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An innovative process combining roasting and tempering was proposed to promote puffing and mechanical dehulling of jicaro seeds. Roasting was performed at three temperatures (120 °C, 140 °C, and 160 °C) and for six residence times (80–180 s). A previous seed tempering was performed at 15% moisture content for 24 h, by spraying the seeds with an amount of water calculated to reach the final moisture content of 15%. The following parameters were monitored as a function of time to optimize the roasting operation: percentage of open seeds, whiteness of cotyledons, and content of two volatile compounds, 2,5-dimethylpyrazine and ethyl-2-methylbutyrate which are considered as the key jicaro note. The optimal roasting was achieved at 160 °C for 150 s with 90% open seeds. The optimal mechanical dehulling was achieved after tempering the roasted seed at 10% moisture content with a yield of 75%. The lightness evolution followed a zero-order kinetic with an activation energy of 103 kJ mol −1 . Ethyl-2-methylbutyrate and 2,5-dimethylpyrazine increased with the temperature and period of roasting. [ABSTRACT FROM AUTHOR]

We investigated coffee beans porosity to demonstrate its effects on predicting heat and mass transfer during roasting. Calculated porosity from experimental data from electronic microscopy pore size and distribution for green bean and roasted beans were evaluated. Porosity of 9.8% and 34.2% for green and roasted beans were found. These values defined the limits of a dynamic model, which was developed and introduced as subroutine into a 3-D modeling of coffee roasting. Hot air at 473 K and 503 K roasted single and group beans during 200 s for fixed Reynolds number. Modeled and experimental data of temperature from Arabica bean agreed well. It was observed that porosity affected heat and moisture loss rate during roasting. The results can help to understanding the roasting process, or studying processes of food products that require roasting by means of hot air, like grains or seeds. [ABSTRACT FROM AUTHOR]

The uniqueness and consistency of commercial food and beverage brands are critically important for their marketability. Thus, it is important to develop quality control tools and measures, so that both companies and consumers can monitor whether a given food product or beverage meets certain quality expectations and/or is consistent when purchased at different times or at different locations. In this study, we characterized the consistency (levels of extractable protein and reducing sugars) of 15 brands of roasted coffee beans, which were obtained from a supermarket at two dates about six months apart. Coffee brands varied markedly in extractable protein and reducing sugar contents between dates, and also within and among roasting classes (light, medium, medium-dark, and dark roasts). We acquired hyperspectral imaging data (selected bands out of 220 narrow spectral bands from 408 nm to 1008 nm) from ground samples of the roasted coffee beans, and reflectance-based classification of roasting classes was associated with fairly low accuracy. We provide evidence that the combination of hyperspectral imaging and a general quality indicator (such as extractable protein content) can be used to monitor brand consistency and quality control. We demonstrated that a non-destructive method, potentially real-time and automated, and quantitative method can be used to monitor the consistency of a highly complex beverage product. We believe the results from this study of brand consistency are not only of relevance to the coffee industry but to a wide range of commercial food and beverage brands. [ABSTRACT FROM AUTHOR]

Food microstructure influences the characteristics of end products. X-ray micro-computed tomography (μCT) enables investigating internal structure of food products non-destructively. High-resolution X-ray μCT, in combination with image analysis, was used to visualise and quantify the impact of conventional oven and forced convection continuous tumble (FCCT) roasting (180 °C for 140 s) on the microstructure of whole wheat kernels. After image acquisition, two-dimensional (2D) cross-sectional images were reconstructed into three-dimensional (3D) volumes. Quantitative parameters, i.e. volume, porosity, expansion ratio (ER) and relative density, were calculated. Oven roasting was associated with a significantly ( P < 0.05) larger increase in kernel volume (4.47%) than FCCT roasting (1.57%). Porosity was higher in the oven-roasted samples (10.33 ± 4.63%), indicating a more destructive impact on the internal structure (FCCT = 8.29 ± 2.29%). Roasting introduced cavities and cracks within the wheat kernels, resulting in a decrease in whole kernel density (oven = 2.76%; FCCT = 0.55%), however the material density remained unaffected during FCCT roasting. [ABSTRACT FROM AUTHOR]

This study aimed to analyze experimentally and by modeling the shrinkage deformation of Japanese eggplant ( Solanum melongena ) during roasting by simultaneous heat and moisture transport model coupled with a structural mechanics model applicable to a body undergoing volumetric changes, as a consequence of moisture removal. Cylindrical slices (45 mm × 10 mm) were roasted for up to 15 min. Roasting experiments were performed using a convection-oven at 250 °C. Several coefficients and parameters required for calculations were experimentally obtained. An implicit finite element method was applied using a FORTRAN program. In this study, an approximately equal reduction rate in moisture content losses and volume shrinkage was observed ( R 2 ≥ 0.99). The volumetric ( S v ) and directional shrinkage were successfully estimated by developed empirical equations (e.g. R 2 > 0.98 for S v ). The simulation of temperature and moisture distribution undergoing shrinkage deformation confirmed the importance of internal evaporation in the transport model. [ABSTRACT FROM AUTHOR]

A three cylindrical roll crusher was used in this study to solve the comminution problem and to improve oil and protein yields in aqueous extraction processing (AEP) of peanuts. We combined confocal laser scanning microscopy (CLSM) and particle size distribution analysis to investigate the effect of different peanut processing material on oil and protein extraction. A proper roasting treatment (150 °C) is beneficial to oil extraction yield. However, the protein yield has been declining from 84.33% to 51.40% with the increase of roasting temperature from (130 °C–210 °C). The optimal average particle size of peanut paste in AEP was 15.2 μm which could hardly find intact oil bodies by CLMS. Nevertheless, the remained intact of protein body still could be found in insoluble fraction. In AEP, highest free oil yield (92.2%) was achieved with roasted peanut (150 °C, 20 min) using 1: 5 solid to liquid ratio (twice ground peanut pastes/water), pH 9, 60 °C for 2 h and demusification by adding 0.5% (w/w) Protex 50FP at pH 4.5 and incubating at 50 °C for 2 h. Without roasting treatment, the oil contents of insoluble and residual cream fractions from AEP were highly correlated with their protein contents (R 2 = 0.8724, 0.9178, respectively). Additionally, the exposure of interior hydrophobic groups of peanut protein adhere more oil to the protein body surface, which may have led to increment in the oil content of insoluble fraction. [ABSTRACT FROM AUTHOR]

The aim of this work was to compare different texture test conditions for the evaluation of instrumental mechanical and acoustic properties of raw and roasted hazelnut ( Corylus avellana L.) kernels cv. Tonda Gentile Trilobata (TGT). A comparison of compression and shear tests, test speed (0.2, 1.0, 10.0 mm/s), and analyzed axis (x, y, z) combinations was performed. Joint mechanical and acoustic emission acquisitions were used for the first time on hazelnut kernels. The compression test method using 1.0 mm/s speed and analyzed on the x-axis showed the lowest variability of the results. These conditions were then used to evaluate raw kernels during 12 months of storage, conducted in-shell (at ambient temperature) and shelled (refrigerated, vacuum, frozen, with nitrogen modified atmosphere). The main differences among storage conditions were evidenced in rupture force, rupture slope and acoustic maximum peak parameters. [ABSTRACT FROM AUTHOR]

Non enzymatic browning (NEB) kinetics were studied at 125, 135 and 145 °C during a cocoa beans roasting process aimed to reach a final moisture content of 2 g 100 g −1 . Colour lightness and hue angle decreased with roasting time following a first and a zero order kinetic, respectively. Moisture content being equal, high temperature-short time (HTST) roasting processes minimized the extent of browning reaction. Melanoidins increased with roasting time following an asymptotic kinetic. Moisture content being equal, HTST processes maximized the melanoidins formation. The energy of activation of melanoidin formation (132 kJ mol −1 ) was higher than those of colour changes and polyphenol oxidation (between 60 and 80 kJ mol −1 ), thus NEB during roasting is not solely dependent on Maillard reaction occurrence. Hydroxymethylfurfural (HMF) increased exponentially with roasting time but its final content was low (0.1–0.8 g kg −1 ). HTST processes minimized the HMF formation, which was not temperature dependent and was influenced by concentration. [ABSTRACT FROM AUTHOR]

Thermal energy changes the chemical composition of cocoa, which is related to its quality, during roasting. The effect of the heating rate on the physicochemical changes of cocoa, and the dynamics of generation and degradation of volatile compounds during heating are still unknown. Therefore, the weight loss of cocoa and the chemical composition of the released gases released at temperatures from 40 to 350 °C were identified in using a μ-reactor (PTV-GC-MS) with heating rates of 2 (β 1), 4 (β 2), and 8 °C sec−1 (β 3). The thermal process was divided into three stages (raw ‒ dry, dry – roasted, and roasted – over-roasted). Higher heating rates cause lower volatilization at the same temperature due to shorter residence times. Likewise, more compounds were identified in the gas-fraction at β 1 than at β 2 and β 3 with the same temperatures. Also, a 2D phenomenological model coupled to kinetics was made to predict phenomena such as thermal differentials, water and gas content, solid fractions, conversion, pressure, and gas outlet rate. • Cocoa quality begins in the tree and develops in the processing. • Small-scale studies and modelling are valuable tools to understand cocoa roasting. • A 2D model coupled to kinetics was able to show experimentally invisible phenomena. [ABSTRACT FROM AUTHOR]

Abstract: A numerical model of the coffee roasting process under operating conditions is proposed. This numerical tool is able to simulate the behaviour of all the components of a batch roaster as well as the roasting process of the coffee beans within the drum. The model evaluates the heat and mass transfer between a hot air flow and the coffee beans during the roasting process on the basis of the physical properties of the coffee and the operation of the roasting machine. Different submodels are included in the modelling in order to address particular thermo-physical processes, such as the evaporation of coffee moisture and the heat released or absorbed by the beans due to the roasting reactions. The proposed numerical model is thus able to predict the performance of the coffee roaster in terms of pressure, temperature and mass flow rate in the main sections of the system, as well as fuel consumption. In addition, the temperature profile of the coffee beans within the roasting drum is evaluated as a function of the system’s working conditions. Different roasting machine control strategies can therefore be compared and the effects on the coffee roasting profile can be analyzed. Experimental data in the literature on a laboratory roaster are used as a reference to validate the results provided by the numerical model. Finally, the tool’s predictive capabilities are addressed by simulating an industrial coffee roasting machine. [Copyright &y& Elsevier]

Abstract: A validated mathematical model has been used to perform multi-objective optimization of beef roasting, considering the minimization of both cooking time and weight loss. Simulations were performed using irregular geometrics models of beef semitendinosus muscle and constant oven temperature. Minimum temperature of 72°C at the coldest point was imposed as a constraint. From model results a compromise situation was encountered, since no operative condition lead simultaneously to optimal values of both objectives, i.e., an increase in oven temperature leads to a decrease in cooking time, between −0.25 and −0.325min/°C, and an increase in weight loss, between 0.175 and 0.275%/°C. In this sense, not one, but a set of optimal solutions was found in the Pareto sense. Experimental cooking tests were performed, which are in good agreement with model simulations. Furthermore, energy consumption for each optimal solution obtained in the optimization problem was estimated, being lower using low oven temperatures. [Copyright &y& Elsevier]

Abstract: The present work reports on a microstructural characterization of Coffea arabica beans in the course of roasting by means of X-ray microtomography technique (μCT). In fact, the aim of this study is to demonstrate the capability of μCT as a useful tool for the characterization of microstructure of C. arabica beans at different roasting times: from green to very dark. μCT is a non-invasive technique that has the ability to image low moisture materials by using the differences in X-ray attenuation arising, mainly, from differences in density within the specimen. Green coffee beans were roasted and sampled at the following roasting times; 2, 3, 4 and 5min. Several parameters such as percentage object volume (POV), density, total volume and pore size distributions were calculated for each roasting time and their variations discussed. The results from this study show how the microstructure of the coffee bean evolves with increasing roasting time, for example, the increase in total pore volume, the increase in porosity and density due to the rupture of bonds in the internal structure of the coffee beans during roasting. μCT has proven to be a suitable technique for microstructural analysis of roasted foods such as coffee bean and provides an accurate analysis of the pores and microstructure during the roasting process. [Copyright &y& Elsevier]

Abstract: In this work a numerical model, based on a 3D geometry, able to describe the heat and moisture transfer inside a coffee bean during the roasting process, was developed. The model makes reference to a rotating cylinder roaster in natural convection conditions. For the multiphysics model development heat and mass transfer equations inside the coffee bean were numerically solved using a finite element technique. Two domain geometries were tested. One simplified, based on a simple semi-ellipsis, and one made acquiring the shape of an Arabica coffee bean using a 3D scanner. To validate the numerical model, green coffee bean was singularly roasted using a rotating drum roasters prototype. The calculated moisture concentration and time–temperature curves were then compared with the observed data. The calculated temperature values, in the centre of the bean, appear to be in good agreement with those measured inserting thermocouples into the coffee bean (RMSE 5.97°C). Similarly the calculated volume averaged moisture was in good agreement with the experimental data (RMSE 264.251mol/m3) over the entire time span. This model can be useful to optimise the roasting process control. [Copyright &y& Elsevier]

Abstract: The use of infrared (IR) heating for improving the microbial safety and processing efficiency of dry-roasted almonds was investigated. Almonds were roasted at 130, 140 and 150°C with three different methods: IR roasting, sequential infrared and hot air (SIRHA) roasting, and traditional hot air (HA) roasting. The heating rate and pasteurization efficacy of almonds under different roasting methods and temperatures were evaluated. Pediococcus sp. NRRL B-2354 was used as a surrogate for Salmonella enterica Enteriditis PT 30 for evaluating the pasteurization efficacy of different processing methods and conditions. When SIRHA roasting at 130, 140 and 150°C roasting temperatures was used to produce medium roasted almonds, 4.10-, 5.82- and 6.96-log, bacterial reductions were achieved with 38%, 39% and 62% time saving compared to HA roasting at each temperatures, respectively. The decimal reduction time of the bacteria at all roasting temperatures were calculated for SIRHA roasting as 8.68, 3.72 and 1.42min, respectively, with a correlation coefficient greater than 0.92 and the thermal resistance constant was found as 25.4°C. The total color change followed zero-order reaction kinetics and the activation energies were 73.58, 52.15 and 67.60kJ/mol for HA, IR and SIRHA roasting, respectively. No significant difference (p >0.05) was observed in sensory quality of medium roasted almonds processed with different roasting methods. We conclude that the SIRHA roasting is a promising new method for the production of dry-roasted pasteurized almonds. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a meat oven cooking model is developed, and its ability to predict three main process variables – evaporative loss, dripping loss and cooking time – is evaluated. Heat transfer is modelled by Fourier’s law, while the internal moisture content variation is modelled as a function of water demand, which depends on the water holding capacity of beef. Experimental cooking of semitendinosus muscle samples was carried out in a convective oven to obtain general information about the process and to assess the model accuracy. Simulations were done by means of the finite element method, using three-dimensional irregular geometries as simulation domains. The model predictions were in good agreement with the experimental ones; the average absolute relative error was 3.91% for cooking time prediction, and 7.96% for total weight loss prediction. [Copyright &y& Elsevier]

Abstract: Stress relaxation characteristics of moth bean (raw and roasted) flour doughs having different moisture contents were determined at two different strain levels (0.05 and 0.50). The decaying relaxation curves for raw flour showed an initial stress between 2 and 22kPa when the moisture content varied from 28% to 34% at a strain of 0.05. Roasted flour doughs exhibited initial stresses between 0.06 and 2kPa at moisture contents between 40% and 46%. Dough formation was not possible below 40% moisture content for roasted samples. An increase in moisture content markedly decreased initial and residual stresses. It is desirable that dough should possess a low value of residual stress when used for developing flattened/sheeted products. Models containing two or three parameters were found suitable for large-strain stress relaxation characteristics while low-strain data can be modelled by a 4-element Maxwell model with residual stress. [Copyright &y& Elsevier]

Abstract: The objective of the present study was to perform experimental and theoretical analyses of the process of roasting turkey breast slices in a steam-convection oven with a view to determining the optimal values of temperature and steam saturation during roasting, under the assumption of a constant slice thickness. The roasting process was conducted at air temperature of 160°C, 180°C, 200°C and 220°C and steam saturation of 0%, 20%, 50%, 70% and 90%. Two qualitative criteria based on eating quality and nutritive value have been applied in process optimization. Those criteria proved to be mutually opposing. As regards eating quality, the best product was that roasted at a temperature of 160°C without the application of steam in the oven. The same product was characterized by the lowest nutritive value. Nevertheless, it should be noted that the protein content of turkey meat, largely responsible for its nutritive value, is related to changes in protein concentrations in samples resulting from weight loss during cooking. The highest nutritive value was noted in respect of the product roasted at a temperature of 200°C with 20% steam saturation. Both optimal products were microbiologically safe. [Copyright &y& Elsevier]

Abstract: A 3-factor Box–Behnken experimental design was applied to study the effects of operative conditions on hazelnut color and texture in a two-step roasting process, with the first step carried out under moist conditions. The analysis of effects and the response surface models showed that, in the chosen experimental conditions, the only significant factor was the treatment time of the second step, which affected both hazelnut texture and color. The ultrastructures of a selected design sample, roasted under moist or dry conditions in the first step, were compared to that of a conventional roasted sample. The accelerated storage of these three samples highlighted that the first step, carried out under the selected moist conditions, leads to a delay of peroxide formation. The increased preservation of cellular integrity observed by scanning electron microscopy and, possibly, the content of tocopherols both seemed to contribute to the extension of hazelnut shelf-life. [Copyright &y& Elsevier]

Abstract: The presence of defective coffee beans is known to depreciate the quality of coffee beverage consumed worldwide. These beans represent about 15–20% of the total coffee produced in Brazil and, although they are separated from the non-defective beans, they are still commercialized in the coffee trading market. Thus, it was the aim of this work to verify if physical characteristics provide an effective discrimination of defective and non-defective coffees of both Arabica and Robusta species, before and after roasting. The evaluated parameters were size (volume), density and color. The results obtained in the present study showed that, within a given coffee species, defective beans can be separated from non-defective ones by sieving, before roasting. In the case of Arabica coffees, size separation between non-defective and defective can also be accomplished after roasting. Prior to roasting, color separation will be effective for Robusta coffees, but ineffective for separation of non-defective, immature and light sour Arabica beans. [Copyright &y& Elsevier]

Abstract: The objective of this study was to analyze the volatile profiles of both green and roasted coffee beans, for assessment of roasting degrees under two different processing temperatures. Volatiles extraction and concentration were performed by solid phase micro-extraction (SPME) of the ground coffee headspace and analysis of the volatiles profile was performed by GC–MS. Four SPME fibers were evaluated, with the one that extracted the highest amount of substances (DVB/CAR/PDMS) being selected. Statistical analysis of the data by principal components (PCA/clusters) showed that the volatile components profile provided separation of green and roasted coffees and also separation according to roasting degree and roasting temperature. Results also indicate that color and weight loss measurements alone are not reliable for roasting degree assessment. [Copyright &y& Elsevier]

Abstract: In this study, the possibility of using microwave–infrared combination oven for roasting of hazelnut was investigated. In addition, regression models for the responses: L* value, a* value, textural properties and moisture content of hazelnuts were obtained and the optimum roasting conditions were determined by using response surface methodology. Conventionally roasted hazelnut at 150°C for 20min was considered for comparison. For hazelnuts, 2.5min roasting time at 90% microwave power, 60% upper halogen lamp power, and 20% lower halogen lamp power were found to be optimum roasting conditions. Hazelnuts roasted at this optimum point had comparable quality with conventionally roasted ones with respect to color, texture, moisture content and fatty acid composition. [Copyright &y& Elsevier]

Abstract: The radical scavenging activity (RSA) of coffee brews obtained from different types of coffee was studied as a function of the roasting degree and equivalent thermal effect (expressed as ), and the relative contribution of the phenolic fraction (PF) and non-phenolic fraction (NPF) to the overall RSA was evaluated. Brews extracted from medium roasted coffee showed a higher RSA than those from green coffee due to an increase of the RSA of the NPF upon roasting. The RSA of the NPF increased with increasing roasting degree together with the accumulation of brown coloured Maillard reaction products (MRPs). Brews from dark coffee showed lower RSA than those from medium roasted coffee due to polyphenols degradation which, in turn, caused an RSA depletion not counterbalanced by an increase of the RSA of NPF. The relative contribution of NPF to the overall RSA of the brew is in fact much lower than that of the PF. Roasting processes with similar values resulted in the same RSA independent of an average temperature variation from 170 to 190°C and coffee type. The AOA changes in brews from commercial coffee samples (medium and dark roasted) were more dependent on roasting severity than on the type of coffee. [Copyright &y& Elsevier]

Abstract: Roasting is normally done to enhance the flavour and to improve organoleptic properties of the food grains. Roasting is a high temperature short time (HTST) heat treatment process and the temperatures used are normally in the range of 280–350°C. In the present study a continuous fluidized bed roaster (FBR) using flue has been designed and used to roast wheat grain. The product obtained thus has been compared to that obtained by using a traditional method, i.e., roasting in a bed of hot sand. Parameters such as moisture content, bulk density, product colour, crispness, microstructure, and total and acid insoluble ash, are considered in the study. Sand contamination in traditionally roasted wheat has been shown by the presence of acid insoluble ash (0.12%). The bulk density decreased from 833kg/m3 for raw wheat to 526 and 555kg/m3 for sand and fluidized bed roasted wheat, respectively. The moisture content decreased from 10% to 3% for sand as well as fluidized bed roasted wheat. Colour (expressed as Chroma) of the sand roasted wheat was in the range of 18–32 and that of the fluidized bed roasted wheat 23–32. Textural measurements in terms of compressive strength was between 222–331N and 129–299N for sand and fluidized bed roasted wheat, respectively. It is noted that the optimally roasted wheat using FBR has peak force of 30N with colour (Chroma) value of about 31, total ash of 1.2% and acid insoluble ash of 0.04%. SEM images of the microstructure have indicated FB roasted wheat to have greater porosity which will result in this wheat requiring lower energy for size reduction. [Copyright &y& Elsevier]

Abstract: The effects of particle size, fermentation, roasting time and roasting temperature of cocoa nibs on cocoa butter extraction using supercritical fluid technology were studied. The effect of particle size was studied using cocoa liquor (D =0.074mm), ground cocoa nib (D =0.25–0.50mm and 1.0–1.2mm) and whole cocoa nibs at 35MPa, 60°C and flow rate of 2ml/min using supercritical carbon dioxide (SC-CO2). The effect of degree of fermentation was studied using unfermented, partly fermented and fermented cocoa, whereas the effect of roasting using roasted and unroasted cocoa nibs. Fermentation and roasting studies were conducted under the same operation conditions as particle size study using SC-CO2 but with ethanol (25% w/w) as cosolvent. Cocoa butter extracted from the three studies was analyzed for total fat content (%), triglycerides and fatty acid methyl ester. The results showed that the extraction yield was significantly increased by a reduction in particle size. The highest yield was also obtained using unfermented cocoa, roasted for 35min and at 150°C. Generally, cocoa butter had similar triglycerides and fatty acid methyl ester composition at 5, 10 and 15h extraction time. Glycerol-1,3-dipalmitate-2-oleate (POP), glycerol-1-palmitate-2-oleate-3-stearate (POS), and glycerol-1,3-distearate-2-oleate (SOS) account for most of the triglycerides, with POS (42.52–46.44%) being the major component. Palmitic, stearic and oleic were the main fatty acids in the extracted cocoa butter, with stearic acid being the highest component (33.70–40.22%). [Copyright &y& Elsevier]

Abstract: This work is the application of SAFES technique for roasting bean coffee. The roasting operation was divided in to three changing stages, determined with the beginning of the pyrolysis and the cooling bean. All data were based on bibliographical search, where the raw material was bean coffee (Arabian from Brazil), the roasting operation variables were 200°C of temperature and 12min. of roasting time and the rest of the bibliography data were all the necessary tools to develop all tensors (relationship between components, phases and aggregation state). The energy generated in the pyrolysis reaction is included in the enthalpy variation. The transformation tensor was calculated using the weight loss curve and the roasting tensor described all changes, dehydration, glass transition, sugar degradation and chemical and biochemical reactions. The energy balances are described in enthalpy and entropy variations. In short, the SAFES technique works to describe this operation, is useful to determine and predict all changes in the food matter and permits us to determine the behaviors involved in this operation. [Copyright &y& Elsevier]

Abstract: In this research, round hazelnut cultivars (Foşa, Palaz and Tombul) harvested from the Ordu, Giresun and Trabzon regions in 2001 and 2002 were supplied by the Fiskobirlik Company. Changes in L, a and b values of hazelnut varieties during different roasting applications (125–165°C, 10–55min) were used to determine the optimum conditions of the roasting process and develop mathematical equations. As a result of variance analysis, the effects of the roasting process, cultivars and measurement types on colour values (L, a and b) of hazelnuts were found to be statistically significant (p <0.01). Values of a and b for hazelnut samples showed an increase while L decreased. The regression coefficients (R 2) which described the prediction models for the dependent variables ranged from 0.73 to 0.97. In addition, changes in colour values, particularly a and L values, gave high R 2 and the obtained three-dimensional (3D) nonlinear equations may be utilized to determine the optimum roasting degree based on time and temperature. [Copyright &y& Elsevier]

Abstract: In this paper, an experimental and theoretical analysis of the heat and mass transfer was carried out to evaluate the coffee bean’s temperature and moisture content during the roasting in batch system. Arabica coffee from Colombian origin was roasted using different air temperatures between 190 and 300°C, during 10min. Bean’s temperature and weight loss have been measured on-line by robust sensors. The experimental results allowed better understanding of the phenomena that appears during roasting. For example, an evident increase of the bean’s temperature curve tendency is observed when this one exceeds the 250°C, it is probably due to the end of exothermic reactions and to the beginning of the bean burn. The experimental data of moisture shown a decrease of 10.5% d.b. to 0–7% d.b. A dynamic model is evaluated and analyzed to predict bean’s temperature and moisture content during roasting. The results (simulations and experimental kinetics) were in good agreement. This model can be used for on-line estimation and control of coffee roasting. [Copyright &y& Elsevier]

Abstract: The Ivory Coast cocoa beans were roasted in a convective oven at 110, 135 and 150°C, at the air flow rate of 1.0m/s and relative air humidity (RH) of 0.8–0.4%, 2.0% and 5.0%. Pigmentation expressed as both OD460/OD525 and a ratio of anthocyanins to yellow and brown pigments (F1/F3) and water content were assayed throughout cocoa roasting. The experiments provided evidence that higher humidity of air (particularly of 5.0%) was beneficial to the color of roasted cocoa beans. The beans roasted at 135 and 150°C displayed desired coloration (OD460/OD525 above 1.1, and F1/F3 below 0.33). [Copyright &y& Elsevier]

Abstract: Roasting is the basic unit operation in the sesame paste production. Sesame seeds were roasted using conventional method at 120, 150, and 180°C for 120min. The effect of heating time and temperatures on the moisture content, color and texture of sesame seeds were investigated. The changes occurred in the moisture content, color values (L-, a-, and b-) and textural properties (hardness and fracturability) of sesame seeds were simulated using exponential, kinetic and polynomial models. Two parameter exponential and Page models provided the satisfactory description for the moisture content changes. The variations in the color parameters of sesame seeds during conventional roasting were adequately simulated by cubic polynomials. The zero-order kinetic model satisfactorily described the reduction in the hardness and fracturability of sesame seeds. The one-step nonlinear regression analysis was used to determine the temperature dependence of the model coefficients. The temperature dependence of moisture and color models was described by linear function relationship, but Arrhenius-type relationship was used for textural models. The activation energy for sesame seeds was estimated to be 6.9 and 9.8kJ/mol for hardness and fracturability changes, respectively over the temperature range of the study. [Copyright &y& Elsevier]

Abstract: The processing of particles in rotating cylinders is heavily influenced by the types of flow regimes within the cylinders during rotation. Conventional industrial coffee roasting is performed in rotating cylinders. Coffee beans undergo drastic physical and chemical changes during roasting and, due to that fact, the types of flow regime within the roaster will also vary. The types of flow regimes will, in turn, affect the uniformity of processing and ultimately the quality of the roasting. In this study, a small scale acrylic model of a cylindrical roaster was built and used to study the different forms of transverse motion of a bed of coffee beans during rotating motion. The model has internal mixing bars similar to those of industrial roasters. The model allowed the visualization of the flow regimes and their transitions, giving a preliminary idea of the regimes to be recommended for operation of conventional industrial roasters. [Copyright &y& Elsevier]

Abstract: Seeds of five desi (PBG-1, PDG-4, PDG-3, GL-769, and GPF-2) and one kabuli type (L-550) chickpea cultivars were evaluated for their physicochemical (seed weight, seed volume, hydration capacity, hydration index, swelling capacity and swelling index), cooking, instrumental textural (hardness, cohesiveness, gumminess, springiness, chewiness and fracturability) and roasting (puffing capacity, puffing index, and expansion index) characteristics and related to each other. Significant variation in physicochemical, cooking, textural and roasting properties was observed among different chickpea cultivars. The results showed that cultivars having higher seed weight and volume had higher cooking time, swelling capacity and hydration capacity. The interrelationships between roasting characteristics of seeds from different chickpea cultivars showed a significant negative correlation of puffing capacity, puffing index and expansion index with seed weight, volume, swelling and hydration capacity. The kabuli type chickpea cultivar was observed to have poor roasting and textural properties. Swelling and hydration capacity correlated well with cooking time, springiness and hardness of soaked chickpea seeds. Cooking time had a positive correlation with hardness and gumminess and a negative correlation with springiness. It was also observed that cultivars with high fat and carbohydrate and low fiber content had high soaked-seed hardness. [Copyright &y& Elsevier]

Roasting of barley is currently an artisan process. As regulations and customer specifications become more precise, and experienced operators retire, a new approach to roast barley production is needed. To improve the quality of product greater understanding of the process is required. To enable automatic control methods to be implemented a model of the roasting process has been developed and tested on a spouted-bed roaster. The model uses parameters measured by other workers in fields such as grain drying and allows the change in temperature and moisture content of the barley to be predicted throughout the roasting period: a good fit between theory and experiment is obtained without recourse to any fitted parameters. This will enable changes in product characteristics to be modelled as a function of roasting control parameters such as temperature and time. [Copyright &y& Elsevier]

Carbon dioxide is produced as a result of many reactions that take place during roasting of coffee. Although some carbon dioxide is released during roasting and upon grinding, some is trapped and slowly released creating a packaging problem. Either vacuum packaging to prevent a billowing of the package or special film to release CO2 from inside the package are required. In addition, the coffee is usually tempered in order to maximize release of CO2 before packaging. In this research, the diffusion kinetics of carbon dioxide release from fresh roasted and ground coffee during tempering were determined. The CO2 degassing results fit a series expansion of Fick’s law for unsteady state diffusion using either one or two effective diffusivities based on an analysis of transport mechanisms. The calculated effective diffusivity was between 0.5 and 10×10−13 m2/s. It appears that pressure flow and Knudsen diffusion take place and are important during tempering. [Copyright &y& Elsevier]

The three-dimensional transient heat transfer of roasted meat during air blast cooling process was modelled by the finite element method for evaluating the cooling performance. Moisture loss rate was considered in the model to account for the weight loss during air blast cooling. The model includes the variations in physical properties of the roasted meat and in operating conditions during the air blast cooling process. A user-friendly computer program developed in visual C++ by the authors was used to solve the model. The model was validated by comparing the numerical solutions with the experimental results. The comparison showed that the maximum deviation between the predicted and experimental core temperatures was within 2.4°C. The deviation between the predicted and experimental total weight loss was 2.5%. The model and software can also be used to analyse other thermal processing procedures of foods with some modifications. [Copyright &y& Elsevier]