Enhanced Color Stability Research Articles

Fluorescent Protein PEGylation for Stable Photon Manipulation in Deep‐Red Light‐Emitting Devices

AbstractPEGylation is a classic strategy to reduce denaturation and immunogenicity in therapeutic proteins, bioimaging, and drug delivery. However, this concept has not been applied to incorporate biogenic materials as functional components in optoelectronics. Herein, PEGylation is rationalized as an effective tool to stabilize fluorescent proteins in solid‐state photon manipulation down‐converters integrated into bio‐hybrid light‐emitting diodes. In short, the archetypal red‐emitting protein mCherry is nonspecifically PEGylated with methoxypolyethylene glycols (mPEG) chains of different lengths (mPEG‐350/‐750/‐2000). These derivatives hold the same photoluminescence figures‐of‐merit of mCherry, but an improved resistance against organic solvents, pH, temperature, and polymers (in solution/dry‐coatings) upon increasing the mPEG length. Indeed, the best‐performing mCherry‐mPEG‐2000 adduct leads to deep‐red devices with threefold enhanced color stability (>300 h) under harsh operation conditions (150 mW cm−2) over the prior art. Different device architectures along with spectroscopic, thermocycling, and electrochemical impedance spectroscopy studies of the prepared coatings aid in rationalizing that PEGylation successfully reduces i) nonreversible thermal denaturation, ii) aggregation in solid‐state, and iii) photo‐induced oxidation and H+‐transfer deactivation of the chromophore, since oxygen diffusivity and H+‐reorganization across the protein skeleton are slowed down by strong H+‐bonding/hydrophobic mCherry‐mPEG interactions. Hence, this simple supramolecular modification is of utmost relevance for future advances in protein‐based optoelectronics.

Enhancing Insight into Photochemical Weathering of Flax and Miscanthus: Exploring Diverse Chemical Compositions and Composite Materials.

The accelerated weathering of flax and miscanthus fibers possessing distinct chemical compositions was investigated. The chosen fibers included raw, extractive-free (EF) and delignified samples (x3), alone and used as fillers in a stabilized polypropylene blue matrix (PP). Modifications in both color and the chemical composition of the fibers throughout the weathering process under ultraviolet (UV) light were meticulously tracked and analyzed by spectrophotometry and attenuated total reflectance with Fourier-transform infrared spectroscopy (ATR-FTIR). The inherent nature and composition of the selected fibers led to varied color-change tendencies. Raw and EF flax fibers exhibited lightening effects, while raw and EF miscanthus fibers demonstrated darkening effects. Extractives exhibited negligible influence on the color alteration of both flax and miscanthus fibers. This disparity between the fibers correlates with their respective lignin content and type, and the significant formation of carbonyl (C=O) groups in miscanthus. Better stability was noted for delignified flax fibers. A comparative study was achieved by weathering the PP matrix containing these various fibers. Contrary to the weathering observations on individual fibers, it was noted that composites containing raw and EF flax fibers exhibited significant color degradation. The other fiber-containing formulations showed enhanced color stability when compared to the pure PP matrix. The study highlights that the UV stability of composites depends on their thermal history. As confirmed by thermogravimetric analysis (TGA), fiber degradation during extrusion may affect UV stability, a factor that is not apparent when fibers alone are subjected to UV aging.

Transparent bamboo as a replacement for glass: Effects of lignin decolorisation methods on weatherability

Transparent bamboo proved to be a promising substitute for glass due to its high light transmittance and excellent mechanical properties. Nevertheless, it was susceptible to outdoor weathering, which negatively affected its physical and mechanical properties. In this study, two decolorisation methods, namely the delignification method and the lignin modification method, were used to produce transparent bamboos with epoxy resin, referred to as DL-TB and LM-TB, respectively. The changes in surface color, optical and mechanical properties, wettability, thermal stability, and thermal insulation properties of transparent bamboo during accelerated UV weathering were evaluated. Additionally, the deterioration mechanism of DL-TB and LM-TB was investigated. The findings revealed that DL-TB demonstrated better transparency and mechanical properties than LM-TB, although it exhibited lower thermal insulation properties. Furthermore, DL-TB demonstrated enhanced color stability and higher hydrophobicity on weathered surfaces than LM-TB. Unexpectedly, the tensile properties of both two transparent bamboos significantly improved after weathering, especially for LM-TB, which was due to the EP post-curing and the formation of more hydrogen bonds between lignin and EP. These observations revealed that lignin played a key role in the photodegradation process of transparent bamboo, but further attempts should be made in future studies to improve its color stability.

Development and characterization of a novel bigel system based on candelilla wax oleogel and guar gum hydrogel for heat-triggered release properties

This study introduces an innovative approach for the encapsulation and heat-triggered release of natural pigment, paprika oleoresin (PO) as a model pigment, by formulating oleogel-in-hydrogel bigels incorporating candelilla wax (CW). By varying the CW concentrations, the impact on the critical physicochemical properties of bigels was investigated. Increasing CW concentration from 2 to 8% elevated the sol-gel transition temperature (Tg) of the oleogels significantly, ranging from 45.83 ± 0.83 to 61.38 ± 0.51 °C (p < 0.05). Across all CW concentrations, high encapsulation efficiency over 95% was consistently observed. Conversely, reducing CW concentration increased droplet size within the bigels, varying from 13.19 ± 2.97 to 2.97 ± 0.60 μm (p < 0.05). Notably, these bigels exhibited distinct heat-triggered pigment release characteristics. In specific, the amount of released PO decreased with increased CW concentration, resulting in a lower ΔE* value. Correlation analysis highlighted CW's positive correlation with the Tg of the oleogel and bigel lightness, and its negative correlation with droplet size, cumulative pigment release content, release rate constant, redness, yellowness, and ΔE* of the bigel. These results indicate that controlling pigment release through CW-based bigels with thermoresponsive properties can enhance color stability and preserve the integrity of pigment during heat processing. This novel bigel system with heat-triggered release properties holds promise for wider application in the food industry. Overall, it addresses the critical need to stabilize and precisely regulate natural pigment release, which is important for both product quality and consumer satisfaction in the food industry.

Assessing the Impact of Pomegranate Peel Extract Active Packaging and High Hydrostatic Pressure Processing on Color and Oxidative Stability in Sliced Nitrate/Nitrite-Reduced Iberian Dry-Cured Loins

Our study aimed to assess the impact of active packaging with pomegranate peel extract (0.06 mg gallic acid eq./cm2) and/or high-pressure treatment (600 MPa, 7 min) on the instrumental color, lipid, and protein oxidation of Iberian dry loins formulated with reduced nitrate/nitrite levels (0, 37.5, and 150 mg/kg) during 100-day refrigerated storage (4 °C). CIE L*a*b* coordinates were measured, and malondialdehyde, carbonyls, and free thiol contents served as markers for lipid and protein oxidation. Active packaging lowered CIE L* (35.4 vs. 34.1) and a* (15.5 vs. 14.5) and increased yellowness (15.6 vs. 16.3) and hue (45.2 vs. 48.4), while pressurization increased CIE L* (33.1 vs. 36.3) and diminished a* values (16.1 vs. 13.9). Ongoing nitrate/nitrite amounts significantly influenced lipid peroxidation, protein carbonyl formation, and free thiol loss. Active packaging and high-pressure processing had varying effects on carbonyl and thiol contents. Neither pressurization nor active packaging impacted malondialdehyde formation. Pressurization enhanced the formation of 4-HNE (503 vs. 697 pg/g). Protein oxidation proved more sensitive to changes, with active packaging offering protection against protein carbonylation (15.4 vs. 14.7 nmol carbonyls/mg protein), while pressurization induced thiol loss (34.3 vs. 28.0 nmol Cys eq./mg protein). This comprehensive understanding provides essential insights for the meat industry, emphasizing the necessity for customized processing conditions to enhance color stability, lipid preservation, and protein integrity in dry-cured loin slices.

The effect of modified atmosphere packaging at an early postmortem stage on lamb meat quality during subsequent aging.

This study explores the influence of modified atmosphere packaging (MAP) on fresh lamb meat quality with respect to gas concentration, rigor state, and post-mortem aging time. A comparison was done for the quality characteristics of lamb Longissimus thoracis lumborum chops that had been packaged separately in air, 75%O2 +25%CO2 MAP or 50%O2 +50%CO2 MAP at 1, 6, and 24h post-mortem and then stored for 6, 12, 24, 72, and 144h post-mortem, and the quality of lamb chops had been evaluated at each post-mortem period separately. Chops packaged at 1 and 6h post-mortem in MAP had reduced pH decline, less purge loss, and enhanced redness at early post-mortem storage times. Lamb color stability was evidently greater in 75%O2 +25%CO2 MAP than in 50%O2 +50%CO2 MAP during the early storage period when a* and R630/R580 were taken into account. Shear force values were lowest in lambs packaged at 1h post-mortem with 75%O2 +25%CO2 MAP at 12h post-mortem and then increased until 72h post-mortem, suggesting that rigor has been delayed by such a high O2 MAP. Thus, fresh lamb quality was maintained most effectively when packaged at 1h post-mortem in 75%O2 +25%CO2 MAP for consumption at 12h post-mortem. The exact mechanisms and optimization of MAP based on Chinese retail conditions should be considered in future studies. PRACTICAL APPLICATION: In this study, three slaughter patterns in the meat industry involving boning immediately after dressing (hot-boning) and chilling for a short period (warm-boning) or overnight (cold-boning) are considered, as well as the behavior of non-immediate consumption after purchase. Modified atmosphere packaging provides an effective preservation of early post-mortem muscles with enhanced color stability, water holding capacity, and texture during refrigerated storage. This could provide new insights into how to process lamb muscles in the early post-mortem period to improve and stabilize lamb quality.

Non-iridescent Structurally Colored Pigments Based on CB@SiO2@TiO2 Core-Bishell Nanospheres with Enhanced Color Stability and Excellent Photocatalytic Activity.

In recent years, artificial amorphous photonic structure (APS) materials with high color saturation and angle independence have been competitively reported. However, there is a lack of research into their functionalization and application in practical environments. Here, with practical applications in mind, we prepared APS pigments based on CB@SiO2@TiO2 core-bishell nanospheres and demonstrated high color saturation, enhanced color stability, and excellent photocatalytic activity. SiO2 effectively protected the carbon black particles from ablation during the calcination process. Paints composed of ethanol, ethyl cellulose (EC), and pigments could be spray-coated on any substrate to prepare a structurally colored coating without limitation. The coatings show good mechanical stability and photothermal stability. The color of the structurally colored pigments can be easily changed by adjusting the sizes of the CB@SiO2@TiO2 nanospheres. The photocatalytic activity of the pigments on formaldehyde (HCHO) and methylene blue (MB) solution and reaction kinetics of their degradation were studied by experiment. The results showed that the photocatalytic activity of the pigments increased with the increase of the TiO2 loading, and the degradation rate of HCHO reached 96.7% for 3 h and that of MB reached 97.9% for 60 min when the TiO2 shell thickness was 40 nm. The structurally colored pigments based on CB@SiO2@TiO2 nanospheres effectively solve the environmental problems caused by the application of pigments and have a promising future in the fields of color decoration, display, and painting.

Oxidation of Wine Polyphenols by Electrochemical Means in the Presence of Glutathione.

The oxidation of wine may be beneficial or harmful to its quality. On the one hand, controlled oxidation can lead to the development of desirable sensory characteristics for red wine, such as enhanced color stability. Alternatively, oxidation can lead to white wine browning and a decrease in fruity aromas, and the development of an off flavor and wine polyphenols are also involved. The presence of glutathione (GSH) can help mitigate the negative effects of oxidation by acting as a protective antioxidant. In order to better understand the antioxidant role played by GSH, wine polyphenols oxidation experiments by electrochemical means in the presence of GSH were carried out. The oxidation behavior of polyphenols representing different phenolic classes commonly found in wines, including protocatechuic acid (PCA), caffeic acid (CAF), epicatechin (EC), and rutin (Ru), was investigated using cyclic voltammetry and bulk electrolysis. We identified the oxidation products and reaction pathways of these polyphenols using ultra-high-performance liquid chromatography coupled with mass spectrometry (UPLC-MS), in both the absence and the presence of glutathione (GSH). UPLC-MS was utilized to demonstrate that, in the presence of glutathione (GSH), the four molecules were subjected to electrochemical oxidation, resulting in the formation of mono- and bi-glutathione conjugates. A two-electron oxidation process combined with the removal of two protons is the first step in transforming polyphenol molecules. As a result, the corresponding quinone is formed. The quinone can then be reduced back to its original form by glutathione (GSH), or it can interact further with GSH to produce mono- and bi-glutathione conjugates. These results contribute to understanding and predicting the oxidative degradation pathway of polyphenols in wine. Understanding this process seems important for winemakers to control and optimize the sensory characteristics of their wines.

Phytoferritin functions in two interface-loading of natural pigment betanin and caffeic acid with enhanced color stability and the sustained release of betanin.

Betanin, a natural red pigment, is sensitive and prone to fading and discoloration, affecting its stability and bioavailability. Phytoferritin is a nano-diameter protein with unique interior-/exterior-interfaces. By the unique interfaces and pH-induced self-assembly of ferritin, a ferritin-betanin complex (FB) with an encapsulation efficiency of 17.66 ± 1.24% was prepared. The caffeic acid-FB (CFB) was further fabricated by attaching ferritin with caffeic acid, and the binding number n of caffeic acid was 88.47 ± 9.49, with a binding constant K of (1.63 ± 0.33) × 104 M-1. Fluorescence and Fourier transform infrared analysis indicated that the encapsulation of betanin and the binding of caffeic acid influenced the ferritin structure. The interaction between caffeic acid and ferritin was mainly through van der Waals forces and hydrogen bonds. TEM and DLS showed that the globular structure and diameter (12 nm) remained in CFB. Furthermore, the ferritin and caffeic acid exhibited a synergistic effect in enhancing thermal, light, and ferric ion stabilities, and controlled the betanin release in a more sustained manner in the simulated gastrointestinal tract. In addition, the antioxidant capacity of CFB was enhanced compared with free betanin. This study promotes the bioavailability of betanin by two interface-loading of ferritin, and guides the use of ferritin nanoparticles as a nanocarrier for pigment stabilization.

Copigmentation effect of flavonols on anthocyanins in black mulberry juice and their interaction mechanism investigation

Copigmentation effect of flavonoids on black mulberry juice and its main anthocyanin, cyanidin-3-O-glucoside (C3G), was evaluated. Results showed that the hyperchromic effect of flavonols, such as kaempferol (KAE), hyperoside (HYP), rutin (RUT), quercetin (QTI) and isoquercitrin (IQT), was better than that of quercitrin (QTR) and catechin (CAT). The degradation rate constant (k) of C3G decreased by 8.6 %∼50.0 % when KAE, HYP, RUT, QTI and IQT were added, whilst half-life (t1/2), activation energy (Ea) and hydration reaction equilibrium constant (pKh) increased by 7.4 %∼99.0 %, 60.0 %∼95.7 % and 8.3 %∼37.8 % respectively. Meanwhile, the maximum absorption wavelength of the mixture displayed bathochromic shift. Molecular simulation indicated that the interaction energy with C3G was KAE > HYP > RUT > QTI > IQT > QTR > CAT. The main driving force forming C3G-flavonol complex were hydrogen bond and Van der Waals interaction. These results will provide theoretical reference to enhance color stability of food rich in anthocyanins.

Acylated anthocyanins: A review on their bioavailability and effects on postprandial carbohydrate metabolism and inflammation.

Anthocyanins, the natural red and purple colorants of berries, fruits, vegetables, and tubers, improve carbohydrate metabolism and decrease the risk factors of metabolic disorders, but their industrial use is limited by their chemical instability. Acylation of the glycosyl moieties of anthocyanins, however, changes the chemical properties of anthocyanins and provides enhanced stability. Thus, acylated anthocyanins are more usable as natural colorants and bioactive components of innovative functional foods. Acylated anthocyanins are common in pigmented vegetables and tubers, the consumption of which has the potential to increase the intake of health-promoting anthocyanins as part of the daily diet. For the first time, this review presents the current findings on bioavailability, absorption, metabolism, and health effects of acylated anthocyanins with comparison to more extensively investigated nonacylated anthocyanins. The structural differences between nonacylated and acylated anthocyanins lead to enhanced color stability, altered absorption, bioavailability, in vivo stability, and colonic degradation. The impact of phenolic metabolites and their potential health effects regardless of the low bioavailability of the parent anthocyanins as such is discussed. Here, purple-fleshed potatoes are presented as a globally available, eco-friendly model food rich in acylated anthocyanins, which further highlights the industrial possibilities and nutritional relevance of acylated anthocyanins. This work supports the academic community and industry in food research and development by reviewing the current literature and highlighting gaps of knowledge.

Enhancement of color stability in strawberry nectar during storage

Strawberry anthocyanins often undergo chemical degradation during storage, which leads to color fading and bioactivity loss. These changes are increased by ascorbic acid, which accelerates anthocyanin degradation. The present study investigated the effect of citric acid as an alternative to ascorbic acid to adjust strawberry nectar pH. Several additions were also used as co-pigment sources to enhance color stability during a five-month dark storage period at ambient temperatures. The results showed that citric acid increased the stability of total and monomeric anthocyanin and reduced the formation of polymeric color. The fortification of the strawberry nectar with 0.2% green tea extract, 3% hot rosella extract, and 0.5% low-methoxyl pectin in the presence of citric acid led to enhance strawberry nectar color, high stability, and reduce anthocyanin degradation.

Effect of ultraviolet protective agents on maxillofacial silicone elastomer, part 1: Color stability after artificial aging

Statement of problemSilicone elastomers have been widely used for rehabilitation of facial defects for more than 50 years. However, color change is the most common problem limiting the service life of facial prostheses. Whether the addition of ultraviolet protectives may enhance color stability of these materials is unclear. PurposeThe purpose of this in vitro study was to investigate the effect of ultraviolet protectives on the color stability of maxillofacial silicones after artificial aging. Material and methodsSix color groups (unpigmented, white, yellow, red, blue, and mixed) of addition-type maxillofacial silicone were prepared. Four ultraviolet protectives benzophenone-3, ethylhexyl methoxycinnamate, titanium dioxide, and ethylhexyl salicylate at 0.5% and 1% concentrations by weight were incorporated into the silicone before polymerization. The specimens were artificially aged in an accelerated weathering chamber for 300 and 600 hours and in a thermocycling device. The color change values (E) of the maxillofacial silicones were evaluated. Data were statistically analyzed by using 4-way ANOVA. The differences were compared by the Tukey honestly significant difference test (α=.05). ResultsBenzophenone-3 and ethylhexyl methoxycinnamate protectives did not reduce the ΔE values, and the 1% titanium dioxide groups exhibited lower ΔE values than the 0.5% titanium dioxide groups. Ethylhexyl salicylate protective generally reduced the ΔE values significantly in all color and aging groups when compared with the control groups (P<.05). In all control and ultraviolet protective groups, the highest ΔE values were seen with the red color in 300 and 600 hours of aging. Generally, no significant difference (P>.05) was seen in the ΔE values, which were clinically acceptable among the thermocycled color groups. After 600 hours of accelerated aging, the ΔE values were found to be higher than the values of 300-hour aging. ConclusionsEthylhexyl salicylate protective incorporated into maxillofacial silicones may improve color stability.

Impact of L-glutamine as replacement of dietary antibiotics during post weaning and transport recovery on carcass and meat quality attributes in pigs

Dietary L-glutamine could be used as an antibiotic alternative to alleviate post-weaning and transport stress. However, the impact of supplementing L-glutamine to newly weaned and transported pigs on final carcass and meat quality characteristics is currently unknown. Therefore, the objective of this study was to evaluate the impact of 0.2% dietary L-glutamine supplementation during post-weaning and transport recovery on carcass and meat quality attributes in pigs. A total of 480 mixed-sex pigs were studied in two production seasons, July-January and April-September (from weaning to harvest), where pigs were randomly assigned to 3 different diets (Non: no antibiotic, Anti: 441 ppm chlortetracycline and 38.6 ppm tiamulin, Gln: 0.20% L-glutamine with no antibiotics) for 14 days after weaning and transport, and then all pigs were fed a basal diet until reaching market weight. Pairs of longissimus dorsi (LD) and psoas major (PM) muscles were obtained from 1 d and 7 d postmortem carcass sides (n = 10 gilts/dietary treatment/season replicate). Overall, no negative impacts of Gln were observed in carcass characteristics including loin eye area, back fat, and muscling score. Dietary Gln did not affect chemical and physical attributes of porcine muscles including pH, protein and lipid content, SF, and WHC (P > 0.05). The Gln treated pigs had decreased CIE L* and hue, suggesting enhanced color stability. April-September replicates had a faster pH decline, paler surface color, higher intra-muscular fat deposition, improved tenderness and water-holding capacity as indicated by lower shear force values, thaw-purge loss, and cooking loss compared to their July-January counterparts (P < 0.05). These results suggested that L-glutamine supplementation as a nutraceutical mitigation strategy could have equivalent impacts on fat and lean accretion, SF, and WHC and some positive impacts on meat color attributes compared to meat from pigs treated with antibiotics.

Applying microwave energy to fabricate powder coatings with strong and stable metal shine

Metallic pigmented powder coating, composed of coating powders and metallic pigments, has been drawing more attention and occupying more market share with more stringent environmental pressure on traditional metallic solvent paint. To overcome the shortcomings of the thermal bonding method that aims at bonding the two incompatible ingredients, a self-designed microwave bonding device was first developed and tested in the present work. Taking advantage of the heating-selectivity of the microwave, a lower bonding temperature was obtained when compared to the thermal bonding method. Also, through the analysis of bonding rate and color difference, a higher bonding quality and enhanced color stability were found. More bondings between coating particles and Al flakes were clearly observed by SEM and EDS in the microwave-bonded samples. The microwave bonding is proved to be a feasible and efficient method and thus the bonding device has great potential to replace the present bonding machine.

Lipid Oxidation and Color Stability of Spiced and Unspiced Pork Sausage with a Novel Antioxidant Mixture of Rosemary Extract and Phospholipase A2

ObjectivesThe objective of this study was to measure the loss of redness and onset of lipid oxidation in pre-rigor pork sausage containing synthetic antioxidants (Syn) compared to rosemary extract (R), and a combination of R with different concentrations of phospholipase A2 (R+P) over both light display and frozen storage.Materials and MethodsOur work examined pre-rigor spiced and unspiced pork sausage. Tissue from sows for both spiced and unspiced sausage was coarse ground and cooled to 1–3°C with dry ice within 1-h post-exsanguination. Water, treatments and seasonings were added, and the sausage stuffed within 2 h post-exsanguination for spiced sausages. Water and treatments were added 24 h post-exsanguination for the unspiced sausage. Sausages were stored in the dark at –20°C (to 110 and 245 d for unspiced and spiced, respectively) prior to light display. Sausages were sampled for color and lipid oxidation on approximately 40-d intervals of –20°C dark storage and 7–9 d of light display (5°C). In spiced sausage, R (type HT-P) was added at 200 ppm, PLA2 was added at 0.4 ppm. Butylated hydroxyanisole (BHA), propyl gallate (PG) and citric acid (CA) were each added at 0.01% of the estimated fat and collectively formed the Syn treatment. Spices consisted of sucrose, ginger, coriander, nutmeg, white pepper, and MSG. In unspiced sausage R was added at 200 ppm, PLA2 added at 0.4 ppm and 10 ppm, and BHA, CA and PG added at the same levels as in spiced sausage. Color stability was measured based on redness (a*). Peroxide values (PVs) were measured spectrophotometrically, headspace hexanal was measured via gas chromatography (GC) and α tocopherol depletion was measured with HPLC fluorescence detection as markers of lipid oxidation. Total lipids were fractionated to gravimetrically quantify neutral lipids, free fatty acids and polar lipids and to measure PVs in the aforesaid fractions. Unspiced sausages were only stored for 110 d because of rampant lipid oxidation and loss of color.ResultsIn spiced sausage, R and R+P displayed better color stability than both the control (no antioxidant, C) and Syn. Syn displayed the lowest hexanal values. R had the highest PVs and both Syn and R+P were significantly lower. Free fatty acids were the most heavily oxidized fraction on an oil basis, while neutral lipids were the most oxidized lipid on a wet weight basis. Alpha tocopherol did not deplete through 245 d in spiced sausage but was not detected in the unspiced sausage.In unspiced sausage, R+P was examined at two different levels (0.4 ppm and 10 ppm PLA2). R+P (10 ppm) exhibited lower headspace hexanal than R alone and R+P at both levels performed as well as Syn. In addition, R+P at both levels displayed significantly better color stability than R alone and was as good as Syn.ConclusionIn conclusion, R+P decreased lipid oxidation (compared to R) and enhanced color stability (compared to R) and offer an alternative to synthetic antioxidants in pre-rigor pork sausage. Furthermore, spiced pork sausage displayed mean redness values above 9 through 245 d, compared to only 75 d in unspiced sausage.

Preparation of Noniridescent Structurally Colored PS@TiO2 and Air@C@TiO2 Core-Shell Nanoparticles with Enhanced Color Stability.

Natural amorphous photonic crystals benefit from reflectance at selective wavelengths in some specific existing natural systems. Noniridescence from natural organisms has also attracted great interest for various examples in bionic colors, pigments, and paintings. Here, Air@C@TiO2 sphere was obtained by the first calcination of PS@TiO2 core-shell nanoparticles in nitrogen to ensure the integrity of the shell structure followed by low-temperature calcination to obtain the appropriate color saturation. We demonstrate that, compared with the prepared colored PS@TiO2/carbon black (CB) pigments, angle-independent hollow Air@C@TiO2 nanoparticles have enhanced color stability under the action of in situ synthesized carbon black (CB). Our results suggest that it is easy to change the color of these Air@C@TiO2 spheres by adjusting the sphere structure sizes, which have the potential to show visual signaling.

Lipid Oxidation and Color Stability of Spiced and Unspiced Pork Sausage with a Novel Antioxidant Mixture of Rosemary Extract and Phospholipase A2

ObjectivesThe objective of this study was to measure the loss of redness and onset of lipid oxidation in pre-rigor pork sausage containing synthetic antioxidants (Syn) compared to rosemary extract (R), and a combination of R with different concentrations of phospholipase A2 (R+P) over both light display and frozen storage.Materials and MethodsOur work examined pre-rigor spiced and unspiced pork sausage. Tissue from sows for both spiced and unspiced sausage was coarse ground and cooled to 1–3°C with dry ice within 1-h post-exsanguination. Water, treatments and seasonings were added, and the sausage stuffed within 2 h post-exsanguination for spiced sausages. Water and treatments were added 24 h post-exsanguination for the unspiced sausage. Sausages were stored in the dark at –20°C (to 110 and 245 d for unspiced and spiced, respectively) prior to light display. Sausages were sampled for color and lipid oxidation on approximately 40-d intervals of –20°C dark storage and 7–9 d of light display (5°C). In spiced sausage, R (type HT-P) was added at 200 ppm, PLA2 was added at 0.4 ppm. Butylated hydroxyanisole (BHA), propyl gallate (PG) and citric acid (CA) were each added at 0.01% of the estimated fat and collectively formed the Syn treatment. Spices consisted of sucrose, ginger, coriander, nutmeg, white pepper, and MSG. In unspiced sausage R was added at 200 ppm, PLA2 added at 0.4 ppm and 10 ppm, and BHA, CA and PG added at the same levels as in spiced sausage. Color stability was measured based on redness (a*). Peroxide values (PVs) were measured spectrophotometrically, headspace hexanal was measured via gas chromatography (GC) and α tocopherol depletion was measured with HPLC fluorescence detection as markers of lipid oxidation. Total lipids were fractionated to gravimetrically quantify neutral lipids, free fatty acids and polar lipids and to measure PVs in the aforesaid fractions. Unspiced sausages were only stored for 110 d because of rampant lipid oxidation and loss of color.ResultsIn spiced sausage, R and R+P displayed better color stability than both the control (no antioxidant, C) and Syn. Syn displayed the lowest hexanal values. R had the highest PVs and both Syn and R+P were significantly lower. Free fatty acids were the most heavily oxidized fraction on an oil basis, while neutral lipids were the most oxidized lipid on a wet weight basis. Alpha tocopherol did not deplete through 245 d in spiced sausage but was not detected in the unspiced sausage.In unspiced sausage, R+P was examined at two different levels (0.4 ppm and 10 ppm PLA2). R+P (10 ppm) exhibited lower headspace hexanal than R alone and R+P at both levels performed as well as Syn. In addition, R+P at both levels displayed significantly better color stability than R alone and was as good as Syn.ConclusionIn conclusion, R+P decreased lipid oxidation (compared to R) and enhanced color stability (compared to R) and offer an alternative to synthetic antioxidants in pre-rigor pork sausage. Furthermore, spiced pork sausage displayed mean redness values above 9 through 245 d, compared to only 75 d in unspiced sausage.

Preparation of dye-grafted-silica/poly(acrylate) color coatings with enhanced color stability at elevated temperatures

PurposeThe purpose of this paper is to investigate the effects of dipentaerythritol hexaacrylate (DPHA) and 3-(trimethoxysilyl)propyl methacrylate-modified silica nanoparticles (MSiO2) contents on the performances of the Disperse Red 1 (DR1)-grafted-silica/poly(acrylate) color hard coatings.Design/methodology/approachThe organic dye DR1 was silylated by reaction with the coupling agent 3-isocyanatopropyltriethoxysilane in methyl ethyl ketone. The silylated-DR1 thus obtained was grafted on MSiO2 to form dye-grafted silica (GSiO2). This hybrid dye was then UV-cured with the cross-linking agent, DPHA, to yield color coatings. Thermal durability of the coatings was evaluated based on their CIE (international commission on illumination) chromaticity coordinates and UV/Vis transmittances.FindingsThe results indicated that GSiO2-coatings could tolerate thermal attack better than pristine DR1-coatings or dye-absorbed silica (DSiO2)-coatings because of the fact that DR1 was more finely dispersed in the polymer binder when covalently bonded to the silica particles. Under optimal conditions, coatings with very small change of saturation and hue after high-temperature treatments were obtainable. These coatings appeared transparent, had 3H-6H pencil hardness and adhered perfectly onto the poly(methyl methacrylate) substrates.Practical implicationsDye-grafted color coatings may find applications such as color filter photoresists for displays, microelectronics, printed circuit boards, etc.Originality/valueThe performances of the coatings were evaluated in terms of mechanical strength, adherence to the substrate, transmittance and color stability against heat treatments, which have not been disclosed. Also, using a newly developed triangular composition diagram, suitable ranges for preparing useful color coatings were accessed. The present method deserves further research studies on green and blue dyes.

White Light Emission and Enhanced Color Stability in a Single-Component Host.

Eu3+ ion can be effectively sensitized by Ce3+ ion through an energy-transfer chain of Ce3+-(Tb3+) n-Eu3+, which has contributed to the development of white light-emitting diodes (WLEDs) as it can favor more efficient red phosphors. However, simply serving for WLEDs as one of the multicomponents, the design of the Ce3+-(Tb3+) n-Eu3+ energy transfer is undoubtedly underused. Theoretically, white light can be achieved with extra blue and green emissions released from Ce3+ and Tb3+. Herein, the design of the white light based on these three multicolor luminescence centers has been realized in GdBO3. It is the first time that white light is generated via accurate controls on the Ce3+-(Tb3+) n-Eu3+ energy transfer in such a widely studied host material. Because the thermal quenching rates of blue, green, and red emissions from Ce3+, Tb3+, and Eu3+, respectively, are well-matched in the host, this novel white light exhibits superior color stability and potential application prospect.