Photographic Emulsions Research Articles

Enhancing Biodegradable Packaging: The Role of Tea Polyphenols in Soybean Oil Body Emulsion Films

To address the increasingly diverse demands for biodegradable packaging materials, such as for their physical properties and antioxidant properties, this study incorporated tea polyphenols (TPs) into soybean oil body emulsions (SOBs) and added a certain proportion of sodium alginate (SA) and octenyl succinic starch sodium (SSOS) to prepare a biodegradable soybean oil body–tea polyphenol (ST) emulsion film. The study systematically evaluated the effects of different concentrations of TP (0–6 wt.%) on the structure, physicochemical properties, antioxidant activity, and antibacterial activity of ST films. The results showed that the physical properties, such as tensile strength and elongation at break, of the films increased significantly with the addition of TP, and the antioxidant and antibacterial activity also increased with the increase in TP concentration. When TP concentration was 2.5 wt.%, the barrier properties of the film (ST-2.5) significantly improved (p < 0.05), while water content and water solubility decreased. The Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis results showed that the structure of ST films became tighter at this point. The addition of TP also affected the sensory properties of ST films, such as with an increase in the opacity of the film. Compared with the control, the light transmittance of ST-6.0 decreased by 23.68% at a wavelength of 600 nm, indicating a significant reduction in film transparency. Moreover, the biodegradability test showed that ST films have good degradability. Therefore, the ST film, as a functional edible film, has broad application prospects in the food packaging industry.

Charge Regulation in Liquid Films Stabilized by Ionic Surfactants: Change in Adsorption with Film Thickness and Phase Transitions

When a liquid film is thinning, the charge and the potential of its surfaces change simultaneously due to the interaction between the two surfaces. This phenomenon is an example for charge regulation and has been known for half a century for systems featuring aqueous solutions in contact with metals, salts, biological surfaces covered by protolytes, etc. Few studies, however, investigated regulation in foam and emulsion films, where the charge is carried by soluble ionic surfactants. This work presents an analysis of the phenomenon for surfactants that follow the classical Davies adsorption isotherm. The electrostatic disjoining pressure Πel was analyzed, and the Davies isotherm was shown to lead to Πel ∝ h−1/2 behavior at a small film thickness h. As usual, the charge regulation regime (constant chemical potential of the surfactant) corresponded to a dependence of Πel on h between those for constant charge and constant electric potential regimes. The role of the background electrolyte was also studied. At the water–air interface, many ionic surfactants exhibit a surface phase transition. We show that the interaction between the two surfaces of a foam film can trigger the phase transition (i.e., the film changes its charge abruptly), and two films of different h values can coexist in equilibrium with each other – one covered by surfactant in the 2D gaseous state and another in the 2D liquid state.

Improved konjac glucomannan/curdlan-based emulsion coating by mung bean protein addition for cherry tomato preservation.

Biopolymer-based emulsion systems have been used for food preservation. In this study, mung bean protein (MBP) was added to konjac glucomannan (KGM)/curdlan-based camellia oil emulsion (KC-CO) to develop KCM-CO emulsion system. KCM-CO emulsions showed good compatibility and stability during storage. The confocal laser scanning microscopy, atomic force microscope, and infrared spectroscopy revealed that camellia oil was successfully emulsified by MBP, and the resulting droplets were evenly distributed in the polysaccharide network formed by KGM and curdlan micelles based on hydrogen bonds. The emulsions behaved as an elastic solid, and the KCM-CO emulsion films exhibited a compact microstructure, and the emulsification of MBP enhanced the compatibility, as K54C40M6-CO had the smoothest surface. The addition of MBP significantly improved the elongation at break (EAB), water contact angle (WCA), dissolution, and gas permeability of the emulsion films. K54C40M6-CO showed the largest EAB (37.6%), strong hydrophobicity (WCA=97.8°), and low water vapor and oxygen permeability. In the preservation experiments, K54C40M6-CO coating significantly delayed the weight loss (by 41.2%) and firmness decline (by 54.5%), and maintained the appearance, total solids, total acids, and ascorbic acid content of cherry tomatoes, and inhibited the respiratory intensity by 44.2%. This coating showed great potential for fruit and vegetable preservation.

The amyloid fibril-stabilized Pickering emulsion significantly enhances the mechanical and barrier properties of Konjac Glucomannan active films for cherry preservation.

Konjac glucomannan (KGM), a natural polymer, is an excellent candidate for use in food packaging due to its desirable film-forming characteristics. However, the limited barrier, antioxidant, and antimicrobial properties of pure KGM films restrict their practical applications. To reinforce the barrier and functional properties of KGM-based films, tea tree oil (TTO) Pickering emulsions stabilized by chitosan-modified soy protein derivative-amyloid fibril (AFS) were prepared and incorporated into KGM matrices. The effects of these Pickering emulsions on the structural and functional properties of KGM films were systematically investigated. The results indicated a favorable compatibility between Pickering emulsions and KGM. The strong interactions among KGM, AFS, and TTO lead to a denser and more compact film structure, improving barrier properties. Specifically, the water vapor and oxygen permeability values of the Pickering emulsion films (group E4C1) were reduced to 0.326g·mm/(m2·day·KPa) and 4.63g/m·s·Kpa, respectively. The tensile strength and elongation at the break of the film were increased respectively to 35.02MPa and 71.8%. The incorporation of TTO markedly enhanced water resistance, with the total antioxidant capacity of group E5C1 being 9.92 times greater than that of pure KGM films, as well as improving the antimicrobial activity of the KGM-based films. Furthermore, the emulsion film demonstrated effective preservation of cherries, extending their shelf life by approximately 10days. In conclusion, this study successfully developed a film with enhanced barrier properties and antimicrobial activity, presenting promising applications in food preservation and packaging.

Effect of Persian gum-gelatin based-pickering emulsion film loaded with Thyme essential oil on the storage quality of Barred mackerel (Scomberomorus commerrson) fillet

Effect of Persian gum-gelatin based-pickering emulsion film loaded with Thyme essential oil on the storage quality of Barred mackerel (Scomberomorus commerrson) fillet

Black goji anthocyanin-loaded emulsion film stabilized by rice protein hydrolysate complexes as pH-sensitive indicator for salmon freshness

Black goji anthocyanin-loaded emulsion film stabilized by rice protein hydrolysate complexes as pH-sensitive indicator for salmon freshness

Development of konjac glucomannan-based active-intelligent emulsion films loaded with different curcumin-metal chelates: Stability, antioxidant, fresh-keeping and freshness detection properties

The aim of this study was to develop konjac glucomannan (KGM)-based active-intelligent emulsion films loaded with different curcumin-metal chelates, where six types of films were prepared and their corresponding properties were investigated. The FTIR and XRD results showed that curcumin chelated with metal ions successfully. Moreover, curcumin-Ca chelate had the best thermal stability and antioxidant activity with the DPPH and ABTS radical-scavenging activity values of 38.28 % and 22.79 %, respectively. Furthermore, the results of microstructure and contact angle showed that chelation with metal ions improved the interfacial interactions between curcumin-metal chelates and film matrix. Interestingly, KGM-based active-intelligent emulsion films loaded with curcumin-Ca chelate (Type IV film) displayed the best thermal stability with the highest temperature of maximum weight loss at 380 °C, the best mechanical property, the highest total phenol content (17.31 mg gallic acid/g film), as well as the best antioxidant activity with DPPH and ABTS radical-scavenging activity values of 69.24 % and 58.66 %, respectively, and the best antibacterial activity. Consequently, Type IV film was used for the fresh-keeping and freshness detection of pork. The results showed that the pork packaged with Type IV film displayed excellent fresh-keeping properties, including reducing the increase rate of volatile basic nitrogen (TVB-N) and pH values and the decrease rate of hardness and elasticity of pork during storage time. Meanwhile, the color of Type IV film gradually changed from yellow to red. Therefore, this study suggested that KGM-based active-intelligent emulsion films have great potential application in the fresh-keeping and freshness detection of fresh meat.

From dark matter searches to proton therapy: Measuring target fragmentation with nanometric nuclear emulsions

The DAMON (Direct meAsureMent of target fragmentatiON) project aims to explore the use of Nano Imaging Trackers (NITs) for the first direct measurement of target fragmentation caused by proton beams in cancer treatment. NITs are fine-grained nuclear emulsion films that offer a spatial resolution at the nanometric scale. DAMON’s pilot test exposed a NIT-based detector to 211 MeV protons, paving the way for the first study of target fragmentation in direct kinematics. In this paper the preliminary results regarding the multiplicity of the fragments and their track lengths are reported.

New high-precision measurement system for electron–positron pairs from sub-GeV/GeV gamma-rays in the emulsion telescope

The GRAINE project observes cosmic gamma-rays, using a balloon-borne emulsion-film-based telescope in the sub-GeV/GeV energy band. We reported in our previous balloon experiment in 2018, GRAINE2018, the detection of the known brightest source, Vela pulsar, with the highest angular resolution ever reported in an energy range of >80MeV. However, the emulsion scanning system used in the experiment was designed to achieve a high-speed scanning, and it was not accurate enough to ensure the optimum spatial resolution of the emulsion film and limited the performance. Here, we report a new high-precision scanning system that can be used to greatly improve the observation result of GRAINE2018 and also be employed in future experiments. The scanning system involves a new algorithm that recognizes each silver grain on an emulsion film and is capable of measuring tracks with a positional resolution for the passing points of tracks of almost the same as the intrinsic resolution of nuclear emulsion film (∼70 nm). This resolution is approximately one order of magnitude smaller than that obtained with the high-speed scanning system. With this scanning system, an angular resolution for gamma-rays of 0.1° at 1GeV is expected to be achieved. Furthermore, we successfully combine the new high-precision scanning system with the existing high-speed scanning system, enabling the high-speed and high-precision measurements. Employing these techniques, we reanalyze the gamma-ray events detected previously by only the high-speed scanning system in GRAINE2018 and obtain an about three times higher angular resolution (0.22°) in the 500–700MeV energy range. Adopting this technique in future observations may provide new insights into the gamma-ray emission from the Galactic center region and may realize polarization measurements of high-energy cosmic gamma-rays.

The Role of Formulations in the Ageing Process of Vinyl Acetate Based Emulsion Films: A Multivariate Approach

Vinyl acetate (VAc)-based emulsions represent one of the main media used by modern and contemporary artists. Their long-term behaviour is still not completely understood, especially due to the scarce knowledge on the influence of other compounds in the formulation, which may impact ageing over time. Besides the polymer backbone based on vinyl acetate, other co-monomers and additives can be added to the emulsion to alter the final film’s physical, chemical, and optical properties. By extension, the formulation will also impact the long-term stability of artworks and objects on which it has been applied, as well as possible current and future conservation interventions such as cleaning. For those reasons, studies shedding light on the correlation between composition and long-term stability are largely necessary. In this study, different emulsions, including homopolymers, copolymers, plasticised, and un-plasticised compositions, were gathered and artificially aged. A multivariate analyses approach based on the application of principal component analyses (PCA) and hierarchical cluster analyses (HCA) was employed for the first time on the combination of data obtained by pH, contact angle (CA), colour measurements, Fourier transform infrared spectroscopy in attenuated total reflection (FTIR-ATR), and size exclusion chromatography (SEC). This approach helped to highlight the changes that occurred during ageing and find correlations with the formulation compositions. The results further sustain the thesis that not all vinyl acetate-based emulsions are chemically the same and that their formulation deeply impacts their long-term behaviour.

Cosmic rays, radiocarbon and the beginning of high-energy particle physics: Marietta Blau and the “disintegration stars”

Abstract This brief review describes the discovery of cosmic rays by Victor Hess from the Vienna Radium Institute and the later contribution of Marietta Blau through her observation of “disintegration stars” in photographic emulsion plates exposed to cosmic-ray bombardment. Marietta Blau, a nearly forgotten cosmic-ray pioneer from the Vienna Radium Institute, developed the nuclear emulsion technique for studying nuclear reactions, eventually discovering the disintegration of nuclei through high-energy cosmic rays. Blau survived the Holocaust by escaping to Mexico City from 1939 to 1944. Starting in 1948 at Columbia University, later as a staff member of Brookhaven National Laboratory and then University of Miami, she performed fundamental and original research with nuclear emulsions exposed to 3-GeV protons at the Brookhaven Cosmotron and to 6-GeV protons at the Berkeley Bevatron. Blau returned to Vienna in 1960, where at the Radium Institute a classical β-decay counting facility for radiocarbon dating had been installed, which was finally superseded by the Vienna Environmental Research Accelerator (VERA), a modern versatile accelerator mass spectrometry facility.

Multifunctional composite film of curcumin Pickering emulsion stabilized by lignocellulose nanofibrils isolated from bamboo shoot shells for monitoring shrimp freshness

Concerns about food safety and environmental impact from chemical surfactants have prompted interest in natural lignocellulosic materials as alternatives. In this study, we combined hydrated deep eutectic solvent (DES) pretreatment with ultrasound treatment to prepare lignocellulosic nanofibrils (LCNF) from bamboo shoot shells with appropriate surface properties for stabilizing Pickering emulsions. The pretreatment intensity effectively modulated the surface characteristics of LCNF, achieving desirable wettability through lignin retention and in-situ esterification. The resulting LCNF/curcumin Pickering emulsion (CPE) demonstrated curcumin protection and pH-responsive color changes, while the ensuing CPE/PVA composite film exhibited ultraviolet shielding, mechanical strength, oxygen barrier, and antioxidant properties. Furthermore, the CPE/PVA film showed promise as a real-time indicator for monitoring shrimp freshness, maintaining sensitivity to spoilage even after six months of storage. These findings advance the advancement of green LCNF technologies, providing eco-friendly solutions for valorizing bamboo shoot shells and enhancing the application of LCNF in Pickering emulsions.

Improved moisture barrier and mechanical properties of rice protein/sodium alginate films for banana and oil preservation: Effect of the type and addition form of fatty acid

Attenuating the moisture sensitivity of hydrophilic protein/polysaccharide-based films without impairing other properties remains a challenge. Fatty acid dispersed in Pickering emulsion was proposed to overcome such issue. An increase in fatty acid chain length slightly reduced the water vapor permeability (WVP) of emulsion films. As the number of fatty acid double bonds increased from 0 to 1, the WVP of emulsion films was significantly decreased by 14.02% while mechanical properties were significantly enhanced. More hydrogen bonds and stronger electrostatic interactions in the presence of fatty acids were observed by molecular dynamics simulation. The weight loss of bananas coated with oleic acid-incorporated film-forming emulsion was 6.81% lower than that of uncoated group after 4 days, and the corresponding film was more effective to delay oil oxidation than the commercial polypropylene film, indicating that the film is a promising alternative to food coating and packaging material.

Double-layer films based on konjac gum and hydroxypropyl methyl cellulose loaded with thyme essential oil Pickering emulsion: Preparation, characterization, and application

Due to the challenges posed by petroleum-based plastics in terms of degradation and their contribution to environmental pollution, researchers have focused on natural biodegradable packaging materials. Herein, a biodegradable, unidirectional released, bilayer active film based on Konjac gum/hydroxypropyl methylcellulose (KGM/HPMC) were developed. Specifically, Pickering nano-emulsion was formed via ultrasonic self-assembly of Thyme essential oil (TEO) and a suspension of oxidized chitin nanocrystals. The dual-network form by KGM/HPMC effectively incorporated the TEO droplets in Pickering nano-emulsion through intermolecular hydrogen bonding, demonstrating good solubility between the TEO droplets and film matrix. The mechanical properties of the active film are greatly improved due to the protective effect provided by the outer layer in the double-layer active emulsion film design. Furthermore, the double-layer active film enables a unidirectional release of essential oils, thereby enhancing the efficiency of essential oil utilization. In addition, the double-layer active film has beneficial properties, including antioxidation, antibacterial effects, ultraviolet radiation protection, and biodegradability compared to cling film. This film was employed for the preservation of salmon, and the findings indicated that the bilayer active film, formulated with 15% Pickering emulsion content, notably retarded the escalation of total volatile basic nitrogen (TVB-N) and pH levels in salmon. Furthermore, it successfully reduced the proportion of dominant bacteria (specifically Pseudomonas) in salmon samples. The double-layer active film developed in this study demonstrates the potential for extending the shelf life of aquatic products.

Nuclear emulsion film production system for experiments in full-area scanning and analysis era

Research utilizing the sub-micron three-dimensional spatial resolution of nuclear emulsion detectors has been expanding in various fields, triggered by the development of automated emulsion scanning technology. This paper describes a new production system capable of supplying several thousand square meters of nuclear emulsion film per year. The development and introduction of improved emulsion gel, knife coating, and drying equipment have enabled the mass production of double-side coated nuclear emulsion films with thick emulsion layers suitable for full-area scanning and analysis. This system has played an essential role in numerous nuclear emulsion experiments.

Pectin-based cinnamon essential oil Pickering emulsion film with two-sided differential wettability: A major role in the spatial distribution of microdroplets

Pickering emulsions have attracted much attention as a novel emulsifying technology. This research to explore Zein-Citrus pectin nanoparticles stabilized cinnamon essential oil (CEO) Pickering emulsion (ZCCPEs) for constructing Pickering emulsion edible film (PEF). Unlike traditional research, which focuses on antibacterial and antioxidant activities, our research examined the physical properties of PEF, specifically changes in wettability. The results show that PEF has better transparency and tensile strength than the pectin alone direct emulsion film (PAEF), and the spatial distribution of Pickering emulsion droplets gives different wettability on both sides of PEF. The partially hydrophobic upside has important application value in food packaging. At the same time, the PEF is biodegradable and environmentally non-polluting. The edible film loaded with essential oils, developed based on the Pickering stabilization mechanism in this study, possesses several desirable characteristics for potential used as bioactive packaging films in food applications.

Cinnamaldehyde emulsions for a composite film based on polyvinyl alcohol/hydrophobically modified konjac glucomannan matrix: Degradability and bacteriostatic properties

Biodegradable polyvinyl alcohol (PVA) and hydrophobically modified deacetyl konjac glucomannan (DK) films loaded with cinnamaldehyde (CA) emulsion were developed and characterized. The particle size of 957.4 nm and encapsulation rate of 91.23 % confirmed that CA had been embedded in the O/W emulsion system. SEM and AFM analysis showed that the PVA/DK film was more compatible, while the CA emulsion provoked bubbles and bumps on the surface, significantly gaining roughness (Ra). Besides, the water absorbency and water vapors permeability of DK after acetylation modification was lower. Meanwhile, PVA and DK had complementary roles, blending the two to enhance the water resistance of PVA and ameliorate the fragile defects of DK while accelerating the degradation of the film. Above all, the CA emulsion film possesses a vigorous antibacterial effect on Escherichia coli and Staphylococcus aureus, and the PVA/DK/CA film has a potential application in food packaging.

Photography’s Other Sensitivities

This article sets out to challenge the idea of photography as a medium that deals purely in the visible. Taking the example of the mid-twentieth-century British photography industry, this article considers photographic sensitivity as part of a sensory economy in which human, technological and environmental sensing are mutually entangled. I emphasise these interlinked sensing systems, and what I see as the “passive agency” of photographic materials, showing how photographic emulsions are capable of registering much more than visible light or even radiation. Chemical photographic materials had distinct cultural biases built into them, yet often registered entities other than those they were designed to picture. Great effort went into restricting photographic sensitivities, as well as into cultivating them. By the 1930s, the photographic materials factories had air purification and climate control systems, sensitometry laboratories and specialist tropical materials. Their sensitised materials and chemicals transformed ecosystems and participated in a “technological sensory training”, shaping what people could perceive.

Sustainable pectin-based film for carrying phenolic compounds and essential oil from Citrus sinensis peel waste

Currently, food science faces the challenge of finding methods to deliver functional and nutritional compounds in ready-to-eat products. Biopolymeric films enriched with essential oils are an emerging strategy for incorporating valuable components into edible carrier matrices. This study investigated the wastewater from orange peel hydrodistillation as a source of phenolic compounds and an innovative ingredient to develop bioactive limonene-loaded pectin-based films, addressing waste disposal challenges by developing a multi-functional packaging material. The objective was to evaluate the effects of formulation synergies, particularly pectin-phenolic interactions, on the physicochemical, rheological properties, and essential oil retention capacity of film-forming emulsions, and then assess the effects on the physicochemical and mechanical properties of the films. Films were analyzed for morphology, water vapor permeability, light transmittance, mechanical, chemical, and physical properties, and encapsulation efficiency. Three formulations were evaluated: pectin control (PC), pectin with Tween-80 surfactant (PT), and pectin with phenolic-rich wastewater (PPW). PPW emulsions displayed higher viscosity, consistency, kinetic stability, and essential oil retention compared to PC. The resulting environmentally-friendly films exhibited increased thickness, improved oil droplet distribution, a more crystalline structure, lower clarity, better flexibility, and increased water vapor permeability. Altered FTIR spectrum bands suggested potential pectin-phenolic interactions, influencing film physicochemical properties through mechanisms such as enhanced crosslinking. The PT film-forming emulsion demonstrated lower kinetic stability and less homogeneity than PC and PPW, showing that the use of the commercial surfactant (0.1g/100 g of film-forming emulsion) led to less favorable performance in terms of emulsion stability and film properties compared to PPW and PC. Conclusively, utilizing orange residue for bioactive pectin-based films offers valuable insights for promoting shelf life, reducing the need for formulation surfactants, and adding nutritional value in food applications, while simultaneously repurposing underutilized waste. This research also contributes to insights into the development of more stable emulsions for creating uniform films.

Improving the antioxidant ability of gelatin-chitosan film by incorporating an oil-in-water (O/W) Pickering emulsion emulsified by betanin-loaded quaternary ammonium-functionalized mesoporous silica nanoparticles

Active food packaging films with biological activities are a promising food technology, and antioxidant ability is one of the most important biological activities. In this study, an antioxidant active packaging film was prepared by directly blending gelatin, chitosan and a novel O/W Pickering emulsion and then drying. The emulsion was prepared from two antioxidant compounds, Mesona Chinensis essential oils (MCB-EO) and betanin-loaded quaternary ammonium-functionalized mesoporous silica nanoparticles (betanin-QAMSNPs), which provide this emulsion with high antioxidant activity. After adding the emulsion, the water content (26.63 %), water solubility (28.3 %), and water contact angle (86.2°) of the film are lower than those of the gelatin-chitosan film. The thickness and water vapour permeabilities of the betanin-Pickering emulsion film are 275.25 µm and 4.802 × 10−10 g·s−1·m−1·Pa−1, respectively, which are higher than those of gelatin-chitosan films. Adding betanin-Pickering emulsions can decrease the roughness of the surface, which is observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The DPPH and ABTs+ free radical scavenging capacities of the betanin-Pickering emulsion films are 21.77 % and 91.87 %, respectively, which are higher than those of the gelatin-chitosan films (4.64 % and 61.15 %), indicating that adding the betanin-Pickering emulsion can enhance the antioxidant ability of the gelatin-chitosan films. The betanin-Pickering emulsion films can inhibit the oxidation of soybean oil. In conclusion, in this study, a novel food packaging film was successfully prepared and has potential application as an antioxidant food packaging material.