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Calcium alginate spheres with a volume of about 5 mL can be used for important purposes. Those that incorporate oolong tea give, in addition to the recreational aspect, the possibility of drinking small quantities of this tea, because oolong tea can be used as a compound with antioxidant properties. This incorporation can be achieved by reverse spherification (5 mL). Six types of spheres have been made, all of them with calcium alginate and the presence or absence of agar-agar and xanthan gum—XG—in two concentrations. The weight loss of the spheres, the release of bioactive compounds over time (a total of 48 h), the surface (internal and external) of the membranes, and the physical characteristics of these membranes have been analyzed. The data obtained indicate that the presence of XG prevents the formation of precipitates inside the spheres and slows down weight loss. It also provides opacity to the spheres. However, the incorporation of agar-agar does not have a significant influence on the different parameters analyzed. The release of catechins reaches a maximum of 80% of what could be achieved under ideal conditions, and it reaches 90% in the first 3 h. The incorporation of XG increases the shelf life of the spheres, slows down the release of chelate, and decreases weight loss over time, allowing for a new perspective on the spherification process. [ABSTRACT FROM AUTHOR]

Myrtus communis L. is a species of the Myrtaceae family that is found in the Mediterranean region, and it is traditionally recognized for its importance and different uses. The objective of this study was to determine the effect of M. communis L. leaf extract (MCLE), which was incorporated directly into alginate spheres and films, on preserving oil-in-water emulsions from oxidation. For this purpose, the solvent extraction (with ethanol at 40, 60, and 80%) of the antioxidant compounds was optimized (total phenolic compounds (TPCs) and total flavonoid content (TFC)) along with the scavenging activity. The best condition for the extraction corresponded with 60% ethanol (MCLE60), with a TPC of ~66.06 g GAE/L and a TFC of ~18.91 g QE/L, which was selected for use in the following assays. MCLE60 showed a considerable radical scavenging activity (24.85 mmol TE/L in FRAP, 28.75 mmol TE/L in DPPH, 30.61 mmol TE/L in ABTS, and 14.94 mmol TE/L in ORAC), which was probably due to its content in the phenolic compounds arbutin (122.08 mg/L), epicatechin (73.89 mg/L), sinapic acid (51.85 mg/L), and gallic acid (36.72 mg/L). The oil-in-water emulsions with the MCLE60 spheres showed the best oxidative stability (TBARS ~2.64 mg MDA/kg of emulsion, PV ~35.7 meq hydroperoxides/kg of emulsion) in comparison to the control. The film was also able to protect the emulsion from oxidation for more than a week at 30 °C (TBARS ~1.9 mg MDA/kg of emulsion). The alginate films with MCLE60 presented an important release of phenolic compounds in water and acetic food simulants, while in both ethanol simulants, the release of TPC remained more stable over time. Thus, this study highlights the potential uses of MCLE as a natural ingredient for emulsion oxidative preservation and the production of alginate delivery systems (spheres and films). [ABSTRACT FROM AUTHOR]

The interest in natural sources with high antioxidant powder has recently increased in several sectors. Ionic gelation methods could be used to protect bioactive substances to control the kinetics and release of these ingredients to the food matrix. This study dealt with the evaluation of the antioxidant capacity and scavenging activity of extracts of Hibiscus Sabdariffa L. (HSL) (with 50% ethanol) encapsulated in calcium alginate spheres as a new source for preserving food against oxidative damage. Their antioxidant activity was measured in different o/w emulsions in which HSL spheres reduced the formation of hydroperoxides (~80%) and thiobarbituric-acid-reactive substance products (~20%). The scavenging activity of HSL extracts was measured in different food simulants (water, water acidified with 3% acetic acid, ethanol at 50%, and pure ethanol), and corresponded to 0.20–0.43, 0.31–0.62, and 11.13–23.82 mmol Trolox/mL extract for Trolox equivalent antioxidant capacity (TEAC), 2,2-diphenylpicrylhydrazyl (DPPH), and oxygen radical absorbance capacity (ORAC) assays, respectively. In general, the best antiradical activity was observed in the ethanolic and acidified mediums, in which the highest concentration of released polyphenols ranged from 0.068 to 0.079 mg GAE/mL. This work indicates the potential of alginate spheres for encapsulating antioxidant compounds as an innovative strategy for several industrial applications. [ABSTRACT FROM AUTHOR]

Phenolic compounds that come from natural products are a good option for minimizing lipid oxidation. It should be noted that these are not only introduced directly into the food, but also incorporated into edible biofilms. In contact with food, they extend its useful life by avoiding contact with other surface and preventing deterioration air, one of the main objectives. In particular, gelatin is a biopolymer that has a great potential due to its abundance, low cost and good film-forming capacity. The aim of this study has been to design and analyse gelatin films that incorporate bioactive compounds that come from the walnut and a by-product, the walnut shell. The results showed that mechanical and water vapor barrier properties of the developed films varied depending on the concentration of the walnut, shell and synthetic antioxidant. With increasing walnut concentration (15%) the permeability to water vapor (0.414 g·mm/m2·day·Pascal, g·mm/m2·day·Pa) was significantly lower than the control (5.0368 g·mm/m2·day·Pa). Furthermore, in the new films the elongation at the break and Young's modulus decrease by six times with respect to the control. Films with pure gelatin cannot act as an antioxidant shield to prevent food oxidation, but adding pecan walnut (15% concentration) presents 30% inhibition of the DPPH stable radical. Furthermore, in the DSC, the addition of walnut (15 and 9% concentrations), showed the formation of big crystals; which could improve the thermal stability of gelatin films. The use of new gelatin films has shown good protection against the oxidation of beef patties, increasing the useful lifetime up to nine days, compared to the control (3–4 days), which opens up a big field to the commercialization of meat products with lower quantities of synthetic products. [ABSTRACT FROM AUTHOR]

Chitosan is increasingly used for safe nucleic acid delivery in gene therapy studies, due to well-known properties such as bioadhesion, low toxicity, biodegradability and biocompatibility. Furthermore, chitosan derivatization can be easily performed to improve the solubility and stability of chitosan–nucleic acid polyplexes, and enhance efficient target cell drug delivery, cell uptake, intracellular endosomal escape, unpacking and nuclear import of expression plasmids. As in other fields, chitosan is a promising drug delivery vector with great potential for the fish farming industry. This review highlights state-of-the-art assays using chitosan-based methodologies for delivering nucleic acids into cells, and focuses attention on recent advances in chitosan-mediated gene delivery for fish biotechnology applications. The efficiency of chitosan for gene therapy studies in fish biotechnology is discussed in fields such as fish vaccination against bacterial and viral infection, control of gonadal development and gene overexpression and silencing for overcoming metabolic limitations, such as dependence on protein-rich diets and the low glucose tolerance of farmed fish. Finally, challenges and perspectives on the future developments of chitosan-based gene delivery in fish are also discussed. [ABSTRACT FROM AUTHOR]