Advances in enhancing the mechanical properties of biopolymer hydrogels via multi-strategic approaches.

The limited mechanical properties of biopolymer-based hydrogels have hindered their widespread applications in biomedicine and tissue engineering. In recent years, researchers have shown significant interest in developing novel approaches to enhance the mechanical performance of hydrogels. This review focuses on key strategies for enhancing mechanical properties of hydrogels, including dual-crosslinking, double networks, and nanocomposite hydrogels, with a comprehensive analysis of their underlying mechanisms, benefits, and limitations. It also introduces the classic application scenarios of biopolymer-based hydrogels and the direction of future research efforts, including wound dressings and tissue engineering based on 3D bioprinting. This review is expected to deepen the understanding of the structure-mechanical performance-function relationship of hydrogels and guide the further study of their biomedical applications.

Microencapsulation of Bifidobacterium bifidum F-35 via modulation of emulsifying technique and its mechanical effects on the rheological stability of set-yogurt.

Microencapsulation of B. bifidum F-35 was carried out through emulsification technique in order to increase the microbial load while maintaining the rheological functions of set-yogurt. To produce single-layer (SL) microcapsules of whey protein, the pH was adjusted to 6.4 within Transglutaminase-induced gelation. Sodium alginate was processed as the external layer using calcium-induced gelation (pH 5.5) to produce the double-layer (DL) microcapsule. Scanning electron microscopy revealed that SL and DL microcapsules had sizes of 10 and 280 µm, respectively. The highest microbial load was clearly visible in the DL sample. According to texture profile analysis, the DL sample had the highest levels of gumminess, chewiness, and adhesiveness. The free sample outperformed the encapsulated samples in terms of springiness and cohesiveness. Although the SL sample had the highest viscosity, it produced a deformed gel when firmness was measured. In terms of firmness, the DL sample performed quite well. The viability of encapsulated B. bifidum F-35 in DL was higher than SL microcapsules during storage. Microencapsulation of B. bifidum F-35 with whey protein and sodium alginate is a promising technique that could improve the rheological properties of set-yogurt as a popular vehicle for bioactive ingredients.

Production of ingredient type flavoured white enzyme modified cheese.

Enzyme modified white cheese (EMWC) was produced to use as flavouring ingredient. White cheese curd coupled with low fat was hydrolysed using combination of proteinases/peptidase to produce a range of proteolysed products followed by lipolysis. The results revealed that lowering pH 5.6 known to impart flavour strength of cheese. The inclusion of enzyme preparations significantly elevated free amino acids and free fatty acids. Developed EMWC had relatively higher levels of volatiles and improved sensory characteristics including less negative attributes such as, astringent, bitter, pungent, rancid, smoky, and more positive attributes, such as the strength of buttery, sweaty, caramel and nutty notes. Spray-dried EMWC powders had low moisture content and water activity values whereas, scanning electron micrographs showed spherical with a uniform distribution and large microparticles size. Because consumers like low fat products with cheese flavour, EMWCs are important products. Thus, process demonstrates the potential to be a cost-effective to produce EMWC flavour as ingredient and may suited to the products in which added.

Effect of phosphates on gelling characteristics and water mobility of myofibrillar protein from grass carp (Ctenopharyngodon idellus).

Effect of phosphates on the heat-induced gel characteristics of myofibrillar protein (MP) from grass carp was investigated. Both heating and phosphates exerted significant influences. Heating induced more elastic, water-holding and less flowing gel. But phosphates had diverse effects at different temperatures. At 4 °C and 40 °C, phosphate as a dominant factor reduced the gel elasticity and resistance and increased flowability with increasing levels of phosphates. Furthermore, 280 mg/kg sodium pyrophosphate (SPP) or 440 mg/kg sodium triphosphates (STP) transformed MP from weak gel into concentrated solution. It clarified phosphates disentangled MP macromolecules and inhibited their aggregation and pre-gelation at low temperature. At 80 °C, heating accompanied with phosphates governed MP gelation. The appropriate level of phosphates (SPP superior to STP) endowed MP-phosphate gels with the lowest flowability and greatest elasticity, textural properties as well as finest microstructures. Besides, phosphates entrapped a portion of weak immobile water more tightly into smaller-sized pores of protein network.

Chitosan-glucose Maillard reaction products and their preservative effects on fresh grass carp (Ctenopharyngodon idellus) fillets during cold storage.

BACKGROUND: A decreasing freshness occurrs in Ctenopharyngodon (C.) idellus during post-mortem storage. In the present study, chitosan-glucose Maillard reaction products (CG-MRPs) were prepared by heating chitosan and glucose at different reaction temperatures and then used for preserving the freshness and quality of C. idellus fillets during cold storage (4 °C). RESULTS: High temperature enhanced the chitosan-glucose Maillard reaction and promoted the accumulation of melanoidins and intermediate compounds. The reducing power of CG-MRPs increased with an increasing reaction temperature. CG-MRPs inhibited the microbial growth rate and retarded the oxidation of proteins, lipids and nucleotides in C. idellus fillets by suppressing total bacterial count, total volatile basic nitrogen, thiobarbituric acid reactive substances and K values during cold storage. Furthermore, CG-MRPs prolonged shelf-life. The fillets treated with the CG-MRPs prepared at 120 °C showed an especially longer shelf-life (7 days). The preservative effect of CG-MRPs on fillets was the result of antibacterial components (melanoidins, reductone and furfural) in CG-MRPs and a reducing power against the oxidative degradation of proteins, nucleotides and lipids in C. idellus fillets. CONCLUSION: The present study demonstrates that, for C. idellus fillets, treatment with CG-MRPs prepared at 120 °C for 40 min could be a feasible approach for maintaining the freshness of C. idellus fillets and prolonging shelf-life during cold storage. © 2018 Society of Chemical Industry.

Effect of different oils and ultrasound emulsification conditions on the physicochemical properties of emulsions stabilized by soy protein isolate.

The effects of different ultrasound emulsification conditions (20 kHz at 50-55 W cm-2, 40% amplitude for 2, 6, 12 or 18 min) on the physicochemical properties of soybean protein isolate-stabilized emulsions containing medium chain triglycerides (MCT), and long chain triglycerides (LCTs, palm, soybean and rapeseed oils) were investigated. It was found that MCT oil emulsions had the minimum droplet size (d4,3) of 0.5 ±â€¯0.0 µm after ultrasound emulsification for 18 min. Moreover, results indicated that MCT oil emulsions had better emulsion stability (using distilled water as a water phase at neutral pH and room temperature) and higher adsorbed protein amounts at their interface than the LCTs emulsions. However, the absolute zeta (ζ)-potential values of MCT oil emulsions were the lowest among all the oil-in-water emulsions. Interestingly, the particle size of palm oil emulsion decreased after heat treatment at 90 °C for 30 min. In conclusion, high intensity ultrasound (HIU) could be considered as a useful emulsification technology to produce emulsions stabilized by soy protein isolate. However, the physicochemical properties of emulsions were different based on the types of oils as well as HIU time.

Comparative Assessment of the Bioremedial Potentials of Potato Resistant Starch-Based Microencapsulated and Non-encapsulated Lactobacillus plantarum to Alleviate the Effects of Chronic Lead Toxicity.

Lead (Pb) is a well-recognized and potent heavy metal with non-biodegradable nature and can induce the oxidative stress, degenerative damages in tissues, and neural disorders. Certain lactic acid bacterial strains retain the potential to mitigate the lethal effects of Pb. The present work was carried out to assess the Pb bio-sorption and tolerance capabilities of Lactobacillus plantarum spp. Furthermore, potato resistant starch (PRS)-based microencapsulated and non-encapsulated L. plantarum KLDS 1.0344 was utilized for bioremediation against induced chronic Pb toxicity in mice. The experimental mice were divided into two main groups (Pb exposed and non-Pb exposed) and, each group was subsequently divided into three sub groups. The Pb exposed group was exposed to 100 mg/L Pb(NO3)2 via drinking water, and non-Pb exposed group was supplied with plain drinking water during 7 weeks prolonged in vivo study. The accumulation of Pb in blood, feces, renal, and hepatic tissues and its pathological damages were analyzed. The effect of Pb toxicity on the antioxidant enzyme capabilities in blood, serum, as well as, on levels of essential elements in tissues was also calculated. Moreover, KLDS 1.0344 displayed remarkable Pb binding capacity 72.34% and Pb tolerance (680 mg/L). Oral administration of both non- and PRS- encapsulated KLDS 1.0344 significantly provided protection against induced chronic Pb toxicity by increasing fecal Pb levels (445.65 ± 22.28 µg/g) and decreasing Pb in the blood up to 137.63 ± 2.43 µg/L, respectively. KLDS 1.0344 microencapsulated with PRS also relieved the renal and hepatic pathological damages and improved the antioxidant index by inhibiting changes in concentrations of glutathione peroxidase, glutathione, superoxide dismutase, malondialdehyde, and activated oxygen species, which were affected by the Pb exposure. Overall, our results suggested that L. plantarum KLDS 1.0344 either in free or encapsulated forms hold the potentiality to deliver a dietetic stratagem against Pb lethality.

Non-thermal combined treatments in the processing of açai (Euterpe oleracea) juice.

Quality parameters of açai juice processed with ultrasound-assisted, ozone and the combined methods were analyzed in this work. Two ultrasound energy densities (350 and 700 J·mL-1) and two ozonization times (5 and 10 min with 1.5 ppm) were analyzed for pure açai juice and 8 different treatments (22 complete factorial). To evaluate the quality parameters of the juice, physical-chemical analyzes such as pH, titratable acidity, cloud value, non-enzymatic browning, rheology, antioxidant activity (DPPH and ABTS), phenolic compounds, anthocyanins, enzymatic activity (peroxidase and polyphenol oxidase) and microbial counts (mesophilic bacteria, molds and yeasts) were conducted. The treatments with ozone were better for microbial inactivation and the ultrasound for enzymatic inactivation. In general, the use of non-thermal methods can be a good alternative for the processing of açai juice.

Effect of ultrasound on size, morphology, stability and antioxidant activity of selenium nanoparticles dispersed by a hyperbranched polysaccharide from Lignosus rhinocerotis.

The differences between ultrasonic and non-ultrasonic approaches in synthesizing Lignosus rhinocerotis polysaccharide-selenium nanoparticles (LRP-SeNPs) were compared in terms of size, morphology, stability and antioxidant activity by UV-VIS, FT-IR, X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) with high resolution TEM. Results indicated that the SeNPs were associated with the LRP macromolecules in a physical adsorption pattern without breaking chemical bonds, and the ultrasonic treatment reduced the size of SeNPs, narrowed the size distribution as well as improved the stability. Due to the LRP compact coil structure loosed under ultrasonic cavitation, the SeNPs could be easily diffused into the LRP internal branches instead of gathering on the LRP surface and were well dispersed and eventually stabilized throughout the extended branches. After ultrasound treatment, the SeNPs had a minimum average diameter of ∼50 nm and the LRP-SeNPs could remain homogeneous and translucent for 16 days within 200 nm size. Furthermore, the ultrasound-treated LRP-SeNPs exhibited higher DPPH and ABTS radical-scavenging abilities than those untreated with ultrasound. This difference may be attributed to the reason that ultrasound can reduce the SeNPs size and increase the specific surface area, which provides sufficient active sites to react with the free radicals and suppress the oxidizing reactions. The integrated results demonstrated that ultrasound played a crucial role in the dispersion, size control, stabilization and antioxidant activity of SeNPs.

Star Anise (Illicium verum Hook. f.) as Quorum Sensing and Biofilm Formation Inhibitor on Foodborne Bacteria: Study in Milk.

Bacteria use quorum sensing (QS) systems to communicate with each other and regulate microbial group behavior, such as the secretion of virulence factors, including biofilm formation. In order to explore safe, edible agents, the potential of star anise (SA) as an anti-QS and antibiofilm agent and its possible application in milk safety were investigated. Staphylococcus aureus , Salmonella Typhimurium, Pseudomonas aeruginosa , and biosensor strain Chromobacterium violaceum were selected as test strains for QS, biofilm, and exopolysaccharide assays. The percent acidities and total plate counts were determined to evaluate the quality of biofilm-inoculated and noninoculated milk. The yield of SA extraction was 25.90% ± 0.2% (w/w). At sub-MIC, SA extract did not show any effect on bacterial growth. The production of violacein was inhibited by 89% by SA extract. The extract also inhibited the formation of biofilm by up to 87% in a dose-dependent manner. Inhibition rates of 70.45%, 42.82%, and 35.66% were found for exopolysaccharide production. The swarming motility of S. aureus was reduced by about 95.9% by SA extract. Confocal laser scanning microscopy analysis confirmed that the development of biofilm architecture was hampered. It was found that SA extract could delay the spoilage of milk. In the endeavor to avoid drug resistance, pathogenesis, and resistance to biocides while improving food safety and avoiding health hazard issues arising from synthetic chemicals, SA extract could be used as a potential QS and biofilm inhibitor.

Microencapsulation of Oils: A Comprehensive Review of Benefits, Techniques, and Applications.

Microencapsulation is a process of building a functional barrier between the core and wall material to avoid chemical and physical reactions and to maintain the biological, functional, and physicochemical properties of core materials. Microencapsulation of marine, vegetable, and essential oils has been conducted and commercialized by employing different methods including emulsification, spray-drying, coaxial electrospray system, freeze-drying, coacervation, in situ polymerization, melt-extrusion, supercritical fluid technology, and fluidized-bed-coating. Spray-drying and coacervation are the most commonly used techniques for the microencapsulation of oils. The choice of an appropriate microencapsulation technique and wall material depends upon the end use of the product and the processing conditions involved. Microencapsulation has the ability to enhance the oxidative stability, thermostability, shelf-life, and biological activity of oils. In addition, it can also be helpful in controlling the volatility and release properties of essential oils. Microencapsulated marine, vegetable, and essential oils have found broad applications in various fields. This review describes the recognized benefits and functional properties of various oils, microencapsulation techniques, and application of encapsulated oils in various food, pharmaceutical, and even textile products. Moreover, this review may provide information to researchers working in the field of food, pharmacy, agronomy, engineering, and nutrition who are interested in microencapsulation of oils.