Soy Protein Isolate as Emulsifier of Nanoemulsified Beverages: Rheological and Physical Evaluation

The production of biologically active molecules or the addition of new bioactive ingredients in foods, thereby producing functional foods, has been improved with nanoemulsion technology. In this sense, the aim of this work was to develop nanoemulsified beverages as potential candidates for the encapsulation of bioactive compounds, whose integrity and release across the intestinal tract are controlled by the structure and stability of the interfaces. To achieve this, firstly, a by-product rich-in protein has been evaluated as a potential candidate to act as an emulsifier (chemical content, amino acid composition, solubility, ζ-potential and surface tension were evaluated). Later, emulsions with different soy protein isolate concentrations (0.5, 1.0, 1.5 and 2.0 wt%), pH values (2, 4, 6 and 8) and homogenization pressures (100, 120 and 140 PSI) were prepared using a high-pressure homogenizer after a pre-emulsion formation. Physical (stability via Backscattering and drop size evolution) and rheological (including interfacial analysis) characterizations of emulsions were carried out to characterize their potential as delivery emulsion systems. According to the results obtained, the nanoemulsions showed the best stability when the protein concentration was 2.0 wt%, pH 2.0 and 120 PSI was applied as homogenization pressure.

Incorporation of ZnO Nanoparticles into Soy Protein-Based Bioplastics to Improve Their Functional Properties

The union of nanoscience (nanofertilization) with controlled release bioplastic systems could be a key factor for the improvement of fertilization in horticulture, avoiding excessive contamination and reducing the price of the products found in the current market. In this context, the objective of this work was to incorporate ZnO nanoparticles in soy protein-based bioplastic processed using injection moulding. Thus, the concentration of ZnO nanoparticles (0 wt%, 1.0 wt%, 2.0 wt%, 4.5 wt%) and mould temperature (70 °C, 90 °C and 110 °C) were evaluated through a mechanical (flexural and tensile properties), morphological (microstructure and nanoparticle distribution) and functional (water uptake capacity, micronutrient release and biodegradability) characterization. The results indicate that these parameters play an important role in the final characteristics of the bioplastics, being able to modify them. Ultimately, this study increases the versatility and functionality of the use of bioplastics and nanofertilization in horticulture, helping to prevent the greatest environmental impact caused.

Evaluation of smart gelatin matrices for the development of scaffolds via 3D bioprinting

Throughout history, different techniques have been used for the development of scaffolds for Tissue Engineering. Among them, three-dimensional (3D) printing for this application has been recently enhanced due to its ease in defining the structure of the material. In this sense, a novel potential alternative could be the development of a three-part device whose leading utility is to improve the introduction of the scaffold in a bioreactor. Thus, the device consists of a polycaprolactone support on which smart gelatin (GE) matrix, and finally, on top, a collagen (C) scaffold. This gelatin matrix is included to integrate the scaffold into the support, but once both are assembled, it must be removed, leaving only the support and the scaffold. Thus, in the present work, a small gelatin matrix has been evaluated. To this end, matrices with different gelatin percentages were studied, evaluating their mechanical and morphological properties at different temperatures (22 and 37 °C) to control their deposition and elimination. The results show the high application of this smart matrix for the development of scaffolds via 3D bioprinting for Tissue Engineering.

Alternative processing methods of hybrid porous scaffolds based on gelatin and chitosan

The present work focuses on the development of scaffolds based on gelatin and chitosan using different protocols based on the general processing of phase separation, derived from the fabrication of hydrogels and freeze-drying. The scaffolds were produced with 1 wt% of two different biopolymers, i.e. gelatin (GE) and chitosan (CH), and the influence of the ratio between the two polymers was analyzed, as well as three different processing methods. This analysis consisted in assessing their mechanical properties by strain and frequency sweep tests, and comparing their microstructure and fiber arrangement by means of porosimetry, scanning electron microscopy (SEM) and degree of crosslinking. The results obtained show that the properties of the scaffolds were strongly dependent on the proportion of the raw materials used, as well as on the processing method. As a result, it was found that synergy occurred when a 1:1 gelatin:chitosan ratio was used, and when the temperature was increased, since it favors the solubilization of biopolymers and their interaction during mixing.

Development of pea protein-based bioplastics with antimicrobial properties

BACKGROUND

In the present work, bioplastics from renewable polymers were studied in order to reduce the huge generation of plastic wastes, causing an environmental problem that continues owing to the increasing demand for plastic products.

RESULTS

Bioplastics with much better antimicrobial properties, in particular against Gram-positive bacteria, were obtained with the addition of nisin to the initial protein/plasticizer mixture. However, the addition of nisin produces more rigid but less deformable bioplastics (higher Young's modulus but lower strain at break).

CONCLUSION

The results obtained are useful to demonstrate the antimicrobial properties of pea protein-based bioplastics by adding nisin and make them suitable as potential candidates to replace conventional plastics in food packaging. © 2016 Society of Chemical Industry.

Microstructural, mechanical, and histological evaluation of modified alginate-based scaffolds

Scaffolds are three-dimensional structures used for tissue regeneration being the base in tissue engineering. These scaffolds are obtained from natural and/or synthetic polymers and they should satisfy some specific requirements such as biocompatibility, suitable mechanical, and microstructural properties to favor cellular adhesion and neovascularization. This work shows a preclinic study about the production of low and medium molecular weight alginate through the use of calcium salts (calcium glutamate). The results showed prove that better structures, distribution, and pore sizes as well as better mechanical properties correspond to medium molecular weight alginate and higher calcium salts concentration. This type of scaffold, after muscular cells cultivation, has been proved as an excellent material for muscle growth. The histopathological analysis shows a low inflammatory response, without a foreign body reaction, suitable neovascularization and good fibroblasts incorporation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 3107-3114, 2016.

Influence of collagen concentration and glutaraldehyde on collagen-based scaffold properties

Several studies have shown the influence of the physical properties of scaffolds on their mechanical properties. An initial characterization of a type of collagen protein was carried out by studying its composition andits solubility at different pH values and infrared spectroscopy. Subsequently, porosity and scaffold pore size were studied, assessing how varying the composition of the initial solution (increasing the protein concentration or adding glutaraldehyde) changed the properties of the final scaffolds obtained. Lastly, rheological measurements were performed to evaluate the mechanical strength of the scaffolds. The initial characterization revealed that the type I collagen protein used is considerably denatured. In addition, increasing the protein content in the scaffold decreases the porosity, related to an increase in the elastic modulus producing an enhancement of its mechanical strength, while adding glutaraldehyde to the scaffold increases its mechanical strength without lowering its pore size or porosity. The results obtained are useful in that they demonstrate that it is possible to design a scaffold with specific properties, by just controlling the collagen concentration or adding glutaraldehyde to the initial solution. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1462-1468, 2016.