Reddening by UV Irradiation after Smoke-Heating in Sugi (Cryptomeria japonica D. Don) Black Heartwood

Holzforschung ◽  
2001 ◽  
Vol 55 (4) ◽  
pp. 347-354 ◽  
Author(s):  
Saori Maruyama ◽  
Futoshi Ishiguri ◽  
Minoru Andoh ◽  
Zensaku Abe ◽  
Shinso Yokota ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Uv Irradiation ◽  
Cryptomeria Japonica ◽  
Color Change ◽  
Ph Value ◽  
Uv Light ◽  
Japanese Cedar ◽  
Color Changes ◽  
Black Heartwood ◽  
Thermally Treated

Summary Sugi (Japanese cedar, Cryptomeria japonica D. Don) green logs with black heartwood were smoked, heated, and smoke-heated separately to improve the heartwood color. After each treatment, changes in heartwood color, pH, and extract amounts were examined. In addition, changes in heartwood color caused by UV irradiation were observed. Heating and smoke-heating of logs prevented the heartwood from discoloring to black, and the resulting color of thermally-treated heartwoods was yellow-white, whereas smoking alone allowed discoloration to black. The pH value decreased from the original 7.6 to 6.8 by smoking and to 6.5 by thermal treatment. The results obtained here suggest that a pH drop in heartwood by thermal treatment is involved in color changes of black heartwood. When thermally-treated black heartwood was exposed to UV light, redness and yellowness increased and brightness decreased. The resulting color tone was reddish brown. The color of non-thermally-treated woods, however, showed little change. Furthermore, acetone, ethanol, and methanol extracts of thermally-treated black heartwood showed an increase in redness by UV irradiation, but the residues showed little color change. The coloring substances relating to the reddening of heartwood could be extracted with these solvents, particularly with methanol. Reddening in black heartwood by a combination of smoke-heating and UV irradiation is considered to be due to a decrease in brightness and an increase in both redness and yellowness.

scholarly journals Color changes of blackberry as affected by freezing rate

2008 ◽  
pp. 63-68 ◽  
Author(s):  
Dobrila Randjelovic ◽  
Ljubo Vracar ◽  
Aleksandra Tepic
Keyword(s):  
Chemical Analysis ◽  
Sensory Evaluation ◽  
Color Change ◽  
Ph Value ◽  
Market Value ◽  
Anthocyanin Content ◽  
Preparation Process ◽  
Surface Color ◽  
Color Changes ◽  
Reference Parameters

Fast frozen blackberry partially change its surface color from characteristic black to copper-redish color. This change decreases the market value, especially when the product is intended for export. For these reasons classic tunnels for slow freezing are being more widely used nowadays. In order to clarify mentioned phenomena, a detailed monitoring of preparation process and freezing, as well as changes of frozen blackberry fruits in industrial conditions was carried out. Along with sensory evaluation of surface color changes, chemical analysis of reference parameters of fresh and frozen fruits were performed. The results of sensory evaluation confirmed evident color change of fruits frozen by slow (and fast) treatment; the chemical analysis confirmed unchanged total solids and anthocyanin content, as well as changes in pH value and vitamin C, in comparison to fresh blackberry fruits.

Comparative Effects of Thermal, High Hydrostatic Pressure, and UV-C Processing on the Quality, Nutritional Attributes, and Inactivation of Escherichia coli, Salmonella, and Listeria Introduced into Tiger Nut Milk

2019 ◽  
Vol 82 (6) ◽  
pp. 971-979 ◽  
Author(s):  
YAN ZHU ◽  
ASMA A. ELBRHAMI ◽  
VLADIMIR POPOVIĆ ◽  
TATIANA KOUTCHMA ◽  
KEITH WARRINER
Keyword(s):  
Escherichia Coli ◽  
Hydrostatic Pressure ◽  
Thermal Treatment ◽  
Vitamin C ◽  
High Hydrostatic Pressure ◽  
Color Change ◽  
Uv Light ◽  
Significant Loss ◽  
Total Phenolic ◽  
Uv C

ABSTRACT Tiger nut milk is a low-acid health beverage that is marketed with the claims of being high in protein, monounsaturated fatty acid (oleic acid), fiber, starch, and minerals, in addition to vitamins C and E. In this study, the effect of nonthermal processing with UV light (UV-C) or high hydrostatic pressure (HHP) on the nutritive content (protein, vitamin C, polyphenols, and antioxidant), and quality characteristics (viscosity and color) of tiger nut milk were compared with thermal processing. Baseline studies established the treatments parameters to support a >5-log CFU reduction of Escherichia coli P36, Listeria innocua ATCC 51742, and Salmonella Typhimurium WG49 introduced into tiger nut milk and then treated with thermal or nonthermal methods. The thermal treatment at 60°C for 30 min, HHP at 500 MPa for 120 s, and UV-C at 45.2 mJ cm−2 were required to achieve the target 5-log reduction. Thermal treatment resulted in a significant loss (P < 0.05) of total protein (34.9%), total phenolic content (28.7%), and vitamin C (27.1%) and negatively affected the tiger nut milk color, along with decreasing its viscosity. In contrast, HHP and UV-C light treatment retained protein and antioxidant content in tiger nut milk with no significant (P > 0.05) color change being recorded. Therefore, from a processing prospective, either UV-C light or HHP could be used to treat tiger nut milk, although additional hurdles to control the potential outgrowth of Clostridium botulinum during storage would be required. HIGHLIGHTS

Photostabilizers performance on the surface analysis of green composites

2020 ◽  
Vol 29 (1) ◽  
pp. 57-64
Author(s):  
Hasret Ece Sönmez ◽  
Mehmet Safa Bodur ◽  
Alper Adrian Baysan ◽  
Mustafa Bakkal ◽  
Ersin Serhatli
Keyword(s):  
Surface Analysis ◽  
Color Change ◽  
Uv Light ◽  
Light Exposure ◽  
Accelerated Weathering ◽  
Reinforced Composites ◽  
Color Changes ◽  
Photodegradation Mechanism ◽  
Ldpe Composites

In this work, various stabilizers have been introduced to prevent or delay degradation due to ultraviolet (UV) light exposure to prolong the service life of cotton fiber-reinforced composites. The effect of various additives like hindered amine light stabilizer, UV absorber (UVA), and antioxidant as photostabilizers of CF/low-density polyethylene (CF/LDPE) composites was compared. We showed how they influence to delay or eliminate the photodegradation of CF/LDPE subjected accelerated weathering. Surface analysis was performed by Fourier transform infrared spectroscopy and color measurements. The results showed us the insight of the photodegradation mechanism of weathered CF/LDPE composites undergoing photooxidative reactions which causes a loss surface quality such as micro-cracking and color change. Among the stabilizers, UVA was found to be the most effective to delay some color changes in long term.

scholarly journals Evaluation of the process thermal treatment of maple wood saturated water steam in terms of change of pH and color of wood

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2550-2559
Author(s):  
Ladislav Dzurenda ◽  
Anton Geffert ◽  
Jarmila Geffertová ◽  
Michal Dudiak
Keyword(s):  
Thermal Treatment ◽  
Color Change ◽  
Ph Value ◽  
Statistical Processing ◽  
Color Difference ◽  
Acer Pseudoplatanus ◽  
Water Steam ◽  
Saturated Water ◽  
Before And After ◽  
Total Color Difference

Changes in maple wood’s pH and color (Acer pseudoplatanus) were evaluated before and after thermal treatment process with saturated water steam. Maple wood was thermally treated at temperatures: tI = 105 ± 2.5 °C, tII = 125 ± 2.5 °C, and tIII = 135 ± 2.5 °C for τ ≤ 12 hours. Direct pH measurement of maple wood with a moisture content above the fiber saturation point (FSP) was performed using a pH-meter SI 600 with a Lance FET + H puncture probe. The polynomial dependence of pH and total color difference ∆E* on temperature t time τ was calculated by statistical processing of measured results. The correlation between the total color difference ∆E* of maple wood in the process of thermal color modification and the pH value is expressed y the equation: ∆E* = 4.5516∙(pH)2 – 48.405∙(pH) + 134.35. This dependence is a suitable tool for assessing the achieved color change based on the change of wood pH in the technological process.

scholarly journals Wettability and Color Change of Thermally Treated Poplar OSB after Accelerated Weathering Test

2018 ◽  
Author(s):  
Francesco Negro ◽  
Paola Cetera ◽  
Corrado Cremonini ◽  
Luigi Todaro ◽  
Roberto Zanuttini
Keyword(s):  
Thermal Treatment ◽  
Color Change ◽  
Oriented Strand Board ◽  
Accelerated Weathering ◽  
Poplar Wood ◽  
Industrial Coating ◽  
Accelerated Weathering Test ◽  
Coniferous Wood ◽  
Main Components ◽  
Thermally Treated

Oriented strand board (OSB) panels are widely marketed for several applications, from building to packaging. The manufacturing of poplar OSB started recently in Northern Italy representing a relevant innovation in the sector since this product is usually made of coniferous wood. The thermal treatment is widely used for reducing the hygroscopicity of wood-based products, nonetheless it influences the mechanical behavior and degrades the main components of wood, which can affect their finishing. Therefore, it is important to know the properties of the treated surfaces. To this purpose, in this study a lot of OSB panels, made of poplar wood, 15 mm thick and with a density of 590 kg/m3, were thermally treated under vacuum conditions at 190 °C for 2 h and then subjected to accelerated weathering. The changes in color and in wettability due to treatment and accelerated weathering were studied. The thermal treatment determined a significant darkening of the color; the accelerated weathering darkened the untreated surfaces and, on the opposite, lightened the thermo-treated surfaces. The wettability decreased after thermal treatment and increased after weathering, more evidently in treated panels. Overall, this study improves the knowledge about the behavior of the surface of thermo-treated poplar OSB, which is relevant for the industrial coating of this product.

scholarly journals Development and Evaluation of the Chromatic Behavior of an Intelligent Packaging Material Based on Cellulose Acetate Incorporated with Polydiacetylene for an Efficient Packaging

Biosensors ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 59 ◽  
Author(s):  
Lina D. Ardila-Diaz ◽  
Taíla V. de Oliveira ◽  
Nilda de F. F. Soares
Keyword(s):  
Cellulose Acetate ◽  
Color Change ◽  
Uv Light ◽  
Research Field ◽  
Polymerization Time ◽  
Intelligent Packaging ◽  
Color Coordinates ◽  
Color Changes ◽  
Consumer Safety ◽  
Temperature Exposure

Global growth of the food industry and the demand for new products with natural characteristics, safe conditions and traceability have driven researches for the development of technologies such as intelligent packaging, capable to fulfil those needs. Polydiacetylene (PDA) is a synthetic material that has been highlighted in research field as a sensor substance, which can be used to produce intelligent packaging capable to detect chemical or biochemical changes in foods and in their environment due to PDA’s color transition from blue to red. This work focused on the development and optimization of an intelligent packaging constituted of a polymeric matrix of cellulose acetate-based incorporated with PDA as the substance sensor. Cellulose acetate films (3% wt.) were developed by a casting method, and the amounts of triethyl citrate plasticizer (TEC) (0–25% wt. of cellulose-acetate) and PDA (0–60 mg) were analyzed to optimize the conditions for the best color transitioning at this study range. The compound amounts incorporated into polymeric matrices were established according to Central Composite Designs (CCD). Three more design variables were analyzed, such as the polymerization time of PDA under UV light exposition (0–60 min), pH values (4–11) and temperature exposure on the film (0–100 °C), important factors on the behavior of PDA’s color changing. In this study, film thickness and film color coordinates were measured in order to study the homogeneity and the color transitioning of PDA films under different pH and temperature conditions, with the purpose of maximizing the color changes through the optimization of PDA and TEC concentrations into the cellulose acetate matrix and the polymerization degree trigged by UV light irradiation. The optimal film conditions were obtained by adding 50.48 g of PDA and 10% of TEC, polymerization time of 18 min under UV light, at 100 °C ± 2 °C of temperature exposure. The changes in pH alone did not statistically influence the color coordinates measured at the analyzed ratio; however, variations in pH associated with other factors had a significant effect on visual color changes, and observations were described. PDA films were optimized to maximize color change in order to obtain a cheap and simple technology to produce intelligent packaging capable to monitor food products along the distribution chain in real time, improving the food quality control and consumer safety.

scholarly journals Effects of UV light irradiation on color changes in thermally modified rubber wood based on FTIR

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5179-5197
Author(s):  
Xiaowen Li ◽  
Tongtong Li ◽  
Guanjun Li ◽  
Min Li ◽  
Quanji Lu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Color Change ◽  
Uv Light ◽  
Untreated Wood ◽  
Transformation Process ◽  
Carbonyl Groups ◽  
Chemical Changes ◽  
Color Changes ◽  
Rubber Wood ◽  
Treatment Conditions

To evaluate the effects of chemical changes during thermal modification on the resistance of wood against photodegradation, heat-treated specimens of rubber wood (Hevea brasiliensis) were exposed to ultraviolet light for 384 h. The color changes in the exposed wood surfaces were analyzed using a colorimeter; the chemical changes were monitored using Fourier-transform infrared spectroscopy (FTIR). The photoweathering performances of rubber wood treated at 155 °C for 2 h, 155 °C for 6 h, and 185 °C for 2 h were similar to that of untreated wood, as the lignin did not undergo profound chemical transformation under mild modification conditions. However, compared to untreated rubber wood, the photoaging performances of rubber wood treated at 185 °C for 6 h and 215 °C for 2 h were notably changed. The transformation process was confirmed by FTIR. A good linear relationship between color change and lignin degradation was observed after mild, but not severe, heat treatment. The concentration of carbonyl groups in the wood specimens generally increased during photoaging, although not all samples showed a good correlation between color change and the concentration of carbonyl groups. Only the photochromic performance of wood changed notably when lignin was extensively modified under severe heat-treatment conditions.

Improvement of Heartwood Color of Black-Colored Sugi (Cryptomeria japonica D. Don) by UV Irradiation after Smoke Heating

Holzforschung ◽  
2000 ◽  
Vol 54 (3) ◽  
pp. 294-300 ◽  
Author(s):  
Futoshi Ishiguri ◽  
Kikuko Saitoh ◽  
Minoru Andoh ◽  
Zensaku Abe ◽  
Shinso Yokota ◽  
...  
Keyword(s):  
Metal Ions ◽  
Uv Irradiation ◽  
Cryptomeria Japonica ◽  
Treated Wood ◽  
Hot Water ◽  
Sodium Potassium ◽  
Color Changes ◽  
Red Color ◽  
Treatment Changes ◽  
Weak Acidic Condition

Summary Black-colored heartwood of sugi (Cryptomeria japonica D. Don) logs with bark attached were smoked, heated, and smoke-heated separately to improve the heartwood color. After each treatment, changes of heartwood color, amounts of extracts (hot water, 1 % sodium hydroxide, and ethanol-toluene), metal ions (sodium, potassium, calcium and magnesium), and pH were examined. In addition, changes of heartwood color by UV irradiation (wavelength at 254 nm and 365 nm) also were studied. Heating and smoke-heating of logs prevented blackening of the heartwood, leading to a yellow-white heartwood color, whereas smoking did not largely change the heartwood color. Almost no differences in the amounts of extracts and metal ions were found in the control and treated woods. Thermal and smoke treatments decreased the pH from the original 8.1 to 6.0 and 7.4, respectively. The results obtained suggest that the changes of pH by both heating and smoking relate to the heartwood color changes in black-colored sugi. In the heated and smoke-heated woods, redness and yellowness were increased by the subsequent UV irradiation at 365 nm, whereas brightness was decreased. Apparently, the heartwood color of black-colored sugi was changed from yellow-white to red by the UV irradiation, the red color being the normal heartwood color of sugi. However, UV irradiation did not cause significant changes in the heartwood color in the control and smoked woods. These results suggest that UV irradiation of the thermally treated wood showing the resulting yellow-white color recovered the redness as found in normal red-colored heartwood, which seems to be caused by chemical changes of pigments under a weak acidic condition in the black-colored heartwood of sugi.

scholarly journals Genetic effects on heartwood color variation in Cryptomeria japonica

2016 ◽  
Vol 65 (2) ◽  
pp. 80-87 ◽  
Author(s):  
Naoko Miyamoto ◽  
Kazuya Iizuka ◽  
Jin’ya Nasu ◽  
Hiroo Yamada
Keyword(s):  
Cryptomeria Japonica ◽  
Color Change ◽  
Japanese Cedar ◽  
Color Variation ◽  
Spatial Autocorrelation Analysis ◽  
Autocorrelation Analysis ◽  
Color Traits ◽  
Causative Agents ◽  
The Difference ◽  
High Repeatability

Abstract To obtain fundamental and useful information regarding heartwood color traits in Japanese cedar, the validity of using L* index for expressing heartwood color and genetic and environmental influences on heartwood color were analyzed using 118 clones with 303 individuals aged approximately 30 years. As for three clones with typical reddish and blackish heartwood, relationships between heartwood color and moisture/potassium content, which were pointed out as ones of the causative agents of blackish heartwood, and the color change after approximately 20 years of conservation were investigated. Based on the continuity, width range, and standard deviation of each index of L*a*b* data, L* was found out to be an appropriate index to express heartwood color in this species. L* values significantly differed between clones. A moderately high repeatability of clones was detected in L* value. Spatial autocorrelation analysis also showed a stronger effect genetically than environmentally. Moisture and potassium contents significantly differed between two groups of reddish and blackish heartwood. Therefore, the absorption and accumulation of water and potassium into trunk may be genetically regulated. As for the L* value of heartwood color after approximately 20 years of conservation, the difference between two groups was still significant, but the lightness in blackish heartwood increased such that the difference was greatly reduced.

scholarly journals Investigation of the selective color-changing mechanism of Dynastes tityus beetle (Coleoptera: Scarabaeidae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiyu Sun ◽  
Wei Wu ◽  
Limei Tian ◽  
Wei Li ◽  
Fang Zhang ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Color Change ◽  
Incidence Angle ◽  
Ion Beam ◽  
Three Dimensional ◽  
Water Infiltration ◽  
Photonic Materials ◽  
Local Color ◽  
Water Contact ◽  
Color Changes

AbstractNot only does the Dynastes tityus beetle display a reversible color change controlled by differences in humidity, but also, the elytron scale can change color from yellow-green to deep-brown in specified shapes. The results obtained by focused ion beam-scanning electron microscopy (FIB-SEM), show that the epicuticle (EPI) is a permeable layer, and the exocuticle (EXO) is a three-dimensional photonic crystal. To investigate the mechanism of the reversible color change, experiments were conducted to determine the water contact angle, surface chemical composition, and optical reflectance, and the reflective spectrum was simulated. The water on the surface began to permeate into the elytron via the surface elemental composition and channels in the EPI. A structural unit (SU) in the EXO allows local color changes in varied shapes. The reflectance of both yellow-green and deep-brown elytra increases as the incidence angle increases from 0° to 60°. The microstructure and changes in the refractive index are the main factors that influence the process of reversible color change. According to the simulation, the lower reflectance causing the color change to deep-brown results from water infiltration, which increases light absorption. Meanwhile, the waxy layer has no effect on the reflection of light. This study lays the foundation to manufacture engineered photonic materials that undergo controllable changes in iridescent color.

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