scholarly journals Mechanical and chemical resistance of thermochromic packaging prints

2020 ◽  
Author(s):  
Sonja Jamnicki Hanzer ◽  
◽  
Rahela Kulčar ◽  
Marina Vukoje ◽  
Petra Širol ◽  
...  
Keyword(s):  
Standard Method ◽  
Food Packaging ◽  
Visual Inspection ◽  
Chemical Resistance ◽  
Uv Light ◽  
Chemical Degradation ◽  
Temperature Sensitive ◽  
Severe Damage ◽  
Thermochromic Effect ◽  
Adverse Environmental Conditions

Thermochromic inks are temperature-sensitive materials that change colour due to a temperature change. These inks are mostly printed on smart packaging applications where they are used in a form of temperature indicators. The colorants in these inks are microencapsulated which makes the prints obtained with these inks more sensitive to abrasion in comparison to the prints obtained with conventional inks. Thermochromic prints are also very sensitive to adverse environmental conditions, such as exposure to UV light, heat and certain chemicals and solvents. Abrasion and chemical resistance of thermochromic prints obtained on metallized label papers are discussed in this paper. For that purpose, two thermochromic UV screen inks were printed on two types of metalized papers that are commonly used as food packaging labels. The prints thus obtained were then subjected to a rub test in accordance with standard method BS 3110. Rub test was performed using Hanatek RT4 Rub and Abrasion Tester. The degree of rubbing was assessed by visual inspection and by detection of the colorimetric changes on the prints after their exposure to rubbing. Assessment of prints' resistance to various liquid agents (water, ethanol and citric acid) was done in accordance to standard method ISO 2836. Evaluation of chemical degradation on prints was done by the spectrophotometric measurements. The results of conducted research showed good rub resistance of these inks, as no rubbing was detected, but poor resistance to all liquid agents they were exposed to. Exposure to ethanol, particularly, caused severe damage to the prints. The bleeding of the colorants from the prints was also detected. However, even though the prints were not able to completely withstand exposure to specific liquid agents which was demonstrated by their optical deterioration, the thermochromic effect was still present in them after resistance tests were conducted.

scholarly journals Development and Characterization of Functional Starch-Based Films Incorporating Free or Microencapsulated Spent Black Tea Extract

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3898
Author(s):  
Surakshi Wimangika Rajapaksha ◽  
Naoto Shimizu
Keyword(s):  
Antioxidant Activity ◽  
Lipid Oxidation ◽  
Food Packaging ◽  
Uv Light ◽  
Antioxidant Properties ◽  
Black Tea ◽  
Wall Material ◽  
Food Simulants ◽  
Black Tea Extract ◽  
Tea Extract

Antioxidant polyphenols in black tea residue are an underused source of bioactive compounds. Microencapsulation can turn them into a valuable functional ingredient for different food applications. This study investigated the potential of using spent black tea extract (SBT) as an active ingredient in food packaging. Free or microencapsulated forms of SBT, using a pectin–sodium caseinate mixture as a wall material, were incorporated in a cassava starch matrix and films developed by casting. The effect of incorporating SBT at different polyphenol contents (0.17% and 0.34%) on the structural, physical, and antioxidant properties of the films, the migration of active compounds into different food simulants and their performance at preventing lipid oxidation were evaluated. The results showed that adding free SBT modified the film structure by forming hydrogen bonds with starch, creating a less elastic film with antioxidant activity (173 and 587 µg(GAE)/g film). Incorporating microencapsulated SBT improved the mechanical properties of active films and preserved their antioxidant activity (276 and 627 µg(GAE)/g film). Encapsulates significantly enhanced the release of antioxidant polyphenols into both aqueous and fatty food simulants. Both types of active film exhibited better barrier properties against UV light and water vapour than the control starch film and delayed lipid oxidation up to 35 d. This study revealed that starch film incorporating microencapsulated SBT can be used as a functional food packaging to protect fatty foods from oxidation.

scholarly journals Preparation of Antioxidant and Antibacterial Chitosan Film from Periplaneta americana

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 53
Author(s):  
Sicong Chen ◽  
Xunfan Wei ◽  
Zhuoxiao Sui ◽  
Mengyuan Guo ◽  
Jin Geng ◽  
...  
Keyword(s):  
Food Packaging ◽  
Periplaneta Americana ◽  
Uv Light ◽  
Radical Scavenging ◽  
Chitosan Film ◽  
American Cockroach ◽  
Raw Material ◽  
Potential Resource ◽  
Radical Scavenging Ability ◽  
Dpph Radical Scavenging

Among different insects, the American cockroach (Periplaneta americana) has been bred in industrial scale successfully as a potential resource of protein, lipid, and antibacterial peptide. However, the application of its chitosan has not been studied widely, which has hindered the sufficient utilization of P. americana. In this paper, the chitosan from P. americana was separated, characterized, and processed into film (PaCSF) to examine its potential of being applied in food packaging. As the results of different characterizations showed, PaCSF was similar to shrimp chitosan film (SCSF). However, concerning the performances relating to food packaging, the two chitosan films were different. PaCSF contained more water (42.82%) than SCSF did, resulting in its larger thickness (0.08 mm). PaCSF could resist UV light more effectively than SCSF did. Concerning antioxidant activity, the DPPH radical scavenging ability of PaCSF increased linearly with time passing, reaching 72.46% after 8 h, which was better than that of SCSF. The antibacterial activity assay exhibited that PaCSF resisted the growth of Serratia marcescens and Escherichia coli more effectively than SCSF did. The results implied that P. americana chitosan could be a potential raw material for food packaging, providing a new way to develop P. americana.

Bioactive chitosan/ellagic acid films with UV-light protection for active food packaging

2017 ◽  
Vol 73 ◽  
pp. 120-128 ◽  
Author(s):  
Carla Vilela ◽  
Ricardo J.B. Pinto ◽  
Joel Coelho ◽  
Maria R.M. Domingues ◽  
Sara Daina ◽  
...  
Keyword(s):  
Ellagic Acid ◽  
Food Packaging ◽  
Uv Light ◽  
Active Food Packaging ◽  
Light Protection

Phase-Change Heat Transfer Measurements Using Temperature-Sensitive Paints

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Husain Al Hashimi ◽  
Caleb F. Hammer ◽  
Michel T. Lebon ◽  
Dan Zhang ◽  
Jungho Kim
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Uv Light ◽  
Flow Boiling ◽  
Low Cost ◽  
Data Interpretation ◽  
Temperature Sensitive ◽  
Time Resolved ◽  
Light Emitting ◽  
Phase Change Heat Transfer

Techniques based on temperature-sensitive paints (TSP) to measure time-resolved temperature and heat transfer distributions at the interface between a wall and fluid during pool and flow boiling are described. The paints are excited using ultraviolet (UV) light emitting diodes (LEDs), and changes in fluorescence intensity are used to infer local temperature differences across a thin insulator from which heat flux distribution is obtained. Advantages over infrared (IR) thermometry include the ability to use substrates that are opaque to IR (e.g., glass, plexiglass and plastic films), use of low-cost optical cameras, no self-emission from substrates to complicate data interpretation, high speed, and high spatial resolution. TSP-based methods to measure wall heat transfer distributions are validated and then demonstrated for pool and flow boiling.

Role of ZnO Nanoparticles for improvement of Antibacterial Activity in Food Packaging

2021 ◽  
pp. 128-131
Author(s):  
Saira Sehar ◽  
Amiza Amiza ◽  
I. H Khan
Keyword(s):  
Antimicrobial Activity ◽  
Particle Size ◽  
Surface Area ◽  
Zno Nanoparticles ◽  
Food Packaging ◽  
Antimicrobial Agents ◽  
Uv Light ◽  
Zno Nps ◽  
Long Time

Nanotechnology advancement leads to development of antimicrobial agents like ZnO nanoparticles. These nanoparticle have their main applications in food packaging. when these nanoparticles incorporate into the food surface, it will kill all bacterias residing on the surface and food become free of bacteria. In this way, food can be stored for a long time because its shelf life is improved. Antimicrobial activity of ZnO nanoparticles can be improved by increasing surface area, reducing particle size and large concentration of ZnO –NPS. Antimicrobial activity increases by increasing intensity of UV light. As UV light fall on ZnO nanoparticles, it increases ZnO surface area and hence anrtimicrobial activity will be increased. Exact mechanism of Antimicrobial activity is still unknown but some processes have been presented.

Synthesis and properties of temperature-sensitive and chemically crosslinkable poly(ether-urethane) hydrogel

2015 ◽  
Vol 6 (19) ◽  
pp. 3671-3684 ◽  
Author(s):  
Ruizhi Li ◽  
Na Liu ◽  
Bingqiang Li ◽  
Yinong Wang ◽  
Guolin Wu ◽  
...  
Keyword(s):  
Uv Light ◽  
Temperature Sensitive ◽  
Physiological Temperature

The PEU-MA solutions can gelate at physiological temperature, and be further crosslinked by UV light.

Tolerances of barley cultivars to post-emergence herbicides

1986 ◽  
Vol 26 (3) ◽  
pp. 383 ◽  
Author(s):  
D Lemerle ◽  
CR Kidd ◽  
BJ Read
Keyword(s):  
New South ◽  
Spring Barley ◽  
Crop Damage ◽  
Rhynchosporium Secalis ◽  
Plant Responses ◽  
Severe Damage ◽  
Barley Cultivars ◽  
South Wales ◽  
Barley Leaf ◽  
Adverse Environmental Conditions

Sixteen spring barley cultivars were tested in southern New South Wales for their tolerances to 12 post-emergence herbicides applied at the recommended rates and at three times those rates. Examples of unsafe combinations of cultivars and herbicides (at recommended rates) that have a risk of crop damage in this environment include: Shannon with bromoxynil at 0.42 kg/ha; Panvan with bromoxynil plus MCPA at 0.42 + 0.42 kg/ha; Bandulla, Beecher, Clipper, Malebo, Panvan and Weeah with dicamba at 0.08 kg/ha; and Clipper, Galleon, Lara and Shannon with dicamba plus MCPA at 0.11 + 0.48 kg/ha. Severe damage occurred to barleys from diclofop-methyl at 0.56 kg/ha and from chlorsulfuron at 0.01 8 kg/ha. Cultivars which showed tolerance were Grimmett, Lara, Stirling and Shannon with chlorsulfuron, and Shannon and Weeah with diclofop-methyl. The use of rates three times those recommended by the manufacturers in these experiments identified the susceptibility of additional cultivars which could be at risk of crop damage from overdosing, incorrect timing of application, or adverse environmental conditions. For example, Lara and Corvette with bromoxynil at 1.26 kg/ha; Corvette and Shannon with bromoxynil plus MCPA at 1.26 + 1.26 kg/ha; Corvette, Cutter, Galleon, Lara, Panvan, Schooner, and Shannon with dicamba plus MCPA at 0.33 + 1.44 kg/ha. The grain yields ofall cultivars were unaffected by both rates of difenzoquat, diuron, linuron, methabenzthiazuron or 2,4-D. The risks of crop damage v. the benefits of weed control are discussed. Seasonal variation was observed in the herbicidexcultivar interactions and this variation was sometimes of a greater magnitude than the differences between the cultivars. An interaction was observed between the incidence of barley leaf scald (Rhynchosporium secalis) and treatment with chlorsulfuron or diclofop-methyl. Routine screening of herbicides and crop cultivars for dangerous interactions is recommended, and we need a greater understanding of the effects of environmental factors on plant responses to herbicides.

scholarly journals Effect of the Concentration of Pigment Slurry on the Film Performances of Waterborne Wood Coatings

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 635 ◽  
Author(s):  
Yan ◽  
Chang ◽  
Qian
Keyword(s):  
Chemical Resistance ◽  
Impact Resistance ◽  
Base Material ◽  
Chinese Fir ◽  
Temperature Sensitive ◽  
Coating Film ◽  
Wood Coating ◽  
Wood Coatings ◽  
Surface Decoration ◽  
Thermochromic Pigment

Wood surface decoration and protection has become a topic of public concern. In this paper, a temperature-sensitive and reversible thermochromic waterborne wood coating was prepared by using Chinese fir board as the base material and a waterborne wood coating with the pigment slurry of thermochromic microcapsules as the paint base. The optical properties, mechanical properties and chemical resistance of the waterborne wood coating were tested, and its microstructure was analyzed. The results showed that when the concentration of thermochromic pigment slurry was 30.0%, the thermochromic property of the waterborne wood coating was best. The gloss of the waterborne wood coating with 15.0% pigment slurry of thermochromic microcapsules was high. The concentration of thermochromic pigment slurry had no effect on the adhesion, impact resistance, or chemical resistance of the waterborne wood coating. Based on the above results, the waterborne wood coating on Chinese fir had the best comprehensive performance when the concentration of thermochromic pigment slurry was 15.0%. This work will provide a technical reference for the industrialization of the thermochromic coating film on wood.

Story Damage Identification of Irregular Buildings Based on Earthquake Records

2013 ◽  
Vol 29 (3) ◽  
pp. 963-985 ◽  
Author(s):  
Jer-Fu Wang ◽  
Chi-Chang Lin ◽  
Ging-Long Lin ◽  
Chun-Hao Yang
Keyword(s):  
Damage Assessment ◽  
Visual Inspection ◽  
Damage Identification ◽  
Damage Index ◽  
Analytical Formula ◽  
Mode Shapes ◽  
Severe Damage ◽  
Concrete Building ◽  
Damage Condition ◽  
Identification Techniques

In this paper, a story damage index was developed to evaluate the damage condition of a torsionally coupled building based on its dominant modal frequencies and mode shapes. This index has an analytical formula with a calculated value ranging from 0 (undamaged) to 1.0 (collapsed) to indicate the reduction of story lateral stiffness. The involved computation is simple once the modal parameters of any three modes are obtained through system identification techniques from few floor acceleration measurements. The damage region within a story can also be identified through tracking the change of eccentricity of center of rigidity. This index was verified by numerical simulations and a data analysis of the ASCE benchmark model. In addition, it was also applied to the damage assessment of a four-story reinforced concrete building in Taiwan, which experienced severe damage during the 2006 Taitung Beinan earthquake ( M = 6.2). The results agree fairly well with the visual inspection and show the applicability of the proposed damage assessment technique.

Characterization of UV-Peroxide Killing of Bacterial Spores

2003 ◽  
Vol 66 (7) ◽  
pp. 1233-1240 ◽  
Author(s):  
JEFFREY S. REIDMILLER ◽  
JEREMIAH D. BALDECK ◽  
GLEN C. RUTHERFORD ◽  
ROBERT E. MARQUIS
Keyword(s):  
Uv Irradiation ◽  
Food Packaging ◽  
Uv Light ◽  
Bacterial Spores ◽  
Experimental Conditions ◽  
Hydrogen Peroxide Treatment ◽  
Spore Killing ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Copper Cations

Advantage is taken in many sterilization processes, especially for food packaging materials, of the synergy between H2O2 and UV irradiation for spore killing. The nature of the synergy is currently not well defined in terms of targets and mechanisms. We found that under some experimental conditions, the synergistic killing of spores of Bacillus megaterium ATCC 19213 appeared to be mainly UV-enhanced peroxide killing, while under other conditions, it appeared to be mainly peroxide-enhanced UV killing. Lethal combinations of H2O2 and UV irradiation for spores resulted in only modest increases in auxotrophic mutations among survivors, indicative of little DNA damage, in contrast to higher mutation levels after dry-heat damage at 115°C. However, the combination of UV light and peroxide did lead to major inactivation of glucose 6-phosphate dehydrogenase, an enzyme that was used to monitor the damage to bacterial protein. Synergistic UV-H2O2 killing was reduced by agents such as pyruvate, thiosulfate, and iron or copper cations, which appeared to act at least in part by reacting chemically with H2O2, and was only slightly affected by the use of UV light at a wavelength of 222 nm rather than 254 nm. Hydrogen peroxide treatment can precede UV irradiation for synergistic killing by some hours with an interim of drying for spores of Bacillus subtilis A, a spore type used commonly for the validation of aseptic processes. Synergistic killing of dried spores or those in suspensions was accelerated at higher temperatures (50°C) rather than at lower temperatures (25°C).

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