Quality Characteristics of Senior-Friendly Gelatin Gels Formulated with Hot Water Extract from Red Maple Leaf as a Novel Anthocyanin Source

The objectives of this study were to evaluate antioxidant capacity of hot water extract from red maple leaf with different extraction times (experiment I) and to determine their impacts on color, free anthocyanin content, and hardness of gelatin gels (experiment II). In experiment I, hot water extraction time (30, 60, 120, 180, and 360 min at 60 °C) was fixed as a main effect. The different extraction times had no impacts on total polyphenol content and DPPH radical scavenging activity (p > 0.05). However, extraction time for 360 min could decrease anthocyanin content as well as ferric reducing antioxidant power (p < 0.05). In experiment II, 6%, 18%, and 30% gelatin gels were prepared without/with red maple leaf extract (1000 mg/L). The red maple leaf extract significantly increased redness, yellowness, and hardness, but decreased free anthocyanin content. Such impacts were obviously observed at high gelatin concentration. Thus, red maple leaf extract could be a novel anthocyanin source for improving antioxidant capacity and reddish color of gelatin gels. However, the addition amount of red maple leaf extract may be limited in the development of senior-friendly jelly food for soft texture in that it could increase the hardness of the gelatin gel.

Influence of the NaIO4 Concentration on the Gelation and the Adhesive Strength of Pyrocatechol/Pyrogallol Containing Gelatin Hydrogels

The presence of catechol groups in hydrogels, either grafted to the constituting polymers or added in the gel formulation allow to increase the adhesion strength of such hydrogels. In this investigation, we add pyrocatechol (1,2-benzenediol) and pyrogallol (1,2,3-benzenetriol) in gelatin solution to form hydrogels using sodium periodate as an oxidant with the aim to induce interactions between pyrocatechol/pyrogallol and the gelatin chains. The gelation kinetics of the hydrogels as well as their adhesion strength and toughness are evaluated as a function of the concentration in NaIO4 for a constant concentration-10 mM-in pyrocatechol/pyrogallol. It came out that the addition of pyrogallol to gelatin (10% w/v) did not improve the adhesion strength on stainless steel when compared to a pristine gelatin gel. As an interesting finding, the addition of pyrocatechol to gelatin allowed for a major improvement of the adhesive strength between two stainless steel plates and allowed to stabilize the gel up to 50°C. However, the pyrogallol modified gelatin gels displayed no thermal stabilization compared to pristine gelatin. The major differences between pyrocatechol and pyrogallol modified gels are explained on the basis of the electrophilicity of the oxidized polyphenols. In addition, the self-healing behavior of the gelatin based gels was investigated as a function of their composition.

Thermal Inactivation of Butyrylcholinesterase in Starch and Gelatin Gels

The present study demonstrates a simple approach to enhancing thermal stability of butyrylcholinesterase (BChE) by using natural polymers. Analysis of thermal inactivation of the tetrameric BChE in starch and gelatin gels at 50–64 °C showed that thermal inactivation followed second-order kinetics and involved two alternating processes of BChE inactivation, which occurred at different rates (fast and slow processes). The activation enthalpy ΔH# and the activation entropy ΔS# for BChE in starch and gelatin gels were evaluated. The values of ΔH# for the fast and the slow thermal inactivation of BChE in starch gel were 61 ± 3, and 22 ± 2 kcal/mol, respectively, and the values of ΔS# were 136 ± 12 and −2.03 ± 0.05 cal∙K−1∙mol−1, respectively. Likewise, the values of ΔH# for BChE in gelatin gel were 58 ± 6 and 109 ± 11 kcal/mol, and the values of ΔS# were 149 ± 16 and 262 ± 21 cal∙K−1∙mol−1, respectively. The values of the activation parameters obtained in this study suggest that starch gel produced a stronger stabilizing effect on BChE exposed to elevated temperatures over long periods compared with gelatin gel.

Drug delivery via tattooing: Effect of needle and fluid properties

Tattooing is a commonplace practice among the general populace in which ink is deposited within dermal tissue. Typically, an array of needles punctures the skin which facilitates the delivery of a fluid within the dermis. Although, a few studies in the past have investigated the potential of tattooing as an intradermal (ID) drug injection technique, an understanding of the fluid dynamics involved in the delivery of fluid into skin is still lacking. Herein, we sought to provide insight into the process via an in vitro study. We utilize a five needle flat array (5F) with a tattoo machine to inject fluids into gelatin gels. High-speed imaging was used to visualize the injection process and estimate the amount of fluid delive red after each injection upto the 50th injection. We investigate the role of reciprocating frequency (f) of the needle array and the physical properties of the fluids on the volume (Vo) and the percentage delivery (η) after injection. In addition, we illustrate the physical mechanism of fluid infusion during tattooing, which has not been reported. An understanding of the injection process via tattooing can be useful in the development of ID tattoo injectors as drug delivery devices.

Modified Fish Gelatin as an Alternative to Mammalian Gelatin in Modern Food Technologies

This review considers the main properties of fish gelatin that determine its use in food technologies. A comparative analysis of the amino acid composition of gelatin from cold-water and warm-water fish species, in comparison with gelatin from mammals, which is traditionally used in the food industry, is presented. Fish gelatin is characterized by a reduced content of proline and hydroxyproline which are responsible for the formation of collagen-like triple helices. For this reason, fish gelatin gels are less durable and have lower gelation and melting temperatures than mammalian gelatin. These properties impose significant restrictions on the use of fish gelatin in the technology of gelled food as an alternative to porcine and bovine gelatin. This problem can be solved by modifying the functional characteristics of fish gelatin by adding natural ionic polysaccharides, which, under certain conditions, are capable of forming polyelectrolyte complexes with gelatin, creating additional nodes in the spatial network of the gel.

Comparative Study of the Structural Properties, Color, Bioactive Compounds Content and Antioxidant Capacity of Aerated Gelatin Gels Enriched with Cryoconcentrated Blueberry Juice during Storage

Cryoconcentrated blueberry juice (CBJ) was incorporated into aerated gelatin gel and the effects on the mechanical properties, phenolic compounds and antioxidant activity (AA) were evaluated at day 1 and day 28 under refrigerated storage. At day 1, 8 g of gelatin gel and 40 g of CBJ (called M5) exhibited a soft texture and heterogeneous and non-spherical small bubbles, with values close to 10.5, 8.0 and 7.1 N, for hardness, gumminess and chewiness, respectively. M5 presented an increase of approximately 1.7, 1.9 and 1.9, and 1.2, 1.8, 2.1 and 1.3 times in comparison to the other samples, for total polyphenol, anthocyanin and flavonoid contents, and individual phenolic compounds, 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays, respectively. At day 28, the samples showed a weakening of the 3D network, with high degradation of phenolic compounds and AA due to the oxidation, polymerization and syneresis. Therefore, CBJ might be an interesting functional ingredient to add to (aerated and non-aerated) gelatin gel without affecting its properties, and thus different food products with high nutritional values and without added artificial sweeteners could be developed. Additionally, the gelatin gel/CBJ combinations might be suitable for additive manufacturing as a coating of food matrices.