Methods for determining color characteristics of vegetable raw materials. A review

Food product quality defines a complex of food product properties such size, shape, texture, color and others, and determines acceptability of these products for consumers. It is possible to detect defects in plant raw materials by color and classify them by color characteristics, texture, shape, a degree of maturity and so on. Currently, the work on modernization of color control systems has been carried out for rapid and objective measuring information about color of plant raw materials during their harvesting, processing and storage. The aim of the work is to analyze existing methods for determining color characteristics of plant raw materials described in foreign and domestic studies. Also, this paper presents the results of the experimental studies that describe the practical use of methods for measuring food product color. At present, the following methods for determining color characteristics by the sensor analysis principle are used: sensory, spectrophotometric and photometric. These methods have several disadvantages. Therefore, computer vision has found wide application as an automated method for food control. It is distinguished by high confidence and reliability in the process of determining freshness, safety, a degree of maturity and other parameters of plant raw materials that are heterogeneous in terms of the abovementioned indicators. The computer vision method is realized in the following systems: conventional, hyperspectral and multispectral. Each subsequent system is a component of the preceding one. Materials presented in the paper allow making a conclusion about the effectiveness of the computer vision systems with the aim of automatic sorting and determining quality of plant raw materials in the food industry.

Multifunctional Dyeing of Wool Fabrics Using Selenium Nanoparticles

This work aims to utilize selenium nanoparticles (Se-NPs) as a novel dyestuff, which endows wool fibers with an orange color because of their localized surface plasmon resonance. The color characteristics of dyed fibers were evaluated and analyzed. The color depth of the dyed fabrics under study was increased with the increase in Se content and dyeing temperature. The colored wool fabrics were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and an X-ray diffraction (XRD) analysis. The results indicated that spherical Se-NPs with a spherical shape were consistently deposited onto the surface of wool fibers with good distribution. In addition, the influence of high temperature on the color characteristics and imparted functionalities of the dyed fabrics were also investigated. The obtained results showed that the proposed dyeing process is highly durable to washing after 10 cycles of washes, and the acquired functionalities, mainly antimicrobial activity and UV-blocking properties, were only marginally affected, maintaining an excellent fastness property.

Influence of the surface characteristics of corrugated cardboard on the quality of inkjet printing

This paper investigates the quality of inkjet printing on corrugated cardboard with various characteristics such as the presence of surface coating, the type of cardboard structure, the corrugated layer profile, and the corrugated cardboard height. The color characteristics of the corrugated board surface of studied samples were analyzed in the CIE Lab system; the value of the discrepancy in the shade of white was established when compared with the reference values of the ISO 12647 standard. During the study, the main criteria for assessing the quality of color reproduction of inkjet imprints were analyzed: an indicator of the general contrast level (K), the value of color differences for the basic tone shades (ΔE), and the volume of the body color coverage (ΔE2). It was found that when printing on various types of corrugated cardboard, there is a general decrease in the overall contrast value. The actual level of color differences is ΔE=10...45 and exceeds the permissible standards for the color reproduction quality. This adversely affects the reproduction of different color tones in the printed image. In general, the quality of color reproduction differs for the test samples of corrugated cardboard in terms of the magnitude of the spread in the values of color distortions on the tone shades. The influence of the main characteristics of the investigated samples of corrugated cardboard on the quality indicators of inkjet printing has been analyzed. In particular, a significant influence of the index of color characteristics of the surface of corrugated cardboard L* and the type of corrugated board structure on the quality of color reproduction has been established. The study results reported here could make it possible to reasonably approach the selection of the corrugated board structure that is optimal in composition, increase the productivity of the technological process for manufacturing containers, and stabilize the quality of printing on corrugated cardboard

The determination of synthesis conditions and color properties of pigments based on layered double hydroxides with Co as a guest cation

Nail polish, in particular gel polish, is the most commonly used cosmetic product. A component of the gel polish, which determines the consumer color characteristics of the gel polish. Layered double hydroxides (LDH) are promising pigments. To expand the range of colors and shades of pigments, the use of LDH with colored host and guest cations is promising. The parameters of synthesis and color characteristics of samples of Zn-Co and Cu-Co hydroxide pigments were studied. To obtain LDH with Co as a guest cation in the synthesis, the conversion of cobalt to the trivalent state was carried out at a temperature of 80 °C using oxidation with atmospheric oxygen or sodium hypochlorite. The oxidation efficiency was evaluated by X-ray phase analysis by the presence or absence of cobalt-containing phases. The color characteristics of the synthesized pigment samples were studied by spectroscopic measurement and calculation in RGB, CIELab, and LCH color models. The low efficiency of cobalt oxidation at the moment of Zn-Co LDH synthesis with atmospheric oxygen at an elevated synthesis temperature of 80 °C was shown, while cobalt was released as a separate Co3O4 phase. A higher efficiency of cobalt oxidation at the moment of synthesis using sodium hypochlorite with the formation of Zn-Co LDH was revealed. It is recommended to use the hypochlorite oxidation of Co2+ to Co3+ in the LDH synthesis with Co in the form of a guest cation. The formation of a separate phase of zinc oxide was found in both types of oxidation due to the thermal decomposition of zinc hydroxide. Comparative analysis of color characteristics showed that all samples have a brown color of different saturation. It was revealed that during the formation of Co-containing LDH, the lightness of the color decreases. Color saturation increases in the case of a colored host cation, such as Cu.

NEW ACID-BASIC INDICATORS: RESEARCH USING A SMARTPHONE

Modern cameras, desktop scanners, smartphones allow not only registering an image, but also determining its color characteristics. That allows us to quickly, objectively and automatically determine the color characteristics of colored samples in acid-base titration, because there is a significant error at visually determining the pH range of the color transition. In analytical chemistry the characteristics of acid-base indicators are very important, in particular their pH transition interval. But the disadvantage of most indicators is the wide range of color transition: from 1 to 3 pH units. The aim of this work is to find new acid-base indicators that change color in an alkaline environment and have a narrow pH range of the color transition. We have developed the apparatus and technique of convenient and highprecision simultaneous determination of the pH of the medium and the color of the acidbase indicators. In acid-base titration the PH measurements were performed with a combined glass electrode AD1131 by рН-meter AD1000. The color transition was determined with help of a smartphone with the subsequent processing of the results by computer software. The color characteristics were measured for each channel of the RGB model in the range from 0 to 255. Our apparatus is small and mobile, and allows us simultaneously to measure the pH of the medium and accurately to determine the color characteristics. As a result, we can construct graphical dependencies of color on pH for each channel of the RGB model. We found the N-arylsulfonyl-2-aroylamido-1,4-benzo(naphto)quinone monoimines and 2,5-dibenzoylamido-1,4-benzoquinone are good acid-base indicators. They “work” in the pH range from 8.82 to 11.35 and have a very narrow color transition interval from 0.10 to 0.61. Solutions of these compounds in an alkaline medium have bright intense colors due to formation of mesomeric ions. That allows using of these indicators in the titration of weak acids with strong bases and vice versa by the method of neutralization.

INFLUENCE OF HEAT TREATMENT ON AROMA AND COLOR CHARACTERISTICS OF WHEAT BREAD

В формировании потребительских предпочтений важная роль отводится внешнему виду и аромату пищевых продуктов. При выпечке хлебобулочных изделий в процессе меланоидинообразования происходит изменение цвета и появление характерного хлебного запаха. Целью работы явилось исследование ароматобразующих веществ и цветовых характеристик белого пшеничного хлеба, подверженного термической обработке. Объектами исследований служили образцы белого пшеничного хлеба, нагревание которых проводили в сушильном шкафу при температурах 90, 120, 150, 180 и 210°С с интервалом в 10 мин на протяжении 2 ч. Исследование летучих компонентов осуществляли методом газовой хроматографии с масс-селективным детектированием. Образцы фиксировали фотоаппаратом Canon EOS 750D. В результате исследований обнаружено более 120 летучих веществ, идентифицировано 76, из них 31 существенно влияет на аромат белого хлеба. В основном это карбонильные соединения и низшие жирные кислоты, а также спирты, сложные эфиры и некоторые серосодержащие соединения. Анализ изменения цветовых характеристик белого пшеничного хлеба показал, что с увеличением температуры нагревания наблюдается значительное потемнение образцов. Если при температуре 90°С происходит еще незначительное изменение цвета, даже после 2-часового воздействия, то при увеличении температуры до 180–210°С цвет образцов хлеба темнеет в первые 10 мин и в последующем меняется незначительно. Таким образом, результаты исследований показали, что температуру и длительность обжарки необходимо оптимизировать для создания наиболее востребованных потребительских свойств продукта. In the formation of consumer preferences FOR food an important role belongs to appearance and aroma. At baking as a result of the melanoid formation process the color changes and typical of bread aroma appears. The purpose of work was studying the aroma-forming substances and color characteristics of the white bread at heat treatment. The objects of the research were samples of white bread heated in a drying oven at temperatures of 90, 120, 150, 180 and 210°C with a time interval of 10 minutes for 2 hours. The volatiles were investigated by gas chromatography with mass-selective detection. The image was recorded on a Canon EOS 750D camera. As a result of the research more than 120 volatile substances were detected, it is identified 76 from which 31 make an essential contribution to aroma of white bread. Basically, these are carbonyl compounds and lower fatty acids, as well as alcohols, esters and some sulfur-containing compounds. An analysis of the change in the color characteristics of white bread showed that with an increase in the heating temperature a significant darkening of the samples is observed. At a temperature of 90°C there is still a slight color change even after a 2-hour exposure to temperature, then as the temperature increases to 180–210°C, the color of the bread samples becomes darker within the first 10 minutes and then changes insignificantly. Thus, the results of research have shown that the temperature and duration of roasting should be optimized to create the most popular consumer properties of the product.

Physicochemical and color characteristic of the Bawakaraeng Forest Honey, South Sulawesi

Honey is a thick liquid produced by bees consisting of natural sugars derived from flower nectar or plant secretions. The content of monosaccharides and fructose causes the sweetness of honey, and glucose compounds are naturally found in honey derived from the juices of food carried by bees. This study aims to determine physicochemical and color characteristics of forest honey from Bawakaraeng Mountain with the quality of honey obtained in accordance with the Indonesian National Standard. Characterization of the physicochemical quality of total sugar content was measured using a refractometer, acidity by pH meter, and color characteristics by Hunter Methods using chromameter instruments. In the results, color characterization of forest honey L* 22.28-22.46; a* 3.30-3.37; b* 4.74-4.87, L value indicates a lightness level that tends to be dark and a yellow-red chromatic color range (YR). Then water content is 21.06%, total sugar content is 49.53%, and pH 4. Finally, physicochemical and color characteristics analysis of forest honey needs to be studied more rapidly on the content of bioactive compounds and their benefits for health. The potential of forest honey from the Sinjai Regency is a new functional food that provides high antioxidant content value and rich nutrients.

METHODOLOGICAL AND TECHNICAL ENVIRONMENT OF WATERCOLOR PAINTING FOR STUDENTS-ARCHITECTORS

The article considers that watercolor technique is the most advanced one for the transfer of living architectural forms of structures in the drawing. Drawings of architectural projects should give a full understanding of the correct purpose, about the cost-effectiveness, strength and beauty of the future building. Therefore, drawings must be clear, understandable, expressive, their graphic performance must be based on the high foundations of realistic art. Watercolor is a professional and traditional visual means of an architect. Watercolor is an amazing material that combines the ability to comprehend both the pictorial, color organization of the image and the graphic, sign-tonal one. The architect, referring to the picturesque development of the drawing, first of all, must determine its purpose and choose from all the numerous visual techniques of watercolor painting those that will better contribute to the expressiveness of this drawing. Then they will be correctly used: the perfect visual equipment, a large arsenal of tools, a wide range of techniques, a large palette of colors, various possibilities of tools and materials. These features allow you to cope with multitasking in a wide variety of visual arts. The main features of watercolor painting are high airiness and transparency. However, architectural watercolor has its own specific conventions, some generalization, laconicism, business simplicity, clarity, a certain limited palette of colors, but at the same time it successfully fulfills its task only when it proceeds from the position of realistic painting.Such watercolor techniques as: “wet”, “dry”, “glaze”, “ά la prima” are considered The technique of watercolor painting is a visual reflection of the main theoretical postulates of the composite space organization on the plane. Watercolor techniques solve these problems and clearly show the interaction of tonal and color characteristics of all elements of the composition.