB were used to determine their effects to bread quality and starch physicochemical properties. During bread fermentation, AmyM or AmyM-TR2 continuously degraded the starch, resulting in more obvious decrease in relative crystallinity, the ordered structure, pasting viscosities and gelatinization enthalpy of starch than in control. The dough treated with AmyM or AmyM-TR2 increased bread volume and slowly digestible starch content, decreased bread hardness, and extended bread shelf life and as compared with control, and the dough treated with AmyM-TR2 had better improvement effects than AmyM. The volume and slowly digestible starch content of bread from the treatment of AmyM-TR2 increased by 9.74% and 7.56% in normal wheat, 1.42% and 10.28% in waxy wheat as compared with AmyM, respectively. AmyM-TR2 affected the substrate targeting, proximity and structure disruption effects, which contributed to the degradation of more starch than AmyM.

Effect of multipin atmospheric cold plasma discharge on functional properties of little millet (Panicum miliare) flour

The effect of multipin electrical discharge atmospheric cold plasma treatment on functional properties of little millet flour was investigated for value addition to this millet. Millet flour was treated at two different powers of 13 and 24 W with exposure for 10 min, 20 min and 30 min. Water and oil absorption capacity, swelling capacity, solubility index, least gelatinization concentration, color, viscosity, dispersibility, bulk and true densities of the control and plasma treated flour were studied. Plasma treatment was observed to enhance the functional properties of the millet flour, whilst the physical properties remained unchanged. The microstructure of the millet flour showed breakdown of starch granules, while the diffractograms revealed a decrease in relative crystallinity due to depolymerization of starch caused by the action of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in cold plasma. Overall plasma treatment can be explored for development of a process to enhance functionality of millet flour for applications in food systems.

Understanding how different modification processes affect the physiochemical, functional, thermal, morphological structures and digestibility of cardaba banana starch

In this study, starch was isolated from cardaba banana starch and was subjected to modification by heat-moisture treatment, citric acid, octenyl succinic anhydride, and sodium hexametaphosphate. Both the native and modified cardaba banana starches were examined for chemical, functional, pasting, thermal, morphological, structural, and antioxidant properties, as well as in vitro starch digestibility. Modification significantly influenced the properties of the cardaba banana starch. Cross-linking treatment improved the water, oil absorption, alkaline hydration capacity, swelling power, solubility and paste clarity of the starch. The final viscosity of the banana starch paste was increased alongside succinic anhydride modification which in turn enhanced the suitability of the starch in the production of high viscous products. Both FTIR spectra and X-ray diffractograms confirmed the starch had a C-type starch which was not affected by modification. Modification led to a decrease in relative crystallinity of the starch with succinylation having the maximum effect. The starch fractions; both SDS and RS significantly increased due to modification while the hydrolysis and glycemic index of the starch were significantly decreased by chemical modification. In conclusion, both physical and chemical modification of cardaba banana starch produced a starch that can serve as functional food or functional food ingredients.

Influence of ultrasound and microwave treatments on the structural and thermal properties of normal maize starch and potato starch: A comparative study

The effects of ultrasound and microwave on the physicochemical properties of normal maize and potato starches were compared. The cavitation effect of ultrasound loosened the internal space and destroyed the structure of starch granules, increased the damaged starch content, which was consistent with the decrease in relative crystallinity and the number and brightness of Maltese crosses, and the increase in D(0.5) and D(4,3) values. Microwave vibrated the molecules inside the granules and generated heat to destroy the structure of starch. The content of damaged starch was significantly lower in microwave-treated starch compared with ultrasound-treated starch. Microwave treatment promoted the formation of amylose–lipid complex, with the larger peak area at 20°(2θ) than that of the ultrasound-treated starch. The type of starch and the treatment sequence showed a significant effect. The results might help understand the mechanism of ultrasound and microwave treatments influencing the structural properties of starches.

Effect of Heat-Moisture Treatments on Digestibility and Physicochemical Property of Whole Quinoa Flour.

The starch digestion processing of whole grain foods is associated with its health benefits in improving insulin resistance. This study modified the digestibility of whole quinoa flour (WQ) via heat-moisture treatment (HMT), HMT combined with pullulanase (HMT+P), HMT combined with microwave (HMT+M), and HMT combined with citric acids (HMT+A), respectively. Results showed that all the treatments significantly increased (p < 0.05) the total dietary fiber (TDF) content, amylose content, and resistant starch (RS) content, however, significantly decreased (p < 0.05) the amylopectin content and rapidly digestible starch (RDS) content of WQ. HMT+P brought the highest TDF content (15.3%), amylose content (31.24%), and RS content (15.71%), and the lowest amylopecyin content (30.02%) and RDS content (23.65%). HMT+M brought the highest slowly digestible starch (SDS) content (25.09%). The estimated glycemic index (eGI) was respectively reduced from 74.36 to 70.59, 65.87, 69.79, and 69.12 by HMT, HMT+P, HMT+M, and HMT+A. Moreover, a significant and consistent reduction in the heat enthalpy (ΔH) of WQ was observed (p < 0.05), after four treatments. All these effects were caused by changes in the starch structure, as evidenced by the observed conjunction of protein and starch by a confocal laser scanning microscope (CLSM), the decrease in relative crystallinity, and transformation of starch crystal.

Effect of High Pressure Treatment on Structural, Functional, and In‐Vitro Digestibility of Starches from Tubers, Cereals, and Beans

AbstractStarch from different sources (wheat, rice, corn, waxy corn, potato, sweet potato, and kidney bean) are subjected to high pressure treatment (HPT) at 300 and 600 MPa and are evaluated for changes in digestibility, structural, thermal, and pasting properties. HPT alters the surface of starch granules and significantly disrupts morphology of granules. Increase in average granule size and decrease in relative crystallinity is observed in high pressure treated starches. However, a significant decrease average granule size is observed at 600 MPa. High pressure treated starches show progressive reduction in both swelling power and solubility with increase in pressure. HPT results in reduction in gelatinization temperatures and enthalpy of gelatinization (ΔHgel) while starches except potato starch treated at 600 MPa do not show any endothermic peak indicating complete destruction of crystalline structure. Peak and final viscosity of native starches is higher than those of their counterpart high pressure treated starches except waxy corn starch. Increase in gel firmness and destruction of internal structure of starches especially that of tuber starches treated at high pressures is observed. HPT lowered rapidly digestible starch fraction and increased slowly digestible starch and resistant starch fraction.

Effects of tamarind seed polysaccharide on physicochemical properties of corn starch treated by high pressure homogenization

High-pressure homogenization (HPH) and Tamarind seed polysaccharide (TSP) are usually used to change structure and properties of native starch. In this study, native corn starch was treated by HPH at 0, 40, and 80 MPa, respectively, and physicochemical properties of the treated corn starch in the presence of TSP were analyzed. Results showed that TSP molecules interact with the high-pressure homogenized corn starch (40 MPa) to increase viscosity, thermal and freeze-thaw stability, and elasticity of starch paste, and limit starch digestion. After gelatinization, the homogenized starch formed a sponge-like network and stable gel with TSP inclusion. This resulted in a decrease in relative crystallinity from 6.77% to 3.22% (40 MPa treated starch with TSP inclusion) during the retrogradation process. This study showed that the addition of TSP to HPH treated corn starch can improve the thermal and freeze-thaw stability of the gel and delay the digestion and retrogradation of the starch.

Effects of heat–moisture treatment conditions on the physicochemical properties and digestibility of field bean starch (Vicia faba var. minor)

In the presented study, starch of two cultivars of field bean was modified via the heat-moisture treatment (HMT) at various moisture contents (15 and 30%) and temperatures (100 and 120 °C) to determine HMT effect on its physicochemical properties and digestibility. Non-modified (NM) starches showed only slight variation in properties, with the tested varieties differing only in slowly digestible starch (SDS) and resistant starch (RS) content. The HMT was shown to decrease the swelling power and amylose leaching and higher phase transition temperatures and wider gelatinization temperature ranges in all modification conditions. These effects were caused by changes in the starch structure, as evidenced by the observed the decrease in relative crystallinity. The changes were the most pronounced in the starches treated at the higher moisture level. The HMT modification modified also starch digestibility. The total content of SDS and RS in non-gelatinized HMT starches modified at 15% moisture content was higher than that determined in the starch modified at 30% moisture content. In most gelatinized HMT starches, the SDS content decreased and that of RS did not change significantly compared to the native starch. Despite modified physicochemical properties, those starches still represent a good source of resistant starch.

English

This study compared the structural and rheological properties of native (GB0), 12 h (GB12), 24 h (GB24), 36 h (GB36), 48 h (GB48) and 72 h (GB72) germinated glutinous brown rice starch to improve the market value of glutinous rice through germination. The proportion of A chains (DP 6-12) increases and the proportion of B1 chains (DP 13-24) decreased with germination time. Interestingly, we observed that the total proportion of B2 and B3 chains decreased, but was recovered after germination at 36 h. The effect of germination on the distribution of amylopectin length results in a decrease in relative crystallinity, gelatinisation temperature, gelatinisation enthalpy and pasting viscosities. In this study, we found that GB12 starch gel has the weakest thermal stability and its shear resistance is more difficult to retrogradation; while GB36 has the highest chain association (retrogradation) which is induced by cooling. Key words: Glutinous brown rice, germination, starch, structural properties, rheological properties. &nbsp;

Effect of Controlled Hydrothermal Treatments on Mung Bean Starch Structure and Its Relationship with Digestibility.

The changes in structure and digestion properties of mung bean starch due to hydrothermal treatment at various controlled temperatures were investigated. Results showed the increase in onset temperature (To) from 66.33 °C to 76.69 °C and decrease in enthalpies (∆Hg and ∆Hr) until the starch was completely gelatinized. The degree of molecular order (DMO) and degree of double helix (DDH) were significantly (p < 0.05) reduced from 1.35 to 1.01 and 1.38 to 0.98 respectively. X-ray diffraction (XRD) indicated the consecutive decrease in relative crystallinity (RC) while RVA analysis showed that peak and final viscosities were decreased significantly (p < 0.05). However, digestion kinetics indicated that degree of gelatinization increased the access of enzymes. As starch was partially gelatinized it yielded significantly lower glycemic index but no significant (p > 0.05) change in starch digestibility was observed after 70 °C. Hence, 70 °C can be considered as the critical hydrothermal treatment temperature in mung bean starch. Pearson’s correlation analysis indicated that controlled hydrothermal treatment had negative effect on the DMO, DDH, RC and the granular damage increased vulnerability of mung bean starch to digestion. These findings gave insight into sequential changes in the structure and digestibility occurring during gelatinization process due to hydrothermal treatment. Controlled gelatinization in mung beans at 70 °C is useful and must be employed to produce the foods with lower starch digestibility.

Effect of γ-radiation on physico-chemical, morphological and thermal characteristics of lotus seed (Nelumbo nucifera) starch

Native and gamma (γ) irradiated lotus seed starches were studied for their physicochemical, thermal, pasting and morphological properties. Upon gamma irradiation of 5, 10, 15 and 20 kGy, amylose content of starches was decreased as the dose of irradiation was increased. Lotus seeds starch granules had bimodal size distribution varying in size from small to large. Observation under scanning electron microscope (SEM) showed that at low dose of irradiation (5, 10kGy), no significant changes were observed in shape and size. However, minor alterations were notice during treatment of 15kGy and 20 kGy, which included roughness. Irradiation significantly decreased the pasting properties (peak, trough, final and setback viscosities) of the starch. For native starch, To, Tp, and Tc of 137.44 °C, 138.29 °C and 143.21 °C and 169.51 °C, 169.72 °C, and 177.73 °C respectively was observed for first and second peak. Upon irradiation, the gelatinization temperatures were decreased. The irradiated starch showed no change in diffraction pattern compared to native lotus seed starch but a dose-dependent decrease in relative crystallinity was observed.