Food Biophysics最新文献

Legume proteins were utilized in this study to electrospin an bioactive component for use in food packaging. Firstly, the protein extraction from legumes with ultrasound assistance with the use of deep eutectic solvents (UA-DES) has been studied. The optimum extraction conditions were determined. Secondly, lentil protein isolate (LPI) and chickpea protein isolate (CPI) produced by the UA-DES were used in nanofiber production by electrospinning using polyvinyl alcohol (PVA) at different ratios. Lastly, the usability of fibers obtained from protein isolates and PVA in coating bioactive components was tested using ferulic acid (FA). The encapsulation properties of nanofibers produced at a ratio of 50:50 (PVA:PI) were investigated. The characteristic and antibacterial properties and release kinetics of the produced FA-loaded nanofibers were evaluated. The distribution of FA within the fibers was confirmed by fluorescence microscopy. Furthermore, the antibacterial properties were proven and the release kinetics of the produced FA-loaded fibers in different food simulants were determined. As a result, the final encapsulated material obtained by coating FA with nanofibers created with PVA and LPI-CPI mixtures might have suitable properties which may be used in various food applications.

Abstract

The present study was designed to extract the lignin fraction from date palm tree leaves and explore its incorporation into carboxymethyl cellulose (CMC) based composite films at varying concentrations as reinforcing agent. Structural studies revealed that the interaction between lignin and CMC improved the film characteristics and showed good compatibility between these polymers. X-ray diffraction (XRD) results revealed that the crystalline structure of CMC and lignin (CMC-Lignin) films was enhanced by the addition of lignin. The addition of lignin significantly enhanced the mechanical properties in terms of the tensile strength (TS) and elongation at break (EAB) of the CMC-Lignin films from 18.29 to 32.61 MPa and 32.5–45.3%, respectively. Physical properties in terms of thickness, solubility, moisture content, and water vapor permeability (WVP) were improved from 0.09 to 0.14 mm, 84.75 to 51.03%, 31.34 to 19.30%, and 4.98 to 1.08 × 10⁻¹⁰ g m⁻¹s⁻¹Pa⁻¹, respectively. The addition of lignin changed the optical properties of the films, making them darker and opaquer. CMC-Lignin films showed improved antioxidant and antimicrobial properties and manifest as viable alternatives to plastic packaging and can be successfully used as a sustainable packaging material in the food industry.

Abstract

To improve the emulsifying property of sodium caseinate (NaCas) as stabilizer of oil-in-water emulsions and encapsulation of bioactive compounds, three hexaglycerol mono-fatty acid esters were chosen as small molecular weight surfactants to complex with NaCas. Hexaglycerol monooleate (HGMO) was found to be the optimal surfactant and the optimal mass ratio was 1:1, through characterization of particle size, Zeta-potential, and turbidity. Fluorescence and FTIR spectra indicated that the hydrophobic interaction and hydrogen bond provided driving forces to the formation of stable complex. The complexation of HGMO to NaCas increased the surface hydrophobicity and decreased surface tension compared with NaCas, and strengthened the EAI and ESI. The NaCas-HGMO complex had good stabilization on rice bran oil-in-water emulsions, in a wide pH and ionic strength, and the forwarding Cur encapsulation in O/W emulsions dramatically reduced the degradation during storage at 4℃. Therefore, the present NaCas-HGMO complex might be employed as an effective emulsifier to stable O/W emulsions that load lipophilic bioactives in functional foods or beverages.

Octyl gallate (GAC8) as a bioactive compound has excellent antibacterial effectiveness, but its poor hydrophilicity limits its applications. In this work, GAC8 was encapsulated into hydroxypropyl-β-cyclodextrin (HPβCyD) cavity to form an inclusion complex (GAC8/HPβCyD-IC), and their antibacterial activities were investigated. Phase solubility test suggested that the aqueous solubility of GAC8 was prominently enhanced after forming the inclusion complex. The aqueous solution of GAC8/HPβCyD-IC yielded uniform fiber morphology with ~ 900 nm average fiber diameter. The fabricated GAC8/HPβCyD-IC nanofibers (GAC8/HPβCyD-IC NFs) were characterized by ¹H NMR, FT-IR, XRD, DSC, and TGA, revealing successful synthesis of GAC8/HPβCyD-IC NFs and the thermal stability of GAC8 was enhanced by inclusion complexation with HPβCyD. Furthermore, GAC8/HPβCyD-IC NFs possessed antibacterial activity against E. coli (12.5 mm zone of inhibition), S. aureus (18.5 mm zone of inhibition). The results of DNA and protein leakage in the experiment indicated that GAC8/HPβCyD-IC NFs can disrupt the membrane integrity of bacteria. Meanwhile, GAC8/HPβCyD-IC NFs suppressed the colony growth of E. coli on Chinese giant salamander meat. Overall, the nanofibers encapsulating GAC8/HPβCyD-IC were potential antibacterial food packaging materials.

This study aims to assess the physicochemical and mechanical properties of O/W emulsion gels formulated with quinoa protein partial hydrolysates (QPH). The effect of varying QPH concentrations (0.5%, 1%, and 2%) on these attributes was also investigated. The QPH were obtained from quinoa protein concentrate (QPC) after treatment with alcalase. Surface hydrophobicity (S₀) and emulsifying properties of QPH suspensions were determined. Microstructure, color, water holding capacity (WHC), thermal stability, as well as textural properties of the formulated emulsion gels, were also evaluated. After the hydrolysis treatment, S₀ exhibited a significant increase (p = 0.006). The emulsifying activity of QPH also increased (p = 0.002), while the emulsion stability decreased (p < 0.000) as QPH concentrations increased. Confocal laser scanning microscopy images showed that in QPH-based emulsion gels, oil droplets seemed to be more associated with each other forming a three-dimensional network that was less bound to the matrix, in comparison with QPC-based emulsion gels. In addition, hydrolysis produced a significant reduction in WHC of emulsion gels (p = 0.000); however, in all samples evaluated the WHC was around 70%. Furthermore, after heat treatment, there was a decrease in this parameter (p < 0.000). The evaluation of textural properties showed that hardness was significantly lower for emulsion gels formulated with QPH (p < 0.000); whereas no differences between emulsion gels with 0.5% QPC and those with 0.5, 1, and 2% QPH were obtained. Therefore, hydrolysates have the potential to be used in emulsion gel formulation and could be applied to the development of soft-solid food products.

The gelation of soybean and amaranth proteins through a three-step-strategy: heat-induced denaturation at low protein content (2 or 4 wt%) in the presence of calcium (0.075–0.250 mmol Ca/g protein) and at pH 7.0, followed by freeze drying, and rehydration at higher protein content (10 or 13 wt%) was evaluated for mixtures 80:20 (soybean:amaranth) and for soybean proteins alone. Gelation was favored by high protein contents during denaturation and rehydration, and by a Ca²⁺:protein ratio of 0.100 mmol Ca/g protein. Gels were soft (hardness from texture profile analysis was 0.26 N) and self-supporting and exhibited excellent water-holding capacity (99% upon centrifugation at 20,000xg). The aggregates formed during denaturation were weakly associated upon rehydration and were mostly extractable with water, which partially explained the softness of gels. The appropriate Ca²⁺:protein ratio would lead to a particular distribution of Ca²⁺ between free in solution and bound to proteins, which in turn balanced associations and repulsions allowing gelation. The presence of 20% amaranth proteins led to a more brownish color, a higher adhesiveness and a lower cohesiveness (texture), lower storage modulus, apparent viscosity, consistency index, and area of hysteresis (rheology) when compared to gels containing only soybean proteins. The mechanical differences suggest that soybean proteins dominated the three-dimensional matrix while amaranth proteins were less engaged and acted as a filler.

Abstract

In this study, α-, β-, γ-cyclodextrin (CD) and carbon quantum dots (CQs) nanocomplexes loaded with quercetin (Qu) were prepared successfully. The results showed that incorporation of CQs increased the Qu encapsulation efficiency and the stability of the nanocomplexes. Fourier transform infrared spectra showed that Qu, CQs and CD were mainly linked by hydrogen bonds. X-ray diffraction results showed that the crystal structures of Qu/CD-CQs were completely different from those of Qu, CD and Qu/CD. The results from differential scanning calorimetry, thermogravimetric analysis and scanning electron microscopy provided evidence for the formation of Qu/CD-CQs. Moreover, compared with Qu, the synthesized Qu/CD-CQs exhibited better physicochemical stabilities, and CD and CQs synergistically improved the stability and bioavailability of Qu. The release of Qu from Qu/CD-CQs was controlled. These results suggested that Qu was efficiently encapsulated by α-, β-, γ-CD and CQs, and the resulting nanocomplexes have great potential for use as nanofunctional foods.

Abstract

Soy protein isolate (SPI) and its mixture with other biopolymers, such as linear polysaccharides, have been considered as potential components to form biodegradable packaging. Films based on SPI (5% m/m film-forming solution) were prepared with the addition of sodium alginate (ALG) at different concentrations and pH values. The mechanical properties and oxygen permeability were studied and correlated with the crystallinity (X-ray), Fourier transform infrared (FT-IR) spectroscopy and the microstructure (scanning electron microscopy - SEM) of the films. The addition of ALG caused expressive changes in the structural arrangement of the SPI films, especially at pH 6 and 8. The FT-IR spectra of the films also showed the effects of the pH and ALG concentration on the relative intensity of the protein absorption bands, indicating stronger interaction between SPI and ALG at pH 11 than at pH 6 and 8. The resistance of the films was improved with the increasing addition of the polysaccharide, and with the highest alkalinity. Oxygen permeability evaluation of the films formed at pH 11 showed a significant decrease in permeability with increasing incorporation of ALG into the film matrix. The results indicate that the structure and the properties of the SPI-based films were modified and improved with ALG. It was concluded that alginate incorporation in SPI-based films with pH 11 improves mechanical and oxygen barrier properties.