Physical and mechanical properties of peanut protein films

The properties of peanut protein films were modified using physical and chemical treatments, and their effects on color, mechanical strength, water solubility and barrier to water vapor and oxygen of the films were investigated. Physical treatments consisted of heat denaturation of film-forming solution for 30 min at 60°C, 70°C, 80°C and 90°C, ultraviolet irradiation of films for up to 24 h, and three ultrasound processes of film-forming solution. Chemical treatments consisted of addition of aldehydes and anhydrides. Heat curing at 70°C, ultraviolet irradiation for 24 h, ultrasound for 10 min in a water-bath, and formaldehyde and glutaraldehyde addition caused a significant increase in the tensile strength of the films. The water vapor permeability (WVP) and oxygen permeability (OP) of the films decreased after heat denaturation and aldehyde treatment. OP also decreased with UV treatment. Heat curing was the most effective treatment, making the films stronger, more resistant to water and less permeable to water vapor and oxygen.     

Pyrolysis of cellulose, xylan and lignin with the K2CO3 and ZnCl2 addition for bio-oil production

The chemical structure of liquid products of the wood biopolymers, i.e. cellulose, xylan and lignin pyrolysis at 450 °C with and without the 10 wt.% addition of potassium carbonate or zinc chloride was investigated. The yield of liquid products of pyrolysis was in the range of 24-44 wt.% and their form was depending on the chemical structure of pyrolyzed material. The potassium carbonate and zinc chloride addition to biopolymers has also influenced the temperature range of samples decomposition as well as the structure of resulted bio-oils. All bio-oils from biopolymer were dark-brown water-oil emulsions. Contrarily, bio-oils obtained from biopolymer with K₂CO₃ or ZnCl₂ addition were orange liquids with well-separated water and oil phases. All analyses proved that the composition and the quality of bio-oil strongly depends on both the nature of the starting sample and the presence of the additive. The FT-IR analyses of oils showed that oxygen functionalities and hydrocarbons contents highly depend on the type of biopolymer. Results confirmed the significant removal and/or transformation of oxygen containing organic compounds due to the zinc chloride and potassium carbonate presence during pyrolysis process.     

Comparative Evaluation of Physical Properties of Edible Chitosan Films Prepared by Different Drying Methods

Edible films are alternative packaging, which have recently received much attention due mainly to environmental reasons. Edible films may be formed from edible biomaterials such as polysaccharides, proteins, or lipids. Among these biopolymers, chitosan is of interest because it has a good film-forming property and is biodegradable, biocompatible, and nontoxic. Several techniques have been used to prepare edible chitosan films with various degrees of success. However, it is always interesting to find an alternative technique to produce films of superior quality at shorter processing (drying) time. In this study, the influences of different drying methods and conditions on the drying kinetics and various properties of chitosan films were investigated. Drying at control conditions (ambient air drying and hot air drying at 40°C) as well as vacuum drying and low-pressure superheated steam drying (LPSSD) at an absolute pressure of 10 kPa were carried out at different drying temperatures (70, 80, and 90°C). The properties of chitosan films, in terms of color, tensile strength, percent elongation, water vapor permeability (WVP), glass transition temperature (T _g ), and crystallinity, were also determined. Based on the results of both the drying behavior and film properties, LPSSD at 70°C was proposed as the most favorable conditions for drying chitosan films.     

Chitosan gel film bandages: Correlating structure,composition, and antimicrobial properties

Chitosan gel films were successfully obtained by evaporation cast from chitosan solutions in aqueous acidic solutions of organic acids (lactic and acetic acid) as gel film bandages, with a range of additives that directly influence film morphology and porosity. We show that the structure and composition of a wide range of 128 thin gel films, is correlated to the antimicrobial properties, their biocompatibility and resistance to biodegradation. Infrared spectroscopy and solid‐state ¹³C nuclear magnetic resonance spectroscopy was used to correlate film molecular structure and composition to good antimicrobial properties against 10 of the most prevalent Gram positive and Gram negative bacteria. Chitosan gel films reduce the number of colonies after 24 h of incubation by factors of ～10⁵–10⁷ CFU/mL, compared with controls. For each of these films, the structure and preparation condition has a direct relationship to antimicrobial activity and effectiveness. These gel film bandages also show excellent stability against biodegradation with lysozyme under physiological conditions (5% weight loss over a period of 1 month, 2% in the first week), allowing use during the entire healing process. These chitosan thin films and subsequent derivatives hold potential as low‐cost, dissolvable bandages, or second skin, with antimicrobial properties that prohibit the most relevant intrahospital bacteria that infest burn injuries. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Lignin solvated in zwitterionic Good's buffers displays antibacterial synergy against Staphylococcus aureus

The volume of industrial lignin is expected to increase with the deployment of biorefineries that convert lignocellulosic biomass to renewable chemicals and fuels. Interest in using lignin for value-added biomedical applications requires understanding of its effects on mammalian and microbial cells, which has been impaired by the toxicity of the solvents used to solubilize lignin. In this study, lignin is solvated in zwitterionic Good's buffers compatible with culture media. Up to 100 mg lignin can be solvated in 1 ml of 3-morpholinopropane-1-sulfonic acid (MOPS, pH 7.2) within 60 min at room temperature, whereby MOPS acts as a chaotropic agent. The addition of MOPS-solvated lignin to cultures of Staphylococcus aureus UAMS-1 containing a subinhibitory concentration of tunicamycin reduced growth more than 99% compared to tunicamycin alone, making lignin of interest as an antibiotic adjuvant. This effect of lignin is attributed to damage to the bacterial cell membrane.     

Nanocellulose-based polymer composites for energy applications—A review

With rapid fossil fuel consumption and ecological concerns, alternative options of green energy development and its efficient storage technology is an emergent area of research. Nanocellulose is observed to be a very-promising sustainable and environmentally friendly nanomaterial for green and renewable electronics for advanced electrochemical energy conversion/conservation devices. This review begins with a basic introduction on the sources and properties of nanocellulose. It provides an overview of the recent advancements made by researchers in integrating nanocellulose with active materials to form a flexible film/aerogel/3D structures as a substrate for powering portable electronics, electric vehicles, etc. The review highlights the use of nanocellulose-based composites in energy conversion devices such as solar cells, piezoelectric materials, and lithium ion batteries. Recent research shows that the power conversion efficiency of solar cells and the piezoelectric performance of piezoelectric materials can be increased when the matrix is reinforced with nanocellulose. The review also focuses on the updates of nanocellulose-based composites in separators, binders, and electrodes of energy conservation devices such as supercapacitors, and energy capture devices such as CO₂ separators. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48959.     

Assessment of formulation parameters needed for successful vitamin C entrapped polycaprolactone nanoparticles

Vitamin C (Vit.C)-entrapped polycaprolactone (PCL) nanoparticles (Vit.C–PCNs) were prepared by encapsulation of Vit.C into PCL-based nanoparticles (PCNs) which were prepared using double emulsion method with two steps. First, the inner aqueous phase (W₁) was added to dichloromethane solution containing PCL with homogenization to form primary emulsion (W₁/O) which was emulsified with the outer aqueous phase (W₂) containing polyvinyl alcohol as stabilizer to attain the double emulsion (W₁/O/W₂). Versatile parameters were investigated to reach to the most successful formulation for Vit.C–PCNs, such as time, effect of speed of homogenization on drug encapsulation efficiency, etc.     

Synthesis, characterization and biodegradation of biodegradable-cum-photoactive liquid-crystalline copolyesters derived from ferulic acid

Novel biodegradable-cum-photoactive liquid-crystalline copolyester was prepared by melt polycondensation of ferulic acid (FA), 4-hydroxybenzoic acid (HBA) and d,l-lactic acid (LA) in the presence of acetic anhydride and a transesterification catalyst. The chemical structures and properties of the synthesized copolyesters were characterized by means of viscosity measurements, Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (¹H NMR), differential scanning calorimetry (DSC), thermogravimetry (TGA), polarizing light microscopy (PLM) and ultraviolet spectroscopy (UV). It was found that modestly increasing LA content and adjusting feed ratios could enhance the solubility and biodegradability of the copolyesters, still retaining the liquid crystallinity. The obtained copolyester could degrade in phosphate buffer solution (pH 7.2) with enzyme proteinase K, and could crosslink by UV-irradiation at ambient temperature.     

Investigation of the behaviour of chitosan microparticles as pH responsive hydrogels in the gastro-intestinal tract using magnetic resonance imaging

The objective of this research was to determine whether chitosan microparticles could be developed as potential satiety enhancing ingredients by investigating their swelling behaviour in the gastro-intestinal tract using magnetic resonance imaging (MRI). Previous work undertaken using a covalently cross-linked composite of chitosan and bovine serum albumin (BSA) showed this system swells in gastric conditions in vitro (Butler, Clark, & Adams, 2006). This paper describes the preparation and characterisation of chitosan/BSA microparticles cross-linked using 25 mM and 100 mM glutaraldehyde (GDA). 1.5% chitosan/15% BSA microparticles cross-linked with 25 mM GDA swell by 100% in simulated gastric conditions. We found an experimental correlation between the transverse NMR relaxation time, T₂, and swelling of the microparticles in vitro. Our study of four volunteers showed swelling of these microparticles in the human stomach, observed from increases in T₂ of the microparticles using non-invasive MRI. As such, our initial results, with 4 volunteers, suggest that this system could be used as a potential satiety enhancing agent in vivo as we would expect it to provide gastric distension due to swelling at low pH. Further studies with more volunteers would be necessary to confirm our initial findings.