Active gelatin films incorporated with eugenol nanoemulsions: effect of emulsifier type on films properties

The objective of this work was to study the impacts of the addition of eugenol nanoemulsions (NE) stabilised with two natural emulsifiers, soy lecithin (SL) or sodium caseinate (NaCas), on the properties of gelatin films for active packaging. All the films added with NE displayed higher tensile strength and elongation at break than control films. Films added with NaCas-stabilised NE were more resistant to tension compared to films added with SL-stabilised NE. Gelatin films added with both NE, showed significant differences in surface roughness compared to control film. Fourier-transform infrared spectra showed that both NE achieved complete miscibility within the films. Differential scanning calorimetry analyses suggested compatibility among both NE embedded into the films. These films indicated great antioxidant activities monitored via ABTS radical scavenging activities. These findings are essential to better design active films incorporated with nanoemulsions, in order to optimise film formulation rationally towards their eventual application as food packaging.     

Mesoporous silica nanoparticle core-shell matrix (MSN CSM) engineered by green approach for pH triggered release of anticancer drugs

The present work exhibits an alternative route to design a nano-carrier using simple electrostatic interactions of biopolymeric layers on Mesoporous Silica Nanoparticle surface using Layer by Layer (LbL) technique. The doxorubicin (DOX) loaded MSN nano-carrier is coated with positively charged chitosan followed by a coating of negatively charged sodium carboxymethyl cellulose (Na-CMC) to form a DOX-loaded MSN Core-Shell Matrix (DOX-MSN CSM). The prepared MSN nano-carrier exhibits a high encapsulation efficiency of DOX (～93 %) due to its porous nature (～832 m²/gm) and negative surface charge (-21.5 mV). It exhibits a controlled release of DOX (～21 %) at physiological pH (7.4 pH) and improved drug release (～67 %) at cancer cells pH (5.4 pH) after 48 h. Further, the in-vitro cell line study using MDA-MB 231 cells reconfirms the slower and controlled release of DOX from the engineered DOX-MSN CSM. The confocal microscopy result shows that the DOX is internalized via endocytosis into the nucleus of the cells. The cell viability assay confirms more cells viable (～76 %) for DOX-MSN CSM than free DOX (～49 %) at the end of 24 h. The present study shows an alternate route to the conventional complex multi-step processes such as coupling reactions or chemical crosslinkers involving solvents. The proposed MSN core–shell matrix can be a potential nano-carrier for cancer drug delivery.     

Polymeric nanomicelles for cancer theragnostics

Recently, interdisciplinary research in cancer diagnosis and therapy has evolved to the point where nanotechnology particularly polymeric nanodelivery systems are utilized for theragnostic applications. Nanoscale are being trialed for specific targeted delivery of drugs, micelles, antibody, DNA, protein, etc. to cancer sites to improve the therapeutic efficacy due to improved distribution specificity, increased internalization, and intracellular drug delivery that minimize the side effects. Polymeric micelles have been subjected to extensive studies in the field of drug delivery, functioning as drug solubilizers and carriers. More recently, a micelle constructed as a hybrid from hydrophilic oligonucleotide and hydrophobic polymer has drawn close attention. Mostly used micelles are synthesized with polymer and have several physical properties, including molecular weight and copolymer block composition, which can be tailored to alter the vesicle structure. In this review, we focused on the different polymeric nanodelivery systems is association with different type of cancer therapeutics such as micelles, drug, aptamer, DNA, recombinant protein, miRNA, siRNA, small inhibitors, gene, antibody, proteins and some conjugating molecules that involved in cancer therapy have been discussed.     

Opportunities for bio-based packaging technologies to improve the quality and safety of fresh and further processed muscle foods

It has been well documented that vacuum or modified atmosphere packaging materials, made from polyethylene- or other plastic-based materials, have been found to improve the stability and safety of raw or further processed muscle foods. However, recent research developments have demonstrated the feasibility, utilization, and commercial application of a variety of bio-based polymers or bio-polymers made from a variety of materials, including renewable/sustainable agricultural commodities, and applied to muscle foods. A variety of these bio-based materials have been shown to prevent moisture loss, drip, reduce lipid oxidation and improve flavor attributes, as well as enhancing the handling properties, color retention, and microbial stability of foods. With consumers demanding more environmentally friendly packaging and a desire for more natural products, bio-based films or bio-polymers will continue to play an important role in the food industry by improving the quality of many products, including fresh or further processed muscle foods.     

Constrained mixture design applied to the development of cassava starch-chitosan blown films

Films composed of cassava starch, chitosan and glycerol were produced by blown extrusion and employing a design for constrained surfaces and mixtures. The effects of the components of the mixture on the mechanical properties, water vapor permeability (WVP) and opacity of the films were studied. According to the models generated by the design, the concentration of starch had a positive effect in all properties. The plasticizer glycerol and its interactions with other components had a positive effect on increasing the WVP. The presence of a higher relative concentration of chitosan favored the formation of more rigid and opaque and less permeable films. In general, the concentrations of starch, chitosan and glycerol led to changes in the film properties, potentially affecting their performance. The design for constrained surfaces and mixtures proved to be a useful tool for this type of study due to the complexity of the conditions of film formation.     

Microstructure and properties of glycerol plasticized soy protein plastics containing castor oil

A series of glycerol-plasticized soy protein plastics containing castor oil were prepared by intensive mixing and hot pressing. The microstructure and properties of the resulting plastics were characterized with scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and mechanical tests. With small amount of castor oil incorporated (glycerol/oil ratio above 8:2), castor oil dispersed in the protein matrix homogeneously. At high concentrations, phase separation occurred. The adding of castor oil led to significant increase of storage modulus as well as glass transition temperatures attributed to glycerol-rich and protein-rich domains. Plastics containing castor oil exhibited improved tensile strength and Young’s modulus under high humidity (75% RH), compared with neat glycerol plasticized protein plastics. Especially, incorporation of low content of castor oil (glycerol/oil ratio = 9:1) would result in the simultaneous enhancement of tensile strength, elongation at break and Young’s modulus. Increasing castor oil content also enhanced the thermal stability of the protein plastics.     

Physical aging of processed fragmented biopolymers

Low moistures foods containing starches exhibit a sub-T_g endotherm (55–60 °C) when they are stored at constant temperatures. Although the origin of the endotherm is still debatable, it has been attributed to the water–hydroxyl group interactions and/or enthalpic associations between water and carbohydrates. In the present study, physical aging of the starch components of corn flakes prepared with two different levels of starch fragmentation was studied using thermal and rheological methods. A sub-T_g endotherm was observed at temperatures around 50–60 °C by both DSC and Oscillatory Squeezing Flow measurements. An increase of 1.5% of moisture content was observed for both fragmented flakes during aging. The temperatures at which the sub-T_g endotherms occurred were independent of aging and moisture content increase during storage, whilst enthalpy increased with both aging time and moisture content. Although the moisture content of the two types of flakes were different the aging time at which the first endotherm appeared and the rate at which the enthalpy increased were dependent only on the level of starch fragmentation. Corn flakes with a high level of starch fragmentation required a longer period of aging time before the presence of the endotherm could be detected and had a greater rate of increase in enthalpy. Overall, flakes having higher starch fragmentation absorbed more water, and the percent of water uptake decreased with aging time. Flakes with low starch fragmentation exhibited little to no change in water uptake during aging.     

Solution-processed natural gelatin was used as a gate dielectric for the fabrication of oxide field-effect transistors

Biocompatible and biodegradable materials are attractive for environmentally safe, flexible and biosustainable devices since they are nontoxic renewable materials with a low cost. Gelatin, a natural protein, is a promising biopolymer for photography, cosmetic manufacturing and food. In this paper, solution-processed natural gelatin was used as a gate dielectric for the fabrication of oxide field-effect transistors (FETs). Similarly to a polyelectrolyte, mobile ions can be generated in gelatin in air environment. A high gate specific capacitance larger than 0.93 μF/cm² was obtained in gelatin processed at low concentrations, due to the formation of electric-double-layers (EDLs). As gelatin films processed at a low concentration of 0.02 g/mL, the fabricated FETs showed excellent electrical performances. The average current on/off ratio and the mobility were estimated to be 1.36 × 10⁵ and 33.2 cm²/V, respectively. The proposed technique may be application in the bioelectronics field, including biosensors and synaptic devices.     

Structure and properties of polylactide/natural rubber blends

Polylactide, PLA, is a biodegradable thermoplastic polyester derived from biomass that has restricted packaging applications due to its high brittleness and poor crystallisation behaviour. Here, new formulations based on natural rubber–PLA blends have been developed. The processing windows, temperature, time, and rotor rate, and the rubber content have been optimised in order to obtain a blend with useful properties. The rubber phase was uniformly dispersed in the continuous PLA matrix with a droplet size range from 1.1 to 2.0 μm. The ductility of PLA has been significantly improved by blending with natural rubber, NR. The elongation at break improved from 5% for neat PLA to 200% by adding 10 wt% NR. In addition, the incorporation of NR not only increased the crystallisation rate but also enhanced the crystallisation ability of PLA. These materials are, therefore, very promising for industrial applications.     

Spray-Drying Microencapsulation of Anthocyanins by Natural Biopolymers: A Review

There has been an increased interest in the development of food colorants from natural sources as alternatives to synthetic dyes because of both legislative actions and consumer concerns. Anthocyanins are of great interest for the food industry since they give a wide range of colors as well as nutraceutical activities. Nevertheless, due to their low stability to environmental conditions during processing and storage, introducing those compounds into foods is challenging. Microencapsulation may be an efficient way to introduce such compounds into those products. An important step in developing microcapsules is the selection of a biopolymer (wall material) which meets the required criteria. Hence, this review will focus on microencapsulation of anthocyanins with different biopolymers through spray drying to develop natural colorant pigments which possess high stability, solubility, and dispersibility. Our goal is to give updated information regarding microencapsulation of anthocyanins by spray drying, as well as its effectiveness, developments, and optimized conditions which will be discussed.