Search

The interactions of gelatin (G) with sodium carboxymethyl cellulose (CMC) were investigated at different pHs. Isothermal titration calorimetry (ITC) was used to determine the type and magnitude of the energies involved in the G-CMC complexation process and evaluated the thermodynamic behavior of their complexation. Moreover, dynamic light scattering (DLS), Zeta potential, optical microscopy and thermogravimetric analysis (TGA) were applied to better understand the sum of complex phenomena at the origin of G-CMC coacervates formation. Also, coacervated G-CMC was further used for CLA encapsulation at different core/wall ratios (1:1, 2:1 and 3:1). Results revealed that coacervates size ranged between 5 and 200 μm and increased with decreasing pH. Similar trend was observed with G-CMC complex coacervates morphological evolution. Additionally, the structuring stages were characterized by exothermic signals and were mainly controlled by favorable enthalpy changes due to electrostatic interactions between both biopolymers. ITC further confirmed that G and CMC electrostatically interacted with high affinity (K = 4.12 × 10 7  ± 1.62 × 10 7  M −1 ) at pH 4.40, and revealed that this binding was mainly driven by enthalpy. In addition, the microencapsulated CLA (CLA:GCMC, 2:1) capsules were multinuclear rod like and showed high encapsulation efficiency, yield and payload of 93.50%, 96.50% and 64.34%, respectively, confirming the potential of G-CMC complex coacervates for bioactive molecules encapsulation. The present study provided useful information about G-CMC complexation and binding processes, which could facilitate their application in functional ingredients encapsulation for food, nutraceutical and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

A simple, rapid, and sensitive method named critical desiccation state Raman spectroscopy (CDSRS) has been developed for detecting native and glycosylated protein. Raman spectroscopy was performed within 1 min and without background subtraction. Results showed that Raman intensity of 1 μL of low concentration dispersions of biomacromolecule analytes remarkably increased from weak to high signal-to-noise ratio during the progressive desiccation process, and high-quality CDSRS spectra of biomacromolecule analytes could easily be obtained under the critical desiccation state, especially those such as zein and whey protein isolate-dextran conjugate which were difficult and even impossible to detect from their solid powders or low concentration dispersions by conventional Raman spectroscopy. Therefore, CDSRS would provide an opportunity to obtain high-quality Raman spectra from biomacromolecule analytes, which would be beneficial to elucidate the relationship between secondary structures and functional properties of protein and to control the formation of food hydrocolloids with desirable physicochemical properties. [ABSTRACT FROM AUTHOR]

In this work, vitamin A (V A) and vitamin D (V D3) were co-encapsulated in the emulsion stabilized by sodium octenyl succinate starch/chitosan/tannic acid (OSA-S/CS/TA) complex. The influence of TA concentration on emulsion stability was estimated, and the underlying mechanism was revealed from the perspective of interface characteristic. The TA incorporation improved the long-term and thermal stability of the emulsion. Compared with the emulsion without TA, the retention rate of V A and V D3 increased by 15.2%–24.5% after storage, and the oxidative product decreased by 23.9%–43.3% after heating. TA was anchored at the oil-water interface to reduce the interfacial tension and form the interfacial film with antioxidation and viscoelasticity. TA and OSA-S/CS were combined by hydrogen bonds at sequential two sites (ΔH 1 = −36.42 kJ mol−1, ΔS 1 = −0.04 kJ mol−1·K−1, ΔH 2 = −2.77 × 103 kJ mol−1, ΔS 2 = −9.25 kJ mol−1·K−1). The research expanded the application of TA, V A, and V D3 in food systems. [Display omitted] • The tannic acid prevented vitamin A and vitamin D3 degradation in the emulsion. • The tannic acid anchored at the oil-water interface was over 70%. • The interfacial viscoelasticity and antioxidation of the emulsion were enhanced. • The tannic acid was bonded with OSA starch/chitosan complex by hydrogen bonding. [ABSTRACT FROM AUTHOR]

The complexation mechanism of gelatin (G) and carboxymethyl cellulose (CMC) and their coacervates formation process were studied as a function of pH and protein (Pr) to polysaccharide (Ps) mixing ratio (Pr:Ps). Three different CMCs were chosen (FL9, FH9 and FVH6) and five mixing ratio of 1:1, 6:1, 7:1, 8:1 and 9:1 (w/w), were studied to disclose their individual coacervates transition pattern for zeta potential, turbidity, morphology, size distribution and coacervates yield. The coacervates formation mechanism and stability of formed coacervates were examined using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), Circular Dichroism (CD), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Coacervates with better morphology, good size distribution and highest yield were observed with G-FL9 at mixing ratio of 7:1 and pH 4.40. The evaluation of coacervates formation mechanism showed that G molecules experienced a conformational change in its secondary structure from a flexible pattern to an ordered poly-proline II (PPII) helix. The vibrations of O H and N H bonds spectra at 3437 and 3449 cm −1 , respectively for G/CMC coacervates, shifted to lower wave numbers due to the conformational changes of gelatin and CMC, during the coacervates formation. G/CMC complex coacervates were more thermally stable than individual gelatin. Therefore, these complex coacervates will be able to protect and deliver heat sensitive bioactives and food ingredients. [ABSTRACT FROM AUTHOR]

The study aims to use thermal processing to enhance sodium release from surimi matrix during oral processing and therefore improve the saltiness perception. Surimi gels were prepared by one- and two-stage heating, containing water bath heating (WB90), microwave heating (MW10), two-stage water bath heating (WB40+WB90), and water bath combined with microwave heating (WB40+MW10). The physicochemical properties including gel strength, protein degradation, and microstructure of surimi gels were compared. The water and sodium mobility of surimi gels were characterized by 1H low field NMR and 23Na NMR. Sodium release from matrix during oral processing and sensory evaluation of saltiness difference were employed to verify the enhancement effect of saltiness perception caused by thermal processing. WB40+MW10 improved surimi gel strength by reducing the degradation of myosin heavy chain. Microstructure observations showed that WB40+WB90 gels had a relatively rough and loose microstructure with curved small gaps, whereas WB40+MW10 gels exhibited a denser microstructure. The water and sodium mobility of WB40+MW10 gels (T 21 88.08 ms, D 6.68 × 10−10 m2/s) were significantly higher than those of WB40+WB90 gels (T 21 83.10 ms, D 6.35 × 10−10 m2/s). WB40+MW10 gels eliminated the tortuosity effect of water and sodium diffusion, resulting in 1.12 times higher sodium release than WB40+WB90 gels. The triangle sensory evaluation also showed that WB40+MW10 gels were perceived as saltier than WB40+WB90 gels, achieving a 15% salt reduction effect. This study provides a promising heating method to improve the saltiness perception of fish products by enhancing sodium release during oral processing. [Display omitted] • Water bath-microwave heating enhanced the saltiness perception of surimi gels. • Water bath-microwave heating induced a microstructure conducive to sodium diffusion. • Gaps distributed in the gel network caused a tortuosity effect of sodium diffusion. • Water/sodium mobility enhancement promoted sodium release and saltiness perception. [ABSTRACT FROM AUTHOR]