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

Author(s):  
И.М. ПОЧИЦКАЯ ◽  
Ю.Ф. РОСЛЯКОВ ◽  
В.В. ЛИТВЯК ◽  
Н.В. КОМАРОВА ◽  
Е.И. КОВАЛЕНКО

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.

2018 ◽  
Vol 3 (4) ◽  
pp. 38-48 ◽  
Author(s):  
Zenon V. Lovkis ◽  
Irina M. Pochitskaya ◽  
Natallia V. Komarova

The article presents the study results of changes in the odor profile and color characteristics in beef under various heat treatment conditions. More than 120 volatile substances are identified. In samples subjected to short-term and minor heat treatment, 2-methyl-butene and ethyl hexanoate were found in significant amounts. In samples subjected to prolonged roasting at low temperature, as well as in samples subjected to processing at higher temperature for less time period, was found 3,5-dimethyl–4-octanone. Analysis of changes in color characteristics showed that increase in heating temperature results in significant darkening of the samples. The maximum heating temperature of 210 °C had the most significant effect on the color change. After heating for more than 30 minutes, carbonization of the samples occurred. The results indicate that controlling the temperature and duration of heat treatment helps to obtain the finished product of desired color.


BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5574-5585
Author(s):  
Intan Fajar Suri ◽  
Jong Ho Kim ◽  
Byantara Darsan Purusatama ◽  
Go Un Yang ◽  
Denni Prasetia ◽  
...  

Color changes were tested and compared for heat-treated Paulownia tomentosa and Pinus koraiensis wood treated with hot oil or hot air for further utilization of these species. Hot oil and hot air treatments were conducted at 180, 200, and 220 °C for 1, 2, and 3 h. Heat-treated wood color changes were determined using the CIE-Lab color system. Weight changes of the wood before and after heat treatment were also determined. The weight of the oil heat-treated wood increased considerably but it decreased in air heat-treated wood. The oil heat-treated samples showed a greater decrease in lightness (L*) than air heat-treated samples. A significant change in L* was observed in Paulownia tomentosa. The red/green chromaticity (a*) of both wood samples increased at 180 and 200 °C and slightly decreased at 220 °C. The yellow/blue chromaticity (b*) in both wood samples increased at 180 °C, but it rapidly decreased with increasing treatment durations at 200 and 220 °C. The overall color change (ΔE*) in both heat treatments increased with increasing temperature, being higher in Paulownia tomentosa than in Pinus koraiensis. In conclusion, oil heat treatment reduced treatment duration and was a more effective method than air heat treatment in improving wood color.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Renping Cheng ◽  
Ying Guo

Abstract The effect of heat treatment on amethyst color was studied from a new perspective of chromaticity of gemstones and the cause of amethyst coloration was discussed based on the results of X-ray diffraction, ultraviolet–visible spectroscopy. The results show that the amethyst color has no significant relationship with cell parameters but the crystallinity index decreases as temperature rises. The absorption band at 545 nm in the UV–visible spectrum can be related to a charge-transfer transition of Fe3+ and O2−, which has a significant relationship with amethyst lightness and chroma. The color at different temperatures can be divided into three stages: The amethyst stage with temperature below 420 °C, the prasiolite stage with temperature between 420 and 440 °C where the color center is the most unstable, the citrine stage with temperature above 440 °C. The color change degree of heated amethyst is related to its initial color. When the initial color is darker, the color difference of heated amethyst is larger, and the easier it is to change the color after heat treatment. A more appropriate heating temperature to obtain citrine by heating amethyst is about 560 °C.


2017 ◽  
Vol 7 (3) ◽  
pp. 15-21 ◽  
Author(s):  
Михаил Ермоченков ◽  
Mihail Ermochenkov ◽  
Андрей Хроменко ◽  
Andrey Khromenko

Heat treatment is widely used to improve the properties of wood. Such processes include drying and thermal modification. Thermal modification is heating wood without oxygen, accompanied by heat destruction. Thermally modified wood can be used as structural and finishing materials. This puts the task of determining its thermal and physical, physical and chemical, biological, and ornamental properties and their change during heat treatment. The article presents the results of experimental and computational studies of color characteristics of the wood of birch, their change in the process of thermal modification. Thermal decomposition is a complicated multi-stage physical and chemical process. Thermal decomposition of material causes changes in its composition, structure, accompanied by alterations of its properties. Wood can be considered as a multicomponent composite material, consisting of hemicellulose, cellulose, lignin and other components. Each component decomposes in the temperature range that causes the multistage process of thermal degradation. The degree of thermal degradation of the material is determined by the kinetics of occurrence of each stage and the degree of its perfection. Thermal decomposition kinetics of wood can be determined by the results of thermal and gravimetric experiments. In the article the model of determining the color characteristics of wood as a function of the degree of completion of individual stages of thermal degradation is suggested. Model of decomposition of color for RGB components is used for identifying. Color identification of the samples of original birch wood in RGB coordinates was performed. The parameters of thermal effects, allowing to obtain wood with given degree of thermal decomposition are defined. Heat treatment of samples and identification of their color is made. The dependence of RGB parameters from time and intensity of heat treatment is studied. Empirical relations to determine the identifying characteristics of color, as a function of the degree of completion of stages of thermal destruction, in RGB and LAB systems are obtained in explicit form.


Holzforschung ◽  
2011 ◽  
Vol 65 (3) ◽  
Author(s):  
Miyuki Matsuo ◽  
Misao Yokoyama ◽  
Kenji Umemura ◽  
Junji Sugiyama ◽  
Shuichi Kawai ◽  
...  

Abstract The color properties of aging wood samples from historical buildings have been compared with those of recent wood samples that were heat treated at temperatures ranging from 90°C to 180°C. The results of kinetic analysis obtained by the time-temperature superposition method showed that the color change during natural aging was mainly due to a slow and mild oxidation process. In other words, heat treatment could accelerate the changes in wood color that occur during aging. In one sample, the color change (ΔE* ab ) after 921 years at ambient temperature was almost equivalent to that of heating (artificial aging) approximately for 6.7 h at 180°C. The results have been interpreted that the aging and the subsequent change in wood color begin at the time of tree harvesting.


2021 ◽  
Vol 10 (4) ◽  
pp. e54310414307
Author(s):  
Maria Julia Lima Motta ◽  
Victor de Miranda Ladewig ◽  
Joel Ferreira Santiago Junior ◽  
Renata Rodrigues Almeida-Pedrin ◽  
Thais Maria Freire Fernandes Poleti ◽  
...  

Objective: this study compared the force degradation and color change of esthetic elastomeric chains of four commercial brands. Materials and methods: the study analyzed 10 medium-force esthetic elastomeric chains with 6 links of Morelli, Orthometric, Eurodonto and 3M brands from sealed packages within the expiration date. The elastics were stretched twice their length, according to the manufacturer's recommendations, and were immersed in artificial saliva at 37°C. The forces were measured with an orthodontic dynamometer at onset and at intervals of 1, 7, 14, 21 and 30 days after immersion. The force degradation was evaluated calculating the percentage of force lost in relation to the initial force in each time interval, for each group tested separately and also between them. The color change was evaluated by visual analysis scale by observation of photographs of chain elastics before and after study completion by 31 examiners. The ANOVA test of repeated measures was applied considering 2 factors, time and groups, and the Tukey test was used for analysis of multiple comparisons. A significance value of 0.05% was adopted for the analyses. Results: the elastics showed great force degradation. After 7 days the groups presented degradation around 50% of the initial force. In the evaluation between groups, the elastics showed significantly different mean forces. When assessing color change, the scores assigned by examiners evidenced less color changes for elastics of Eurodonto brand. Conclusion: regardless of the commercial brand, transparent elastomeric chains show significant force degradation values ​​after 1 day. The scores assigned to color change evidenced that all commercial brands showed staining, with the best results for Eurodonto elastics.


2011 ◽  
Vol 214 ◽  
pp. 531-534 ◽  
Author(s):  
Qiang Shi ◽  
Fu Cheng Bao ◽  
Jian Xiong Lu ◽  
Jing Hui Jiang

In this study the effect of high temperature on color change of okan wood was investigated. Wood specimens were subjected to heat treatment at 160°C, 180°C,200°C,220°Cfor 4 hours with the superheated steam as a heating medium and a shielding gas. Color changes were measured in the Minolta Croma-Meter CR-300 color system. The color parameters L*, a*, b* were determined by the CIEL*a*b* method on the surface of untreated and treated wood, and their variation with regard to the treatment (△L*,△a*,△b* ) were calculated. It was found that heat treatment resulted in a darkening of wood tissues, Color became dark with the temperature increases. The darkening accelerated when treatment temperature exceeded approximately 200°C. We found that heat treatment temperature were substantially important regarding the color responses. Strong correlations between total color difference and the treatment temperature were found. The effect of treatment temperature on color change in sapwood is more obvious than that in heartwood, the color of sapwood and heartwood tended to be more uniform when the temperature reaches more than 200°C.


2021 ◽  
Vol 26 (2) ◽  
Author(s):  
Alana Dantas MOREIRA ◽  
Jamille Barros FERREIRA ◽  
Claudia Trindade MATTOS ◽  
Mariana MARQUEZAN ◽  
Mônica Tirre de Souza ARAÚJO ◽  
...  

ABSTRACT Objective: To assess the color of different orthodontic resin bonding agents exposed to three antiseptic mouthrinses for a prolonged time interval (10-year aging simulation). Methods: 160 specimens were distributed into four groups, according to the orthodontic resin bond agent (Concise, Transbond XT, Transbond Plus Color Change, and Natural Ortho). Each group was exposed to different antiseptic mouthrinses: alcohol-based (Listerine®), alcohol-free (Oral-B®), chlorhexidine (Periogard®) and distilled water as the control. Specimens were submitted to two cycles of staining and artificial aging. Color was evaluated by means of a digital spectrophotometer at the beginning of the experiment and after every cycle. The system used to assess color changes was the CIE L*a*b*. Data was analyzed using the ANOVA and Tukey post-hoc test. Results: After simulation of 10 years of aging, Transbond XT and Natural Ortho composites presented no statistically significant differences in ∆E when exposed to different mouthrinses. The Concise composite specimens exposed to alcohol-free mouthrinse presented a significant difference when compared with specimens from the same group exposed to other antiseptic mouthrinses. Transbond Plus Color Change specimens exposed to chlorhexidine mouthrinse and to alcohol-containing mouthrinse presented a significant difference when compared with the specimens from the group exposed to water and alcohol-free antiseptic. Conclusion: All orthodontic resin bonding agents tested presented clinically perceptible color changes when exposed to at least one of the mouthrinses, except for the Natural Ortho composite. The Concise composite exposed to the alcohol-free solution was the resin that presented the highest color change values.


BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5179-5197
Author(s):  
Xiaowen Li ◽  
Tongtong Li ◽  
Guanjun Li ◽  
Min Li ◽  
Quanji Lu ◽  
...  

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.


Author(s):  
И.М. ПОЧИЦКАЯ ◽  
Ю.Ф. РОСЛЯКОВ ◽  
В.В. ЛИТВЯК ◽  
А.Н. ЮДЕНКО

Исследовано влияние температуры и длительности нагревания на деградацию аминокислот в пищевых продуктах. Образцы белого пшеничного хлеба подвергали термической обработке при температурах 90, 120, 150 и 180°С с интервалом в 30 мин в течение 2 ч. Количество аминокислот определяли методом высокоэффективной жидкостной хроматографии с предколоночной дериватизацией с использованием о-фталевого альдегида. Установлено, что с повышением температуры и увеличением длительности нагревания наблюдается снижение содержания аминокислот. Определены особенности реагирования аминокислот на воздействие температуры. Установлено, что на снижение содержания аспарагиновой кислоты в большей степени влияет высокая температура, чем время термообработки. Заметное снижение содержания тирозина в образцах выявлено при термообработке в течение 30–60 мин при температуре 180°С. Для аргинина характерно линейное снижение содержания при температуре 120–180°С. Содержание гистидина медленнее снижается при незначительном повышении температуры, а при высоких температурах увеличение времени термообработки ускоряет реакцию. Количество лизина существенно снижается при повышении температуры, а время нагревания влияет незначительно, причем чем выше температура, тем меньше влияние продолжительности нагревания. Отмечено повышение содержания отдельных аминокислот, что, возможно, связано с процессом ресинтеза. The aim of the work – study the effect of temperature and heating time on the degradation of amino acids. In the studies, samples of white wheat bread were heat treated at temperatures of 90, 120, 150 and 180°C with a time interval of 30 min for 2 h. Determination of the number of amino acids was carried out using HPLC from pre-columnar derivatization using o-phthalic aldehyde. It is established that with temperature increase and increase in duration of heating decrease in content of amino acids is observed. Some peculiarities of the reaction of amino acids to the effect of temperature have been established. For example, the decrease in the content of aspartic acid is more affected by the high temperature than the time of heat treatment. A noticeable decrease in tyrosine content is observed during heat treatment for 30–60 min at a temperature of 180°C. For arginine it is characterized by a linear decrease of the content in the range of 120–180°C. Histidine slows down with a slight increase in temperature, and at high temperatures, an increase of the heat treatment time accelerates the reaction. The amount of lysine falls more strongly with increasing temperature, and the heating time affects slightly, and, the higher the temperature, the less time affects. An increase in the content of individual amino acids is also noted, which is probably connected with the process of resynthesis.


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