Ethyl Cellulose-Core, OSA Starch-Shell Electrosprayed Microcapsules Enhance the Oxidative Stability of Loaded Fish Oil.

The encapsulation and the oxidative stability of cod liver fish oil (CLO) within coaxial electrosprayed (ethyl cellulose/CLO) core-(octenyl succinic anhydride, OSA-modified starch) shell, and monoaxial electrosprayed ethyl cellulose/CLO microcapsules were investigated. Core-shell (H-ECLO) and monoaxial (ECLO) electrosprayed microcapsules with an average diameter of 2.8 ± 1.8 µm, and 2.2 ± 1.4 µm, respectively, were produced. Confocal microscopy confirmed not only the core-shell structure of the H-ECLO microcapsules, but also the location of the CLO in the core. However, for the ECLO microcapsules, the CLO was distributed on the microcapsules' surface, as also confirmed by Raman spectroscopy. Atomic force microscopy showed that the average surface adhesion of the H-ECLO microcapsules was significantly lower (5.41 ± 0.31 nN) than ECLO microcapsules (18.18 ± 1.07 nN), while the H-ECLO microcapsules showed a remarkably higher Young's modulus (33.84 ± 4.36 MPa) than the ECLO microcapsules (6.64 ± 0.84 MPa). Differential scanning calorimetry results confirmed that the H-ECLO microcapsules enhanced the oxidative stability of encapsulated CLO by about 15 times, in comparison to non-encapsulated oil, mainly by preventing the presence of the fish oil at the surface of the microcapsules, while ECLO microcapsules enhanced the oxidative stability of CLO about 2.9 times due to the hydrophobic interactions of the oil and ethyl cellulose. Furthermore, the finite element method was also used to evaluate the electric field strength distribution, which was substantially higher in the vicinity of the collector and lower in the proximity of the nozzle when the coaxial electrospray process was employed in comparison to the monoaxial process.

Enhanced electric field and charge polarity modulate the microencapsulation and stability of electrosprayed probiotic cells (Streptococcus thermophilus, ST44).

The effect of the polarity of the direct current electric field on the "organization" of Streptococcus thermophilus (ST44) probiotic cells within electrosprayed maltodextrin microcapsules was investigated. The generated electrostatic forces between the negatively surface-charged probiotic cells and the applied negative polarity on the electrospray nozzle, allowed to control the location of the cells towards the core of the electrosprayed microcapsules. This "organization" of the cells increased the evaporation of the solvent (water) and successively the glass transition temperature (Tg) of the electrosprayed microcapsules. Moreover, the utilization of auxiliary ring-shaped electrodes between the nozzle and the collector, enhanced the electric field strength and contributed further to the increase of the Tg. Numerical simulation, through Finite Element Method (FEM), shed light to the effects of the additional ring-electrode on the electric field strength, potential distribution, and controlled deposition of the capsules on the collector. Furthermore, when the cells were located at the core of the microcapsules their viability was significantly improved for up to 2 weeks of storage at 25 °C and 35% RH, compared to the case where the probiotics were distributed towards the surface. Overall, this study reports a method to manipulate the encapsulation of the surface charged probiotic cells within electrosprayed microcapsules, utilizing the polarity of the electric field and additional ring-electrodes.

Texture and viscoelastic characteristics of silver carp (Hypophthalmichthys molitrix) surimi affected by combination of washing regimes and hydrogen peroxide.

This study aimed to apply H2 O2 at different concentrations in combination with mince:water (M:W) ratios and different washing cycles (WCs) to produce surimi gel from silver carp without compromising its quality characteristics. Color, texture, microstructure, and rheological properties of surimi gels were investigated. Water holding capacity, texture profile, and gel strength showed a greater dependency on number of WCs than the M:W ratios and percentage of H2 O2 (p < .05), that is, higher WCs, firmer surimi gel. Accordingly, T2 (one WC, 2% H2 O2 , 1:3), T10 (two WC, 1% H2 O2 , 1:2), and T16 (three WC, 1% H2 O2 , 1:2) treatments resulted the most cohesive and resilient surimi compared with the rest (p < .05), confirmed by scanning electron microscopy images. However, all treated fish mince samples with H2 O2 , resulted in a surimi gel with lower texture quality compared with the control surimi prepared by conventional washing process without H2 O2 (p < .05). A temperature sweep test was conducted based on the linear viscoelastic region stress and frequency values and the aforementioned surimi gels exhibited an obvious valley shape pattern at temperature range of 48-62°C. In the creep-recovery test, the Burgers model satisfactorily described the internal structure of the surimi gel samples as the lowest deformation belonged to the control samples followed by T2. However, after 300 s strain, neither of surimi gels were fully recovered their original shape. Altogether, further studies are needed to clarify the effects of H2 O2 in reduction of WCs, without significantly affecting the textural and rheological properties of resultant surimi gel.

Bladder wall biomechanics: A comprehensive study on fresh porcine urinary bladder.

Regenerative medicine for reconstructive urogenital surgery has been widely studied during the last two decades. One of the key factors affecting the quality of bladder regeneration is the mechanical properties of the bladder scaffold. Insight into the biomechanics of this organ is expected to assist researchers with functional regeneration of the bladder wall. Due to extensive similarities between human bladder and porcine bladder, and with regard to lack of comprehensive biomechanical data from the porcine bladder wall (BW), our main goal here was to provide a thorough evaluation on viscoelastic properties of fresh porcine urinary BW. Three testing modes including Uniaxial tensile, ball-burst (BB) and Dynamic Mechanical Analysis (DMA) were applied in parallel. Uniaxial tests were applied to study how different circumferential and longitudinal cut-outs of lateral region of BW behave under load. DMA was used to measure the viscoelastic properties of the bladder tissue (storage and loss modulus) in a frequency range of 0.1-3Hz. BB was selected as a different technique, replicating normal physiological conditions where the BW is studied in whole. According to uniaxial tests, the anisotropic behavior of bladder is evident at strain loads higher than 200%. According to DMA, storage modulus is consistently higher than loss modulus in both directions, revealing the elasticity of the BW. The stress-strain curves of both uniaxial and BB tests showed similar trends. However, the ultimate stress measured from BB was found to be around 5 times of the relevant stress from uniaxial loading. The ultimate strain in BB (389.9 ± 59.8) was interestingly an approximate average of rupture strains in longitudinal (358 ± 21) and circumferential (435 ± 69) directions. Considering that each testing mode applied here reveals distinct information, outcomes from the combination of the three can be considered as a helpful data-base to refer to for researchers aiming to regenerate the bladder.