Roasting Time Research Articles

Karakteristik Teh Jelai (Coix Lacryma-Jobi.L) dengan Perlakuan Waktu dan Suhu Roasting yang Berbeda

Jelai (Coix Lacryma Jobi.L) seeds are grains that have the potential to be processed into herbal teas which are served either hot or cold. Jelai tea can be processed through a high-temperature roasting process to enhance the aroma and taste. Temperature and length of roasting time are factors that affect grain characteristics. The purpose of this study was to evaluate the effect of temperature and roasting time on water content, color of barley powder and the effect of temperature and roasting time on pH, total dissolved solids, and organoleptic of jelai tea. The study used a factorial completely randomized design (CRD) with two factors: (t) roasting temperature (180oC, 200oC, 220oC) and (f) roasting time (5 minutes, 10 minutes, 15 minutes). The roasting temperature and time reduced the water content of jelai powder from 11.04% to 1.57% (wb), increased the dissolved solids from 0.26 oBrix to 5.16 oBrix, and lowered the pH from 7.04-6.79. The higher the temperature and roasting time, the darker the color of the powder and the barley tea (brown), increase the burning aroma (burn aroma), nutty smelling, burn flavor and the sour taste of jelai tea. The highest results were obtained at 220oC combined roasting time of 10 minutes and 15 minutes. Overall, the level of panelist acceptance of jelai tea was in the rather favorable category for all treatments (2.77 – 3.42).

Process and mechanism of preparing metallized blast furnace burden from metallurgical dust and sludge

Metallurgical dust and sludge are solid waste resources with recycling value. In recent years, rotary hearth furnace has become the most important means to treat metallurgical dust and sludge because of its wide range of raw materials and strong treatment capacity. In this study blast furnace ash and converter sludge were selected as the research objects, and high-quality metallized pellets were prepared based on the rotary hearth furnace process. The strength changed of pellets, the reduction process of iron oxides and the removal process of zinc during the roasting of pellets in rotary hearth furnace were studied. To explore the reasonable roasting condition for preparing metallized pellets in rotary hearth furnace. The optimum roasting temperature of the pellets was 1250℃ and the roasting time was 25 min. The compressive strength, metallization rate and dezincification rate of metallized pellets reached 1361N, 97.44% and 95.67%, respectively. The efficient resource utilization of various metallurgical dust and sludge is realized.

XPS Investigation of Magnetization Reduction Behavior and Kinetics of Oolitic Hematite in Gas-Based Roasting

Magnetization reduction roasting is an important method for the utilization of oolitic magnetite. In this study, the magnetization reduction behavior and kinetics of oolitic hematite in gas-based roasting were systematically investigated by X-ray photoelectron spectroscopy (XPS). The results revealed that under optimal roasting conditions of 650 °C, a roasting time of 60 min, and a CO concentration of 30%, the magnetization reduction rate of the roasted product reached 44.34%. Furthermore, the weak magnetic separation concentrate presented a TFe of 58.09% and a concentrate iron recovery of 94.3%. The results of the XPS spectrum indicated that the peak area ratio (Fe2+/Fe3+) gradually increased with an increase in roasting temperature, roasting time, and CO concentration, while over-reduction occurred when the roasting temperature exceeded 750 °C. The investigation of magnetization roasting kinetics for varying particle sizes demonstrated that the magnetization reduction process is controlled by chemical reaction, with a corresponding activation energy range of 42.96 kJ/mol to 63.29 kJ/mol, indicating the particle size has little effect on the magnetization reduction of oolitic hematite.

The effect of roast profiles on the dynamics of titratable acidity during coffee roasting.

Coffee professionals have long known that the "roast profile," i.e., the temperature versus time inside the roaster, strongly affects the flavor and quality of the coffee. A particularly important attribute of brewed coffee is the perceived sourness, which is known to be strongly correlated to the total titratable acidity (TA). Most prior work has focused on laboratory-scale roasters with little control over the roast profile, so the relationship between roast profile in a commercial-scale roaster and the corresponding development of TA to date remains unclear. Here we investigate roast profiles of the same total duration but very different dynamics inside a 5-kg commercial drum roaster, and we show that the TA invariably peaks during first crack and then decays to its original value by second crack. Although the dynamics of the TA development varied with roast profile, the peak TA surprisingly exhibited almost no statistically significant differences among roast profiles. Our results provide insight on how to manipulate and achieve desired sourness during roasting.

The Effect of Using Fast Roast and Slow Roast Roasting Techniques on the Chemical and Organoleptic Characteristics of Robusta Coffee Beans (Coffea robusta L.)

One of the commodities with the highest economic value in the plantation sector in Indonesia is coffee. In 2016 there was a significant difference between the area of robusta and arabica coffee, with the area of robusta coffee being superior. The wide difference between robusta and arabica coffee plantations is because robusta coffee is considered a potential opportunity in developing the community's economy compared to arabica coffee with a particular market. To improve the taste or quality of coffee production, one of the factors is the roasting process. Currently, the demand for coffee production is increasing with the need for maximum quality and taste of coffee beans, so the processing of coffee plants must be very concerned and improved. Therefore this study aims to determine the roasting technique with a roasting machine and its effect on improving the quality and taste of coffee beans that are popular with consumers. This study used a Split Plot Design (SPD) using the basic pattern of a completely Randomized Design consisting of 2 levels. The first factor is the roasting time as the main plot with four levels. Then the second factor is the roasting temperature with two levels. Each factor was repeated four times so there were 32 experimental units. The results of this study indicate that in the roasting process using slow roast and fast roast techniques, roasting time affects all observation parameters, namely moisture content, pH value, brix value, flavor, aroma, and caffeine. However, the roasting temperature only affects moisture content, brix value, and caffeine.

Collaborative separation of nickel and iron from nickel laterite ore and red mud

ABSTRACT In this study, we investigated a nickel laterite ore with Ni content of 1.56 wt% and a red mud with Fe content of 20.98 wt%, the main Ni-bearing mineral in the nickel laterite ore was nickel-lizardite, and the main Fe-bearing mineral in the red mud was hematite. A novel process of roasting and magnetic separation was purposed to extract nickel and iron from the nickel laterite ore and red mud. The nickel laterite ore, red mud, calcium chloride, and coke were mixed and put in a roaster for roasting, and the ferronickel concentrate was obtained from the roasted ore by magnetic separation. The results showed that a ferronickel concentrate with Ni content of 7.97 wt%, Fe content of 73.09 wt%, iron recovery of 76.87%, and nickel recovery of 90.28% was obtained under the optimal conditions: a mass ratio of m (nickel laterite ore): m (red mud) : m (coke) : m (calcium chloride) : of 0.6:0.4:0.2:0.1, a roasting temperature of 1373 K, a roasting time of 90 min, a grinding fineness of − 0.045 mm occupying 90%, and a magnetic field strength of 0.20 T. The main minerals in the ferronickel product were metallic Fe and FeNi.

Oyster shell-modified lignite composite in globular shape as a low-cost adsorbent for the removal of Pb2+ and Cd2+ from AMD: Evaluation of adsorption properties and exploration of potential mechanisms

A low-cost composite adsorption material has been synthesized from fishery wastes and natural minerals to address challenges such as ecological balance destruction caused by high concentrations of Pb and Cd in acid mine drainage (AMD), unreasonable use of low-caloric lignite, and environmental pollution caused by idle accumulation of oyster shells. This new adsorbent can effectively treat AMD by improving acidity and adsorbing Pb2+ and Cd2+. In this study, oyster shell-modified lignite composite in globular shape (OSL-G) was synthesized by using pyrolyzed oyster shell and lignite, with the addition of bentonite adhesive. The adsorption properties of OSL-G on AMD were evaluated, and the potential mechanism of OSL-G repairing AMD was explored. The results showed that when the mass ratio of oyster shell to lignite was 1:1, oyster shell-modified lignite composite (OSL) was synthesized at 900 °C for 20 min. When the adhesive content was 15.50 %, the roasting temperature was 640 °C, and the roasting time was 2.35 h, OSL-G was synthesized and the adsorption effect was the best. The OSL-G could effectively treat AMD with pH 4 ∼ 5 and initial Pb2+ and Cd2+ concentrations of 10 mg/L within 600 min at a dosage of 4 g/L. The OSL-G adsorption process followed the quasi-second-order kinetic model and the Freundlich model. The maximum adsorption saturation capacities of Pb2+ and Cd2+ were 107.2821 mg/g and 8.3777 mg/g at 298.15 K, respectively. The adsorption process was a multistep controlled spontaneous endothermic process. The potential mechanism was mainly the adsorption-condensation coexistence results of electrostatic adsorption, neutralization precipitation, ion exchange, and surface complexation. The removal rates of Pb2+ and Cd2+ of the recovered OSL-G (ROSL-G) were still high, reaching 57.26 % and 50.38 % after 5 times of adsorption–desorption, respectively. The applicability of ROSL-G after adsorption–desorption for other heavy metal components in AMD proved its good application potential. This study suggested that OSL-G can be used as a promising environmentally friendly adsorbent for AMD. This study provided a broad picture of the management and reuse possibilities of fishery wastes and natural mineral resources, and addressed established, current, and potential strategic needs, particularly in terms of sustainability challenges and ecological civilization construction.

Formulation of weaning food from yellow maize (Zea mays L.) and red millet (Eleusine coracana L.), enriched with pretreated African locust beans (Parkia biglobosa Jacq.) flour

This work aimed to formulate adequate weaning food with acceptable protein and mineral contents from yellow maize and red millet enriched with pretreated Parkia biglobosa (PB). PB seeds were boiled to facilitate dehulling. The dehulled seeds were divided into different portions, which were respectively fermented (3 and 6 days), oven roasted (175 °C for 20 and 40 min), and microwaved (450 W for 15 and 30 min). Maize and millet flours used as control samples, were respectively mixed (1:1 w/w) with pretreated PB seed flours, to constitute fourteen formulations. These formulations were analyzed for their proximate, mineral compositions, physical and functional properties, total phenolic content and antioxidant activity. There was significant increase in protein, carbohydrate and lipid contents for formulations made with PB roasted in oven (175 °C, 40 min) and in microwave (450 W, 30 min). Protein content of all formulated infant flours was above 15 g/100 g DW recommended value for infant complementary foods. The highest energy value (485.09 kcal) was obtained with the formula maize and P. biglobosa oven roasted at 175 °C for 40 min. The formulated flours have the required values of K, P, Ca, Mg and Na as recommended by the WHO. Formulations made with pre-fermented PB exhibited the highest swelling capacity (173.43%), water holding capacity (230.85 %), total phenolic content (48.32 mg GAE/g) and antioxidant activity (95.78%). Their least gelation concentration values decreased compared to the sample added with untreated PB. With a maximum value of 10.25, titratable acidity increased with roasting time while the pH value decreased. Porosity decreased with processing time. The value of the Hausner ratio (HR < 1.4) revealed that the formulated flours have good flowability behavior. Based on the obtained result, pretreated dehulled PB seeds could be recommended in the enrichment of complementary food made from maize and millet.

Preparation of aluminum fluoride from carbon residue in aluminum electrolysis cell by roasting-leaching method

The carbon residue is a hazardous waste generated by the aluminum electrolysis production process, which contains a large amount of electrolyte fluoride salts. In order to recover the electrolyte components in carbon residue, this paper proposes a new method of using carbon residue to prepare aluminum fluoride by converting Na5Al3F14 and Na3AlF6 in carbon residue into aluminum fluoride to realize the recycling of fluoride in carbon residue. In the initial step, optimal parameters for carbon removal during roasting have been determined, including an oxygen flow rate of 7 g/min, a roasting temperature of 670 °C, and a roasting time of 80 min. The roasted clinker is obtained, and the removal rate of carbon reaches 99.95 % while the loss rate of fluorine is 0.48 %. In the second step, the mix anhydrous Al2(SO4)3 with roasted clinker for roasting. The optimal roasting temperature of 670 °C, the time of 10 min, and the mass ratio of anhydrous Al2(SO4)3 to roasted clinker of 5:5 could convert fluoride to AlF3 products, with a conversion rate of 99.76 % and a loss rate of fluorine of 1.05 %. Finally, by removing sulfate impurities through water leaching for 15 min at 35 °C and with a liquid-solid ratio of 6 ml/g, the loss rate of fluorine is 3.98 %. This process yields AlF3 with a purity of 94.30 %. The recovery rate of fluorine in the whole process is 94.56 %, which successfully achieves the recycling of fluorine in the carbon residue to obtain AlF3 products.

Effect of cumin on flavor and protein oxidation of roast lamb with different roasting time

Effect of cumin on flavor and protein oxidation of roast lamb with different roasting time

Catalytic hydrolysis of monochlorodifluoromethane over ZnO/ZrO2 catalysts at low temperatures.

Monochlorodifluoromethane (HCFC-22) has been identified as a significant contributor to the depletion of the Earth's ozone layer, garnering considerable attention within the scientific community. Consequently, the investigation of Freon degradation has become a central focus of current research efforts. In this study, we opted to employ catalytic hydrolysis as it offers numerous advantages for the degradation of HCFC-22. Specifically, we prepared ZnO/ZrO2 catalysts with hexahedral rod-like structures through citric acid complexation. We examined the impact of various preparation conditions (such as the molar ratio of ZnO to ZrO2, calcination temperature, and calcination time) as well as catalytic hydrolysis conditions (including the amount of catalyst, total flow rate, and catalytic hydrolysis temperature) on the hydrolysis rate of HCFC-22. Characterization of the catalysts was performed using techniques such as XRD, SEM, EDS, TG-DTG, FTIR, N2 adsorption-desorption, CO2-TPD, and NH3-TPD. Our experimental findings revealed the optimal preparation conditions: a catalytic hydrolysis temperature of 100°C, a molar ratio of ZnO to ZrO2 of 0.7, a water bath temperature of 90°C, a roasting temperature of 400°C, and a roasting time of 4h. At a catalytic hydrolysis temperature of 100°C, the hydrolysis rate of HCFC-22 reached 99.81%, with the main hydrolyzed products being HCl, HF, and CO2.

Effect of Power and Exposure Time on the Microwave-Assisted Roasting of Refractory Gold Ore

Reserves of high-grade gold ore worldwide are decreasing, and some industries have started processing refractory gold ore. Refractory gold ore contains sulfide minerals such as pyrite (FeS2), chalcopyrite (CuFeS2), galena (PbS), and sphalerite (ZnS). Gold in refractory ores occurs as fine-size gold-bearing sulfide minerals. In this study, the microwave-assisted roasting method has been investigated as a pretreatment for a refractory gold ore. This method can provide rapid heating radiation, cause micro-cracks, and trigger the decomposition of sulfide minerals. The presence of additive helps in the oxidation of sulfide minerals. The microwave-assisted roasting was carried out using variations in microwave power and time. Microwave power between 300 - 600 watts significantly affected the increase in roasting temperature and weight loss of refractory gold ore. The highest temperature reached 567°C in roasting at 800 watts for 30 minutes. The optimum condition for microwave roasting was achieved at 400 watts of power with a roasting time of 30 minutes. Metals extraction of Cu, Zn, Pb, and Fe reached 97.2%, 82.7%, 16.1%, and 2.1% in water leaching.

A Study on the Influence of Drying and Preheating Parameters on the Roasting Properties of Limonite Pellets

In this experiment, a pellet preparation method was investigated to study the drying, preheating, and roasting properties of limonitic iron ore from a plant in Yunnan. The aim was to improve the subsequent iron-making process of limonitic iron ore and make it a substitute for sintered ore. This substitution would reduce the amount of blast furnace slag in the iron-making process. Bentonite is commonly used as a primary binder in many pelletizing plant operations. However, its excessive usage leads to a higher risk of slagging and coking in the furnace. In this paper, we aim to decrease the quantity of bentonite added, enhance the iron content in the pellets, and reduce impurities to improve the grade of limonite pellets. The results show that the optimal drying, preheating, and roasting temperatures of limonite pellets are 200 °C, 700 °C, and 1250 °C, respectively, and the optimal roasting time is 20 min, when the diameter of the pellets is 8–13 mm. The compressive strength of limonite pellets with the addition of 1.5% bentonite was the highest, meeting the demands of a general blast furnace, based on which the iron grade of limonite pellet ore was increased by 10.63%.

New insights on scandium separation from scandium concentrate with titanium dioxide wastewater.

In this study, a scandium concentrate with Sc2O3 content of 66.24g/t was obtained from V-Ti magnetite tailings by physical concentration, and the main Sc-bearing minerals were augite and hornblende. A novel process of roasting and leaching was proposed to extract scandium from scandium concentrate with titanium dioxide wastewater. Scandium concentrate was pretreated by roasting, and titanium dioxide wastewater was used to directly leach scandium from the roasted ore. The effects of roasting and leaching parameters such as roasting temperature, roasting time, roasting agents, leaching temperature, leaching time, liquid-to-solid ratio, and leaching agents on scandium separation were thoroughly researched in the experimental procedure. The results show that a scandium leaching efficiency of 85.89% was obtained, and the scandium content of leaching residue decreased to 9.31g/t under the optimal conditions: a roasting temperature of 1123K, a roasting time of 120min, a leaching temperature of 343K, a leaching time of 120min, and a m (titanium dioxide wastewater)∶m (roasted ore)∶m (ammonium fluoride) ratio of 8∶1∶0.09. The main findings of the scandium separation mechanism show that Sc-bearing minerals can effectively decompose and release scandium element after roasting, and created favorable conditions for scandium leaching with titanium dioxide wastewater to achieve the purpose of scandium recovery.

Impact of roasting conditions on physicochemical, taste, volatile, and odor-active compound profiles of Coffea arabica L. (cv. Yellow Bourbon) using electronic sensors and GC–MS-O using a multivariate approach

This study investigated the effects of roasting conditions on the physicochemical, taste, and volatile and odor-active compound (OAC) profiles of Coffea arabica L. At 150 ℃, roasting increased chlorogenic acid, total flavonoids, and caffeine concentrations. However, umami and sourness sensor decreased during the roasting process. At 210 ℃ roasting, total flavonoid and caffeine concentrations increased during the roasting process. Aldehydes, ketones, and sulfur-containing compounds dramatically increased during the roasting at 210 ℃ for 20 and 30 min in E-nose analysis. Pyrazines were mainly generated during the roasting at 210 ℃ for 20 and 30 min, and pyrazines showed the highest concentrations among all OACs in GC-olfactometry (GC-O) analysis. E-tongue data showed the separation of beans by roasting temperature. However, the E-nose and GC-O data showed the separation of beans by both roasting temperature and time via multivariate analysis. We identified similar results and patterns in the E-nose and GC-O analyses.

Pengaruh Waktu Penyangraian Terhadap Karakteristik Fisikokimia Kopi Bubuk Robusta Menggunakan Mesin Roasting Elektrik

The quality of coffee powder can be improved if the main stages of the roasting process can be carried out optimally. Hot air-type roasting machines with a combination of 10 minutes and a temperature of 200 C can produce high-quality coffee powder. Therefore, other research is needed using different types of roasting machines and coffee powder quality criteria based on standards set by the government. The electric roasting machine consists of a Teflon heating mat that is directly integrated with temperature-adjustable heating components and has an automatic stirrer. The study used a one-factor Complete Randomized Design (CRD) with four treatment levels and two repeats. The Roast time of robusta coffee beans at a temperature of 200 C with levels (10, 15, 20, and 25) minutes is factor A. The criteria for testing the quality of coffee powder produced by the electric roasting machine state (smell, color, taste) with normal test results, water content ranges from 1.47-5.29%, ash content ranges from 3.53-3.83%, coffee juice ranges from 24.1-25.6%, and caffeine ranges from 1.66-1.78%. Electric roasting machines at a temperature of 200 C and 10 minutes are the best combination of treatment because the ground coffee produced is quality. I am referring to SNI 01-3542-2004 criteria for criteria tested with the most optimal electrical energy efficiency

Formulation of jaggery based sesame (Sesamum indicum L.) seed spread using response surface methodology: A novel alternative for consumers

AbstractThe aim of this study was to develop a jaggery based sesame seed spread. A central composite rotatable design (CCRD) was employed with various parameters: roasting temperatures (Y1: 110–170°C), roasting time period (Y2:10–30 min), Hydrogenated vegetable oil (Y3: 3%–7%), and jaggery level (Y4: 4%–20%) to optimize its process. The evaluation of the sesame spread involved analyzing its texture attributes (adhesiveness, cohesiveness, hardness, and viscosity) and its sensory characteristics (taste, color and appearance, spreadability, aroma, and overall acceptability). The results revealed that the roasting temperatures exerted the highest influence among the tested variables, followed by the roasting time period, jaggery content, and hydrogenated vegetable oil. Optimum sesame spread quality attributes were obtained with roasting temperatures (147°C), roasting time period (27.30 min.), hydrogenated vegetable oil (6.20%), and jaggery content (9.50%). The successful incorporation of jaggery for producing a high‐quality sesame spread resulted in a noteworthy improvement in the quality profile of the sesame spread.

Efficient separation and extraction of lithium from low-grade claystone by chloride salt-enhanced roasting process

The exploitation and extraction of lithium resources are mainly hard rock ore and salt lake brine. However, with the increasing demand of lithium resource market, the developed resources cannot meet the demand gap of lithium resource. In China, as a natural lithium source with considerable reserves, the exploitation and extraction of clay lithium resources can effectively relieve the pressure of lithium resource import. In this study, a green extraction process of low-grade lithium claystone treated by chlorination roasting-water leaching was proposed. The mechanism of lithium conversion under chlorination conditions was also investigated to reveal the fugitive form of lithium in claystone and its migration behavior during the extraction process. The experimental results showed that the optimal reaction conditions were 800 °C, the mixing ratio of the claystone and CaCl2 was 1:0.5, the roasting time was 2 h, the leaching temperature was 90 °C, and the leaching time was 3 h. Under such treatment conditions, the recovery efficiency of lithium could reach 92.35 %. Compared with the traditional roasting-acid leaching method of lithium claystone, it is more environmentally friendly and economical, and has good application prospects.

Valorization of baobab seeds (Adansonia digitata) as a coffee-like beverage: evaluation of roasting time on bioactive compounds.

The baobab tree (Adansonia digitata) can be found in sub-Saharan Africa, and its fruit presents high nutritional value. However, baobab seeds are often discarded and their potential remains underutilized. This study aimed to investigate the effect of roasting time (30/55/80/105min at 200°C) on the physical-chemical properties of baobab seeds and the bioactive compounds in a coffee-like beverage. The results showed a decrease in moisture, Aw (water activity), and hardness of baobab seeds with increasing roasting time. These changes resulted from moisture loss, caramelization, and Maillard reactions, which also affected appearance when compared with unroasted baobab seeds. The pH of the beverage decreased to a value of around 6.01 after 105min of roasting. The total phenolic content and antioxidant activity of the beverage increased with roasting time, reaching 851.2mg GAE/100g (after 80min) and 18.9mmol Fe2+/100g (after 55min), respectively. The caffeine content remained stable around 16mg/100g from 55 to 105min, lower than that of unroasted coffee beans and decaffeinated coffee. These findings suggest the potential for valorizing baobab seeds in the development of a new coffee-like beverage with lower caffeine content.

A novel process of gradient oxidation roasting-acid leaching for vanadium extraction from stone coal

Efficient green vanadium extraction is a research direction of stone coal. This study focuses on efficient green vanadium extraction of stone coal. A gradient oxidation roasting-acid leaching (GORA) process was proposed, which is additive-free and effectively improves the leaching efficiency with preliminary oxidation and further high-temperature reoxidation. The results of this study showed that 95.59 % of −0.074 mm particles were the most appropriate. The suitable roasting temperature and time for preliminary oxidation roasting were 650 °C and 0.5 h, respectively. A porous structure was formed with a specific surface of 2.61 m2/g, and a total pore volume of 0.0164 cm3/g. Further, the optimal conditions of high-temperature reoxidation roasting were 850 °C, 3 h, 35 % O2, and 600 ml/min. The best V2O5 leaching rate of the GORA was 68.89 %, which was 36.23 % higher than that of the raw ore. It was discovered that stone coal could withstand high temperatures without sintering after preliminary roasting. High-temperature reoxidation is a prerequisite for destroying the lattice of vanadium-bearing minerals and promoting vanadium release. Meanwhile, the loose and porous honeycomb particle products promoted subsequent gas–solid and liquid–solid reactions. Therefore, this study provides a novel and effective method for extracting vanadium from stone coal.