Mechanical, thermal and heat sealing properties of fish skin gelatin film containing palm oil and basil essential oil with different surfactants

Gelatin-Based Antimicrobial Films Incorporating Pomegranate (Punica granatum L.) Seed Juice by-Product

Pomegranate (Punica granatum L.) seed juice by-product (PSP) was added as reinforcing and antimicrobial agent to fish gelatin (FG) films as a promising eco-friendly active material for food packaging applications. A complete linkage analysis of polysaccharides in PSP showed xylan and cellulose as main components. This residue showed also high total phenolic content and antioxidant activity. Three formulations were processed by adding PSP to FG (0, 10, 30 wt. %) by the casting technique, showing films with 10 wt. % of PSP the best performance. The addition of PSP decreased elongation at break and increased stiffness in the FG films, particularly for 30 wt. % loading. A good compatibility between FG and PSP was observed by SEM. No significant (p < 0.05) differences were obtained for barrier properties to oxygen and water vapour permeability compared to the control with the incorporation of PSP, whereas water resistance considerably increased and transparency values decreased (p < 0.05). High thermal stability of films and inhibition against S. aureus were observed. The addition of PSP at 10 wt. % into FG was shown as a potential strategy to maintain the integrity of the material and protect food against lipid oxidation, reducing huge amounts of pomegranate and fish wastes.

Effect of Mesoporous Silica Nanoparticles on The Physicochemical Properties of Pectin Packaging Material for Strawberry Wrapping

Citrus peel pectin was used to prepare films (cast with or without glycerol) containing mesoporous silica nanoparticles. Nanoparticles reduced significantly the particle size, and had no effect on the Zeta potential of pectin solutions. Mechanical characterization demonstrates that pectin+nanoparticles containing films slightly increased tensile strength and significantly decreased the Young's modulus in comparison to films made only of pectin. However, elongation at the break increased in the pectin+nanoparticles films cast in the presence of glycerol, while both Young's modulus and tensile strength were reduced. Moreover, nanoparticles were able to reduce the barrier properties of pectin films prepared with or without glycerol, whereas positively affected the thermal stability of pectin films and the seal strength. The 0.6% pectin films reinforced or not with 3% nanoparticles in the presence of 30% glycerol were used to wrap strawberries in order to extend the fruit's shelf-life, over a period of eighty days, by improving their physicochemical properties.

Assessment of the denaturation of collagen protein concentrates using different techniques

The use of collagen and gelatin in the field of regenerative medicine is widely extended. However, most of the studies in this topic are focused on the scaffolds' properties, but only a few are related to the properties of the raw material used. The raw material analysis not only consists of a study of the composition, but also of the denaturation degree that can influence the processing and properties of the structure of the scaffold. Thus, the denaturation degree analysis of different collagen proteins was performed and assessed by the comparison of four different methods: differential scanning calorimetry (DSC), Fourier transform Infrared Spectroscopy (FTIR) and circular dichroism (CD) spectra and sulfhydryls content analysis. DSC measurements put forward a glass transition between 88°C and 95°C as well as from the FTIR measurements; the characteristic peaks for proteins are evidenced. However, from the sulfur content, only a small proportion of free sulfhydryls are present with respect to their total amount. In addition, CD spectra allow to estimate the secondary structure of the protein by the analysis of the α-helix and β-strand and also quantify the denaturation degree with the 'positive/negative ratio' (RPN) from the CD profiles, obtaining values in the range between 25% and 100%.

Gelatin edible coatings with mint essential oil (Mentha arvensis): film characterization and antifungal properties

In this work, mint essential oil (MEO) was added into gelatin films and antifungal activity was evaluated. Five concentrations of MEO (0, 0.06, 0.13, 0.25, 0.38, 0.50% (g/g gelatin)) were incorporated into gelatin solutions. The films were prepared by casting and characterized for their barrier properties, mechanical resistance, morphology, thermal and antifungal activity. The addition of oil into the solution slightly improved water vapor barrier, increased thickness and opacity, decreased transparency and modified thermal and mechanical properties of films. With addition of oil above 0.38%, the films were effective against the growth of Botrytis cinerea and Rhizopus stolonifer, indicating an inhibitory activity. Thus, gelatin-based edible films incorporated with MEO showed to be an effective way to inhibit microbial growth on the film surface.

Antibacterial and Barrier Properties of Gelatin Coated by Electrospun Polycaprolactone Ultrathin Fibers Containing Black Pepper Oleoresin of Interest in Active Food Biopackaging Applications

The present study evaluated the effect of using electrospun polycaprolactone (PCL) as a barrier coating and black pepper oleoresin (OR) as a natural extract on the morphology, thermal, mechanical, antimicrobial, oxygen, and water vapor barrier properties of solvent cast gelatin (GEL). The antimicrobial activity of the developed multilayer system obtained by the so-called electrospinning coating technique was also evaluated against Staphylococcus aureus strains for 10 days. The results showed that the multilayer system containing PCL and OR increased the thermal resistance, elongated the GEL film, and significantly diminished its permeance to water vapor. Active multilayer systems stored in hermetically closed bottles increased their antimicrobial activity after 10 days by inhibiting the growth of Staphylococcus aureus. This study demonstrates that addition of electrospun PCL ultrathin fibers and OR improved the properties of GEL films, which promoted its potential use in active food packaging applications.

Antimicrobial gelatin-based elastomer nanocomposite membrane loaded with ciprofloxacin and polymyxin B sulfate in halloysite nanotubes for wound dressing

Bacterial infection is a major problem world-wide, especially in wound treatment where it can severely prolong the healing process. In this study, a double drug co-delivery elastic antibacterial nanocomposite was developed by combining ciprofloxacin (CPX) and polymyxin B sulfate-loaded halloysite clay nanotubes (HNTs-B) into a gelatin elastomer. CPX nanoparticles which act against both gram positive and gram-negative bacterium were dispersed directly in the matrix, and polymyxin B sulfate was loaded in HNTs and then distributed into the matrix. The effect of CPX and HNTs-B content on the physical properties, cytotoxicity, fibroblast adhesion and proliferation, in vitro drug release behavior and anti-bacterial properties were systematically investigated. The ciprofloxacin crystals and HNT-B were distributed in the matrix uniformly. The HNTs in the drug loading system not only enhanced the matrix' tensile strength but also slowed down the release rate of the high dissoluble polymyxin B sulfate. When the amount of HNT in the matrix increased, the thermal stability and tensile strength also increased but the polymyxin B sulfate release rate decreased because the HNTs prevented the drug release inside. All the nanocomposites exhibited antimicrobial activity against both gram-negative and gram-positive bacteria with the dual combination of drugs released from the nanocomposites. Furthermore, this kind of gelatin-based nanocomposites possesses higher water-absorbing quality, low cytotoxicity, adaptable biodegradability and good elasticity which can satisfy the requirements for an ideal biomaterial for use in wound healing applications.