Influence of fatty acid-esterified waxy maize starch type and concentration on stability and properties of oil-in-water emulsions

Interface behavior and emulsifying capacity of cow cockle starch: A candidate for stabilizing food-grade pickering emulsions

This study comprehensively characterized the interfacial behavior and emulsifying capacity of cow cockle starch (CS), both in its native form and following octenyl succinic anhydride (OSA) modification. By comparing with the most recognized quinoa starch (QS), CS showed promise as a superior alternative to QS as a particle stabilizer in food-grade emulsions. Although the microstructural similarity to QS, CS featured a smaller mean particle size of 1.39 μm and exhibited greater hydrophobicity, as evidenced by a contact angle of 19.4°. At equivalent levels of OSA substitution, OSA-modified CS (CS-OSA) displayed a lower critical concentration, a higher diffusion rate and a greater adsorption density compared to OSA-modified QS (QS-OSA), which facilitated quicker and denser adsorption on the droplet surface. Rheological analysis further revealed that the CS-OSA emulsion formed a stronger gel network than the QS-OSA emulsion. Consequently, CS-OSA emulsions demonstrated superior ionic, centrifugal, and storage stability compared to QS-OSA emulsions.

Fabrication and characterization of decanoyl chloride/curcumin-modified potato starch nanoparticles and the potential application in the stabilization of flaxseed oil-in-water Pickering emulsions

In the current study, gelatinized potato starch was modified by decanoyl chloride and curcumin via esterification and pH-driven method at two pH levels (pH 8 and 12), respectively, followed by precipitation and formation of anionic nanoparticles. The effects of modifications on the various properties of starch nanoparticles were investigated. A decrease in mean particle diameter and branching degree as well as an increase in product mass, fatty acid substitution degree (0.043 to 0.049), curcumin encapsulation efficiency (83.0 % to 86.7 %), and absolute zeta-potential value (-30.3 to -41.2 mV) were observed at pH 12 compared to pH 8. The starch esterification process was confirmed by FTIR and 1H NMR analyses. XRD results revealed changes in the crystallinity index and the crystal pattern from B-type in native starch to V-type in modified starch nanoparticles. Contact angle values of different modified nanoparticles ranged from 85.9° to 130.9°. Pickering emulsions with a mean diameter of 6.79 μm and a zeta-potential value of -30.5 mV were stabilized by decanoyl chloride/curcumin-modified starch nanoparticles. Bright-field microscopy and confocal Raman spectral mapping of Pickering emulsion droplets confirmed the adsorption of modified starch nanoparticles at the interfacial layer. Tailored particle size and hydrophobicity might provide potential advantages for tuning the properties of Pickering emulsions stabilized by these nanoparticles.

Insight into Oil-in-Water Emulsions Stabilized by Cross-Linked and Pregelatinized Starches: The Effect of Molecular Structure, Surface Activity and Proton Molecular Dynamics

Effective formation and stabilisation of emulsions while meeting high consumer requirements, including the so-called green label, is still a technological challenge. This is related to the multitude of emulsion destabilization mechanisms and the vastness of methods used to study them, which implies the need to develop an understanding of the phenomena occurring in emulsions. Commercial starch preparations obtained by physical and chemical modification were used to prepare model emulsions that were studied in terms of their stability. Native potato starch was the reference material. The analytical methods used included rheology, low field nuclear magnetic resonance (LF NMR), size exclusion chromatography with triple detection (SEC), and surface/interfacial tension measurements. The results showed that chemical and physical modification improved the functionality of starch in emulsions. This is due to not only chemical but also physical modifications, i.e., pregelatinization causes changes in the molecular structure of starch, including an increase in the molecular weight and the degree of branching. As a consequence, the conformation of starch macromolecules changes, which results in a change of the dynamics of protons in the continuous phase of the emulsion and the thermodynamics of starch adsorption at the water/oil interface.

Pickering emulsion of camellia oil stabilized by Octenyl succinic acid starch: Interaction, lipid oxidation and digestibility

The application of camellia oil is limited by its susceptibility to oxidation and insolubility in water, particularly under high humidity and temperature conditions. In order to effectively reduce the oxidation rate of camellia oil, prolong the shelf life in order to improve the stability in storage under different conditions, this study encapsulates camellia oil in Pickering emulsions stabilized by Octenyl succinic acid (OSA) starch, achieving a 100-fold reduction in release rate and enhanced lipid oxidation stability. The smooth surface and complete particles of the emulsion were observed and no new chemical bonds were formed. The minimum particle sizes were 1.72 μm and 2.73 μm, when the Pickering emulsion was set at pH 6 and 0.1 M NaCl. In the digestion process, the microstructures observed that Pickering emulsion possessed super stability against oral and gastric digestions, prolonged the release time and improved the bioavailability compared with camellia oil, and the digestibility of the emulsion was 56.16 % within 120 min. All these results indicate that OSA-starch stabilized camellia oil can effectively increase solubility, improve stability and expand the application range.

Physical and oxidative stability of flaxseed oil-in-water emulsions prepared by natural lignin-carbohydrate complex

Flaxseed oil, rich in α-linolenic acid, plays a crucial role in various physiological processes. However, its stability presents certain challenges. In this study, the natural lignin-carbohydrate complex (LCC) was used to prepare the physical and oxidative stability of flaxseed oil-in-water emulsions. The LCC was characterized by HPLC, GPC, and FT-IR. The stability of emulsions was evaluated by viscosity, modulus, and micro-morphology changes. Then, the oxidation products were monitored by UV-vis spectrophotometer and HPLC. The results revealed that the high internal phase emulsion (HIPE) was successfully prepared with 2.5 wt% LCC at an oil/water ratio of 75/25 (v/v). Small droplet size (13.361 μm) and high viscosity (36,500 mPa·s) were found even after 30-day storage. Steric interactions of the LCC play a crucial role in ensuring stability, intricately linked to the interfacial properties of the emulsion. Meanwhile, the oxidative stability of α-linolenic acid in the encapsulated flaxseed oil was significantly higher than that in the bulk flaxseed oil. The results revealed that the LCC as a suitable emulsifier opens a new window for the storage of functional lipids rich in polyunsaturated fatty acids.

Insight into the Feasibility of Fatty Acyl Chlorides with 10-18 Carbons for the Ball-Milling Synthesis of Thermoplastic Cellulose Esters

Fatty acid cellulose esters (FACE) are common cellulose-based thermoplastics, and their thermoplasticity is determined by both the contents and the lengths of the side chains. Herein, various FACE were synthesized by the ball-milling esterification of cellulose and fatty acyl chlorides containing 10-18 carbons, and their structures and thermoplasticity were thoroughly studied. The results showed that FACE with high degrees of substitution (DS) and low melting flow temperatures (Tf) were achieved as the chain lengths of the fatty acyl chlorides were reduced. In particular, a cellulose decanoate with a DS of 1.85 and a Tf of 186 °C was achieved by feeding 3 mol of decanoyl chloride per mole anhydroglucose units of cellulose. However, cellulose stearate (DS = 1.53) synthesized by the same protocols cannot melt even at 250 °C. More interestingly, the fatty acyl chlorides with 10 and 12 carbons resulted in FACE with superior toughness (elongation at break up to 94.4%). In contrast, due to their potential crystallization of the fatty acyl groups with 14-18 carbons, the corresponding FACE showed higher tensile strength and Young's modulus than the others. This study provides some theoretical basis for the mechanochemical synthesis of thermoplastic FACE with designated properties.