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Gómez-Gómez, Omar R., Guadalupe M. Guatemala-Morales, J. Paulo García-Sandoval et Enrique Arriola-Guevara. « Cascade Control of Coffee Roasting Degree in a Spouted Bed Batch Process Based on a Real-Time Imaging Analysis ». Mathematical Problems in Engineering 2020 (3 janvier 2020) : 1–9. http://dx.doi.org/10.1155/2020/3202146.
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On this work, the experimental implementation of a cascade control algorithm to regulate coffee roasting degree in a batch spouted bed process is presented. The control algorithm is composed of an inner control loop that regulates the temperature of the hot air inflow used to roast coffee grains inside a spouted bed, while an outer control loop, based on imaging processing techniques, tracks on real time the coffee roasting degree and decides if the inflow air temperature must be modified. To achieve this goal, a colour-matching algorithm is used to compare a colour spectrum obtained from images acquired on real time, from a peephole on the spouted bed, with the colour spectrums of several reference images with different degrees of roasting. Match scores are computed based on the similarity between the colour spectrums. With the match scores, a roasting index is finally calculated to assess the degree of roasting, allowing to automatically track the roasting progress to decide if the batch roasting process has achieved the desired roasting degree. The experimental results show that the control scheme is able to robustly achieve the desired roasting degree with excellent effectiveness.
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I, Kamal, et Allaf K. « Roasting optimization and kinetics of raw and instant controlled pressure drop pre-treated coffee beans ». Innovaciencia Facultad de Ciencias Exactas Físicas y Naturales 7, no 1 (25 octobre 2019) : 1–16. http://dx.doi.org/10.15649/2346075x.511.
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Introduction: Coffee is one of the most widely consumed beverages in the world. The desired aroma and flavour of coffee are developed duringroasting which is the most important step in coffee processing. Instant Controlled Pressure Drop Process (DIC) technology is controlled hightemperature and short time process which been used successfully to improving the kinetics of drying, extraction, and decontamination of fresh and dried natural products. The main advantages of DIC are that it is a master controlled temperature and time process, the dwell times are short, reducing the chemical degradation, so new products with superior quality attributes may be developed. Materials and Methods: Two coffee beans varieties were investigated by Brazilian and Ethiopian sources. The raw beans were pre-treated using the DIC process under adopted conditions prior to roasting. A two-factor central composite design was used to optimize the settings of roasting time and roasting temperature on response variables of bulk, true and normalized density, and roasting degree. Also, microscopic analysis using Scanning Electron Microscopy (SEM) and kinetics of the roasting processes are included. Results and Discussion: The obtained results confirmed that the roasted DIC treated beans for both varieties have lower densities, higher roasting degree and lower activation energy needed for roasting compared to the raw beans. The physical properties’ magnitude is highly relevant to coffee origin. Roasting time and the temperature seemed to be of significant regarding all the physical characteristics of the beans, however, time was of topmost significance. Besides, treating coffee been by DIC prior to roasting leads to texture modification and conservation of time and energy needed for roasting. Conclusions: The physical properties of the roasted coffee beans are highly affected and changed with the coffee origin, roasting conditions and pre-treatment of coffee beans prior to roasting using the DIC process. The incorporation of the DIC process prior to roasting seemed to achieve more conservation of time and energy needed for roasting compared to the raw untreated beans. The higher degree of roasting and the competitive roasting activation energy of Brazilian coffee beans give aconclusion that more economic roasting process could be achieved with the Brazilian coffee. The pre-treatment by DIC enhances the remarkable reduction in coffee beans density and increasing in the roasting degrees that are in line with the industrial needs of coffee beverages. Response Surface Methodology is an efficient tool for optimization and mathematical modeling of the coffee roasting process.
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Jung, Sunyoon, Sunyoung Gu, Seung-Hun Lee et Yoonhwa Jeong. « Effect of Roasting Degree on the Antioxidant Properties of Espresso and Drip Coffee Extracted from Coffea arabica cv. Java ». Applied Sciences 11, no 15 (29 juillet 2021) : 7025. http://dx.doi.org/10.3390/app11157025.
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Coffee roasting is the process of applying heat to green coffee beans to bring out flavors through chemical changes. This study aimed to investigate the effect of roasting degree on the antioxidant capacities of espresso and drip coffee extracted from Coffea arabica cv. Java in Laos. Green coffee beans were roasted under four conditions (Light-medium, Medium, Moderately dark, and Very dark), and espresso and drip coffee were extracted. The contents of total phenolics (TP), total flavonoids (TF), and chlorogenic acids (CGA) decreased as the roasting degree increased, whereas the caffeine content increased. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was lower in the Medium, Moderately dark, and Very dark compared to the Light-medium. The ferric reducing antioxidant power (FRAP) was lower in the Very dark than the Light-medium, Medium, and Moderately dark. Principal component analysis showed that TP, TF, CGA, caffeine, DPPH radical scavenging activity, and FRAP distinguish coffee extracts with various roasting degrees. Therefore, it is concluded that roasting degree is a modifiable factor for the use of coffee as an antioxidant material in the food industry, and TF, TP, CGA, and caffeine contents, DPPH radical scavenging activity and FRAP are good indicators for determining the antioxidant capacity of coffee.
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Várady, Matúš, Tatiana Hrušková et Peter Popelka. « Effect of preparation method and roasting temperature on total polyphenol content in coffee beverages ». Czech Journal of Food Sciences 38, No. 6 (23 décembre 2020) : 417–21. http://dx.doi.org/10.17221/122/2020-cjfs.
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We evaluated the differences in total polyphenol content (TPC) of beverages prepared by three methods (Hario V60, espresso and pour-over coffee) using single-origin beans roasted at four temperatures. The beans were roasted based on the degree of roasting: the lightest roasting had a final temperature of 204 °C (first roasting), a slightly darker roasting had a final temperature of 205 °C (second roasting), a dark roasting had a final temperature of 215 °C (third roasting) and the darkest roasting had a final temperature of 220 °C (fourth roasting). TPC in the beverage was highest for the Hario V60 for all temperatures, ranging from 32.0 to 46.8 mg GAE g–1 (gallic acid equivalent per 1 g of ground beans). The third roasting had the highest TPC, ranging from 34.6 to 46.8 mg GAE g–1 for all methods of preparation, whereas the content for the fourth roasting ranged from 28.6 to 32.3 mg GAE g–1. Our results indicated that the differences in TPC in the beverage depended on the preparation method (P < 0.001) and the degree of roasting (P < 0.001). The most nutritional coffee was prepared using the Hario V60 with the third roasting.
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Santoso, I., S. A. Mustaniroh et A. Choirun. « Methods for quality coffee roasting degree evaluation : a literature review on risk perspective ». IOP Conference Series : Earth and Environmental Science 924, no 1 (1 novembre 2021) : 012058. http://dx.doi.org/10.1088/1755-1315/924/1/012058.
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Abstract The demand for specialty coffee has increased over the past few years, and several cafes and coffee roasteries are starting to enter the market. Coffee roasting is considered art rather than science that requires a lot of experience from a master roaster. The key parameters used to identify the roast status of the beans are the initial temperature and roasting time from bean samples. The degree of roasting is often the first consideration for consumers when buying coffee. Some of the flavor attributes used to assess coffee are body, aroma, and acidity. Many studies have been done to evaluate the quality of roasted coffee experimentally using different parameters. However, these techniques could not be implemented in real-time and have their limitations. The current need for roasteries is a method of controlling the quality of roasted coffee through risk and a real-time approach. This paper presents a review carried out the methods used to determine roasting degree on risk perspective. This review has covered recent research on coffee roasting evaluation methods on physical, physicochemical, and chemical composition changes.
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Lykasov, Aleksander A., Grigoriy M. Ryss et Dmitrij A. Ponomarev. « Removal of Copper from the Sulphide Copper Smelting Waste Slag ». Materials Science Forum 989 (mai 2020) : 388–93. http://dx.doi.org/10.4028/www.scientific.net/msf.989.388.
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The applicability of chloridizing roasting for removal of copper from the sulphide copper smelting waste slag of the ”Karabashmed'” copper-smelting plant is investigated. Calcium chloride CaCl2 was used as chlorination agent. It is established that the chlorinating roasting of the initial slag presented by fayalite 2FeO∙SiO2, hasn't led to noticeable removal of copper. Considerable degree of removal of copper (more than 90 %) has been reached as a result of the chlorinating of preliminary oxidized slag in which fayalite was oxidized to form Fe2O3 and SiO2. Using a fractional factorial experiment 23–1, dependence of degree of copper removal from preliminary oxidized slag upon temperature of the chlorinating roasting, time of isothermal roasting period and content of CaCl2 was established. It is found that increase of temperature and of CaCl2 content leads to increase in degree of copper removal. The influence of time of isothermal roasting period in the studied interval (2–4 h) is statistically insignificant.
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Cwiková, Olga, Tomas Komprda, Viera Šottníková, Zdeněk Svoboda, Jana Simonová, Jan Slováček et Miroslav Jůzl. « Effects of Different Processing Methods of Coffee Arabica on Colour, Acrylamide, Caffeine, Chlorogenic Acid, and Polyphenol Content ». Foods 11, no 20 (21 octobre 2022) : 3295. http://dx.doi.org/10.3390/foods11203295.
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An effect of a processing method (dry and wet) and a degree of roasting (light, medium, and dark) of 15 coffee (Coffea arabica) samples on the content of caffeine, chlorogenic acid (CQA), total polyphenols (TPP), acrylamide (AA), and on the colour parameters L*, a*, and b* was evaluated. Neither processing nor roasting affected caffeine content (p > 0.05). The degree of roasting accounted for 46% and 72% of explained variability of the CQA content and AA content, respectively (p < 0.05). AA content was in the range from 250 (wet-processed, light-roasted samples) to 305 µg·kg−1 (wet-processed, dark-roasted coffees), but the dark roasting only tended (p > 0.05) to increase AA content. Wet-processed, dry-roasted coffee had higher (p < 0.05) TPP content (48.5 mg·g−1) than its dry-processed, dry-roasted counterpart (42.5 mg·g−1); the method of processing accounted for 70% of explained variability of TPP. Both the method of processing and the degree of roasting affected the L*, a*, and b* values (p < 0.01), but the lower values (p < 0.05) of these parameters in the dark-roasted samples were found only within the wet processing. A negative correlation between the AA content and lightness (L*) was established (r = −0.39, p < 0.05). It was concluded that from the consumers’ viewpoint, the results of the present study indicate relatively small differences in quality parameters of coffee irrespective of the method of processing or degree of roasting.
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Lv, Shuai-Shuai, Yu Zhang, Hong-Jun Ni, Xing-Xing Wang, Wei-Yang Wu et Chun-Yu Lu. « Effects of Additive and Roasting Processes on Nitrogen Removal from Aluminum Dross ». Coatings 12, no 6 (25 mai 2022) : 730. http://dx.doi.org/10.3390/coatings12060730.
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Taking high nitrogen aluminum dross as the research object, the effects of the additives sodium carbonate and cryolite and the roasting process on the denitrification effect of aluminum dross were studied. The principle of additive denitrification was studied by XRD, SEM and TG-DSC. The experimental results show that sodium carbonate and cryolite can quickly reduce the content of aluminum nitride in aluminum dross. The optimum denitrification process parameters were also obtained simultaneously. When the mass ratio of cryolite to aluminum dross was 0.4, the roasting temperature was 900 °C, and the roasting time was 3 h, the denitrification degree could reach 96.19%. When the mass ratio of sodium carbonate to aluminum dross was 0.8, the roasting temperature was 1000 °C, and the roasting time was 4 h, the denitrification degree could reach 91.32%. This study provides a reference for the non-harmful treatment of high nitrogen aluminum dross.
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Diviš, Pavel, Jaromír Pořízka et Jakub Kříkala. « The effect of coffee beans roasting on its chemical composition ». Potravinarstvo Slovak Journal of Food Sciences 13, no 1 (28 mai 2019) : 344–50. http://dx.doi.org/10.5219/1062.
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Drinking coffee has become part of our everyday culture. Coffee cultivation is devoted to over 50 countries in the world, located between latitudes 25 degrees North and 30 degrees South. Almost all of the world's coffee production is provided by two varieties, called ‘Arabica’ and ‘Robusta’ whereas the share of Arabica is 70% of the world's coffee harvest. Green (raw) coffee can not be used to prepare coffee beverages, coffee beans must first be roasted. Roasting coffee and reaching a certain degree of coffee roasting determine its flavor and aroma characteristics. In the present study the fate of sucrose, chlorogenic acid, acetic acid, formic acid, lactic acid, caffeic acid, total phenolic compounds and 5-hydroxymethylfurfural was studied in coffee (Brazil Cerrado Dulce, 100% Arabica) roasted in two ways (Medium roast and Full city roast). It has been found that almost all sucrose has been degraded (96 – 98%) in both roasting ways. During Medium roast 65% of chlorogenic acid contained in green coffee was degraded while during Full city roast it was 85%. During both Medium and Full city roasting, the formation of acetic acid but especially formic and lactic acid was recorded. The highest concentration of organic acids was recorded at Full City roasting at medium roasting times (3.3 mg.g-1 d.w. acetic acid, 1.79 mg.g-1 d.w. formic acid, 0.65 mg.g-1d.w. lactic acid). The amount of phenolic substances also increased during roasting up to 16.7 mg.g-1 d.w. of gallic acid equivalent. Highest concentrations of 5-hydroxymethylfurfural were measured at medium roasting times at both Medium (0.357 mg.g-1 d.w.) and French city (0.597 mg.g-1 d.w.) roasting temperatures. At the end of roasting, the 5-hydroxymethylfurfural concentration in coffee were 0.237 mg.g-1 d.w. (Medium roast) and 0.095 mg.g-1 d.w. (Full city roast).
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Maulid, Muhammad Rifqi, Eko Heri Purwanto, Efri Mardawati, Budi Mandra Harahap et Saefudin Saefudin. « Peningkatan Mutu dan Keekonomian Kopi Arabika Melalui Penyangraian Kompleks ». Jurnal Tanaman Industri dan Penyegar 8, no 1 (30 mars 2021) : 19. http://dx.doi.org/10.21082/jtidp.v8n1.2021.p19-36.
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<em>Quality and techno-economic improvement is important to increase export value of coffee in Indonesia. Complex roasting is one excellent method in increasing the added value of coffee, such as Coffea arabica var. Sigarar Utang which is the best coffee variety in Indonesia. The study was carried out at The Indonesian Industrial and Beverage Crops Research Institute (IIBCRI), Sukabumi, West Java, from January to November 2020 which aimed: (1) to evaluate the effect of initial temperature and roasting degree on the quality of Sigarar Utang coffee bean, and (2) to evaluate the mass balance and economic feasibility of the best roasting treatment. This study was designed in a factorial completely randomized design, using 2 factors, and 2 replications. The first factor was the initial temperature which consisted of 2 levels (185 <sup>o</sup>C dan 210 <sup>o</sup>C), and the second factor was the roasting degree which consisted of 2 levels (light-medium and medium-dark). The variables observed were the water content, ash content, bulk density, brix, titratable acidity, pH, radical scavenging (antioxidant) activity, and caffeine content. The results showed that the complex roasting method with an initial temperature of 210 <sup>o</sup>C and mild-moderate roasting degrees generated a quality of Sigarar Utang coffee originating from Gunung Putri, IIBCRI, closest to the quality I of SNI 01-3542-2004. The roasted coffee beans have a special taste (score 86.51) which is a high added value. The production economic value is feasible to be adopted by small-medium scale coffee industry.</em>
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Tarigan, E. B., E. Wardiana, Y. S. Hilmi et N. A. Komarudin. « The changes in chemical properties of coffee during roasting : A review ». IOP Conference Series : Earth and Environmental Science 974, no 1 (1 janvier 2022) : 012115. http://dx.doi.org/10.1088/1755-1315/974/1/012115.
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Abstract Due to its chemical compounds, coffee has a good taste, pleasant aroma, stimulant effect, and health benefits. Roasting is a critical process to develop a good flavor and cup quality of the coffee brew. This article reviews the coffee chemical reaction proceeds during roasting, evaluates the roasted degree by physic and chemical approach and biochemical changes. The articles were compiled from ScienceDirect, SpringerLink, ResearchGate, and Google Scholar. Out of all of the collected papers, 40 articles were covered in this paper. The initial process of roasting is water content evaporating and continuously is followed by roasting phase including pyrolysis, Maillard reaction and caramelization. The roasted coffee degree is determined by visual, weight loss, acidity, and pop beans sound. The bioactive compounds of coffee such as chlorogenic acids, caffeine, and trigonelline affect brewed coffee’s cup quality. Chlorogenic acid and trigonelline significantly decrease during the roasting process. However, caffein is quite stable during roasting. The roasted coffee performs a function in the consumers’ health since in vitro and in vivo analysis present that bronze roasted espresso has the most powerful activity as anti-inflammatory and antioxidant.
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Yergenson, Nathan, et D. Eric Aston. « Online determination of coffee roast degree toward controlling acidity ». Journal of Near Infrared Spectroscopy 28, no 4 (23 mai 2020) : 175–85. http://dx.doi.org/10.1177/0967033520924493.
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Three methods of measuring coffee roast degree were compared using titratable acidity as an indicator of roast-dependent flavor change. The first roast degree method was based on prediction of the cracks with online near infrared spectroscopy and partial least squares regression, the second was based on changes in online near infrared absorbance, and the third was the common L* value from the CIELAB color space in the visible spectrum. Roasting trials utilized arabica coffee from eight origins in an air roaster, and results demonstrated the superiority of an online near infrared sensor for real-time roast degree measurement. A second dataset with constant temperature roasts showed how acidity can be controlled by changing both the roasting temperature and roast degree, finding the linear effects of roast time and roast degree on acidity.
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Buckel, Kremer, Stegmüller et Richling. « Fast, Sensitive and Robust Determination of Nicotinic Acid (Vitamin B3) Contents in Coffee Beverages Depending on the Degree of Roasting and Brewing Technique ». Proceedings 11, no 1 (16 avril 2019) : 13. http://dx.doi.org/10.3390/proceedings2019011013.
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The vitamin B3 (niacin) is present in various foods. During roasting of green coffee beans, niacin is formed from the alkaloid trigonelline. Therefore, we established a novel fast and sensitive HPLC-MS/MS method to determine niacin in coffee brews from five commercially available coffee samples. Additionally, we investigated the influence of the brewing method, brewing temperature, and degree of roasting on niacin contents. In the respective coffee brews, we were able to show that the content of niacin in coffee beverages is not only affected by the degree of roasting, but also by the extraction performance of different brewing methods to a lesser extent.
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La Mantia, Alessandro, Federica Ianni, Aurélie Schoubben, Marco Cespi, Klemen Lisjak, Davide Guarnaccia, Roccaldo Sardella et Paolo Blasi. « Effect of Cocoa Roasting on Chocolate Polyphenols Evolution ». Antioxidants 12, no 2 (13 février 2023) : 469. http://dx.doi.org/10.3390/antiox12020469.
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Cocoa and chocolate antioxidants might contribute to human health through, for instance, blood flow improvement or blood pressure and glycemia reduction, as well as cognitive function improvement. Unfortunately, polyphenol content is reduced during cocoa fermentation, drying, roasting and all the other phases involved in the chocolate production. Here, we investigated the evolution of the polyphenol content during all the different steps of chocolate production, with a special emphasis on roasting (3 different roasting cycles with 80, 100, and 130 °C as maximum temperature). Samples were followed throughout all processes by evaluating the total polyphenols content, the antioxidant power, the epicatechin content, and epicatechin mean degree of polymerization (phloroglucinol adducts method). Results showed a similar trend for total polyphenol content and antioxidant power with an unexpected bell-shaped curve: an increase followed by a decrease for the three different roasting temperatures. At the intermediate temperature (100 °C), the higher polyphenol content was found just after roasting. The epicatechin content had a trend similar to that of total polyphenol content but, interestingly, the mean degree of polymerization data had the opposite behavior with some deviation in the case of the highest temperature, probably due to epicatechin degradation. It seems likely that roasting can free epicatechin from oligomers, as a consequence of oligomers remodeling.
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Dosmukhamedov, Nurlan Kalievich, Arkady Kaplan, Erzhan Esenbaiuly Zholdasbay, Gulzada Myngyshkyzy Koishina, Yeleussiz Bolatovich Tazhiev, Aidar Argyn, Yerzhan Itemenovich Kuldeyev et Valery Kaplan. « Processing Dross from Hot-Dip Galvanizing by Chlorination Roasting ». Sustainability 13, no 22 (12 novembre 2021) : 12530. http://dx.doi.org/10.3390/su132212530.
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Dross from hot-dip galvanizing is an important source of pure zinc ingots and zinc oxide for use as mineral additives in animal and poultry feed. Thermodynamic calculations have shown the possibility of solving the issue of dross processing by roasting using CaCl2 and NH4Cl. The influence of the consumption of chlorinating reagents, the roasting temperature on the degree of sublimation of Pb, Fe, Ni, Cu and Cd has been investigated. It has been shown that the best results are achieved when roasting the dross with the simultaneous use of CaCl2 and NH4Cl in amounts of 6 and 15% by weight of the feed material. The optimal roasting parameters were established: T = 1000 °C, duration—60 min, air flow—0.1 L/min. Recovered pure zinc oxide composition (%) was: 0.05 Pb, 0.15 Fe, 0.06 Ni, 0.003 Cu and 0.001 Cd. The degree of sublimation of copper, nickel and iron chlorides was ~75%, with lead and cadmium at 90–98% of their initial amount in the dross.
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Lin, Jin, Xingcai Zhu, Kun Yang et Jinhui Peng. « Optimization of Microwave-Assisted Oxidation Roasting of Oxide–Sulphide Zinc Ore with Addition of Manganese Dioxide Using Response Surface Methodology ». High Temperature Materials and Processes 38, no 2019 (25 février 2019) : 301–8. http://dx.doi.org/10.1515/htmp-2017-0184.
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AbstractThe present study deals with a microwave-assisted oxidation roasting oxide–sulphide zinc ore technology of with addition of manganese dioxide. Effects of roasting parameters such as MnO2 addition level, roasting temperature, and holding time are studied by using the Central Composite Design (CCD). Meanwhile, zinc calcines are characterized by phase compositions analyses(XRD), structure characteristics of minerals (FT-IR), micro-area chemical analyses (SEM-EDAX) and elemental valence bonding analyses (XPS), which prove to be in accordance with the CCD results. The optimum roasting conditions are decided as MnO2 addition level being 85.14 %, roasting temperature 680 °C, and holding time 41 mins, and oxidation degree of zinc can reach 88.22 %. Besides, when MnO2 addition level reaches a certain value, zinc will aggregate in a form of ZnMn2O4, one battery material.
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Zakidou, Panagiota, Fotini Plati, Anthia Matsakidou, Evdoxia-Maria Varka, Georgios Blekas et Adamantini Paraskevopoulou. « Single Origin Coffee Aroma : From Optimized Flavor Protocols and Coffee Customization to Instrumental Volatile Characterization and Chemometrics ». Molecules 26, no 15 (29 juillet 2021) : 4609. http://dx.doi.org/10.3390/molecules26154609.
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In this study, the aroma profile of 10 single origin Arabica coffees originating from eight different growing locations, from Central America to Indonesia, was analyzed using Headspace SPME-GC-MS as the analytical method. Their roasting was performed under temperature–time conditions, customized for each sample to reach specific sensory brew characteristics in an attempt to underline the customization of roast profiles and implementation of separate roastings followed by subsequent blending as a means to tailor cup quality. A total of 138 volatile compounds were identified in all coffee samples, mainly furan (~24–41%) and pyrazine (~25–39%) derivatives, many of which are recognized as coffee key odorants, while the main formation mechanism was the Maillard reaction. Volatile compounds’ composition data were also chemometrically processed using the HCA Heatmap, PCA and HCA aiming to explore if they meet the expected aroma quality attributes and if they can be an indicator of coffee origin. The desired brew characteristics of the samples were satisfactorily captured from the volatile compounds formed, contributing to the aroma potential of each sample. Furthermore, the volatile compounds presented a strong variation with the applied roasting conditions, meaning lighter roasted samples were efficiently differentiated from darker roasted samples, while roasting degree exceeded the geographical origin of the coffee. The coffee samples were distinguished into two groups, with the first two PCs accounting for 73.66% of the total variation, attributed mainly to the presence of higher quantities of furans and pyrazines, as well as to other chemical classes (e.g., dihydrofuranone and phenol derivatives), while HCA confirmed the above results rendering roasting conditions as the underlying criterion for differentiation.
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Awwad, Shady, Reem Issa, Lilian Alnsour, Dima Albals et Idrees Al-Momani. « Quantification of Caffeine and Chlorogenic Acid in Green and Roasted Coffee Samples Using HPLC-DAD and Evaluation of the Effect of Degree of Roasting on Their Levels ». Molecules 26, no 24 (11 décembre 2021) : 7502. http://dx.doi.org/10.3390/molecules26247502.
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Chlorogenic acid and caffeine are among the important components in coffee beans, determining the taste and aroma. In addition, phenols and antioxidants content possess vital health values. The main aim of this study is to determine the levels of caffeine and chlorogenic acid in several coffee samples of different origins and degrees of roasting. The coffee samples were extracted using hot water. The levels of caffeine and chlorogenic acid were quantified using high-performance liquid chromatography (HPLC) equipped with a diode array detector, a reverse phase system, and an ODS column (C18). Total phenol and antioxidant contents were previously determined for the same samples. The results showed that the highest content of caffeine was found in the medium roasted coffee (203.63 mg/L), and the highest content of chlorogenic acid content was found in the green coffee (543.23 mg/L). The results demonstrated a negative correlation between the chlorogenic acid levels with the degree of roasting, while it showed a positive correlation between the caffeine levels with the degree of roasting till a certain point where the levels dropped in the dark roasted coffee. The origin of coffee samples did not show any effect on any of the measured variables. Antioxidant effects of coffee samples were largely determined by chlorogenic acid content.
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Tsai, Chia-Fang, et Irvan Prawira Julius Jioe. « The Analysis of Chlorogenic Acid and Caffeine Content and Its Correlation with Coffee Bean Color under Different Roasting Degree and Sources of Coffee (Coffea arabica Typica) ». Processes 9, no 11 (15 novembre 2021) : 2040. http://dx.doi.org/10.3390/pr9112040.
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Coffee is one of the main economic crops in the world and is now widely grown throughout Taiwan. The process of roasting coffee begins with the heating and smooth expansion of raw beans, which leads to changes in appearance and color while affecting the flavor and taste of coffee. So far, most coffee manufacturers have used visual inspection or colorimeter methods to identify differences in coffee quality. Moreover, there is no literature discussing the correlation of roasted bean color with caffeine and chlorogenic acid content. Therefore, the purpose of this experiment was to analyze the chlorogenic acid and caffeine content and their correlation with bean color under different roasting degrees and from different sources to establish basic data for the rapid identification of coffee quality in the future. In this experiment, the coffee Coffea arabica typica from Dongshan, Gukeng, and Sumatra’s Indonesian rainforest was used, and the beans were roasted into four degrees: raw bean, light, medium, and dark roast, to investigate the appearance of the coffee beans and its correlation with caffeine and chlorogenic acid content. The results showed that with a higher roasting degree, caffeine content increased gradually, except for Indonesian beans, but the chlorogenic acid content in all samples showed a declining trend with the increase in roasting degree. The correlation between the chlorogenic acid content and the color space value of the coffee bean color shows that L*, a*, and h° in both ground and unground coffee are highly correlated. The C* value of the ground and unground coffee showed a correlation coefficient of r = 0.159 ns and 0.299 ns, respectively. The correlation between the caffeine content and the color space value of the unground coffee bean shows that the a*, b*, and C* value is highly correlated with the caffeine content. The color space values of ground coffee beans show no correlation with caffeine.
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Ignatova, Dinara, et Nadezhda Makarova. « Antioxidant Properties Research of Various Types of Coffee ». Food Industry 5, no 4 (25 décembre 2020) : 74–81. http://dx.doi.org/10.29141/2500-1922-2020-5-4-11.
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The article presents results of antioxidant compounds determination (total amount of phenolic compounds, total amount of flavonoids) and parameters of the antiradical activity (by the DPPH method) and reducing power (by the FRAP method) in different types of coffee beans depending on roasting degree (weak, medium, strong), coffee variety (Robusta and Arabica) and the importing country. The researchers used the products presented in the retail chains of Samara. The study purpose was to reveal a universal and most common source of functional substances with an antioxidant effect for the human body and use it both in its pure form and in combination with other products (BAS). According to the research results, Robusta coffee (Coffea Canephora) of medium roasting from Brazil has high indicators for all the conducted analyses and can be used as an additional source of antioxidant substances, and as a raw material for obtaining BAS. Coffee Arabica (Coffea Arabica) of medium roasting of Indonesian origin has the highest restoring power, and the highest content of phenols and flavonoids. Coffee Arabica (Coffea Arabica) of a strong degree of roasting from India has the lowest rates. All other types of coffee have average, slightly different results.
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Zięba, Tomasz, Dominika Solińska, Artur Gryszkin, Małgorzata Kapelko-Żeberska, Bartosz Raszewski, Đurđica Ačkar, Jurislav Babić, Borislav Miličević et Antun Jozinović. « Potato Starch Extrusion and Roasting with Apple Distillery Wastewater as a New Method for Resistant Starch Production ». Applied Sciences 11, no 19 (2 octobre 2021) : 9169. http://dx.doi.org/10.3390/app11199169.
Texte intégralRésumé :
Potato starch was extruded and roasted with apple distillery wastewater to produce starch esters substituted with malic acid residues. The starch esterification degree was higher at the higher roasting temperatures. Starch modification contributed to its darker color, its increased resistance to the action of amylolytic enzymes, and its decreased solubility and heat of phase transition. The changes in the other starch properties examined depended on the extrusion and roasting temperatures. The process, which was conducted without a chemical agent—in this case, the process of starch extrusion and roasting with apple distillery wastewater—should be deemed a novel method for resistant starch production.
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Leme, Dimas Samid, Sabrina Alves da Silva, Bruno Henrique Groenner Barbosa, Flávio Meira Borém et Rosemary Gualberto Fonseca Alvarenga Pereira. « Recognition of coffee roasting degree using a computer vision system ». Computers and Electronics in Agriculture 156 (janvier 2019) : 312–17. http://dx.doi.org/10.1016/j.compag.2018.11.029.
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Van Cuong, Tran, Liu Hong Ling, Guo Kang Quan, Shang Jin, Song Shu Jie, Tran Le Linh et Tran Duc Tiep. « Effect of Roasting Conditions on Concentration in Elements of Vietnam Robusta Coffee ». Acta Universitatis Cibiniensis. Series E : Food Technology 18, no 2 (1 décembre 2014) : 19–34. http://dx.doi.org/10.2478/aucft-2014-0011.
Texte intégralRésumé :
Abstract Vietnam Robusta Coffee was roasted at different roasting degree and roasting temperature and 9 element concentrations (K, Mg, Ca, Na, Fe, Cu, Mn, Zn and Pb) of roasted coffee were analyzed by Flame atomic absorption method (FAAS) in this study. The results showed that the concentrations were ranged in 1447.97 ~ 1342.10 (mg/100g), 768.22 ~ 1259.44 (μg/g),10.35 ~ 13.15 (μg/g), and 17.38 ~ 20.97 (μg/g) for element of K, Ca, Cu and Mn in green and roasted coffee beans, respectively. All determined elements were the smallest value in green coffee, then increased with increasing roasting level and reached the highest value in Spain roast (roasting temperature of 250°C). Mg concentration ranged in 682.70 ~ 3647.73 (μg/g); Fe concentration ranged in 37.20 ~ 53.44 (μg/g); Zn concentration ranged in 5.97 ~ 6.89 (μg/g) and Pb concentration ranged in 2.18 ~ 15.04 (μg/100g). Concentrations of all determined elements didn’t change with the increased roasting process.
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Zdybel, Ewa, Tomasz Zięba, Ewa Tomaszewska-Ciosk et Waldemar Rymowicz. « Effect of the Esterification of Starch with a Mixture of Carboxylic Acids from Yarrowia lipolitica Fermentation Broth on Its Selected Properties ». Polymers 12, no 6 (19 juin 2020) : 1383. http://dx.doi.org/10.3390/polym12061383.
Texte intégralRésumé :
Potato starch was esterified with carboxylic acids contained in the fermentation broth from Yarrowia lipolitica yeast production. Various acid concentrations and various roasting temperatures were used to determine effects of process conditions on ester properties, including the number of acid residues attached to starch chains, starch susceptibility to amylolysis, and thermal characteristics of starch phase transitions. Study results demonstrated the effect of both the composition and the dose of the fermentation broth and of roasting temperature of starch on the number of acid residues attached to starch chains. Citric acid was more susceptible to esterification with starch (DS = 5.65%) compared to the α-ketoglutaric acid (DS = 0.12%). In the case of the latter, a higher degree of substitution was determined in the esters produced at higher roasting temperatures. The lowest digestibility (RS = 20%) was demonstrated for the starch esters with the highest degree of substitution with citric acid, whereas all starch esters showed decreased values of the thermal characteristics of pasting.
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Makhotkina, E. S., et M. V. Shubina. « Results of experiments on vanadium extraction out of Kusinsky deposit titanium-magnetite ores enrichment wastes ». Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 75, no 5 (20 juin 2019) : 617–22. http://dx.doi.org/10.32339/0135-5910-2019-5-617-622.
Texte intégralRésumé :
The actuality of exhausted of titanium-magnetite ore deposits wastes is stipulated not only by necessity of their negative impact on environmental elimination, but also by a possibility of application of these wastes as vanadium-containing raw materials. Analysis of existing technological processes for vanadium extraction accomplished. A possibility of vanadium extraction out of Kusinsky deposit titanium-magnetite ore tails studied. Results of experiments on vanadium extraction as soluble vanadates by leaching from the samples after roasting with soda ash, sodium sulfate, calcium oxide, and sodium chloride in various mass ratios presented. It was determined, that additives of sodium chloride and sodium carbonate are the most effective reagents for roasting of this type of vanadium raw materials. A significant effect of titanium-magnetite ore tails chemical composition on the vanadium extraction degree revealed: with an increase content from 0.15% to 0.53% in the ore tails vanadium, the extraction degree increases to 74.8%. When using the sodium chloride reaction additive, it is possible to leach in only one stage using sulfuric acid. Increasing the sodium chloride amount in the roasting mixture leads to a significant increase in the vanadium extraction degree in the leaching solution.
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Vamanu, Emanuel, Florentina Gatea et Diana Roxana Pelinescu. « Bioavailability and Bioactivities of Polyphenols Eco Extracts from Coffee Grounds after In Vitro Digestion ». Foods 9, no 9 (12 septembre 2020) : 1281. http://dx.doi.org/10.3390/foods9091281.
Texte intégralRésumé :
Coffee grounds are a valuable source of bioactive compounds. In Romania, most of the amount obtained is lost through non-recovery; the rest is occasionally used as organic fertilizer. The coffee grounds were selected according to the roasting degree: blonde roasted (BR), medium roasted (MR), and dark roasted (DR). The study aimed to evaluate three extracts, obtained with a mixture of ethanol/water/acetic acid (50/49.5/0.5), depending on the roasting degree. The majority phenolic component, the antioxidant, and anti-inflammatory effect, as well as the role that gastrointestinal transit had on the bioavailability of bioactive compounds were determined. Chlorogenic acid was inversely proportional to the roasting degree. BR showed the best correlation between antioxidant and anti-inflammatory activities in vitro/in vivo. The antiproliferative capacity of the extracts determined an inhibitory effect on the tumor cells. Antimicrobial activities, relevant in the control of type 2 diabetes, were exerted through the inhibition of microbial strains (Escherichia coli). Following gastric digestion, BR demonstrated a maximum loss of 20% in the stomach. The recovery of coffee grounds depended on the pattern of functional compounds and the bioavailability of the main component, chlorogenic acid.
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Zhang, Xinwei, Yonghui Song, Ning Yin, Xinzhe Lan et Jianping Jin. « Study on Vacuum Roasting Pretreatment of Carbonaceous Gold Concentrates Based on Nonoxidation Technology ». Journal of Chemistry 2021 (15 novembre 2021) : 1–18. http://dx.doi.org/10.1155/2021/6848020.
Texte intégralRésumé :
Carbonaceous gold ores are difficult to treat because of the “preg-robbing” by carbonaceous matters and locking by minerals. Roasting is the most commonly used method that is useful in dealing with carbonaceous gold ores. In this study, flotation gold concentrates containing sulfides and carbonaceous matters were investigated to ascertain the reaction process and the matters’ transformation characteristics in different temperatures by vacuum roasting pretreatment. Calcine and volatile condensates were characterized with several techniques. In the process of vacuum roasting, the main chemical reactions were decomposition reaction and carbothermic reduction reactions of sulfide ores, carbothermic reduction reactions of SiO2, and thermal decomposition reactions of organic carbon. The bad effects of “preg-robbing” by carbonaceous matters were greatly weakened by the thermal decomposition and carbothermal reduction. The gold locking minerals were mainly removed by reduction reactions. The sulfides were removed in ways that did not produce SO2. The removal of sulfur and carbonaceous matters during the vacuum roasting process was 95.83% and 65.38%, respectively. Direct cyanidation of the calcine extracted from 2.13% to 88.37% of the gold content with a vacuum degree of 10 Pa and roasting from 25°C to 1,200°C for 30 min.
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Münchow, Morten, Jesper Alstrup, Ida Steen et Davide Giacalone. « Roasting Conditions and Coffee Flavor : A Multi-Study Empirical Investigation ». Beverages 6, no 2 (8 mai 2020) : 29. http://dx.doi.org/10.3390/beverages6020029.
Texte intégralRésumé :
This research investigates the relative importance of two roasting parameters—colour (i.e., roast degree) and time—on the sensory properties of coffee. The paper draws on data from eight studies conducted using sensory descriptive analysis with trained (in six studies) or semi-trained (in two studies) assessors, focusing on a common set of attributes. The results indicated that, while both parameters significantly affected coffee flavour, colour was the stronger predictor of the two. The effects direction for both colour and time were similar and related to the rate of non-enzymatic browning, with darker roasts/longer roasting times associated with an increase in bitterness and a decrease in acidity, fruitiness, and sweetness. With respect to roasting time, we distinguished two phases, “time to first crack”, corresponding to the time between the onset of roasting and the moment where the accumulated steam pressure causes the beans to crack, and “development time”, corresponding to the time elapsed from the first crack to the end of the roasting process. The results clearly indicated that, under the same colour, time variation also influenced flavour, and in particular, development time, rather than time to first crack, had the largest effect on coffee flavour.
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Alessandrini, Laura, Santina Romani, Giangaetano Pinnavaia et Marco Dalla Rosa. « Near infrared spectroscopy : An analytical tool to predict coffee roasting degree ». Analytica Chimica Acta 625, no 1 (septembre 2008) : 95–102. http://dx.doi.org/10.1016/j.aca.2008.07.013.
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Nicoli, M. C., M. Anese, L. Manzocco et C. R. Lerici. « Antioxidant Properties of Coffee Brews in Relation to the Roasting Degree ». LWT - Food Science and Technology 30, no 3 (mai 1997) : 292–97. http://dx.doi.org/10.1006/fstl.1996.0181.
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Romano, Andrea, Luca Cappellin, Sara Bogialli, Paolo Pastore, Luciano Navarini et Franco Biasioli. « Monitoring In Vitro and In Vivo Aroma Release of Espresso Coffees with Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry ». Applied Sciences 12, no 20 (12 octobre 2022) : 10272. http://dx.doi.org/10.3390/app122010272.
Texte intégralRésumé :
This work presents in vitro and in vivo aroma release analysis of three espresso coffees carried out by PTR-ToF-MS headspace and nosespace analysis, respectively. The products were C. arabica coffees prepared using an espresso coffee machine: a low-caffeine C. arabica var. laurina light roast, a low-caffeine C. arabica var. laurina dark roast, and a single-origin coffee from Ethiopia which were roasted to a medium roast degree. Headspace analysis allowed for discrimination between coffees with a prediction accuracy of 92% or higher. Relevant discriminating compounds were related to the roasting degree and varietal compounds. Coffee nosespace consisted of 35 mass peaks overall. Despite this relatively low number of detected peaks, coffee discrimination was still possible with ≥93% accuracy. The compounds most relevant to the discrimination were those related to the roasting degree. Major differences—both qualitative and quantitative—were found between headspace and nosespace profiles.
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Sokolova, Yulia V., et Anton N. Chepikov. « OXIDATIVE ROASTING OF INDUSTRIAL SPENT CATALYSTS CO-Mo/Al2O3 HYDROPROCESSING WITH LIM ». IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 63, no 11 (27 octobre 2020) : 57–64. http://dx.doi.org/10.6060/ivkkt.20206311.6256.
Texte intégralRésumé :
The oxidative roasting of industrial spent catalyst Co-Mo/Al2O3 for the hydrotreatment of diesel fuel with lime in an air atmosphere was studied. Using the data of DTA, TG and X-ray phase analysis, it was found that during roasting, the sulfur and carbon oxides forms CaSO4 and CaCO3, and Mo is converted to calcium molybdate. Using the filtering fixed bed of reagents, the kinetics of roasting was studied. It was found that in the temperature range of 550 – 600 °C with air, supply rate of 3 l/min the process ends in 38 - 44 min for ground and non-ground catalyst. The optimal parameters (lime consumption, temperature, and time of roasting) of the absorption of sulfur oxides during roasting were determined. The degree of sulfur and carbon oxides adsorption is 96 and 36%, respectively. Separation of roasting products using unmilled spent catalyst is proposed into a small fraction (contains a mixture of CaSO4, CaCO3 and CaO) and a coarse (consists of Al2O3, CaMoO4, CoO) fractions, and their separate processing. It has been shown that in the separate processing of roast fractions by a sodium carbonate solution, it is possible to separately obtain alumina (catalyst base) with cobalt oxide, a molybdenum-containing solution, and also a mixture of sulfate, carbonate and oxide calcium. The used method of roasting the spent hydrotreating catalyst with lime will allow hazardous waste of hazard class 3-4 to be disposed of without hazardous waste gas costs. It allows one to obtain, during further processing, molybdenum and cobalt compounds, as well as finely divided alumina.
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Radi, Muhammad Rivai et Mauridhi Hery Purnomo. « Study on Electronic-Nose-Based Quality Monitoring System for Coffee Under Roasting ». Journal of Circuits, Systems and Computers 25, no 10 (22 juillet 2016) : 1650116. http://dx.doi.org/10.1142/s0218126616501164.
Texte intégralRésumé :
Roasting process needs to be monitored and carefully controlled because it plays as the most important stage for determining flavor quality on the final product in the secondary coffee processing. Common quality monitoring method by applying parameters namely roasting time, roasting temperature and grain color may have disadvantages especially for nonuniform quality of green beans and stirring mechanism of regular roasters; therefore, an alternative quality monitoring model is necessary. Because emitted vapor during roasting may represent the occurred reaction stage, it is possible to indicate the roast degree of the coffee grain. This study evaluated the application of an electronic nose based on semiconductor sensor array for quality monitoring of coffee roasting. The electronic nose designed with gas sensor array was integrated to a mini batch coffee roaster. Data including sensor array response, vapor humidity and temperature were recorded in line to the roasting process and compared to the coffee grain color measured with a universal colorimeter. The experiment showed that the gas sensors respond to the emitted coffee flavors, from which a logarithmic profile as a function of grain color was obtained with the highest slope of [Formula: see text]1.6[Formula: see text]V/color difference of roasted coffee. Aroma patterns obtained from sensor responses were then analyzed with principle component analysis (PCA), by which a distinctive profile between initial and final phases of roasting is obtained. Although the corresponding analysis is still unable to distinguish the levels of light, medium and dark (LMD); high sensor responses indicate a further benefit of this system for developing an analogous quality monitoring system.
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Awwad, Shady, Ahmed Abu-Zaiton, Reem Issa, Rana Said, Ahmad Sundookah, Maha Habash, Beisan Mohammad et Mahmoud Abu-Samak. « The effect of excessive coffee consumption, in relation to diterpenes levels of medium-roasted coffee, on non-high-density lipoprotein cholesterol level in healthy men ». Pharmacia 70, no 1 (10 janvier 2023) : 49–59. http://dx.doi.org/10.3897/pharmacia.70.e90495.
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This study was designed to determine the levels of coffee oil and diterpenes and evaluate the correlation between the effect of excessive roasted coffee consumption on non-high-density lipoprotein cholesterol (non-HDL) and the roasting degree effect on the levels of coffee oil and diterpenes extracted from Coffea arabica. The coffee oil and diterpenes were extracted using soxhlet and liquid-liquid extraction. Sixty-six healthy normolipidemic male participants were assigned for this study which consisted of two stages. The first stage is the coffee abstaining stage where subjects were requested to abstain from drinking coffee for 2 weeks. The second stage is the coffee drinking stage which consisted of groups (the control group and coffee-drinking group). The levels of TC, TG, LDL-C, HDL-C, and non-HDL were determined in all participants before and after the experiment. The results indicated that the coffee roasting degree demonstrated a significant increase in the levels of coffee oil and diterpenes ranging from 9.31% (green coffee) to 15.64% (dark roast) and from 0.205% (green coffee) to 0.300% (dark roast) for diterpenes. In conclusion, the current study revealed that excessive consumption of medium roasted coffee was associated with elevated non-HDL levels in normotensive nonsmoker healthy men which might be attributed to the positive association between the degree of roasting and diterpenes levels.
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Klyushnikov, Alexander M., et Evgeny N. Selivanov. « Simulation of the joint processing of pyrrhotite concentrate and nickeliferous oxidized ore ». Butlerov Communications 58, no 5 (31 mai 2019) : 110–17. http://dx.doi.org/10.37952/roi-jbc-01/19-58-5-110.
Texte intégralRésumé :
In this paper the issues of improving the efficiency of processing of pyrrhotite concentrates and magnesia-silicate nickeliferous ores are reviewed. An original technology is proposed, its basic stages are partial oxidative roasting of the concentrate and joint contractile melting the calcine with nickel ores to gain matte. Roasting of the pyrrhotite concentrate allows to extract 70-80% of sulfur from the concentrate into gases riched with SO2, reduce desulfurization during melting and extract nickel, copper, cobalt and precious metals from both raw materials into the matte. The implementation of fluxing potential of nickel ore completely eliminates the use of fluxes during smelting and increases the specific productivity of metallurgical units in concern of raw materials. On the laboratory scale, the modeling of the main technological operations is performed to justify the technology. The possibility of separation of slag and matte with joint reagent-free melting (1400 ºC) of the product of partial oxidative roasting and oxidized nickel ore, taken in equal quantities, is theoretically justified and experimentally confirmed. Parameters of the roasting of the pyrrhotite concentrate: temperature 800 ºС, desulfurization degree 71.7%. Pyrrhotite concentrate contained (% wt.) 1.9 Ni, 0.2 Cu, and 0.06 Co. Oxidized nickel ore contained (%wt.) 1.2 Ni, and 0.06 Co. The slag basicity module (about 1) provides relatively low content of non-ferrous metals in the slag (% wt.): 0.24 Ni, 0.08 Co, and 0.04 Cu. Matte contained (%wt.) 8.9 Ni, 0.22 Co, 0.5 Cu, 58.7 Fe, 25.0 S, and 6.6 O. Extraction level in the matte was 87.8% nickel, 48.0% cobalt, and 73.3% copper from their content in the initial mixture. High levels of matte enrichment degree with respect to the charge were achieved; their values were 5.5 for nickel, 5.7 for cobalt, and 4.5 for copper. Desulfurization degree during melting and metallization degree of matte were close to zero. The matte was suitable for processing with known routes. The results are expected to be used in the development of technologies aimed to resumption of processing of oxidized nickeliferous ores from the Ural deposits.
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Tsai, Yu-Jung, Li-Yun Lin, Kai-Min Yang, Yi-Chan Chiang, Min-Hung Chen et Po-Yuan Chiang. « Effects of Roasting Sweet Potato (Ipomoea batatas L. Lam.) : Quality, Volatile Compound Composition, and Sensory Evaluation ». Foods 10, no 11 (27 octobre 2021) : 2602. http://dx.doi.org/10.3390/foods10112602.
Texte intégralRésumé :
Roasting can increase the Maillard reaction and caramelization of sweet potatoes to create an attractive appearance, color, aroma, and taste, and is rapidly increasing in the commercial market. This study mainly analyzed the influence of roasting sweet potatoes, with and without the peel, on sweet potato quality and flavor characteristics combined with sensory qualities. The results showed that the a* value (1.65–8.10), browning degree (58.30–108.91), total acidity (0.14–0.21 g/100 g, DW), and maltose content (0.00–46.16 g/100 g, DW) of roasted sweet potatoes increased with roasting time. A total of 46 volatile compounds were detected and 2-furanmethanol, furfural, and maltol were identified as the main sources of the aroma of roasted sweet potatoes. A sensory evaluation based on a comprehensive nine-point acceptance test and descriptive analysis showed that roasting for 1 to 2 h resulted in the highest acceptance score (6.20–6.65), including a golden-yellow color, sweet taste, and fibrous texture. The sweet potatoes became brown after roasting for 2.5 to 3 h and gained a burnt and sour taste, which reduced the acceptance score (4.65–5.75). These results can provide a reference for increased quality in the food industry production of roasted sweet potatoes.
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Dippong, Thomas, Monica Dan, Melinda Haydee Kovacs, Emoke Dalma Kovacs, Erika Andrea Levei et Oana Cadar. « Analysis of Volatile Compounds, Composition, and Thermal Behavior of Coffee Beans According to Variety and Roasting Intensity ». Foods 11, no 19 (10 octobre 2022) : 3146. http://dx.doi.org/10.3390/foods11193146.
Texte intégralRésumé :
This study aimed to investigate the ways in which the thermal behavior, composition, and volatile compound contents of roasted coffee beans depend on variety and roasting intensity. The thermal analysis revealed various transformations in coffee composition, namely, drying, water loss, and decomposition of polysaccharides, lipids, amino acids, and proteins. The results showed that volatile compounds are released differently in coffee depending on coffee type and degree of roasting. The most abundant volatile compounds present in the samples were 2-butanone, furan, 2-methylfuran, methyl formate, 2.3-pentanedione, methylpyrazine, acetic acid, furfural, 5-methyl furfural, and 2-furanmethanol. The total polyphenol contents ranged between 13.3 and 18.9 g gallic acid/kg, being slightly higher in Robusta than in Arabica varieties and in more intensely roasted beans compared to medium-roasted beans. The Robusta variety has higher mineral contents than Arabica, and the contents of most minerals (K, Ca, Mg, Fe, Cu, P, N, and S) increased with roasting intensity. Discrimination between coffee varieties and roasting intensities is possible based on mineral and polyphenol contents.
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Cocic, M., M. Logar, S. Cocic, S. Devic, B. Matovic et D. Manasijevic. « Mineralogical transformations in copper concentrate roasting in fluo-solid reactor ». Journal of Mining and Metallurgy, Section B : Metallurgy 43, no 1 (2007) : 71–84. http://dx.doi.org/10.2298/jmmb0701071c.
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This work presents the results of investigation process of copper concentrate roasting in fluo-solid reactor with the aim of studying a transformation degree of primary ore minerals under various technological parameters. Input material (charge) and roasting products (calcine) were investigated by x-ray diffraction, ore microscopy and chemical analysis. The investigation results have shown that reaction of mineral transformation are not completed, i.e. they are developed only partially (12-22%) what is a consequence of insufficient long heating, unsuitable temperature or unfilled other parameters as well as non-uniform grain size. .
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Ryazanov, A. G., A. V. Senin et O. V. Khmeleva. « Zinc Ferrite Decomposition by Sodium Carbonate and Calcium Oxide at Roasting of Steelmaking Dust ». Materials Science Forum 946 (février 2019) : 474–79. http://dx.doi.org/10.4028/www.scientific.net/msf.946.474.
Texte intégralRésumé :
When re-melting scrap in electric arc furnaces (EAF), dust is formed. This dust is a rich zinc-containing raw material. The composition of the EAF-dust from JSC “Pervouralsk New Pipe Plant” was investigated. Dust contains 18 wt.% of zinc, more than 1/3 of zinc is a part of the slightly soluble in acids and alkalis of zinc ferrite ZnFe2O4. The aim of the work is to study the effect of roasting temperatures of 700, 850 and 1000 °C and the effect of CaO and Na2CO3 additives on the decomposition of zinc ferrite. Thermodynamic analysis of chemical transformations in dust during roasting showed that the additions of CaO and Na2CO3 provide destruction of zinc ferrite and promote the transfer of zinc into the acid-soluble form of ZnO. The effect of the roasting temperature, the duration of roasting and the amount of calcium oxide and sodium carbonate additions on the degree of zinc transition into acid-soluble form was studied experimentally. The best results were obtained at 1000 oС. The increase in the roasting time in the interval from 1 to 3 hours promotes an increase in the concentration of acid-soluble zinc in the cinder. The combined additions of 36 wt.% of Na2CO3 and 19 wt.% of CaO above the dust mass are optimal. The proportion of acid-soluble zinc in the cinder increased to 97–99 %, as a result of roasting under optimal conditions.
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Wołosiak, Rafał, Paulina Pakosz, Beata Drużyńska et Monika Janowicz. « Antioxidant Activity of Coffee Components Influenced by Roast Degree and Preparation Method ». Applied Sciences 13, no 4 (5 février 2023) : 2057. http://dx.doi.org/10.3390/app13042057.
Texte intégralRésumé :
Coffee is of interest to consumers and researchers, mainly due to its stimulating properties and positive effects on the human body. Properties of coffee infusions depend on many factors and the most important ones include the roasting process and the brew preparation method. In this paper, we analyzed infusions prepared with the use of pressure methods (professional: espresso and consumer: moka pot brew), obtained from beans roasted to the medium and dark degree, with the aim of determining the share of individual groups of ingredients in the antioxidative properties of coffee. Tested infusions showed various characteristics that were partly related to different parameters of their preparation. In general, a greater amount of phenolic compounds was extracted in moka brews. Espresso, on the other hand, exhibited greater antioxidant activity per portion of the brew and a greater ability to quench free radicals. The degree of roasting had an uneven effect on the antioxidant activity of the brews, depending on the method and its mechanism of antioxidant action. The share of activity of the particular groups of antioxidants in overall activity varied between all methods; the most pronounced changes were observed in the espresso brews. The results indicate, however, that the activity of phenols and melanoidins is based on a mixed mechanism of antioxidant action, but in the case of the latter, the mechanism of hydrogen atom transfer may have an advantage.
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Yang, Jinlin, Wenzhe Xu, Shuo Xu et Shaojian Ma. « Study on graphitization of anthracite and petroleum coke catalyzed by boric acid ». Journal of Physics : Conference Series 2174, no 1 (1 janvier 2022) : 012031. http://dx.doi.org/10.1088/1742-6596/2174/1/012031.
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Abstract Graphite carbon materials have excellent properties and are widely used. Traditional artificial graphite has high energy consumption and high cost, so reducing the energy consumption of artificial graphite has become a research hotspot in recent years. The effect of boric acid on the graphitization of anthracite and petroleum coke was studied, and the parameters such as boric acid content, roasting temperature and holding time were investigated in this paper. The results show that the optimum dosage of boric acid for graphitization of anthracite is 7.5%, and that of catalyst for graphitization of petroleum coke is 5%. The effect of roasting temperature on the graphitization of anthracite and petroleum coke catalyzed by boric acid is remarkable. The best temperature is 1400°C. Roasting holding time has positive effect on the graphitization of anthracite and petroleum coke catalyzed by boric acid. The best roasting holding time is 120min. Under the optimal experimental conditions, the highest graphitization degree of anthracite and petroleum coke catalyzed by boric acid are 23.58% and 23.56%, respectively. The effect of boric acid on anthracite is better than that of petroleum coke.
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Koriyama, Takako, Kiriko Teranaka, Mitose Tsuchida et Midori Kasai. « Effects of Storage and Roasting Condition on the Antioxidant Activity of Soybeans with Different Colors of Seed Coat ». Foods 12, no 1 (24 décembre 2022) : 92. http://dx.doi.org/10.3390/foods12010092.
Texte intégralRésumé :
The DPPH radical scavenging activity and ORAC value of soybeans (yellow soybean, blue soybean, and black soybean) were increased by roasting at above 190 °C. Concerning raw beans, black soybeans with the darkest seed coat color had the strongest antioxidant activity, indicating the effect of the coat pigment. However, the degree of increased antioxidant activity by roasting was almost similar regardless of seed coat color, suggesting that coat color is independent of the increased antioxidant activity. Concerning aged beans stored at 37 °C/75% RH for 60 days, the antioxidant activity increased in yellow soybean and decreased in blue and black soybean compared to before storage. Conversely, when roasted at 190 °C for 20 min, the DPPH values of all the aged beans were significantly increased. Other analyses of roasted beans with and without seed coat showed that changes in the components of cotyledons during storage may have contributed to the increased antioxidant activity of aged beans, regardless of seed coat color. These results revealed that roasting effectively improves the antioxidant activity of aged soybeans, regardless of seed coat color. We concluded that roasting is recommended for antioxidant properties, particularly regarding the effective use of aged beans.
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Gaipov, T. E., A. B. Makhanbetov, B. E. Myrzabekov, A. Tazhibayev, S. Bitursyn, N. Shertayeva, M. Duisembiyev et E. K. Abdulina. « EXTRACTION OF MANGANESE FROM MANGANESE ORES BY ELECTROCHEMICAL LEACHING ». RASAYAN Journal of Chemistry 15, no 03 (2022) : 1806–11. http://dx.doi.org/10.31788/rjc.2022.1536898.
Texte intégralRésumé :
The basis of the traditional technology of hydrometallurgical processing of manganese ore is the process of ore roasting. The results obtained in this article make it possible to exclude the roasting process and directly leach the crushed ore under the action of an electric current. The process of electrochemical leaching includes two simultaneous operations: reduction of hard-soluble higher manganese oxides (pyrolusite - MnO2, vernadite - MnO2- nH2O) in an acid medium and transition of reduced manganese into an aqueous solution. The main part of the reduction process of higher manganese oxides proceeds in the Fe2+ ↔ Fe3+ catalytic system, the remaining part proceeds at the cathode under stirring. The degree of influence of iron (III) ions was determined. During studies on the transfer of manganese into solution from manganese ore by electrochemical leaching, the influence of L:S: ratio, sulfuric acid concentration, and cathodic current density on the degree of manganese extraction were studied. As a result of electrochemical leaching studies in the presence of the catalyst system, Fe2+ ↔ Fe3+ under optimal electrolysis parameters the degree of manganese extraction was 99%.
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Hung, Ying-Che, Ping Chen et Liang-Yü Chen. « Advanced Classification of Coffee Beans with Fatty Acids Profiling to Block Information Loss ». Symmetry 10, no 10 (22 octobre 2018) : 529. http://dx.doi.org/10.3390/sym10100529.
Texte intégralRésumé :
Classification is a kernel process in the standardization, grading, and sensory aspects of coffee industries. The chemometric data of fatty acids and crude fat are used to characterize the varieties of coffee. Two category classifiers were used to distinguish the species and roasting degree of coffee beans. However, the fatty acid profiling with normalized data gave a bad discriminant result in the classification study with mixed dimensions in species and roasted degree. The result of the predictive model is in conflict with the context of human cognition, since roasted coffee beans are easily visually distinguished from green coffee beans. By exploring the effects of error analysis and information processing technologies, the lost information was identified as a bias–variance tradeoff derived from the percentile normalization. The roasting degree as extensive information was attenuated by the percentile normalization, but the cultivars as intensive information were enhanced. An informational spiking technique is proposed to patch the dataset and block the information loss. The identified blocking of informational loss could be available for multidimensional classification systems based on the chemometric data.
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Živković, Živan, Dragana Živković, Aca Jovanovic et Ivan Mihajlovic. « Development of Technology for Reduction Process of Copper Production ». Materials Science Forum 502 (décembre 2005) : 361–66. http://dx.doi.org/10.4028/www.scientific.net/msf.502.361.
Texte intégralRésumé :
In this paper results regarding development of reduction process for copper production are presented. This process is applicable for small smelting plants of capacity up to 30.000 t/year, with capability for treating poly-metallic Cu-Zn-Pb concentrates with dangerous level of toxic components presence (As, Cd, Hg, …). This procedure is interesting because it can be applied for smelters that are supplied from mines at the end of exploitation so in the edge sectors poly-metallic minerals appear. Procedure consists of oxidation roasting of copper concentrate with desulphurisation degree over 98% and reduction smelting of sintered roasting products in shaft furnace of special construction. Using process of slag fuming, the degree of Cu and (Au+Ag) utilization can rise over 98% which results in good economic parameters, environment protection and low investment comparing to technologies currently used, taking in mind that phase of concentration is excluded from this technology.
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Różańska, Maria Barbara, Przemysław Łukasz Kowalczewski, Jolanta Tomaszewska-Gras, Krzysztof Dwiecki et Sylwia Mildner-Szkudlarz. « Seed-Roasting Process Affects Oxidative Stability of Cold-Pressed Oils ». Antioxidants 8, no 8 (16 août 2019) : 313. http://dx.doi.org/10.3390/antiox8080313.
Texte intégralRésumé :
The oxidative stability of vegetable oils mainly depends on their fatty acid composition, their degree of unsaturation, and the presence of compounds with antioxidant activity. This paper reports on the effects of the process of roasting oil seeds, prior to pressing them, on the basic characteristics of the oils produced and their oxidative stability. The differential scanning calorimetry (DSC) technique was used to study the process of oxidation of the oil samples in an oxygen-flow cell. Chromatographic analysis revealed that roasting the seeds increased the levels of chlorophyll and β-carotene in all the cold-pressed oils. Similar results were observed for the oil’s antioxidant activity, measured by the scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical method. Our results also indicated that roasting seeds prior to pressing them for oil had a positive effect on the oil’s stability, as determined by the DSC method. This manifested in both the extension of oxidation induction time and the final oxidation time.
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Zinoveev, Dmitry, Pavel Grudinsky, Andrey Zakunov, Artem Semenov, Maria Panova, Dmitry Valeev, Alex Kondratiev, Valery Dyubanov et Alexander Petelin. « Influence of Na2CO3 and K2CO3 Addition on Iron Grain Growth during Carbothermic Reduction of Red Mud ». Metals 9, no 12 (6 décembre 2019) : 1313. http://dx.doi.org/10.3390/met9121313.
Texte intégralRésumé :
Red mud is a by-product of alumina production from bauxite ore by the Bayer method, which contains considerable amounts of valuable components such as iron, aluminum, titanium, and scandium. In this study, an approach was applied to extract iron, i.e., carbothermic reduction roasting of red mud with sodium and potassium carbonates followed by magnetic separation. The thermodynamic analysis of iron and iron-free components’ behavior during carbothermic reduction was carried out by HSC Chemistry 9.98 (Outotec, Pori, Finland) and FactSage 7.1 (Thermfact, Montreal, Canada; GTT-Technologies, Herzogenrath, Germany) software. The effects of the alkaline carbonates’ addition, as well as duration and temperature of roasting on the iron metallization degree, iron grains’ size, and magnetic separation process were investigated experimentally. The best conditions for the reduction roasting were found to be as follows: 22.01% of K2CO3 addition, 1250 °C, and 180 min of duration. As a generalization of the obtained data, the mechanism of alkaline carbonates’ influence on iron grain growth was proposed.
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Torres, María D., Francisco Chenlo et Ramón Moreira. « Viscoelastic and Textural Characteristics of Gels Obtained from Potato Starch Roasted under Several Temperature-Time Conditions ». International Journal of Polymer Science 2018 (23 décembre 2018) : 1–11. http://dx.doi.org/10.1155/2018/7606359.
Texte intégralRésumé :
The influence of roasting conditions on the potato starch (PS) composition, solubility, crystallinity, gel-forming thermal profiles, and texture of the corresponding gels was studied. Thermorheological testing of roasted starches with (RPS) and without (RPSI) the soluble fraction was conducted on a stress-controlled rheometer. Texture profile analysis (TPA) was used to determine the RPS final gel texture. Solubility tests showed equivalent effects of starch roasting for samples treated at 190°C for 8 h (RPS190-8), 210°C for 6 h (RPS210-6), and 230°C for 4 h (RPS230-4). The apparent amylose content of RPS linearly increased with the decreasing degree of crystallinity. Elastic (G′) and viscous (G″) properties of RPS depended markedly on apparent amylose content and crystallinity. G′gel values of roasted starches linearly increased with the amylose content suggesting a promotion of the amylose breakdown with roasting temperature. Gels prepared with RPS roasted between 120 and 170°C exhibited intermediate strength and fully thermal reversible features. Roasting between 190 and 210°C favoured strong and fully thermal reversible gels. Although RPS230-4 gels exhibited similar strength to RPS190-8 and RPS210-4, no fully thermal reversible gels were obtained. The soluble fraction removal led to a drop the RPSI gels strength with increasing roasting temperature. No water syneresis was identified for RPS gels during one-week ageing, except for RPS230 gels. Relationships between textural parameters from TPA and viscoelastic gel properties determined by rheology were established.
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Makhotkina, E. S., M. V. Shubina et I. G. Shubin. « Investigation of Hydrometallurgical Processing of Titanomagnetite Ore Enrichment Waste ». Solid State Phenomena 299 (janvier 2020) : 1115–20. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.1115.
Texte intégralRésumé :
In the article the negative impact of titano-magnetite ore enrichment waste on the environment and the possibility of its use as vanadium-containing raw materials are overviewed. The chemical and mineralogical composition features of various samples of the Kusinsky deposit titanomagnetite ore tails are presented. Different combinations of their roasting processes (with and without salt additives, with oxides, carbonates, or their compositions) and leaching processes (with water or acid) during hydrometallurgical processing were analyzed.The experiment results on the extraction of vanadium in the form of soluble vanadates from the titanomagnetite ore tails by leaching from samples subjected to roasting with soda ash, sodium sulfate, calcium oxide, and sodium chloride in various mass ratios are presented. The significant influence of ore sample chemical composition on the vanadium extraction degree was revealed. It was revealed that for this type of vanadium raw material additives of sodium chloride and sodium carbonate are most preferable from the vanadium extraction degree point of view.
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Hui, Ming, Xiao Li Shang, Qing Tian et Kai Ping Zhang. « Physical Characterisation of Millet Starch during Roasting ». Advanced Materials Research 550-553 (juillet 2012) : 1288–92. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.1288.
Texte intégralRésumé :
The gelatinization and liquefaction properties of roasted millet starch were investigated in this study. Results showed that the particle morphology of roasted millet starch greatly changed as compared with control, and its solubility and swelling degree increased with temperature increment, in which the former increased rapidly above 70°C and was basically stable after 80°C, while the latter was overall lower than the raw millet starch's. The viscosity of millet starch paste increased with decreasing temperature, but that of the roasted starch increased more slowly than that of the raw. There was little effect of pH value on viscosity of roasted millet starch. Compared with the raw, the roasted millet starch would be firstly reached scheduled DE value under the same conditions, which could reduce liquefaction time in the course of production.