An attempt to cast light into starch nanocrystals preparation and cross-linking

Differences in the Chromogenic Effect of Corn Starch and Potato Starch on Paprika Red Pigment and Structural Characterisation

The present study aims to investigate the chromogenic effect and the interaction between starch-pigment complexes of corn starch (CS) and potato starch (PS) complexed with paprika red pigment. Compared to PS, CS showed 12.5 times higher adsorption capacity for paprika red pigment. Additionally, the a* value of CS-P (26.90 ± 0.23) was significantly higher than that of PS-P (22.45 ± 1.84), resulting in a corn starch-paprika red pigment complex (CS-P) with a more intense red colour. The addition of paprika red pigment significantly decreased the particle size and porosity of CS by 48.14 ± 5.29% and 17.01 ± 3.80%, respectively. Conversely, no significant impact on PS was observed. Additionally, the Fourier transform infrared (FT-IR) spectroscopy results revealed that the starch molecules and paprika red pigment were bound to each other through strong hydrogen bonds. X-diffraction (XRD) results indicated that the starch-paprika red pigment complexes have a V-shaped structure. Furthermore, the relative crystallinity of the complexes between starch and red pepper pigment showed an increasing trend, however, the relative crystallinity of CS increased significantly by 11.77 ± 0.99-49.21 ± 3.67%. Consequently, the CS-P colouring was good.

Insights into the interaction of CaCl2 and potato starch: Rheological, structural and gel properties

High viscosity of starch greatly limit its application in some specific foods, in this work, a novel low-viscosity potato starch (PS) was developed via crosslinking between PS (3 %, w/v) and Ca²⁺ to investigate the effect of CaCl₂ concentration (0.1-5 % CaCl₂, w/v) on the rheological behaviors, structural and gel properties of PS. The results showed that peak viscosity (PV), trough viscosity (TV), final viscosity (FV), and breakdown viscosity (BD) of pasting curves of CaCl₂-treated PS were significantly reduced compared with the native PS. The CaCl₂ treatment also decreased the firmness of the PS gel and increased its pasting temperature (PT) and gelatinization enthalpy (∆H). Moreover, The CaCl₂ treatment also led to more organized crystallites in the PS granules as affected by the slight increase in the ratio of 1044/1015 cm^-1 in the FT-IR analysis, reduced the homogeneity of ordered structures inside granules as indicated by the increase in conclusion temperature (T_c)-onset temperature (T_o) in DSC analysis, and decreased relatively crystallinity revealed by XRD analysis. The findings of this study indicated CaCl₂-treated PS could serve as food ingredients with reduced paste viscosity and regulated paste stability under shear during heating.

Water-in-water Pickering emulsions stabilized by the starch nanocrystals with various surface modifications

HYPOTHESIS

Using the platelet-like starch nanocrystals (SNCs) to stabilize emulsions is attractive because as-prepared emulsions have promising applications in cosmetics and food fields. Limited studies mainly focus on the oil-in-water system, and another important system, the water-in-water emulsions stabilized by SNCs, has not yet been unveiled.

EXPERIMENTS

Two surface modification strategies, crosslinking and acetylation, were applied to tune surface property and aggregation of SNCs, and a common all-aqueous system (dextran/poly(ethylene glycol)) was used here as template. The viscoelasticity and morphology of emulsions were studied in terms of the SNC loadings and polymer ratios.

FINDINGS

Crosslinking results in aggregation of SNCs, and the particle size increases (from 110 nm to 370 nm) with increased levels of substitution. This favors improving emulsifying ability of particles. Acetylation decreases the particle size (∼90 nm) and weakens the affinity of SNCs to the two aqueous phases, improving the emulsifying efficiency of SNCs. More intriguingly, the two emulsion systems show different phase inversion behaviors. The depletion-stabilization mechanism for the cross-linked SNCs and the diffusion-controlled mechanism for the acetylated SNCs are proposed using the emulsion viscoelasticity as probe. This study makes a comprehensive insight into the regulation of water-in-water emulsion morphology and types with the platelet-like SNCs.

Jin Shofu Starch Nanoparticles for the Consolidation of Modern Paintings

Matte, porous, and weakly bound paint layers, typically found in modern/contemporary art, represent an unsolved conservation challenge. Current conservation practice relies on synthetic or natural adhesives that can alter dramatically the optical properties of paints. Alternatively, we propose a novel nanostructured consolidant based on starch, a renewable natural polymer. We synthesized starch nanoparticles (SNPs) to boost their penetration into the porous painted layers; upon solvent evaporation, the particles were expected to adhere to the pigments thanks to their large surface area and abundant -OH groups. The SNPs were formulated through a bottom-up approach, where gluten-removed Jin Shofu wheat starch was gelatinized and then precipitated in a nonsolvent. The low gelatinization temperature of wheat starch is likely key to favor disassembly in alkali and reassembly in the nonsolvent. The synthesis conditions can be tuned to obtain amorphous SNPs of ca. 50 nm with acceptable polydispersity. The particles swell in water to form nanosized gel-like fractal domains (as observed with cryogenic electron microscopy), formed by the organization of smaller units in polymer-rich and -deficient regions. Aqueous and hydroalcoholic particles' dispersions were assessed on aged ultramarine blue mock-ups that mimic degraded modern/contemporary paints. The consolidation effectiveness was evaluated with a specifically designed in-house protocol: the SNPs distribute across the paint section and strongly increase pigments' cohesion while preserving the original optical properties of the painted layer, as opposed to dispersions of bulk starch that simply accumulate on the paint surface, forming superficial glossy films. The Jin Shofu SNPS proved to be a new promising tool for the consolidation of weakened paintings, opening perspectives in the formulation and application of consolidants for modern and contemporary art.

Preparation and characterization of cross-linked starch nanocrystals and self-reinforced starch-based nanocomposite films

In this study, starch-based nanocomposite films reinforced by cross-linked starch nanocrystals (CSNCs) were successfully prepared. CSNCs were obtained by cross-linking reaction between starch nanocrystals (SNCs) and sodium hexametaphosphate (SHMP). Through the characterization and comparison of SNCs and CSNCs in microscopic morphology, degree of substitution, swelling degree, XRD spectrum, and FTIR spectrum, the successful progress of the cross-linking reaction was confirmed. Besides, the effects of adding CSNCs on physiochemical properties of the nanocomposite films including mechanical properties, water vapor permeability, and contact angle were studied. The results confirmed that CSNCs had good enhancement effects on the physicochemical properties of starch-based films due to the self-reinforcing effect, and when the CSNCs content reached 10%, the nanocomposite film had the best overall performance. We further evaluated the cytotoxicity of the nanocomposite. Taken together, it is believed that the reported self-reinforced starch-based films are very promising for food packaging and preservation.

Nano based lutein extraction from marigold petals: optimization using different surfactants and co-surfactants

Nanotechnology has high potential in processing of industrial crops and by-products in order to extract valuable biological active compounds. The present study endeavored to take advantage of nanotech approach (i.e microemulsion, ME), as a novel green technique, for lutein extraction from marigold (Tagetes erecta) as an industrial crop. The pseudo-ternary phase diagrams confirmed the effect of surfactant type on the formation of mono-phasic lutein MEs. The combination of sucrose monopalmitate:1-poropanol (1:5) showed the highest efficiency in the presence of marigold petal powder (MPP, 18%) and water (42%). In addition, the efficiency of primitive MEs (without co-surfactants) was outstandingly increased as MPP was moistened by co-surfactants. Furthermore, different MEs resulted in various droplet size (14–250nm), PDI (0.05–0.32) and zeta potential (−1.96 to −38.50 mV). These findings revealed the outstanding importance of the surfactants and co-surfactants and their ratio on the extraction capability of MEs. These findings also proved the capability of microemulsion technique (MET) as a potential alternative to conventional solvent with possible applicability for extraction of lutein and other industrial plant based bio-compounds.

Optimization of bioactive preservative coatings of starch nanocrystal and ultrasonic extract of sour lemon peel on chicken fillets

Starch nanocrystal (S-NC) was produced after sulfuric acid hydrolysis of potato starch granules and then characterized by laser diffraction particle size analyzer, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Response surface methodology (RSM) was applied to optimize S-NC (2-10%) concentration, sour lemon peel extract (SLPE, 2.5-12.5%) amount, mixing temperature (M-TE, 25-65 °C) and mixing time (M-TI,15-75 min) in the preparation of bioactive coating solutions to develop the high-quality chicken fillets during the cold-storage. The optimized conditions for achieving the highest DPPH inhibition percentage (89.14%), antibacterial activity (Staphylococcus aureus, 3.58-mm; Escherichia coli, 3.14-mm; Listeria monocytogenes, 2.31-mm and Salmonella enterica, 2.24-mm) and lightness value (77.82) and the lowest redness (6.69), yellowness (13.21) values and viscosity (27.5 mPa.s) were 4.0% S-NC, 5.62% SLPE, 51.17 °C M-TE and 43.29 min M-TI. Spraying the optimal coating solution on chicken fillets led to a significant improvement in their physicochemical, textural and sensory characteristics compared to the control during 12-day cold-storage.

Preparation and Characterization of Tadpole- and Sphere-Shaped Hemin Nanoparticles for Enhanced Solubility

Hemin is a potent iron supplement. A major limitation of the applicability of hemin is its extremely low aqueous solubility and bioavailability. The aim of this work is to prepare hemin nanoparticles with improved solubility. Transmission electron microscopic images showed that hemin nanoparticles with different initial concentrations of hemin (0.1 and 0.5 mg/mL) were tadpole-shaped (head of approximately 200 nm and tail of 100 nm) and sphere-shaped (50-100 nm), respectively. Moreover, hemin nanoparticles exhibited higher solubility than free hemin. The solubility of sphere-shaped nanoparticles was 308.2-fold higher than that of pure hemin at 25 °C. The hemin nanoparticles were stable in acidic conditions and displayed excellent thermal stability. These results suggested that hemin nanoparticles could serve as a potential iron supplement with potential applications in the food, biomedical, and photodynamic-photothermal therapy fields.

Preparation and characterization of essential oil-loaded starch nanoparticles formed by short glucan chains

Essential oils (EOs), including menthone, oregano, cinnamon, lavender, and citral, are natural products that have antimicrobial and antioxidant activities. However, extremely low water solubility, and easy degradation by heat, restrict their application. The aim of this work was to evaluate the enhancement in antioxidative and antimicrobial activities of EOs encapsulated in starch nanoparticles (SNPs) prepared by short glucan chains. For the first time, we have successfully fabricated menthone-loaded SNPs (SNPs-M) at different complexation temperatures (30, 60, and 90°C) by an in situ nanoprecipitation method. The SNPs-M displayed spherical shapes, and the particle sizes ranged from 93 to 113nm. The encapsulation efficiency (EE) of SNPs-M increased significantly with an increase in complexation temperature, and the maximum EE was 86.6%. The SNPs-M formed at 90°C had high crystallization and thermal stability. The durations of the antioxidant and antimicrobial activities of EOs was extended by their encapsulation in the SNPs.

Preparation and Characterization of Octenyl Succinic Anhydride Modified Taro Starch Nanoparticles

The polar surface and hydrophilicity of starch nanoparticles (SNPs) result in their poor dispersibility in nonpolar solvent and poor compatibility with hydrophobic polymers, which limited the application in hydrophobic system. To improve their hydrophobicity, SNPs prepared through self-assembly of short chain amylose debranched from cooked taro starch, were modified by octenyl succinic anhydride (OSA). Size via dynamic light scattering of OSA-SNPs increased compared with SNPs. Fourier transform infrared spectroscopy data indicated the OSA-SNPs had a new absorption peak at 1727 cm^-1, which was the characteristic peak of carbonyl, indicating the formation of the ester bond. The dispersibility of the modified SNPs in the mixture of water with nonpolar solvent increased with increasing of degree of substitution (DS). OSA-SNPs appear to be a potential agent to stabilize the oil-water systems.

Starch: State-of-the-Art, New Challenges and Opportunities

The chapter presents a brief account of various topics in starch-based blends, composites and nanocomposites, including structure–property relationships, preparation and characterization of starch nanocrystals, natural fibre-reinforced thermoplastic starch composites, applications of starch nanocrystal-based blends, composites and nanocomposites, chemically modified thermoplastic starches, outstanding features of starch-based hydrogel nanocomposites, fracture and failure of starch-based composites, application of starch-based nanocomposites in the food industry and effects of additives on the properties of starch.