Consistent Characterization of Color Degradation Due to Artificial Aging Procedures at Popular Pigments of Byzantine Iconography

The degradation effects of artificial aging on the “true” pigment color of Byzantine iconography are thoroughly investigated in this work. For this purpose, a multi-material palette is fabricated, consisting of various popular egg-tempera pigments, while the original recipes from the literature are utilized in order to mimic the genuine art of Byzantine painters. Then, artificial aging procedures are appropriately employed to simulate environmental fluctuations in historical buildings, such as churches. A total of four time steps are investigated, including the initial condition, and pigments’ spectra in the ultraviolet/visible (UV/Vis) area are acquired in the diffuse reflectance mode at each individual step. Moreover, a color characterization procedure is realized via the quantification of lightness and saturation by means of the measured UV/Vis spectrum. The main objectives of this work are to determine the color stability, the type of color degradation, and generally the color response through time of the studied pigments. The extracted results indicate that a couple of pigments suffer severe color degradation while the majority present moderate darkening or discoloration.

Inhibition of Protein and Lipid Oxidation in Ready-to-Eat Chicken Patties by a Spondias mombin L. Bagasse Phenolic-Rich Extract

This study evaluated the impact of yellow mombin (Spondias mombin L.) bagasse extract (YMBE) on the color degradation, protein and lipid oxidation in ready-to-eat chicken patties during 15 days of refrigerated storage. Two formulations of chicken patties were developed: chicken patties control - PCON (without the antioxidant extract) and chicken patties with yellow mombin extract - PYME (with the antioxidant extract). The extract was effective in maintaining red color and inhibiting myoglobin degradation in the evaluated samples. The generation of lipid oxidation compounds during storage of the treated samples was delayed by 92.37% for peroxide index, 89.89% for conjugated dienes, 74.29% for tiobarbituric acid reactive substances (TBARs) and 92.55% for ρ-anisidine compared to the control samples. Moreover, the addition of YMBE inhibited the formation of carbonyl compounds during cold storage compared to the control samples. Extracts obtained from the yellow mombin bagasse act as a good natural antioxidant for ready-to-eat chicken patties inhibiting protein and lipid oxidative damage during cold storage, being a potential preservative to replace synthetic antioxidants in meat products.

Removing BOD, COD, and Decolorization of Batik Cual Wastewater Using Fenton Mechanism

During the production of batik cual, thick-colored wastewater is produced. Unfortunately, the wastewater could damage the environment if it is disposed of without specific processing. The Fenton method is an advanced oxidation process (AOPs) that can degrade organic dyes found in liquid waste. In this research, the researchers studied the Fenton mechanism's application to the batik cual wastewater treatment. The Fenton's reagent used was H2O2 with FeSO4.7H2O. Some of the experimental wastewater treatment parameters were the values of biological oxygen demand (BOD), chemical oxygen demand (COD), the degradation efficiency of difficult to decompose organic materials, and the color degradation efficiency in batik cual wastewater. The results show that the Fenton mechanism’s efficiency of removing color from batik cual wastewater is up to 97.8%, COD and BOD removal efficiencies are 76.3% and 75.2%, and the degradation efficiency of difficult to decompose organic matter is 76.8%. Also, the researchers found that the higher amounts of FeSO4.7H2O increase the removal parameters effectiveness. Therefore, the Fenton mechanism can effectively improve the quality of wastewater in batik cual production.

Effect of High Pressure Processing on enzymatic activity for strawberries, sour cherries and red grapes

Color degradation is an important factor that affect the quality and acceptability of fruit juices and purees; several enzymes, as well as the microbial endogenous population are not only responsible for this phenomenon but for changes in flavor and texture. Traditional stabilization methods have been used to preserve these kind of products; however, there is a negative impact on vitamins and bioactive compounds composition. High Pressure Processing (HPP) is a non-thermal alternative that has been applied for the extension of shelf life of fresh products, reducing the adverse effects of classical treatments. The aim of this review is to provide a scientific base on the effect of HPP technology in terms of enzymatic inactivation (peroxidase, polyphenol oxidase, ascorbate oxidase and β-glucosidase) in comparison with a conventional pasteurization process in strawberries, sour cherries and red grapes, and to propose an optimization strategy for the operational parameters to achieve the greatest inactivation

Ekstraksi dan Uji Stabilitas Zat Warna Alami dari Bayam Merah (Alternanthera amoena Voss)

Research on the extraction and stability test of natural dye from red spinach (Alternanthera amoena Voss) has been carried out. This study aims to determine the effect of pH and length of sun exposure on the stability of the dye from red spinach. Extraction using the maceration method with ethanol solvent and measurement using a UV-Vis spectrophotometer. Stability testing is carried out at pH 2-5 and sun exposure for 1-4 hours using a dark and light container. The results obtained, at pH 2 and pH 3, anthocyanins were more stable, compared to pH 4 and 5 which had greater color degradation. In exposure to sunlight, dark containers with a degradation percentage of 31.70% were better than clear containers with a percentage of 48.78%. Keywords: Anthocyanin, red spinach, natural dyes stability.

Analysis of Thermal Degradation in the Annealing Process of Colored Parts Built by Extrusion-Based 3D Printing

With the ever-increasing request of light materials, poly lactic (acid) PLA, have got much in consideration. Low-cost PLA materials have risen its use. Those possess some benefits but nevertheless insufficient mechanical strength. The printed PLA objects have a stumbling block for practical applications. Thus, annealing is an interested alternative to make 3D printed objects strong. This thermal treatment can significantly develop investigational studies and offer technical data. Hence the purpose of this paper is study and discuss how to increase the flexural strength through annealing process. Geometry distortions and color degradation will be analyzed. Differential Scanning Calorimetry, Taguchi Method (TM) and variance (ANOVA) were applied as part of the design experiments and analysis. Twenty-seven printed specimens were tested and factors as temperature, time and color were selected.

Weathering performance of dyed bamboo fiber composites

Flattened and crushed fiber-bundles of moso bamboo (Phyllostachys pubescens) were dyed with a water or alcohol-based dye at 20 °C, 75 °C or 90 °C for 72 h, followed by drying and coating with PF resin. Hot-pressed bamboo fiber composites (BFC) were manufactured, and the weathering performance of the composites made from dyed and natural bamboo material were tested over 90 days of the Autumn/Winter season in Beijing. Dye was able to penetrate the bamboo tissue to create a rich red color that degraded in color faster than BFC made from un-dyed bamboo. BFC made from un-dyed tissue remained a lighter but more consistent color over the weathering period. Dying the bamboo in ethanol-based dye was effective at pigmenting the product, but made it more susceptible to color degradation as well as greater mass and thickness loss due to the chemical degradation of the lignin caused by ethanol. Higher temperature of water dying treatment (90 °C) gave the greatest resistance to mass and thickness loss during outdoor exposure, and the bamboo may have benefitted from the longer period of ‘heat treatment’ during dyeing. Further work is needed to quantify dye leaching from bamboo tissue and to develop more water-tight and color-fast, weather resistant dyes for bamboo products.