In this paper, we propose a feasible, sample preparation free and fast validated methodology for ... more In this paper, we propose a feasible, sample preparation free and fast validated methodology for the detection and quantitative analysis of Minas Frescal cheese waste whey as an adulterant in raw milk using mid-infrared spectroscopy with Fourier transform (FTMIR) along with the chemometric technique of partial least squares (PLS). The PLS model was built in accordance with Brazilian and international guidelines and was analytically validated through the estimate of figures of merit parameters, in accordance with ASTM E1655-05 standard. This model showing an effective and feasible method for quality control of raw milk can be adopted for the quality control by regulatory agencies, as shown by the satisfactory results obtained for all estimated figures of merit with no systematic errors and low errors, with R=0.99.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Adsorption of phenolic amino acids, such as phenylalanine and tyrosine, is quite relevant for the... more Adsorption of phenolic amino acids, such as phenylalanine and tyrosine, is quite relevant for the production of protein hydrolysates used as dietary formulations for patients suffering from congenital disorders of amino acid metabolism, such as phenylketonuria. In this study, an adsorbent prepared from corn cobs was evaluated for the removal of tyrosine (Tyr) from both a single component solution and a binary aqueous solution with phenylalanine (Phe). The adsorption behavior of tyrosine was similar to that of phenylalanine in single component solutions, however, with a much lower adsorption capacity (14 mg g −1 for Tyr compared to 109 mg g −1 for Phe). Tyr adsorption kinetics was satisfactorily described by a pseudosecond-order model as it was for Phe. In adsorption equilibrium studies for binary mixtures, the presence of Tyr in Phe solutions favored Phe faster adsorption whereas the opposite behavior was observed for the presence of Phe in Tyr solutions. Such results indicate that, in binary systems, Phe will be adsorbed preferably to Tyr, and this is a welcome feature when employing the prepared adsorbent for the removal of Phe from protein hydrolysates to be used in dietary formulations for phenylketonuria treatment.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Resumo: O presente estudo teve como objetivo efetuar uma avaliação qualitativa do perfil de compo... more Resumo: O presente estudo teve como objetivo efetuar uma avaliação qualitativa do perfil de compostos voláteis de grãos defeituosos (preto, verde, ardido) e sadios, de forma a tentar identificar possíveis substâncias que possam ser utilizadas como marcadores químicos para a quantificação de grãos defeituosos em café. O vapor diretamente em contato com os grãos (headspace) foi submetido a analise por cromatografia gasosa acoplada a espectrometria de massas. Não foram constatadas diferenças quanto à composição qualitativa dos grãos defeituosos em relação aos sadios. Eles apresentaram os mesmos compostos, porém em diferentes quantidades. O grão defeituoso ardido apresentou as maiores concentrações da maioria dos compostos. Com base na análise dos espectros de massa e comportamento cromatográfico dos compostos voláteis, concluiuse que eles são pertencentes a três classes químicas diferentes, sendo uma única substância na classe I, 3 na classe II e 12 na classe III. Os compostos da classe II e III pertencem a séries homólogas diferentes. Foi possível propor uma estrutura química para as substâncias da classe III. Palavraschave: CGEM; voláteis; grãos defeituosos.
Environmental Engineering and Management Journal, 2014
This study evaluates the potential of Crambe abyssinica press cake, a residue from crambe oil ext... more This study evaluates the potential of Crambe abyssinica press cake, a residue from crambe oil extraction and/or biodiesel production, as an adsorbent for removal of cationic dyes from wastewaters. Batch adsorption tests were performed at 30, 40 and 50 o C. Adsorption kinetics and equilibrium were satisfactorily described by the pseudo second-order and Freundlich models, respectively. Adsorption was spontaneous and exothermic. Fixed bed adsorption (breakthrough curve) was satisfactorily described by the Dose-Response model. The obtained values of maximum adsorption capacity were 79.7 and 102.5 mg g-1 in batch and continuous systems, respectively. Adsorption tests showed that crambe press cake, without any thermal treatment, presented higher adsorption capacity than activated carbons produced from other oilseed press cakes (sunflower, coffee and Raphanus sativus), confirming that this type of waste material is a suitable candidate for use in the production of adsorbents.
A one-dimensional mathematical model was developed for the simulation of limestone calcination in... more A one-dimensional mathematical model was developed for the simulation of limestone calcination in rotary kilns. The model is comprised of ordinary differential equations derived from mass and energy conservation principles. The system of equations is solved by a fourth-order Runge-Kutta method. The model predicts, in the axial direction, temperature profiles for the bed of particles, the gas phase and the kiln internal wall. It also predicts the composition profile for the bed. The results from the simulation of the calcination systems presented good agreement with experimental data measured in a pilot kiln.
Most polymeric materials are synthetic and derived from petroleum, hence they accumulate in landf... more Most polymeric materials are synthetic and derived from petroleum, hence they accumulate in landfills or the ocean, and recent studies have focused on alternatives to replace them with biodegradable materials from renewable sources. Biodegradable wastes from food and agroindustry, such as spent coffee grounds (SCGs), are annually discarded on a large scale and are rich in organic compounds, such as polysaccharides, that could be used as precursors to produce films. Around 6.5 million tons of SCGs are discarded every year, generating an environmental problem around the world. Therefore, it was the aim of this work to develop films from the SCGs polysaccharide fraction, which is comprised of cellulose, galactomannans and arabinogalactans. Two types of crosslinking were performed: the first forming coordination bonds of calcium ions with polysaccharides; and the second through covalent bonds with 1,4-phenylenediboronic acid (PDBA). The films with Ca2+ ions exhibited a greater barrier t...
Cloning techniques are used to improve agronomical traits and answer to the demand for fine choco... more Cloning techniques are used to improve agronomical traits and answer to the demand for fine chocolate. The objective of this study was to predict the concentrations of bioactive amines, phenolic compounds, and the antioxidant potential of dark monoclonal chocolate from nine fine cocoa varieties by FTIR analysis and conventional techniques. Total phenolic compounds, bioactive amines and antioxidant activity varied significantly among chocolates. The antioxidant activity was also affected by the analytical method (DPPH vs. Rancimat). Chemometric models based on FTIR data provided satisfactory predictions of the concentrations of the amines: spermidine (R2 = 0.92; RMSEP = 0.39; RMSEC = 0.21), tryptamine (R2 = 0.92; RMSEP = 0.41; RMSEC = 0.20), cadaverine (R2 = 0.82; RMSEP = 1.58; RMSEC = 0.75) and tyramine (R2 = 0.87; RMSEP = 1.87; RMSEC = 0.68); as well as phenolic compounds and antioxidant activity by Rancimat® (R2 = 0.98; RMSEP = 0.32; RMSEC = 0.21) and DPPH (R2 = 0.97; RMSEP = 4.05; RMSEC = 1.66). The wavenumbers of amines vibrations are among those that most affected antioxidant prediction models, confirming the contribution of amines to the antioxidant activity of chocolates.
Based on the records of 1183 individual fund managers from 1985 to 2010, we investigate manager c... more Based on the records of 1183 individual fund managers from 1985 to 2010, we investigate manager compensation and discipline in the closed-end fund industry and their implications for manager performance and fund discounts. We find that managers generating high shareholder surplus, as proxied by fund premium, capture rents on their skills by expansions of assets under management and increases in management fees; however, managers with a high discount are not penalized accordingly. Managers with poor NAV performance suffer from asset contractions, but such discipline is insignificant for managers with long tenure. In support of the hypotheses of manager entrenchment and decreasing returns to scale, NAV performance and premium decline with manager tenure and the size of assets under management. Finally, consistent with the conjecture that adjustments of assets under management and management fees in response to extreme performance break the premium-performance relation, the fund premium responds positively only to the NAV performance in the medium range.
This work aimed to characterize the fuel properties and to evaluate the kinetics of thermal decom... more This work aimed to characterize the fuel properties and to evaluate the kinetics of thermal decomposition of defective coffee beans (DCB). Three thermogravimetric-based methods were evaluated: Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS) and Friedman. The results showed that DCB presented low activation energy and that the evaluated mathematical models, although satisfactory for describing thermal decomposition in inert atmospheres, did not provide a satisfactory description of the oxidizing process. The enthalpy values indicated that the energy differences between the reagents and the activated complex are related directly to the activation energies. Pre-exponential factors indicated first-order reactions. The immediate analysis and the lignocellulosic contents indicated a biomass with low levels of humidity and ashes, high carbon and volatile concentrations, besides thermal stability. The obtained calorific value was 19.39 MJ/kg. The overall results obtained in the present study indicate that this biomass has the potential to be used as a solid biofuel.
Cloning techniques have been used to improve agronomical traits and to answer to the new demand f... more Cloning techniques have been used to improve agronomical traits and to answer to the new demand for fine chocolate. However, scarce information is available regarding their impact on chocolate quality. This study investigated amino acids and bioactive amines in nine cocoa clones and their impact on quality, safety and functional properties of chocolates. Most of the clones had 18 out of the 20 amino acids investigated (five lacked methionine, one phenylalanine and another alanine, proline and valine). Total levels varied from 28.57 to 84.5 g/kg and ~45% were essential amino acids. Bitter amino acids represented 55%, sweet 19% and umami 2% of total. Spermidine, putrescine, tryptamine, tyramine and phenylethylamine were present in all samples; agmatine was detected in five, cadaverine in eight, histamine in seven, and serotonin in six samples. Total levels varied from 9.10 to 44.09 mg/kg. The presence of spermidine, tryptamine, agmatine and phenylethylamines is relevant due to health promoting properties. Histamine and tyramine levels are not enough to cause adverse effects. Multivariate analyses separated the chocolates into five clusters. This information is relevant for further agronomical studies and in the formulation of cocoa blends for chocolate with unique and optimized nutritional, functional, safety and sensory qualities.
The present work proposes the use of an agro-industrial residue from the sunflower crop as a feed... more The present work proposes the use of an agro-industrial residue from the sunflower crop as a feedstock to produce a low-cost adsorbent with a chemically modified surface bearing sulfonic groups. This modified low-cost adsorbent can be used for the removal of phenylalanine, and can also be applied in the process of obtaining a source of protein supplementation for patients with phenylketonuria. The functionalization of the adsorbent with sulfonic groups was adapted and presented advantages in terms of execution time, energy expenditure, number of reagents used and adsorbed amino acids. The produced adsorbent presented a surface area of 317.31 m2 g−1 with a predominance of micro- and mesopores, that influenced an approximate 30-fold reduction in adsorption equilibrium time. The optimization results indicated a higher adsorption capacity (39.64 mg g−1) in pH = 4; temperature of 25 °C and adsorbent dosage of 10 g L−1. The FTIR analyzes and the qualitative analysis of the elements presen...
Coffee husks are a major by-product of coffee production and are currently being underutilized. T... more Coffee husks are a major by-product of coffee production and are currently being underutilized. The aim of this work was to chemically characterize coffee husks to allow for an adequate evaluation of their potential for valorization. Blanched and non-blanched coffee husks were characterized for extractable and non-extractable phenolics, caffeine, trigonelline content, and for their polysaccharide and proximal composition. The total, soluble and insoluble fiber contents were determined, together with the husks’ technological properties. Antioxidant activity and bioaccessibility of phenolic compounds of coffee husks were evaluated. Two types of husk were studied: one comprised mostly of outer skin and pulp (CH1); and other comprised mostly of parchment (CH2). Blanching had positive effects on non-extractable phenolics, chlorogenic acid and on the bioaccessibility of phenolics, promoting small reductions in extractable phenolics, protocathecuic acid, caffeine and trigonelline contents....
The Specialty Coffee Association (SCA) sensory analysis protocol is the methodology that is used ... more The Specialty Coffee Association (SCA) sensory analysis protocol is the methodology that is used to classify specialty coffees. However, because the sensory analysis is sensitive to the taster’s training, cognitive psychology, and physiology, among other parameters, the feasibility of instrumental approaches has been recently studied for complementing such analyses. Spectroscopic methods, mainly near infrared (NIR) and mid infrared (FTIR—Fourier Transform Infrared), have been extensively employed for food quality authentication. In view of the aforementioned, we compared NIR and FTIR to distinguish different qualities and sensory characteristics of specialty coffee samples in the present study. Twenty-eight green coffee beans samples were roasted (in duplicate), with roasting conditions following the SCA protocol for sensory analysis. FTIR and NIR were used to analyze the ground and roasted coffee samples, and the data then submitted to statistical analysis to build up PLS models in...
The main objective of the present study was to evaluate the variation of physical properties of c... more The main objective of the present study was to evaluate the variation of physical properties of coffee beans during roasting. Characteristics evaluated were: volume, bean and bulk densities, weight loss, and color. Experiments were conducted using a lab-scale roaster, with coffee samples being collected at regular intervals during roasting. The results showed that both volume and weight loss increase during roasting, and that such increase can be described by two lines presenting different slopes, coinciding with the drying and pyrolysis stages. It was also observed that both bulk and bean densities decrease during roasting, due to the increase in volume and simultaneous decrease in mass. The results also show that the variations in color parameters are more expressive at the onset of pyrolysis.
ETP International Journal of Food Engineering, 2016
The preparation of coffee beverage, as well as the industrial production of soluble coffee, gener... more The preparation of coffee beverage, as well as the industrial production of soluble coffee, generates a considerable amount of residues, the spent coffee grounds, SCG. There are no current profitable applications for these residues and an adequate disposal must be carried out since they are heavily pollutant and can be used to adulterate roasted and ground coffee. Thus, the objective of this work was to evaluate the effect of alkaline hydrogen peroxide treatment on the chemical composition and technological properties of spent coffee grounds in order to verify its potential as source of antioxidant dietary fibers. Evaluated parameters included moisture, fat, ash, soluble and insoluble dietary fiber contents, phenolics and in-vitro antioxidant potential, hydration properties and color. Total dietary fibre contents were shown to be high in comparison to commonly employed fibre sources, and increased with peroxide concentration. Phenolics content and the antioxidant activity of the treated spent coffee grounds decreased with increasing hydrogen peroxide concentration. Luminosity values increased significantly, and hydration properties showed a slight improvement with the increase in peroxide concentration. Overall, the alkaline hydrogen peroxide treatment produced an insoluble-fiber-rich material with physical and chemical characteristics that allow for its utilization as a source of antioxidant dietary fibers.
In this paper, we propose a feasible, sample preparation free and fast validated methodology for ... more In this paper, we propose a feasible, sample preparation free and fast validated methodology for the detection and quantitative analysis of Minas Frescal cheese waste whey as an adulterant in raw milk using mid-infrared spectroscopy with Fourier transform (FTMIR) along with the chemometric technique of partial least squares (PLS). The PLS model was built in accordance with Brazilian and international guidelines and was analytically validated through the estimate of figures of merit parameters, in accordance with ASTM E1655-05 standard. This model showing an effective and feasible method for quality control of raw milk can be adopted for the quality control by regulatory agencies, as shown by the satisfactory results obtained for all estimated figures of merit with no systematic errors and low errors, with R=0.99.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Adsorption of phenolic amino acids, such as phenylalanine and tyrosine, is quite relevant for the... more Adsorption of phenolic amino acids, such as phenylalanine and tyrosine, is quite relevant for the production of protein hydrolysates used as dietary formulations for patients suffering from congenital disorders of amino acid metabolism, such as phenylketonuria. In this study, an adsorbent prepared from corn cobs was evaluated for the removal of tyrosine (Tyr) from both a single component solution and a binary aqueous solution with phenylalanine (Phe). The adsorption behavior of tyrosine was similar to that of phenylalanine in single component solutions, however, with a much lower adsorption capacity (14 mg g −1 for Tyr compared to 109 mg g −1 for Phe). Tyr adsorption kinetics was satisfactorily described by a pseudosecond-order model as it was for Phe. In adsorption equilibrium studies for binary mixtures, the presence of Tyr in Phe solutions favored Phe faster adsorption whereas the opposite behavior was observed for the presence of Phe in Tyr solutions. Such results indicate that, in binary systems, Phe will be adsorbed preferably to Tyr, and this is a welcome feature when employing the prepared adsorbent for the removal of Phe from protein hydrolysates to be used in dietary formulations for phenylketonuria treatment.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Resumo: O presente estudo teve como objetivo efetuar uma avaliação qualitativa do perfil de compo... more Resumo: O presente estudo teve como objetivo efetuar uma avaliação qualitativa do perfil de compostos voláteis de grãos defeituosos (preto, verde, ardido) e sadios, de forma a tentar identificar possíveis substâncias que possam ser utilizadas como marcadores químicos para a quantificação de grãos defeituosos em café. O vapor diretamente em contato com os grãos (headspace) foi submetido a analise por cromatografia gasosa acoplada a espectrometria de massas. Não foram constatadas diferenças quanto à composição qualitativa dos grãos defeituosos em relação aos sadios. Eles apresentaram os mesmos compostos, porém em diferentes quantidades. O grão defeituoso ardido apresentou as maiores concentrações da maioria dos compostos. Com base na análise dos espectros de massa e comportamento cromatográfico dos compostos voláteis, concluiuse que eles são pertencentes a três classes químicas diferentes, sendo uma única substância na classe I, 3 na classe II e 12 na classe III. Os compostos da classe II e III pertencem a séries homólogas diferentes. Foi possível propor uma estrutura química para as substâncias da classe III. Palavraschave: CGEM; voláteis; grãos defeituosos.
Environmental Engineering and Management Journal, 2014
This study evaluates the potential of Crambe abyssinica press cake, a residue from crambe oil ext... more This study evaluates the potential of Crambe abyssinica press cake, a residue from crambe oil extraction and/or biodiesel production, as an adsorbent for removal of cationic dyes from wastewaters. Batch adsorption tests were performed at 30, 40 and 50 o C. Adsorption kinetics and equilibrium were satisfactorily described by the pseudo second-order and Freundlich models, respectively. Adsorption was spontaneous and exothermic. Fixed bed adsorption (breakthrough curve) was satisfactorily described by the Dose-Response model. The obtained values of maximum adsorption capacity were 79.7 and 102.5 mg g-1 in batch and continuous systems, respectively. Adsorption tests showed that crambe press cake, without any thermal treatment, presented higher adsorption capacity than activated carbons produced from other oilseed press cakes (sunflower, coffee and Raphanus sativus), confirming that this type of waste material is a suitable candidate for use in the production of adsorbents.
A one-dimensional mathematical model was developed for the simulation of limestone calcination in... more A one-dimensional mathematical model was developed for the simulation of limestone calcination in rotary kilns. The model is comprised of ordinary differential equations derived from mass and energy conservation principles. The system of equations is solved by a fourth-order Runge-Kutta method. The model predicts, in the axial direction, temperature profiles for the bed of particles, the gas phase and the kiln internal wall. It also predicts the composition profile for the bed. The results from the simulation of the calcination systems presented good agreement with experimental data measured in a pilot kiln.
Most polymeric materials are synthetic and derived from petroleum, hence they accumulate in landf... more Most polymeric materials are synthetic and derived from petroleum, hence they accumulate in landfills or the ocean, and recent studies have focused on alternatives to replace them with biodegradable materials from renewable sources. Biodegradable wastes from food and agroindustry, such as spent coffee grounds (SCGs), are annually discarded on a large scale and are rich in organic compounds, such as polysaccharides, that could be used as precursors to produce films. Around 6.5 million tons of SCGs are discarded every year, generating an environmental problem around the world. Therefore, it was the aim of this work to develop films from the SCGs polysaccharide fraction, which is comprised of cellulose, galactomannans and arabinogalactans. Two types of crosslinking were performed: the first forming coordination bonds of calcium ions with polysaccharides; and the second through covalent bonds with 1,4-phenylenediboronic acid (PDBA). The films with Ca2+ ions exhibited a greater barrier t...
Cloning techniques are used to improve agronomical traits and answer to the demand for fine choco... more Cloning techniques are used to improve agronomical traits and answer to the demand for fine chocolate. The objective of this study was to predict the concentrations of bioactive amines, phenolic compounds, and the antioxidant potential of dark monoclonal chocolate from nine fine cocoa varieties by FTIR analysis and conventional techniques. Total phenolic compounds, bioactive amines and antioxidant activity varied significantly among chocolates. The antioxidant activity was also affected by the analytical method (DPPH vs. Rancimat). Chemometric models based on FTIR data provided satisfactory predictions of the concentrations of the amines: spermidine (R2 = 0.92; RMSEP = 0.39; RMSEC = 0.21), tryptamine (R2 = 0.92; RMSEP = 0.41; RMSEC = 0.20), cadaverine (R2 = 0.82; RMSEP = 1.58; RMSEC = 0.75) and tyramine (R2 = 0.87; RMSEP = 1.87; RMSEC = 0.68); as well as phenolic compounds and antioxidant activity by Rancimat® (R2 = 0.98; RMSEP = 0.32; RMSEC = 0.21) and DPPH (R2 = 0.97; RMSEP = 4.05; RMSEC = 1.66). The wavenumbers of amines vibrations are among those that most affected antioxidant prediction models, confirming the contribution of amines to the antioxidant activity of chocolates.
Based on the records of 1183 individual fund managers from 1985 to 2010, we investigate manager c... more Based on the records of 1183 individual fund managers from 1985 to 2010, we investigate manager compensation and discipline in the closed-end fund industry and their implications for manager performance and fund discounts. We find that managers generating high shareholder surplus, as proxied by fund premium, capture rents on their skills by expansions of assets under management and increases in management fees; however, managers with a high discount are not penalized accordingly. Managers with poor NAV performance suffer from asset contractions, but such discipline is insignificant for managers with long tenure. In support of the hypotheses of manager entrenchment and decreasing returns to scale, NAV performance and premium decline with manager tenure and the size of assets under management. Finally, consistent with the conjecture that adjustments of assets under management and management fees in response to extreme performance break the premium-performance relation, the fund premium responds positively only to the NAV performance in the medium range.
This work aimed to characterize the fuel properties and to evaluate the kinetics of thermal decom... more This work aimed to characterize the fuel properties and to evaluate the kinetics of thermal decomposition of defective coffee beans (DCB). Three thermogravimetric-based methods were evaluated: Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS) and Friedman. The results showed that DCB presented low activation energy and that the evaluated mathematical models, although satisfactory for describing thermal decomposition in inert atmospheres, did not provide a satisfactory description of the oxidizing process. The enthalpy values indicated that the energy differences between the reagents and the activated complex are related directly to the activation energies. Pre-exponential factors indicated first-order reactions. The immediate analysis and the lignocellulosic contents indicated a biomass with low levels of humidity and ashes, high carbon and volatile concentrations, besides thermal stability. The obtained calorific value was 19.39 MJ/kg. The overall results obtained in the present study indicate that this biomass has the potential to be used as a solid biofuel.
Cloning techniques have been used to improve agronomical traits and to answer to the new demand f... more Cloning techniques have been used to improve agronomical traits and to answer to the new demand for fine chocolate. However, scarce information is available regarding their impact on chocolate quality. This study investigated amino acids and bioactive amines in nine cocoa clones and their impact on quality, safety and functional properties of chocolates. Most of the clones had 18 out of the 20 amino acids investigated (five lacked methionine, one phenylalanine and another alanine, proline and valine). Total levels varied from 28.57 to 84.5 g/kg and ~45% were essential amino acids. Bitter amino acids represented 55%, sweet 19% and umami 2% of total. Spermidine, putrescine, tryptamine, tyramine and phenylethylamine were present in all samples; agmatine was detected in five, cadaverine in eight, histamine in seven, and serotonin in six samples. Total levels varied from 9.10 to 44.09 mg/kg. The presence of spermidine, tryptamine, agmatine and phenylethylamines is relevant due to health promoting properties. Histamine and tyramine levels are not enough to cause adverse effects. Multivariate analyses separated the chocolates into five clusters. This information is relevant for further agronomical studies and in the formulation of cocoa blends for chocolate with unique and optimized nutritional, functional, safety and sensory qualities.
The present work proposes the use of an agro-industrial residue from the sunflower crop as a feed... more The present work proposes the use of an agro-industrial residue from the sunflower crop as a feedstock to produce a low-cost adsorbent with a chemically modified surface bearing sulfonic groups. This modified low-cost adsorbent can be used for the removal of phenylalanine, and can also be applied in the process of obtaining a source of protein supplementation for patients with phenylketonuria. The functionalization of the adsorbent with sulfonic groups was adapted and presented advantages in terms of execution time, energy expenditure, number of reagents used and adsorbed amino acids. The produced adsorbent presented a surface area of 317.31 m2 g−1 with a predominance of micro- and mesopores, that influenced an approximate 30-fold reduction in adsorption equilibrium time. The optimization results indicated a higher adsorption capacity (39.64 mg g−1) in pH = 4; temperature of 25 °C and adsorbent dosage of 10 g L−1. The FTIR analyzes and the qualitative analysis of the elements presen...
Coffee husks are a major by-product of coffee production and are currently being underutilized. T... more Coffee husks are a major by-product of coffee production and are currently being underutilized. The aim of this work was to chemically characterize coffee husks to allow for an adequate evaluation of their potential for valorization. Blanched and non-blanched coffee husks were characterized for extractable and non-extractable phenolics, caffeine, trigonelline content, and for their polysaccharide and proximal composition. The total, soluble and insoluble fiber contents were determined, together with the husks’ technological properties. Antioxidant activity and bioaccessibility of phenolic compounds of coffee husks were evaluated. Two types of husk were studied: one comprised mostly of outer skin and pulp (CH1); and other comprised mostly of parchment (CH2). Blanching had positive effects on non-extractable phenolics, chlorogenic acid and on the bioaccessibility of phenolics, promoting small reductions in extractable phenolics, protocathecuic acid, caffeine and trigonelline contents....
The Specialty Coffee Association (SCA) sensory analysis protocol is the methodology that is used ... more The Specialty Coffee Association (SCA) sensory analysis protocol is the methodology that is used to classify specialty coffees. However, because the sensory analysis is sensitive to the taster’s training, cognitive psychology, and physiology, among other parameters, the feasibility of instrumental approaches has been recently studied for complementing such analyses. Spectroscopic methods, mainly near infrared (NIR) and mid infrared (FTIR—Fourier Transform Infrared), have been extensively employed for food quality authentication. In view of the aforementioned, we compared NIR and FTIR to distinguish different qualities and sensory characteristics of specialty coffee samples in the present study. Twenty-eight green coffee beans samples were roasted (in duplicate), with roasting conditions following the SCA protocol for sensory analysis. FTIR and NIR were used to analyze the ground and roasted coffee samples, and the data then submitted to statistical analysis to build up PLS models in...
The main objective of the present study was to evaluate the variation of physical properties of c... more The main objective of the present study was to evaluate the variation of physical properties of coffee beans during roasting. Characteristics evaluated were: volume, bean and bulk densities, weight loss, and color. Experiments were conducted using a lab-scale roaster, with coffee samples being collected at regular intervals during roasting. The results showed that both volume and weight loss increase during roasting, and that such increase can be described by two lines presenting different slopes, coinciding with the drying and pyrolysis stages. It was also observed that both bulk and bean densities decrease during roasting, due to the increase in volume and simultaneous decrease in mass. The results also show that the variations in color parameters are more expressive at the onset of pyrolysis.
ETP International Journal of Food Engineering, 2016
The preparation of coffee beverage, as well as the industrial production of soluble coffee, gener... more The preparation of coffee beverage, as well as the industrial production of soluble coffee, generates a considerable amount of residues, the spent coffee grounds, SCG. There are no current profitable applications for these residues and an adequate disposal must be carried out since they are heavily pollutant and can be used to adulterate roasted and ground coffee. Thus, the objective of this work was to evaluate the effect of alkaline hydrogen peroxide treatment on the chemical composition and technological properties of spent coffee grounds in order to verify its potential as source of antioxidant dietary fibers. Evaluated parameters included moisture, fat, ash, soluble and insoluble dietary fiber contents, phenolics and in-vitro antioxidant potential, hydration properties and color. Total dietary fibre contents were shown to be high in comparison to commonly employed fibre sources, and increased with peroxide concentration. Phenolics content and the antioxidant activity of the treated spent coffee grounds decreased with increasing hydrogen peroxide concentration. Luminosity values increased significantly, and hydration properties showed a slight improvement with the increase in peroxide concentration. Overall, the alkaline hydrogen peroxide treatment produced an insoluble-fiber-rich material with physical and chemical characteristics that allow for its utilization as a source of antioxidant dietary fibers.
Uploads
Papers by Adriana Franca