Roasting Process Research Articles

Calcium Chromates’ Formation Behaviors in the Oxidative Roasting Process and Their Leachability in Ammonium Carbonate Solutions

Calcium Chromates’ Formation Behaviors in the Oxidative Roasting Process and Their Leachability in Ammonium Carbonate Solutions

Edible Alginate–Lecithin Films Enriched with Different Coffee Bean Extracts: Formulation, Non-Cytotoxic, Anti-Inflammatory and Antimicrobial Properties

The aim of this study was to analyze the functional properties of newly obtained films based on sodium alginate and lecithin with the addition of antioxidant-rich coffee extracts and to verify their potential as safe edible food packaging materials. In our study, we developed alginate–lecithin films enriched with green or roasted coffee bean extracts. The roasting process of coffee beans had a significant impact on the total phenolic content (TPC) in the studied extracts. The highest value of TPC (2697.2 mg GAE/dm3), as well as antioxidant activity (AA) (17.6 mM T/dm3), was observed for the extract of light-roasted coffee beans. Films with the addition of medium-roasted coffee extracts and baseline films had the highest tensile strength (21.21 ± 0.73 N). The addition of coffee extract improved the barrier properties of the films against UV light with a decrease in the transmittance values (200–400 nm), regardless of the type of extract added. Studies on Caco-2, HepG2 and BJ cells showed that digestated films were non-cytotoxic materials (100–0.1 μg/cm3) and had no negative effect on cell viability; an increase was noted for all cell lines, the highest after 48 h in a dose of 1 μg/cm3 for a film with medium-roasted coffee (194.43 ± 38.30) for Caco-2. The tested films at 20% digestate concentrations demonstrated the ability to reduce nitric oxide (NO) production in the RAW264.7 cell line by 25 to 60% compared to the control. Each of the tested films with coffee extracts had growth inhibitory properties towards selected species of bacteria.

Roasted sesame oil: A review on production technology, flavor chemistry, and other related issues

AbstractSesame oil (SO) produced through roasting technology offers pleasant flavor, often named roasted sesame oil (RSO) in the market. During the RSO production process, roasting is an essential technology in determining the flavor of RSO, which directly influences the consumer acceptance. Therefore, the present work systematically offers current knowledge on flavors and related issues of RSO, which will focus on production technologies (i.e., roasting technology, extraction technology, subsequent processing technology), flavor characteristics and flavor compounds, formation pathways of major flavor compounds (i.e., Maillard reaction pathway, oil oxidation pathway, thermal degradation pathway), and effects of roasting on the nutrition and safety. In addition, the present work provides an outlook for the future development of RSO industry, including the establishment of a grading system for the evaluation of RSO flavors, high‐value utilization of by‐products from RSO processing, and how to improve production efficiency of RSO. This work could provide a better understanding of RSO roasting process and promising information for better production of aromatic, nutritious and safe RSO by controlling/innovating the roasting process.

Sintering Behavior of Molybdenite Concentrate During Oxidation Roasting Process in Air Atmosphere: Influences of Roasting Temperature and K Content.

Sintering is a common phenomenon, which often takes place during the oxidation roasting process of molybdenite concentrate in multiple-hearth furnaces. The occurrence of sintering phenomena has detrimental effects on the product quality and the service life of the furnace. In this work, the influence of two key factors (roasting temperature and K content) on the sintering behavior is investigated using molybdenite concentrate as the raw material. Different technologies such as XRD, FESEM-EDS, and phase diagrams are adopted to analyze the experimental data. The results show that the higher the roasting temperature is, the greater the mass loss and the more serious the sintering degree will be. The results also show that with the increase in K content, the mass loss of the raw material is first increased and then decreased, while its sintering degree is still gradually increased. The sintering products obtained during the oxidation roasting process are often tightly combined with the bottom of the used crucible with a smooth and dense surface structure, while their internal microstructures are very complicated, which not only includes numerous MoO3 species, but also unoxidized MoS2, Mo sub-oxide, SiO2, and a variety of molybdates. Among them, both MoO3 and molybdates can be easily dissolved into the ammonia solution, leading to a residue mainly composed of SiO2 and CaMoO4. This study also finds that the sintering phenomenon is caused by the increase in local temperature and the formation of various low-melting-point eutectics. It is suggested that decreasing the roasting temperature and K content, especially the K content, are effective methods for reducing the sintering degree of molybdenite concentrate during the oxidation roasting process.

Roasted and Unroasted Cocoa Nibs: Bioactive Compounds Analysis and Application in Cereal Bars.

Cocoa beans contain a variety of nutritional compounds and are rich in biologically active substances. The aim of this study was to utilize cocoa nibs (roasted and unroasted) as the main ingredient in the development of an attractive and convenient product. The produced nibs were analyzed for total phenolics, flavonoids, and antioxidant capacity using DPPH, ABTS, and FRAP methods. The primary phenolic compounds and methylxanthines were analyzed by LC/MS. Subsequently, cereal bars were developed, including a control sample (without nibs) and five formulations containing 41% nibs, using various proportions of roasted and unroasted nibs. The influence of the origin of the beans on the product characteristics was also evaluated. The results showed that the roasting process led to a reduction in epicatechin, caffeine, and caffeic acid. Furthermore, the reduction in total phenolics, flavonoids, and antioxidant capacity after roasting was more pronounced in beans from Bahia compared to those from Espírito Santo. Regarding the cereal bars, the results demonstrated that using cocoa from Bahia, the formulation with a higher proportion of unroasted nibs (F80) significantly increased the total phenolic content (1968.85 mg of gallic acid/100 g) and total flavonoids (39.26 mg of quercetin/100 g). This initial study suggests that the use of cocoa nibs as a functional ingredient in cereal bars may be a viable and advantageous option for creating a product with greater antioxidant potential.

Thermal decomposition behavior and kinetic mechanism of waste phosphors during sodium hydroxide roasting

Waste phosphors are critical rare earth secondary resources, and their recycling can help alleviate the depletion of rare earth mineral resources. However, stable Al–Mg spinel structures exist in waste phosphors. The direct acid leaching method remains difficult to use for leaching cerium and terbium. In this paper, the waste phosphors were first pretreated via alkali roasting. NaOH was used as an alkali roasting agent, thus achieving the decomposition of the Al–Mg spinel structure. On the basis of thermodynamic calculations, thermal decomposition experiments were performed. The results showed that when the temperature was greater than 500°C, the waste phosphors could be decomposed into MgO, Eu2O3, Y2O3, CeO2, Tb4O7, NaAlO2, and BaO. The Ce3+ and Tb3+ in the waste phosphors were partially oxidized to Ce4+ and Tb4+, respectively, during the roasting process. The BET surface area and the average pore diameter for the roasted products also increased. Under the conditions of roasting temperature at 900°C, NaOH/sample mass ratio of 2.5, and roasting time of 150min, the leaching efficiencies of Y, Eu, Ce, and Tb could reach 99.4%, 99.1%, 98.5%, and 98.8%. The decomposition process of waste phosphors conformed to the unreacted shrinking core model. In addition, the conversion processes of Ce and Tb depended on the chemical reaction. The results may provide a new direction of development for the resource utilization of waste phosphors.

Quantitative Lipidomics Reveals the Effects of Roasting Degree on Arabica Coffee Beans Lipid Profiles

Lipids in coffee beans undergo morphological changes and migration during the roasting process, but the impact of roasting intensity on lipid profiles remains unclear. The lipidomics characteristics of coffee beans with different degrees of roasting (unroasted green beans, light roast, medium roast, and dark roast) were compared using ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS). A total of 571 lipid metabolites were identified, encompassing 25 species of fatty acyls (FA), 142 species of glycerophospholipids (GP) across 12 subclasses, 42 species of sphingolipids (SP) across four subclasses, 360 species of glycerolipids (GL) across ten subclasses, and two species of prenol lipids (PR). GL content was found to be the highest, followed by FA and GP. Through multivariate analysis, 160 lipids were identified that exhibited significant differences among beans with different degrees of roasting. GP content was significantly influenced by the degree of roasting (p<0.05), with diverse dynamic evolution observed through K-means cluster analysis. These findings have important implications for understanding lipid transformation and its effect on the flavor profile during coffee roasting.

Improving flavor of strong fragrant rapeseed oils by supplementing commercial peptides and sugars

The strong fragrant rapeseed oils (SFROs) attract an increasing consumers' preference due to their strong flavor and attractive appearance. With the accumulated knowledge of flavor formation pathways during producing SFROs, the present study proposed a novel method to enhance SFRO's flavor by directly adding the reducing sugars (glucose and xylose) and commercial peptides during roasting process. Results indicated that supplementation of 3 % rapeseed peptide, 1 % glucose and 0.5 % of xylose gave an attractive color of SFRO with highest red value of 6.5, highest sensory score, enhanced nutty and roasted fragrance and distinguishing sweet flavor. The contents of typical volatile compounds such as pyrazines and furans in R-SFRO also showed the highest levels, proving that addition of the commercial peptide and reducing sugars as the Maillard reaction substrates could significantly enhance the flavor. Additionally, the proposed method showed potency for the large-scale application due to the simple steps, and low-cost input.

Diagnosis and prognosis of soybean roaster failures using particle swarms

In industry, the monitoring and diagnosis of production processes are crucial issues in ensuring plant reliability, performance and quality. In particular, food processing operations, such as coffee roasting, are subject to numerous risks of failure that can impact on productivity and the quality of the final product. In this context, the main objective of this study was to develop an innovative method for the diagnosis and prognosis of failures in a coffee roasting process. The proposed method differs from standard approaches by using the particle swarm optimization (PSO) algorithm applied to the analysis of signatures of key process variables. This new approach has improved fault detection, with a recognition rate of over 90% for the main types of fault identified, such as heating problems, air obstructions or leaks. In addition to diagnostics, the method has also demonstrated its effectiveness in prognosticating the state of health of the process, with an average error on the prediction of remaining service life reduced to 15%, compared with 35% for fixed-threshold methods. This work has therefore enabled us to develop an innovative method offering superior performance to standard approaches for the diagnosis and prognosis of failures in the roasting process.

Product Development and Positioning Strategies for Seaclues Local Coffee

Seacules Coffee Shop uses psychographic, demographic, and behavioral factors to segment the market. Seaclues Coffee Shop's target market includes consumers between the ages of 18 and 45 who lead an active lifestyle and work as professionals or students. Seaclues Coffee Shop's goods are presented as premium coffee beverages. Seaclues serves high-quality coffee beans that have been roasted by a roaster. Coffee is served to customers with high quality services provided in a comfortable atmosphere. By implementing the right positioning strategy, Seaclues Coffee Shop can attract and retain the right customers, increase customer satisfaction, and build long-term loyalty. To respond to the dynamic market, Seaclues Coffee Shop has carried out product development by creating unique and high quality product variants. The quality of Seaclues coffee products comes from high quality coffee beans that go through a roasting process before being processed for serving. Seaclues Coffee Shop develops innovative and unique coffee products by utilizing spices. Accurate positioning and product development help Seaclues Coffee Shop create quality products that are different from competitors, which strengthens Seaclues Coffee Shop's presence in a competitive market.

Roasted Astragalus membranaceus Inhibits Aβ25–35-Induced Oxidative Stress in Neuronal Cells by Activating the Nrf2/HO-1 and AKT/CREB/BDNF Pathways

(1) Background: Astragalus membranaceus (AM) has antioxidant and anti-inflammatory effects, but its specific mechanism of action in the brain is still unclear. In this study, we developed a roasting process to maximize the cognitive improvement impact of AM. We focused on enhancing physiological activity to enhance the brain neuron protection effect and alleviate neuronal damage caused by neurodegenerative diseases. (2) Methods: AM was roasted at 260 °C for 20, 30, or 40 min, and the hot water extracts were tested on HT22 cells for ROS levels, apoptosis, and antioxidant protein expression. The effect on the BDNF-AKT-CREB pathway under stress was also analyzed. (3) Results: Roasted AM decreased ROS production and the expression of apoptosis-related factors while activating the expression of antioxidant proteins in HT22 cells treated with Aβ25–35. In particular, 30 min roasting (R-AM2) significantly reduced ROS production, inhibited cell death, and increased antioxidant protein expression. The Nrf2 pathway was activated Bax, and cleaved caspase-3 levels were reduced. BDNF and p-CREB expression were increased by 20% and 50–70%, respectively. In the MAPK pathway, p-ERK levels were increased by 30%, and p-P38 levels were increased by approximately 20%. (4) Conclusions: These findings suggest that roasted AM upregulates brain-derived neurotrophic factor (BDNF) in HT22 cells, providing neuroprotective effects by activating the AKT/CREB/BDNF pathway and inhibiting neuronal apoptosis. Therefore, roasted AM shows potential as a neuroprotective agent for preventing or treating neurodegenerative diseases, such as Alzheimer’s, linked to BDNF deficiency.

Study on recovering the scattered metals from coal gangue by low-temperature activation and two-stage selective leaching

As metal deposits are developed on a large scale and at high intensity, the strategic metals under “protective measures” will inevitably face resource depletion. It becomes particularly important to sustainably and stably maintain the supply of strategic metals. A method is proposed to selectively extract Li and Ga from coal gangue through a process of ammonium sulfate roasting followed by stepwise leaching. Li and Ga in coal gangue are converted into metal sulfates or ammonium sulfates through low-temperature roasting, and then selectively extracted through a water-acid combined stepwise leaching process. Under the conditions of 450 °C and 2 h, with a coal gangue to ammonium sulfate ratio of 1:2.5, the leaching rates of lithium and gallium reach 88.35 % and 90.28 %, respectively. During the roasting process, ammonium sulfate decomposes into ammonium hydrogen sulfate, which enters the core through the pores of gangue and reacts with kaolinite to enhance activation. Li is converted into lithium sulfate ammonium and extracted through aqueous solution leaching, while metal gallium is first converted into gallium sulfate ammonium and then, with increasing temperature, into ammonium sulfate and extracted through dilute acid leaching.

A Comparison Study on the Recovery of REEs from Red Mud by Sulfation Roasting–Water Leaching and Citric Acid Leaching

In this study, the recovery of rare earth elements (REEs) from red mud (bauxite residue) was explored through a combination of citric acid leaching and sulfation roasting–water leaching processes, introducing an innovative approach to the field. The research uniquely investigates the influence of citric acid on the leaching behavior of REEs and impurities in both untreated red mud and red mud subjected to sulfation roasting, providing a direct comparison of these methodologies. A novel aspect of this study is the evaluation of solvent extraction efficiency using DEHPA, highlighting the selective recovery of REEs over impurities from both citric acid and water-leaching solutions. Furthermore, a comprehensive phase analysis using X-ray diffraction (XRD) was conducted to track the transformations of minerals during the sulfation roasting process, an original contribution to the literature. The findings revealed that over 85% of REEs and major elements such as Fe, Al, Ca, and Ti dissolved in water after sulfation at 105 °C, while iron and titanium dissolution significantly decreased following roasting at 725 °C. Importantly, terbium, neodymium, and gadolinium extraction efficiencies were notably affected by roasting temperature. Citric acid leaching results demonstrated that the direct leaching of red mud leads to higher leaching efficiency than leaching it after the roasting process. Solvent extraction demonstrated lower terbium and neodymium recovery from citric acid solutions compared to water leaching solution. Finally, stripping experiments illustrated that 6M H2SO4 solution is capable of stripping more than 80% of rare earth elements, except terbium.

Water-aerosol-assisted roasting for selective lithium extraction from spent lithium-ion batteries

Selective extraction of lithium from spent lithium-ion batteries (LIBs) represents a promising solution for efficient lithium recovery. Herein, a water-aerosol-assisted roasting technology is proposed to selectively extract lithium from spent lithium transition metal oxides (LTMOs) cathodes. In an exemplary recycling of spent LiCoO2, the cathode material undergoes a low-temperature (350°C) chlorinating roast process to convert it into metal chlorides, followed by a higher-temperature (500°C) roasting to facilitate the selective pyrolysis of CoCl2. The presence of water-aerosol significantly enhances the selective pyrolysis process of CoCl2, reducing roasting time eightfold compared to conventional air roasting. Subsequent water-leaching effectively extracts 99.1 % of lithium as LiCl, while only 0.2 % of cobalt is extracted, ensuring selective lithium recovery. The resulting high-purity LiCl solution and Co3O4 residue are directly utilizable for producing battery-grade Li2CO3 and LiCoO2, respectively. Regenerated LiCoO2 demonstrates excellent cycling stability, retaining 90.5 % of its capacity after 300 cycles at 1C rate. Moreover, this method is applicable to ternary cathodes (NCM) black mass, offering a sustainable, robust, and cost-effective approach for lithium extraction from spent LIBs.

INVESTIGATION OF CONVENTIONAL AND MICROWAVE COMBINED ROASTING EFFECT ON THE PHYSICOCHEMICAL, TEXTURAL AND SENSORY PROPERTIES OF SUNFLOWER SEED

In this study, conventional, microwave, and also a combination of these two methods were applied to compare the quality properties of sunflower seeds. Alternative to conventional roasting at 160°C, microwave roasting at two different powers (300W and 600W) and also microwave with conventional roasting treatment (300 W+160°C, 600 W+160°C) were applied to raw sunflower seeds during 5 and 10 min. for each group. The moisture content of roasted seeds was found to be lower than 6%. The results show that the highest protein and fat content were found in the group of combined methods as 21.09±6.64 and 40.55±0.345% respectively. Additionally, the color values were found to be higher, and hardness and sensory characteristics were protected better after roasting compared to the control (unroasted) group. Roasting of microwave at 600W power for 5 min at 160°C was found to be advantageous for the roasting process of sunflower seed via these properties.

Sulfur fixation performance of calcium-bearing carbonates in iron ore roasting process: Thermodynamics, phase transition, microstructure evolution, and kinetics

Roasting technology is increasingly used in the beneficiation of refractory iron ores. During the roasting process, the presence of pyrite in some iron ores leads to the formation of SO2, requiring effective sulfur fixation techniques. This study proposed an innovative in-situ sulfur fixation method by pre-oxidation roasting, in which sulfur was fixed during the oxidation roasting process before reduction roasting. The effects of the main iron mineral (hematite), primary gangue mineral (quartz), and common calcium-containing carbonate minerals (calcite and dolomite) on sulfur migration during pyrite roasting were investigated, with particular emphasis on the sulfur fixation capabilities of calcite and dolomite. The study included thermodynamic equilibrium analysis, phase transitions and microstructural evolution in different reaction systems. The results showed that calcite and dolomite effectively reduced SO2 emissions by forming CaSO4 and MgSO4, with calcite exhibiting a stronger sulfur fixation capacity for the same mass. Kinetic analysis indicated that pyrite pyrolysis followed a two-step random nucleation and growth model. Furthermore, the addition of calcite increased the apparent activation energy of SO2 formation and altered the reaction pathway, providing insight into the sulfur fixation mechanism of calcite from a kinetic perspective.

Assessment of the impact of microwave roasting on nutrient content, lipid profile, and oxidative stability of pomegranate seed oil

The pomegranate, Punica granatum L. (Punicaceae), stands as one of the most widely employed oils in the cosmetic industry. However, due to its higher content of conjugated linoleic acid, its susceptibility to oxidation is a major challenge, with the most prominent being punicic acid. This study aimed to evaluate the effects of traditional roasting in a microwave on the lipid content, nutritional value, and oxidative stability of Moroccan pomegranate seed oil. The findings indicated a rise in the amount of oil after 15 min of roasting at 650 W, the amount of oil rose from 27.03 to 30.10 (g/100 g). However, the protein content, UV absorbance values, iodine, and saponification values were not significantly affected by a longer roasting time. The peroxide value increases with roasting (1.00 to 5.00 M.eq. O2/kg oil). The roasting process under 350 W did not significantly alter the fatty acid composition. The total tocopherol content exhibits a decrease with increasing roasting time and power, ranging from 333.36 mg/100 g for unroasted seeds to 316.84 mg/100 g for seeds roasted under the conditions of 650 W for 15 min. The roasting process has proven to be critical for the immediate and long-term preservation of the nutritional and physico-chemical properties of pomegranate seed oil.

Tin separation and recovery using the successive conversion of the self-possessed sulfur from low-grade tin middling

Low-grade tin middlings generated from mineral processing of tin tailings are composed of high contents of arsenic and tin, which pose a huge threat to environmental safety if not properly disposed. An approach of arsenic and tin separation from it using a combined roasting process was proposed in this work. First with oxidizing roasting, FeAsS from the tin middling was decomposed to As4 (g) and oxidized to As4O6 (g), achieving the arsenic separation of 97.1%. More importantly, sulfur in FeAsS was oxidized to iron sulfate and retained in the residue, which could be used as curing reagent for tin separation in the followed self-sulfurization roasting. However, massive SO2 (g) generated from the decomposition of iron sulfate volatilized before it sulfurizing SnO2 in the roasting, causing a low tin recovery. CaO could convert iron sulfate to CaSO4, slow the release of SO2 (g) and insure a high S/Sn ratio in the roasting. Moreover, CaO decreased the residue sintering by converting FeS-FeO to Ca2Fe2O5, CaFeO2 and CaS. Tin recovery was promoted and could obtain 98.2%. This study provides a new technical route for the separation and recycle of arsenic and tin from a hazardous material of low-grade tin middling.

Study on the Sulfuric-Leaching Kinetics of Germanium from Zinc Oxide Dust Assisted by Microwave Roasting

Abstract The Ge-bearing zinc oxide dust (ZnO) is commonly leached by sulfuric acid in industry, but the leaching percentage of Ge is only &lt; 60%. To date, there is no suitable industrial process to address this problem. Thus, a novel process of microwave roasting followed by sulfuric acid leaching of Ge from ZnO dust is proposed to further improve Ge extraction from ZnO dust, and the kinetics behaviors and related theoretical models are studied. Results reveal that Ge leaching percentages are markedly increased by microwave roasting, the reaction kinetics follow the shrinking core model of the diffusion process of the solid film, and the apparent activation energy is 2.28 kJ/mol.

Targeting protein aggregation using a cocoa-bean shell extract to reduce α-synuclein toxicity in models of Parkinson's disease

Neurodegenerative diseases are among the major challenges in modern medicine, due to the progressive aging of the world population. Among these, Parkinson's disease (PD) affects 10 million people worldwide and is associated with the aggregation of the presynaptic protein α-synuclein (α-syn). Here we use two different PD models, yeast cells and neuroblastoma cells overexpressing α-syn, to investigate the protective effect of an extract from the cocoa shell, which is a by-product of the roasting process of cocoa beans. The LC-ESI-qTOF-MS and NMR analyses allow the identification of amino acids (including the essential ones), organic acids, lactate and glycerol, confirming also the presence of the two methylxanthines, namely caffeine and theobromine. The present study demonstrates that the supplementation with the cocoa bean shell extract (CBSE) strongly improves the longevity of yeast cells expressing α-syn, reducing the level of reactive oxygen species, activating autophagy and reducing the intracellular protein aggresomes. These anti-aggregation properties are confirmed also in neuroblastoma cells, where CBSE treatment leads to activation of AMPK kinase and to a significant reduction of toxic α-syn oligomers. Results obtained by surface plasmon resonance (SPR) assay highlights that CBSE binds α-syn protein in a concentration-dependent manner, supporting its inhibitory role on the amyloid aggregation of α-syn. These findings suggest that the supplementation with CBSE in the form of nutraceuticals may represent a promising way to prevent neurodegenerative diseases associated with α-syn aggregation.