Effects of Lactobacillus plantarum fermentation on the structure, physicochemical properties, and digestibility of foxtail millet starches.

This study investigated the effects of Lactobacillus plantarum fermentation on the structural, physicochemical, and digestive properties of foxtail millet starches. The fermented starch granules formed a structure with honeycomb-like dents, uneven pores, and reduced particle size. As the fermentation time extended, the amylose content of waxy (0.88 %) and non-waxy (33.71 %) foxtail millet starches decreased to the minimum value at 24 h (0.59 % and 29.19 %, respectively), and then increased to 0.85 % and 31.87 % at 72 h, respectively. Both native and fermented foxtail millet starches exhibited an A-type crystal structure. Compared with native samples, the fermented samples performed enhanced proportion of short-branched chain, crystallinity, and short-range ordered degree. After fermentation for 24 h, the solubility, adsorption capacity, and pasting viscosity of foxtail millet starches improved, whereas the swelling power, pasting temperature, breakdown, setback, and degree of retrogradation reduced. Additionally, fermentation increased the transition temperatures, enthalpy, and digestibility. Overall, Lactobacillus plantarum fermentation is considered a competent choice to regulate the characteristics of foxtail millet starch.

Preparation and characterization of non-crystalline granular starch with low processing viscosity.

Non-crystalline granular starch (NCGS) has advantages in the deep processing of starch owing to its unique structure and function. In this study, NCGS was successfully prepared at a baking temperature of 210 °C, and the morphology, structure, pasting properties, and rheological properties of the NCGS were systematically studied. Compared with native starch, NCGS showed a lower processing viscosity and rapid reduction in the peak viscosity from 3795 to 147 cP. Furthermore, NCGS exhibited impaired short- and long-range ordered structures, as indicated by the lower ratio of absorbance at 1047/1015 cm-1 and decreased crystallinity compared to native starch. Additionally, amylose and amylopectin with long and medium chains in NCGS were degraded into short chains, resulting in an increase in amylose content and branch density. The analysis of the physicochemical properties of NCGS, especially the low processing viscosity, is of great importance for the industrial application of starch, particularly in terms of improving the yield, saving energy, and reducing environmental pollution.

Properties and digestibility of a novel porous starch from lotus seed prepared via synergistic enzymatic treatment.

The objective was to investigate the effect of synergistic enzymatic treatment on the properties and digestibility of a novel C-type lotus seed porous starch (LPS). Scanning electron microscopy showed that the densest and most complete pores were formed on the surface of LPS when the concentration of enzymes added was 1.5% (LS-1.5E). With increases in enzyme addition, the oil and water absorption of the porous starch increased and reached maxima at 1.5% of enzyme. Increased in the specific surface area, total pore volume and average pore diameter of LPS were determined by low-temperature nitrogen adsorption, while when the enzymes exceeded 1.5%, there were no significant changes. Compared to lotus seed starch (LS), the particle size of LPS also decreased. With the increases in enzyme addition, LPS exhibited higher relative crystallinity and ordering structure by XRD and FTIR. The results by SAXS confirmed that LPS had higher ordered semi-crystalline lamellar and denser lamellar structure compared to LS. Low-field 1H NMR spectroscopy indicated that the proportion of bound water in LPS increased, while the proportion of bulk water decreased. Moreover, the degree of hydrolysis of LPS was lower than that of LS, and the content of rapidly digestible starch decreased, while the content of slowly digestible starch and resistant starch increased with the enzyme addition, which was consistent with the structural properties.

Effect of palm wax on the mechanical, thermal, and moisture absorption properties of thermoplastic cassava starch composites.

Thermoplastic starch is a potentially sustainable and biodegradable material. However, it possesses some limitations in terms of mechanical performance and high moisture sensitivity. In this current work, the characteristics of thermoplastic cassava starch (TPCS) containing palm wax at various loading were evaluated. TPCS was prepared via hot pressing by varying the ratios of palm wax (2.5, 5, 10, and 15 wt%). Next, characterization via scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), mechanical, water solubility, thickness swelling and moisture absorption tests, were conducted on the samples. The findings showed that incorporating starch-based thermoplastics with palm wax has remarkably improved mechanical characteristics of the thermoplastic blends. Besides, the morphology of the samples demonstrated irregular and rougher cleavage fracture after palm wax addition. FT-IR indicated the existence of intermolecular interaction between TPCS and palm wax with the intermolecular hydrogen bonds that existed between them. The thermal stability of TPCS has improved with rising palm wax content. The incorporation of 15 wt% palm wax resulted in the lowest moisture absorption value among the samples. Overall, the developed TPCS/palm wax with improved mechanical and moisture resistance characteristics has the potential to be used as biodegradable materials.

Simple thermal and freezing treatments to improve absorption capacity and alter digestibility of canna starch granules.

Swollen canna starches (SCS) were prepared by controlled heating of unmodified and heat-moisture treated (HMT) starch suspensions at sub-gelatinization temperatures; subsequently, freezing was conducted to stabilize the structure of the SCS. Sizes of both unmodified and HMT swollen granules increased with increasing heating temperatures (up to 2.5 times), and freezing resulted in a significant reduction of granular size. The absorption capacities of the swollen starches increased up to 6 times for water and 3 times for tributyrin and palm oil compared to unmodified starch. The differences in absorption capacities of the unmodified and HMT swollen starches were small. Freezing the swollen starches tended to decrease oil and water absorptions, except for unmodified starch swollen at 70 °C, where freezing increased water absorption. Freezing significantly decreased the susceptibility of the swollen unmodified starches to amylase digestion and slowed down the digestion of the swollen HMT starches.

Effects of Inca peanut seed albumin fraction on rheological, thermal and microstructural properties of native corn starch.

In this work, the effect of Inca peanut seed albumin fraction (IPA) on the rheological, thermal and microstructural properties of native corn starch (NCS) was firstly studied. Compared to the NCS, IPA addition could obviously decrease the transparency of NCS, and the transparency of NCS and NCS-IPA suspensions decreased during the storage time. The textural paraments of NCS pastes with or without IPA reached to the maximum at a concentration of 5%. Steady shear rheological tests showed that all systems were non-Newtonian fluid, and the consistency coefficient (K) values reached to the maximum at 5% IPA concentration. The storage and loss modulus values of NCS-IPA pastes were higher than those of NCS pastes, and curves of loss angle (tan δ) indicated that all pastes were typical weak gel. With the increasing addition of IPA, DSC analysis showed that the thermal properties (To, Tp and Tc) of NCS were significantly changed, whereas, there was no distinct difference in the enthalpy. Microscopy illustrated that there were some wrinkle shrinkage and severe folds on the NCS-IPA granules. Fourier-transform infrared (FT-IR) spectroscopy showed that the hydrogen bonding was primarily interaction forces between IPA and NCS molecules.

Insights into the correlations between the size of starch at nano- to microscale and its functional properties based on asymmetrical flow field-flow fractionation.

In this study, the starches were isolated from three botanical sources (i.e., rice, sweet potato, and lotus seed). The size distributions of starch granules and molecules were determined by asymmetrical flow field-flow fractionation (AF4), and compared with those measured from optical microscopy (OM) and dynamic light scattering (DLS). Furthermore, the starches were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). AF4 coupled online with UV-visible, multiangle light scattering (MALS), and differential refractive index (dRI) detectors (AF4-UV-MALS-dRI) was employed for the investigation of the digestion and retrogradation properties of starches. Meanwhile, the relationships between the size of starch at nano- to microscale and its functional properties (i.e., digestibility, retrogradation, and thermal properties) were studied by Pearson correlation analysis. AF4-UV-MALS-dRI was proved to be a rapid and gentle method for the separation and size characterization of starches at both micro- and nano-molecule levels. Moreover, it was demonstrated that AF4-UV-MALS-dRI is a useful tool for the monitoring of the digestion and retrogradation properties of starches. The results suggested that the sizes of starch granules and molecules were to some extent correlated with their thermal properties and digestibility, but not with retrogradation property.

Preparation and characterization of hyacinth bean starch film incorporated with TiO2 nanoparticles and Mesona chinensis Benth polysaccharide.

Hyacinth bean starch (HBS) was used to prepare nanocomposite films with the reinforcement agent of nanotitanium oxide (TiO2-N) and Mesona chinensis Benth polysaccharide (MCP). The effects of TiO2-N and MCP on the moisture combination, rheological properties of film-forming solutions (FFS) and physiochemical properties of films were investigated. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) revealed that HBS, TiO2-N and MCP had good compatibility, while no novel absorption peak in FTIR spectra, and characteristic peaks of TiO2-N were found in XRD patterns of composite films. Contact angle of HBS/TiO2-N/M3 film increased from 65.6° to 90.9°, which illustrated that TiO2-N and MCP effectively enhanced hydrophobicity of films. TiO2-N and MCP positively affected anti-UV light ability of HBS films by resisting most of invisible light. Furthermore, stable and compact network structures were formed by the synergistic effect of TiO2-N and MCP, thereby elongation to break was increased from 17.123% to 28.603% significantly, and heat resistance was enhanced clearly. This study prepared a nanocomposite HBS-based films based TiO2-N and MCP, which had guiding significance for development of functional films and combination of polysaccharides and metallic oxide.

Effect of wheat bran dietary fiber on structural properties of wheat starch after synergistic fermentation of Lactobacillus plantarum and Saccharomyces cerevisiae.

This study investigated the changes in the structure of wheat starch after synergistic fermentation of Lactobacillus plantarum and Saccharomyces cerevisiae at different wheat bran dietary fiber (WBDF) levels. The results showed that WBDF was slightly resistant to the decrease in acidity within the fermentation system. The amylose content decreased from 32.12% to 19.92% (P < 0.05), amylose/amylopectin ratio decreased from 0.47 to 0.25 (P < 0.05), and relative crystallinity decreased from 12.17% to 9.40% (P < 0.05) in the samples containing WBDF compared with the control. Scanning electron microscopy showed more eroded starch as the WBDF level increased. Fourier-transform infrared spectroscopy revealed a decrease in the starch-hydrogen binding absorbance in the 3600-3000 cm-1 wavemumber; and the 1047/1022 and 995/1022 cm-1 data indicated an increase in the degree of order and degree of double helix of the samples containing WBDF. The results of the study might help understand the interaction between dietary fibers and starch during fermentation and guide the production of fermented high-fiber flour products.

Corn starch modification during endogenous malt amylases: The impact of synergistic hydrolysis time of α-amylase and ß-amylase and limit dextrinase.

To expand the utility of barley malts and decrease the cost of enzyme-modified starch production, the structural and physicochemical characteristics of corn starch modified with fresh barley malts at different hydrolysis time were investigated. The results indicated that compared to native starch, A chain (DP 6-12) of the enzyme-treated starches increased at hydrolysis time (≤12 h), but it decreased at hydrolysis time (>12 h). Inversely, B chains (DP > 13) decreased at hydrolysis time (≤12 h) and they generally increased at hydrolysis time (>12 h). The relative crystallinity decreased from 25.63% to 21.38% and 1047 cm-1/1022 cm-1 reduced from 1.042 to 0.942 after endogenous malt amylases at hydrolysis time from 0 to 72 h, and the thermal degradation temperatures decreased from 323.19 to 295.94 °C, whereas the gelatinization temperatures slightly increased. The gel strength decreased at hydrolysis time less than 12 h, but it increased at hydrolysis time more than 12 h. The outcomings would provide a theoretical and applicative basis about how endogenous malt amylases with lower price modify starches to obtain desirable starch derivatives and industrial production.

Effects of microwave treatments and retrogradation on molecular crystalline structure and in vitro digestibility of debranched mung-bean starches.

The objective of this study was to investigate morphology, molecular crystalline structure, and digestibility of debranched mung bean starches with or without microwave treatment and retrogradation at different temperature. The mung bean starch was firstly debranched with pullulanase, and then the debranched starch containing 20% moisture content was treated by microwave irradiation for 3 min with or without further retrograded at +25, +4, or -18 °C for 24 h. All treated starches exhibited the B + V-type crystalline polymorph as determined by the XRD and the 13CNMR. The FT-IR results showed that the debranched starches had lower degree of order but higher degree of double helix than those of the native starch. The microwave treatment or further recrystallization of the debranched starch for more 24 h significantly improved crystalline structure of starch granules with higher degree of relative crystallinity, degree of order, and degree of double helices. The resistant starch content of the treated starch was in a range of 39.7-52.8%, significantly higher than that of the native starch (15.6%). As a result, the microwave-assisted debranched starch with further crystallization for 24 h was found to have highly ordered structure of granules, which highly resisted to the enzyme digestion.

Starch phosphate carbamate hydrogel based slow-release urea formulation with good water retentivity.

In this work, a novel starch phosphate carbamate hydrogel (SPC-Hydrogel) and its corresponding urea hydrogel (SPCU-Hydrogel) slow-release fertilizer (SRF) were prepared by one-step free radical copolymerization of SPC and acrylamide (AM) without and with urea addition. A series of characterization measurements including FTIR, XRD, EDS, XPS are utilized to confirm the successful formation of the SPC-Hydrogel. The SEM shows SPC-Hydrogel has a porous three-dimensional network architecture. Furthermore, SPC-Hydrogel matrix exhibits superior water absorbency achieving 80.2 g/g than that (70.5 g/g) of the native starch hydrogel (NS-Hydrogel) and desirable water retention capacity in soil with a weight loss of only 48% for 13 days. Compared with pure urea and NS based urea hydrogel (NSU-Hydrogel), the SPCU-Hydrogel releases 50.3% for 15 h, achieving an almost complete release more than 25 h in aqueous phase. While only 46.6% of urea is released in 20 days which extends about 30 days in soil column assays. The maize seedlings growth assays also present an intuitive evaluation on the prominent soil water holding and plant growth promotion role of SPCU-Hydrogel. In conclusion, the present work has demonstrated a novel strategy via preparing biomass hydrogel SRF to enhance the utilization effectiveness of fertilizer and retain soil humidity.

Anti-freezing starch hydrogels with superior mechanical properties and water retention ability for 3D printing.

As a novel material that can be used at subzero temperatures, anti-freezing hydrogels have been attracting extensive attention. Inspired by the freeze-tolerance phenomenon in seawater, which is achieved by mixing salts into water, an ionic compound (CaCl2) was used to gelatinize starch to form anti-freezing hydrogels. Native potato starch (NPS) anti-freezing hydrogels were formed at -10 °C, -18 °C, -30 °C, and - 50 °C with 6-9 kPa tensile strength and 100-230% elongation at break. The compressive stress of anti-freezing hydrogels at different environmental temperatures increased from 18.586 kPa to 36.551 kPa with the glass transform temperature of starch hydrogels dropped to -50 °C. The anti-freezing hydrogels showed excellent water retention ability, which could maintain a water content of 55% after 7 days at ambient temperature. The prototyping of anti-freezing starch hydrogels broadens the applications of starch in food, adhesives, medical materials, and intelligent materials.

Rice bran-based bioplastics: Effects of the mixing temperature on starch plastification and final properties.

The agro-food industry produces huge amounts of wastes and by-products with high levels of carbohydrates and proteins, basic food groups that, properly treated, can be employed for the development of bioplastics. These high added-value products represent an alternative to traditional polymers. In this research work, rice bran was mixed with glycerol and water obtaining homogeneous blends which then are processed into bioplastics via injection moulding. The mixing temperature aids starch plastification and thus, affects the properties of the final specimens. In this way, the mechanical characterization revealed improvements for the highest temperature (110 °C) used which, at the same time, exhibited poor physical integrity during water immersion. Although the mechanical properties of the dried system obtained at 80 °C are slightly inferior to those obtained for the non-dried 110 °C system, these specimens are considered more adequate since they exhibited higher physical integrity and, consequently, better operating conditions.

Effect of dual modification sequence on physicochemical, pasting, rheological and digestibility properties of cassava starch modified by acetic acid and ultrasound.

Dual modification of cassava starch was carried out using ultrasonication and acetylation by acetic acid by altering the sequence. The results revealed that the type of modification and sequence of modification for dual modified starches significantly affected the properties of starch. The swelling decreased for all the modified starches whereas solubility decreased for ultrasonicated starches but increased for acetylated starch and dual modified starch where acetylation was done after ultrasonication. The paste viscosities of all the modified starches were found to be significantly lower compared to native starch and the lowest viscosities were observed for dual modified starch where ultrasonication was done after acetylation. The resistant starch and slowly digestible starch content of the modified starches were significantly higher than in native starch, and the type of modification and sequence of modification for dual modified starches seemed to affect the digestibility of starches.

Comparative study on physicochemical properties of starch films prepared from five sweet potato (Ipomoea batatas) cultivars.

Five different sweet potato (Ipomoea batatas) cultivars (Daeyumi, Gogeonmi, Sincheonmi [SCM], Singeonmi, and Sinyulmi [SYM]) were used to extract sweet potato starch (SPS) for developing starch-based films. After the chemical composition and amylose contents of all SPSs were evaluated, the morphological, moisture, mechanical, and barrier properties of the SPS-based films were investigated. As one of the film characteristics, the X-ray diffractograms revealed that the SCM-based film with the highest amylose content (26.34%) had the highest relative crystallinity (24.31%). The SCM-based film also showed higher tensile strength (3.05-fold) and elastic modulus (2.38-fold) than the SYM-based film with the lowest amylose content (21.84%). The water vapor and oxygen permeabilities of the SPS-based films were negatively correlated with the amylose content. Thus, the SCM-based film was less permeable for water vapor (3.16-fold) and oxygen (1.81-fold) than the SYM-based film. These results demonstrated that the sweet potato cultivar, especially the amylose content, plays a significant role in determining the physicochemical properties of the SPS-based films.

Understanding the aggregation structure, digestive and rheological properties of corn, potato, and pea starches modified by ultrasonic frequency.

Corn starch (CS), potato starch (PtS), and pea starch (PS) were modified by ultrasonic frequency (codes as UFCS, UFPtS and UFPS), and changes in aggregation structure, digestibility and rheology were investigated. For UFCS, the apparent amylose content and gelatinization enthalpy (∆H) decreased, while the R1047/1022 values and relative crystallinity (RC) increased under lower ultrasonic frequencies (20 kHz and 25 kHz). For UFPtS, the apparent amylose content, R1047/1022 values and RC increased, while the ∆H decreased under a higher ultrasonic frequency (28 kHz). For UFPS, the apparent amylose content, R1047/1022 values, RC, ∆H decreased at 20 kHz, 25 kHz and 28 kHz. Cracks were observed on the surface of UFCS, UFPtS and UFPS. These aggregation structure changes increased the resistant starch content to 31.11% (20 kHz) and 26.45% (25 kHz) for UFCS and to 39.68% (28 kHz) for UFPtS, but decreased the resistant starch content to 18.46% (28 kHz) for UFPS. Consistency coefficient, storage modulus, and loss modulus of UFCS, UFPtS and UFPS increased, while the flow behavior index and damping factor decreased. Results indicated that CS, PtS and PS had diverse digestion and rheology behaviors after ultrasonic frequency modification, which fulfilled different demands in starch-based products.

Effects of degree of milling on the starch digestibility of cooked rice during (in vitro) small intestine digestion.

Effects of degree of milling on starch digestibility of cooked rice during (in vitro) small intestine digestion were investigated. By fitting starch digestograms to the logarithm of slope plot and combination of parallel and sequential digestion kinetics model, two starch fractions with distinct digestion rate constants were identified. Results from scanning electronic microscope and confocal laser scanning microscope showed that the rapidly digestible starch fraction (RDF) was mainly composed of gelatinized starch, while the slowly digestible starch fraction (SDF) was consisted of relatively intact starch granules, protein matrix encapsulated starch and starch-protein binary complex. The cooked rice with milling treatment had more loosely packed and larger network cells compared to that for brown rice. Consequentially, the RDF content was decreased, while that for SDF was increased by the milling treatment. These results could help the rice processing industry to develop healthy rice products with desirable starch digestibility.

The Fe3O4@apple seed starch core-shell structure decorated In(III): A green biocatalyst for the one-pot multicomponent synthesis of pyrazole-fused isocoumarins derivatives under solvent-free conditions.

In current decades, the fabrication and design of magnetic biocatalysts have been advancing as green catalysts. Hence, in this paper, we use the apple seed starch to create indium(III) immobilized on Fe3O4@apple seed starch core-shell magnetic nanocatalyst (Fe3O4@apple seed starch-In(III)). The prepared catalyst was identified and evaluated with several analysis techniques. The application of this catalyst in the synthesis of isochromeno[4,3-c]pyrazole-5(1H)-one derivates under solvent-free conditions was a new approach with high efficiency. Due to the magnetic nature of the catalyst, the catalyst separation from the reaction medium is easy, and it is reusable for five runs without significant change in catalytic activity. The fabrication of this catalyst is based on green chemistry principles and is more economical and stable than other catalysts in the synthesis of pyrazole-fused isocoumarins heterocyclic compounds.

Dynamic formation and transcriptional regulation mediated by phytohormones during chalkiness formation in rice.

BACKGROUND: Rice (Oryza sativa L.) Chalkiness, the opaque part in the kernel endosperm formed by loosely piled starch and protein bodies. Chalkiness is a complex quantitative trait regulated by multiple genes and various environmental factors. Phytohormones play important roles in the regulation of chalkiness formation but the underlying molecular mechanism is still unclear at present. RESULTS: In this research, Xiangzaoxian24 (X24, pure line of indica rice with high-chalkiness) and its origin parents Xiangzaoxian11 (X11, female parent, pure line of indica rice with high-chalkiness) and Xiangzaoxian7 (X7, male parent, pure line of indica rice with low-chalkiness) were used as materials. The phenotype, physiological and biochemical traits combined with transcriptome analysis were conducted to illustrate the dynamic process and transcriptional regulation of rice chalkiness formation. Impressively, phytohormonal contents and multiple phytohormonal signals were significantly different in chalky caryopsis, suggesting the involvement of phytohormones, particularly ABA and auxin, in the regulation of rice chalkiness formation, through the interaction of multiple transcription factors and their downstream regulators. CONCLUSION: These results indicated that chalkiness formation is a dynamic process associated with multiple genes, forming a complex regulatory network in which phytohormones play important roles. These results provided informative clues for illustrating the regulatory mechanisms of chalkiness formation in rice.