Article

Effect of sugar addition (torrefacto) during roasting process on antioxidant capacity and phenolics of coffee

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Abstract

The addition of sugar during roasting (torrefacto) has been proposed as a technique to increase the antioxidant capacity. However, other factors such as roasting degree and coffee origin also play a key role. Two batches of Colombian green coffee were roasted adding increased amounts of sucrose (0–15 g per 100 g of coffee) to reach the same roasting degree than a commercial Colombian coffee. Moreover, seven conventional roasted coffees from different origins (Colombia, Brazil, Kenya, Guatemala and Vietnam) and roasting degrees (Dark, Medium and Light), and one 100% Torrefacto roasted coffee were analyzed. Although the addition of sugar during roasting increased the DPPH quenching activity, phenolic compounds (5-caffeoylquinic, caffeic and ferulic acids, and 4-vinylguaiacol) were hardly affected by torrefacto roasting process, showing that Maillard and other roasting reactions products, such as browned-colored compounds including melanoidins (Abs 420 nm), have an important role as antioxidants. Principal Component Analysis (PCA) showed that roasting degree also plays a key role on overall antioxidant activity. Moreover, the Absorbance at 420 nm has been proposed as a good marker of torrefacto roasting process, whereas the roasting degree might be better characterized by L* values.

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... On the other hand, Rodrigues and Bragagnolo (2013) found higher contents of chlorogenic acid in decaffeinated coffees, which would explain the increased antioxidant capacity in these samples. In general, values of ABTS, FRAP and TP are similar to those reported by other authors for ground and instant coffees (Fonseca-García, Calderón-Jaimes, & Rivera, 2014; Ludwig et al., 2013). ...
... Summa et al. (2007) found a decrease in color parameters (L ⁄ , a ⁄ and b ⁄ ), when intensity of roasting was increased, similar to those observed in this study. Furthermore Ludwig et al. (2013) found values significant higher (p < 0.05) in a ⁄ (red) and b ⁄ (yellow) parameters in light roast coffee samples than in medium and dark roast coffee samples, finding significant correlations (p < 0.05) between a ⁄ :L ⁄ and b ⁄ :L ⁄ (r = 0.786 and 0.912, respectively), similar to those found in the present research (r = 0.849 and 0.981, respectively for a ⁄ :L ⁄ and b ⁄ :L ⁄ ). ...
... Lyophilized coffees ((L ⁄ (23.9), a ⁄ (7.42), b ⁄ (21.3), c ⁄ (22.6) and h ⁄ (69.9)) showed significant (p < 0.05) higher values than the other soluble coffees ((L ⁄ (18.83), a ⁄ (6.35), b ⁄ (16.5), c ⁄ (17.7) and h ⁄ (68.4)). These values in color parameters are similar to those reported by other authors (Ludwig et al., 2013;Vignoli et al., 2014). Sample 49 (organic lyophilized coffee) exhibited one of the highest color parameters, similar to those observed in AC where displayed the highest values, which is confirmed with a high and positive correlation between color parameters and AC (Table 4). ...
Article
Fifty-eight samples of commercial Colombian coffee with different characteristics (soluble, ground, decaffeinated, etc) were evaluated for antioxidant capacity (AC) (ABTS and FRAP), total soluble phenolics (TP), browning index (BI), color parameters (L∗, a∗, b∗, c∗ and h∗), HMF and furfural. The AC in Colombian coffees was very varied (164–1000, 100.8–885.9 μmol of Trolox equiv/g and 12.5–127 mg gallic acid equiv/g, respectively for ABTS, FRAP and TP). AC, TP, BI, color, HMF and furfural values were higher (p < 0.05) in soluble coffees than in ground ones, showing the lyophilized samples which showed the highest average values. Significant lineal correlations (p < 0.05) were found between AC and color parameters, BI, HMF. No significant (p < 0.05) differences in the AC between the different types of coffee were found. This work confirms the direct relationship between the rate of non-enzymatic browning and antioxidant capacity.
... During the roasting step, most of the aromatic compounds of coffee are generated while others are affected (mostly chlorogenic acids) by the heat treatment. During this process, some other compounds (like melanoidins or quinic acid) appear, which contributes to coffee's antioxidant capacity (Ludwig, Bravo, De Peña, & Cid, 2013). Generally, the main changes in composition involve loss of polysaccharides, oligosaccharides, chlorogenic acids, and trigonelline (Gniechwitz, Reichardt, Blaut, Steinhart, & Bunzel, 2007). ...
... During roasting some compounds, mainly phenolic acids like chlorogenic acids, are either incorporated into melanoidins or degraded, which could result in a loss of antioxidant capacity (Perrone et al., 2012). However, the high temperatures used during coffee roasting allow the generation of other compounds (like melanoidins) via the Maillard reaction; these compounds can also contribute to antioxidant capacity of the coffee brew, compensating for the degradation of polyphenols (Ludwig et al., 2013). Another potential explanation to such differences could be related with the amount of extracted solids (Duarte, Abreu, Menezes, dos Santos, & Gouvea, 2005): roasting degree influences solids extraction, so that roasting increases yield of extraction, and a roasted coffee brew (with more solids) may have higher antioxidant activity than green coffee brew (with a lower amount of solids). ...
... In addition, the levels of the chlorogenic acids fraction were much higher in green coffees than in their respective roasted ones (Table 1). This is in agreement with the findings reported by other authors (Clifford, 2000;Perrone et al., 2012;Ludwig et al., 2013;Liang et al., 2016) and is explained by the degradation of such compounds during roasting. On the other hand, higher amounts of caffeic and ferulic acid were found in roasted coffees, which could be related to the degradation of chlorogenic acids during roasting, yielding their corresponding cinnamates (Clifford, 2000). ...
... 38 In the literature, several studies were found about the antioxidant activity and/or polyphenolic content of coffees roasted at different temperatures and times. 30,39,[41][42][43][44][45] Only one of them examined the poly- phenols and differences in antioxidant content Turkish-style coffee brews. 30 Yet, there is no study, which determines the effect of addition of sugar into the coffee or Turkish-style coffee brew on the polyphe- nolic content and antioxidant activity at the cooking processes. ...
... In heat-treated foods, like coffee, one of the most visual changes is brown color development during the process. 42 In this study, the color of different TCBs was deter- mined by means of the CIELab parameters (L*, a*,b* and also ΔE*, C* and hº as chromaticity parameters) and the Absorbance at 420nm (Table 2). brown color of coffee. ...
... Only, two studies have found on sugar addition. One of them is about sugar adding at roasting process 42 and the other is about sugar addition in tea brew. 69 ...
Article
Introduction: Coffee is one of the most widely consumed beverages by the people all around the world. This study was aimed to evaluate the effect of sugar addition, double effects of sugar addition and roasting degree on the polyphenol content, and antioxidant activity of Turkish-style coffee brews. Materials and Methods: The levels of three phenolic compounds (chlorogenic acid, caffeic acid, sinapic acid) and caffeine by reversed-phase high performance liquid chromatography (HPLC) method, as well as chromaticity parameters, absorbance value at 420 nm, total phenolic and flavonoid content, antioxidant activities with two methods (DPPH and FRAP methods) were determined in different degree of roast Turkish-style coffee brews with sugar and without sugar. Results: It was found that antioxidant activity of Turkish-style coffee brews was increased while the phenolic content was decreased due to the degree of roasting process. Also, the addition of sugar into Turkish-style coffee brews at cooking stage caused decrease both in antioxidant activity and polyphenol content. Conclusion: The study indicated that light roasted coffee brews showed greater polyphenol content and medium roasted coffee brews had greater antioxidant capacity compared to other samples. Consumption of coffee brews without sugar provided the higher health benefits. © 2018, Association of Pharmaceutical Teachers of India. All rights reserved.
... Seluruh senyawa tersebut akan menjadi prekusor flavor dalam pembuatan kopi kulit pisang. Reaksi yang dimungkinkan terjadi pada suhu tinggi diatas 150 °C antara lain reaksi Maillard, karamelisasi, oksidasi dan pirolisis (Ludwig et al., 2013;Lee et al., 2017;Liu et al., 2019). Reaksi ini dapat menghasilkan senyawa antioksidan sehingga kopi yang dihasilkan akan mengandung senyawa antioksidan. ...
... Sehingga semakin lama pengovenan maka suhu bahan semakin meningkat dan jumlah fenol yang terbentuk semakin banyak. Beberapa reaksi yang menghasilkan fenol antaralain karamelisasi, reaksi maillard, dan pirolisis yang terjadi pada suhu tinggi seperti pada penyangraian biji kopi (Ludwig et al., 2013). Jika dibandingkan dengan kopi makan kandungan fenol kopi kulit pisang masih lebih rendah. ...
... Semakin meningkat kandungan fenol makan nilai IC50 semakin turun. Penelitian pada kopi dengan semakin meningkatnya lama penyangraian menyebabkan aktivitas antioksidannya semakin meningkat dan nilai IC50 semakin menurun dan diiringi peningkatan senyawa fenol (Ludwig et al., 2013). Nilai IC50 kopi kulit pisang lebih tinggi dari kulit pisang segar. ...
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Processing coffee from kepok banana peel is an option in diversifying food preparations and providing non-caffeine coffee. This study aims to study the characteristics of banana peel coffee based on fruit maturity and oven duration. In addition, it also analyzes total phenol and its antioxidant activity. The study design used a factorial randomized design with the first factor of fruit maturity (unripe and ripe) and the second factor of oven length (5, 10, and 15 minutes). Banana skin coffee has a yield ranging from 8.6 to 11.6%. Bulk density ranges from 0.43-0.48g/ml. Water content ranges from 3.9-6.39%. Ash content ranges from 0.92-6.79%. The content of phenol ranges from 0.6 to 2.46 mg PE/g. The coffee phenol content of ripe banana peel is larger than unripe. The longer oven increases the phenol content. IC50 and EC50 decrease with increasing phenol. The antioxidant activity of ripe banana peel coffee is larger than unripe
... In another study, green (raw) coffee also resulted in a higher antioxidant activity when compared to the conventional and microwave-roasted samples [38]. In contrast, Ludwig et al., [49] stated an upsurge in the DPPH scavenging of the roasted coffee. e DPPH scavenging of some other plant materials like citrus peels and pomace, fennel seeds [45], and apricot kernels [44] was increased by microwave roasting. ...
... Moreover, the Maillard reaction may also take place due to high temperature during the roasting process, generating a number of compounds, which can contribute to the elevated antioxidant potential of the product [55]. Consequently, all of the substances appearing during roasting process can either compensate for the loss of some compounds or even contribute towards the enhancement in the antioxidant potential [49]. ...
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Coffee is an intricate mixture of thousands of chemical compounds that are accountable for its flavor and aroma. Roasting is a key step in the processing of coffee beans. This study assessed the effect of microwave roasting (MW) and extraction solvents (ES) on the total polyphenol content, total flavonoid content, and antioxidant activity of coffee beans. The untreated and microwave-roasted (MR) coffee beans showed a total polyphenol content of 40.40 and 35.15 mg GAE/gm DW, respectively, when methanol was used as the solvent for extraction. Similarly, for the untreated coffee beans, the methanol extracted coffee had a significantly (p
... Data for all samples, different types of samples (natural, torrefacto, blend and decaffeinated) and different sets of samples (calibration and validation) are shown. The results obtained for the whole group of samples are similar to those described in previous studies (Belguidoum, Amira-Guebailia, Boulmokh, & Houache, 2014;Lopes et al., 2016;Lopez-Galilea, de Pena, & Cid, 2008;Ludwig, Bravo, De Peña, & Cid, 2013). ...
... However, it also shows other interesting results: torrefacto coffee has a significantly lower amount of chlorogenic acid and significantly higher amounts of total phenolics and melanoidins than natural coffee. These results were also reported (López-Galilea, Andueza, Leonardo, Paz de Peña, & Cid, 2006;Lopez-Galilea et al., 2008;Ludwig et al., 2013). Although torrefacto coffee is often considered a poor quality coffee, these results indicate that, overall, it has better health qualities, such as increased its potential antioxidant activity. ...
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Control of coffee quality has a great importance for being one of the most important raw materials within the international trade. The extractable composition of coffee has been studied in recent decades and the use of non-destructive methodologies is being continuously promoted. In this study, near infrared hyperspectral imaging has been applied to develop non-destructive methods for the control of extractable contents of caffeine, chlorogenic acid, total phenolics and melanoidins in coffee beans. Extractable contents and trends obtained among the different coffee types analysed are similar to those obtained previously in other studies. Moreover, modified partial least square (MPLS) regressions produced prediction models with standard errors of prediction in external validation of 12.01%, 15.61% and 17.61% for caffeine, chlorogenic acid and total phenolics, respectively. Therefore, results obtained for these three parameters indicate that NIR spectroscopy has a great potential for their control in coffee beans.
... The occurrence of autoimmune prostatitis in aged male NOD mice may be related to the gradual decline of the body's resistance to prostate antigen as the age increases [33], eventually leading to the occurrence of spontaneous autoimmune prostatitis. Another study found that Kunming mice can also develop spontaneous autoimmune prostatitis by giving passive abstinence for a long time [34]. ...
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Chronic prostatitis (CP) is a common disease in urology and can be develop in all age groups. It is more commonly seen in men over the age of 50. It’s cure rate is low, the recurrence rate is high, the symptoms are complicated, the duration of disease is prolonged, the lingering is difficult to heal, the pain site is extensive and the associated symptoms are more, which bring great physical pain and mental burden to the patient. At present, the etiology, pathology and pathophysiology of prostatitis are not clear yet, and it is still a difficult problem in medical research. The establishment of an effective animal model for experimental research has become an important way to explore its pathogenesis. There are currently several popular modeling methods that vary in degree of operation, success rate, and time length. It would become a trend to study chronic prostatitis through different modeling methods in the future. The successful preparation of animal models can provide the treatment of CP with the corresponding theoretical basis. This article reviews the recent advances in research on rodent models and analyzes the advantages, limitations, and evaluation criteria of various models for reference.
... The typical dark brown colour of SCG is due to the Maillard reaction during roasting green coffee beans. Maillard reaction leads to formation of melanoidins which are responsible for the final colour of the roasted coffee as well as antioxidant, antimicrobial, anticancer activity, etc. [39,40]. The roasting process can be carried out at different temperatures; depending on the temperature, the final colour will change from light to medium light, moderate dark, dark brown, very dark brown. ...
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Green composites were prepared with polypropylene matrix and 20 wt.% spent coffee ground (SCG) powder for uses as a wood plastic composite (WPC). The effects of hydrophobic treatment with palmitoyl chloride on SCG powder is compared with conventional surface treatment based on silanization with (3-glycidyloxypropyl) trimethoxysilane and the use of a maleated copolymer compatibilizer (polypropylene-graft-maleic anhydride, PP-g-MA) in terms of mechanical properties, morphology, thermal properties and water uptake. Composites were previously mixed in a twin-screw co-rotating extruder and subsequently subjected to injection moulding. The comparative effect of the different surface treatments and or compatibilizers on mechanical performance was studied by flexural, impact tests and dynamic mechanical thermal analysis (DMTA-torsion); in addition, the stabilizing effect of SCG was revealed by differential scanning calorimetry (DSC) and thermogravymetric analysis (TGA). As one of the main drawbacks of wood plastic composites and natural fiber reinforced plastics is the moisture gain, water uptake tests were carried out in order to quantify the effectiveness of the hydrophobization process with palmitoyl chloride. Results show a slight increase in flexural modulus for composites with both untreated and treated/compatibilized SCG powder (20 wt.%). As expected, thermal stability is improved as indicated by an increase of more than 8% in the onset degradation temperature by DSC if compared to unfilled polypropylene. Fracture analysis by scanning electron microscopy (SEM) shows better particle dispersion for PP-SCG composites with hydrophobized SCG with palmitoyl chloride treatment; in addition a remarkable decrease in water uptake is observed for composites with hydrophobized SCG.
... No less than 1000 volatile compounds are generated during the roasting process, and between 25 and 35 are responsible for the coffee aroma (Mestdagh et al. 2014). Thus, many factors that change from the harvest of green coffee beans to the consumption of a steaming cup of coffee influence the metabolome of this beverage: Coffee plant species (genetic factor) (Kitzberger et al. 2014) as well as geographical origin and growing conditions (climate, altitude, light, soil, temperature…) (Wei et al. 2012a), diseases and symbiosis (pest and fungi) (Sbrana et al. 2014), harvesting (period), fruit development (Sridevi and Parvatam 2013), drying (dry or wet method) (Duarte et al. 2010), roasting process (duration, shaking, temperature, sugar addition) (Ludwig et al. 2013a;Wei et al. 2012b), grinding, storage (duration, conditions) (Belviso et al. 2014;Yeretzian et al. 2012) and coffee-making and serving techniques (process, time, hot or cold water, additives…) (Afify et al. 2011;Andueza et al. 2009;Caporaso et al. 2014;Durak et al. 2014;Ludwig et al. 2012;Tagliazucchi et al. 2012) are factors known to influence and modulate the chemical composition of a cup of coffee ready for consumption. Finally, after ingestion, the native coffee metabolites are degraded and modified by the gut microbiome and endogenous enzymes during the digestion process to generate new bioactive compounds ( Fig. 2) (Ludwig et al. 2013b;Redeuil et al. 2011). ...
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Coffee is the second most popular beverage in the world after water with a consumption of approximately two billion cups per day. Due to its low cost and ease of preparation, it is consumed in almost all countries and by all social classes of the population through different modes of preparation. Despites its simple appearance, a cup of coffee is in fact a complex mixture that contains hundreds of molecules, the composition and concentration of which vary widely and depend on factors including the origin of the coffee tree or its metabolism. Although an excessive consumption of coffee can be harmful, many molecules that are present in this black decoction exert anticancer properties. This review aims to describe the different primary coffee-containing substances that exert chemopreventive and bioactive activities against the different hallmarks and enabling characteristics of cancer, thus explaining the anticancer health benefit of black coffee.
... In factory, not only did the temperature-rise procedures vary dramatically, but also when to add sugar into vinegar was unfixed. Different sugar addition times might alter AA of decocted vinegars since it has been reported that the addition of sugar contributes to better AA of coffee due to the higher formation of Maillard reaction products, such as melanoidins, during heat treatment (Andueza, Cid, & Nicoli, 2004;Ludwig, Bravo, De Peña, & Cid, 2013;Sánchez-González, Jiménez-Escrig, & Saura-Calixto, 2005). Both reasons mentioned above would lead to large deviation that obscured the variations induced by decoction. ...
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Decoction, the characteristic heat-treatment procedure in Zhenjiang Aromatic Vinegar (ZAV) processing, was performed in laboratory to investigate its effect on the antioxidative activity (AA) of ZAV. Owing to the laboratory-scale decoction, DPPH radical scavenging activity, ORAC value and cellular antioxidant activity (CAA) of ZAV increased by 63, 24 and 54% of that of undecocted vinegar, respectively. Enzymatic assay and HPLC determination proved that phenolic content decreased after the decoction, while melanoidins, also with antioxidative activity and recently found in ZAV, were generated. Regardless of the fluctuation in AA of melanoidins during decoction, increased melanoidin content was responsible for the increase in AA of ZAV. At the end of the decoction, melanoidins accounted for 57.1 and 44.1% of the total AA of ZAV, according to DPPH and ORAC assays, respectively. Incorporation of phenolic compounds into melanoidins and degradation of melanoidins might both occur during decoction.
... The quality of brew coffee depends on multiple factors such as coffee species (Campa, Doulbeau, Dussert, Hamon, & Noirot, 2005;Maeztu et al., 2001) coffee blends (Fujioka & Shibamoto, 2008); bean roasting conditions (Blumberg, Frank, & Hofmann, 2010;Cavaco Bicho, Leitao, Cochicho Ramalho, de Alvarenga, & Cebola Lidon, 2011;Ludwig, Bravo, de Peña, & Cid, 2013;Nunes, Coimbra, Duarte, & Delgadillo, 1997), grinding of the roasted coffee beans (Andueza, de Peña, & Cid, 2003a) and in a great extension the brewing method i.e. drip, espresso (Gloess et al., 2013). One of the most popular presentations of coffee brews in South-Europe is the Italian espresso. ...
... This roasting technique is used in regional preferences for dark brown colors and a strong flavor with bitterness due to caramelization. The addition of sugar at the end of the torrefacto roasting has the goal to intensify the development of the Maillard reactions and also increase the antioxidant capacity of coffee (López-Galilea et al., 2006;Ludwig et al., 2013). ...
... Se ha estudiado que algunas de estas moléculas de características no polifenólicas pueden interaccionar con el FC, lo que puede repercutir en una sobreestimación. Algunos de los principales compuestos que pueden interferir son: azúcares reductores como fructosa y glucosa, aminoácidos y ácido ascórbico (Granato et al., 2016;Lester et al., 2012;Ludwig et al., 2013;Shanmugavelan et al., 2013). A pesar de ser un método desarrollado a mediados de los años 60, no ha sido modificado a través del tiempo y continúa siendo ampliamente aceptado para la cuantificación de compuestos fenólicos en matrices vegetales y sus extractos. ...
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Phosphomolybdic and phosphotungstic acids mixture, known as Folin-Ciocalteu reactive, is one of the main methods for the quantification of polyphenolic compounds in vegetable extracts (FC reactive). However, as other spectrophotometric methods, it can be unspecific and interact with other molecules, such as sugars, present in vegetable extracts, modifying the obtained results. The aim of the present study was to evaluate the effect of glucose, sucrose, fructose, xylose, mannose, rhamnose and arabinose on the quantification of polyphenolic compounds by the FC method. Fructose and xylose showed the highest interaction with FC reactive, while sucrose, mannose, rhamnose and glucose showed the lowest effect. Fructose and mannose reacted differently with both gallic acid solutions and anise, jalapeño hot pepper and traditional Mexican spices (hoja santa and avocado leaves). Fructose increased the response of the method, and consequently overestimated the polyphenolic content, while mannose showed an underestimation. The obtained results showed that sugar content in vegetable extracts may interfere on the estimation of polyphenolic content, especially if high content of fructose is present in the samples.
... Se ha estudiado que algunas de estas moléculas de características no polifenólicas pueden interaccionar con el FC, lo que puede repercutir en una sobreestimación. Algunos de los principales compuestos que pueden interferir son: azúcares reductores como fructosa y glucosa, aminoácidos y ácido ascórbico (Granato et al., 2016;Lester et al., 2012;Ludwig et al., 2013;Shanmugavelan et al., 2013). A pesar de ser un método desarrollado a mediados de los años 60, no ha sido modificado a través del tiempo y continúa siendo ampliamente aceptado para la cuantificación de compuestos fenólicos en matrices vegetales y sus extractos. ...
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Nota: Artículo recibido el 09 de enero de 2017 y aceptado el 24 de abril de 2017. ARTÍCULO ORIGINAL resumeN La mezcla de ácidos fosfomolíbdico y fosfotúngstico es el reactivo esencial de uno de los principales métodos para la cuantificación de compuestos polifenólicos en extractos vegetales conocido como método de reactivo de Folin-Ciocalteu (FC). Sin embargo, al igual que otros métodos espectrofotométricos puede ser inespecífico e interaccionar con otras moléculas como azúcares, presentes en los extractos vegetales, que pueden alterar los resultados encontrados. El objetivo del presente trabajo fue determinar el efecto de la glucosa, sacarosa, fructosa, xilosa, manosa, ramnosa y arabinosa sobre la cuantificación de compuestos polifenólicos mediante el método de FC. La fructosa y la xilosa fueron los azúcares con la mayor reactividad, mientras que la sacarosa, ramnosa, manosa y glucosa presentaron el menor efecto. La fructosa y la manosa tanto en las muestras de ácido gálico como en extractos de anís y chile jalapeño así como de especias tradicionales de la cocina mexicana (hoja santa y hoja de aguacate), reaccionaron diferente, ya que la fructosa incrementó la respuesta del método y consecuentemente sobreestimó el contenido de los compuestos polifenólicos y la manosa los subestimó. Los resultados obtenidos muestran que el contenido de azúcar en extractos puede interferir en la estimación de los compuestos polifenólicos, sobre todo si la concentración es muy alta o la fructosa está presente. Palabras Clave: azúcares, enediol, fenoles totales, Folin-Ciocalteu. New approach to the interaction between Folin-Ciocalteu reactive and sugars during the quantification of total phenols abstract Phosphomolybdic and phosphotungstic acids mixture, known as Folin-Ciocalteu reactive, is one of the main methods for the quantification of polyphenolic compounds in vegetable extracts (FC reactive). However, as other spectrophotometric methods, it can be unspecific and interact with other molecules, such as sugars, present in vegetable extracts, modifying the obtained results. The aim of the present study was to evaluate the effect of glucose, sucrose, fructose, xylose, mannose, rhamnose and arabinose on the quantification of polyphenolic compounds by the FC method. Fructose and xylose showed the highest interaction with FC reactive, while sucrose, mannose, rhamnose and glucose showed the lowest effect. Fructose and mannose reacted differently with both gallic acid solutions and anise, jalapeño hot pepper and traditional Mexican spices (hoja santa and avocado leaves). Fructose increased the response of the method, and consequently overestimated the polyphenolic content, while mannose showed an underestimation. The obtained results showed that sugar content in vegetable extracts may interfere on the estimation of polyphenolic content, especially if high content of fructose is present in the samples.
... Other isolated research but closely related to coffee quality, have analyzed the effects of high temperature methods such as UHT (Ultra High Temperature) on coffee teas, in which the treatment at 120 degrees Celsius, allows pasteurization; it means the microbiological security in coffee teas but it strongly affects caffeine concentration and some phenolic components [61]. The addition of sugar during the toasting process has been proposed as a technique to increase the anti-oxidant capacity of the product [62,63]. Other studies have led to the degradation of liquids and other coffee components when it is exposed to the process under drying and toasting temperatures [5,64]. ...
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One of the most relevant stages of coffee processing is drying due to the fact that it affects the quality of the organoleptic properties of the product. At this stage, there are crucial variables such as the drying time, temperature, airflow, and the physical-chemical characteristics of the drying agent in contact with the grains, and the thickness of the drying layer, among others. This research shortly reviews the coffee drying process, the current technologies used at a national level and international technological development opportunities in order to identify the current status of the process.
... This could be attributed to the phenolic content of this coffee by-product (Monente et al., 2013). Coffee roasting in presence of sugar (torrefacto process) in known to increase the antioxidant capacity of coffee (Ludwig, Bravo, De Peña & Cid., 2013) due to a higher content of melanoidins, although it lowers the content of phenolic compounds. This behavior was found for CMT 20 and CMT 100 and showed an increase in their antioxidant capacity in a statistically significant manner (p < 0.05) as the torrefacto coffee percentage increased. ...
... During the roasting process, sucrose, which is the most prevalent sugar, is almost completely degraded, being used in the Maillard reaction and Strecker degradation, generating several volatile and non-volatile compounds. Among these products, acids and aldehydes are responsible for aroma, and caramelized sugars, are important for colour, viscosity and body attributes ( Pérez-Hernández, et al., 2012;Ludwig et al., 2013). ...
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The Brazilian coffee industry is undergoing a great transformation in order to serve a consumer market that is becoming increasingly demanding with regard to quality. Considering the multiple determinants of the final quality of the product, one must consider factors that are involved in steps from the pre-harvest stage to storage. The execution of the different stages according to good-practice programmes has repercussions on microbiological, physical and chemical characteristics, which in turn affect the quality of the final product with regard to sensorial properties and safety. There has been research progress in the improvement of quality evaluation techniques that minimize the subjective effects of traditional classification. It is also observed that socio-environmental aspects of coffee production, while not the subject of this review, have broadened the concept of quality since an increasing number of consumers are interested in aspects regarding agricultural sustainability in addition to strictly sensorial aspects.
... Moreover, the Maillard reaction takes place due to the high temperatures applied, giving rise to a plethora of compounds which can also contribute to antioxidant capacity (Pastoriza & Rufián-Henares, 2014). Accordingly, all of the compounds that appear during roasting could compensate for the loss of some other substances or even increase antioxidant capacity (Ludwig, Bravo, De Peña, & Cid, 2013). ...
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This study aimed to identify the main compounds and sensory attributes found in green and roasted coffee brews. To this end, sensory analysis techniques and a sensory discrimination test were conducted, and antioxidant capacity and individual phenolic compounds were analyzed. Multivariate statistical analysis was then conducted to identify characteristic compounds and sensory attributes. Antioxidant capacity assays did not show any significant differences between green and roasted coffee brews. However, both the individual phenolic and sensory profiles of green and roasted coffee brews were significantly different. Finally, we were able to identify through multivariate analysis, the sensory attributes and phenols that characterize each type of coffee. In this sense, green coffee brews are characterized by floral, and thin aqueous flavors, whereas, roasted coffee brews are characterized by flavors of chocolate and caramel, and creamy and intense flavors.
... Melanoidins are high-molecular weight products of the Maillard reaction and are known to contribute to a coffee's brown color, flavor, and antioxidant capacity [5,21,[34][35][36][37][38]. Consistent with previous studies [21,[39][40][41], absorbance at 420 nm increased with degree of roast (Figure 2), suggesting an increase in the concentration of browned compounds. Similar to TDS, the difference in the concentration of browned compounds between cold and hot brew samples increased with degree of roast. ...
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The role of roasting in cold brew coffee chemistry is poorly understood. The brewing temperature influences extraction processes and may have varying effects across the roast spectrum. To understand the relationship between brew temperature and roast temperature, hot and cold brew coffees were prepared from Arabica Columbian coffee beans roasted to light, medium, and dark levels. Chemical and physical parameters were measured to investigate the relationships among degree of roast, water temperature, and key characteristics of resulting coffees. Cold brew coffees showed differential extraction marked by decreased acidity, lower concentration of browned compounds, and fewer TDS indicating that cold water brewing extracts some compounds less effectively than hot water brewing. Compounds in coffee did exhibit sensitivity to degree of roast, with darker roasts resulting in decreased concentrations for both hot and cold brew coffees. Total antioxidant capacity (TAC) was only sensitive to degree of roast in cold brew coffees, while hot brew coffees had a constant TAC for all three roast levels. This indicates that the solid bean matrix and its chemical constituents interact with cold water differently than with hot water. Surface wetting, pore dynamics, and solubility all contribute to the extraction potential during brewing and are all functions of water temperature.
... Furthermore, due to high temperature during roasting, the Maillard reaction takes place, producing a number of compounds which can contribute to the antioxidant activity of the product (Liu et al., 2020;Pastoriza & Rufián-Henares, 2014). Consequently, all of the compounds that appear during roasting process could either compensate for the loss of some substances or even contribute toward the increase in antioxidant activity (Ludwig, Bravo, De Peña, & Cid, 2013). ...
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Roasting is an important step of coffee processing which affects its quality characteristics. We investigated the effect of microwave and oven roasting on its physicochemical and antioxidant properties, and the fatty acids content. The oil contents of green and roasted coffee beans were determined as 5.75% (green), 9.65% (oven) and 2.70% (microwave). The total phenol content of green coffee beans was decreased by 13.59% and 16.66% on microwave and oven roasting, respectively. Microwave and oven roasting caused a decrease of 34.76% and 37.63%, respectively in the antioxidant potential of green coffee beans. With few exceptions, the contents of most of the phenolic compounds were increased during roasting of coffee beans. The palmitic acid content decreased, while the oleic, linoleic, linolenic and arachidonic acid contents of roasted coffee bean oils were increased during roasting. This information could be helpful for securing the maximal health benefits of coffee.
... This could be due to the presence of other non-phenolic compounds with high antioxidant activity in the ethanolic extract, the presence of a greater amount of particular phenolic compounds, or a sample/assay problem. It is important to highlight that some interference compounds could affect the Folin-Ciocalteu method, leading to overestimation or underestimation of the results [48][49][50], but the present study did not detect any unique component(s) in the LC-MS profile. A positive correlation between total phenol content and antioxidant activity has previously been reported in two populations of V. carnosa from north Patagonia [19]. ...
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... Higher extractability of monoCQAs than diCQA has been previously reported in coffee beverages. 38 ...
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... Furthermore, due to high temperature during prolonged cooking, the Maillard reaction takes place, producing a number of compounds which can contribute to the antioxidant activity of the product [42]. Consequently, all of the compounds that appear during roasting process could either compensate for the loss of some substances or even contribute towards the increase in antioxidant activity [43] The grilled eggplant presented a higher antioxidant activity than that of the raw fruits [44]. In another study, the antioxidant activity of purple eggplant was decreased while the white eggplant was increased upon microwave cooking as compared to the raw fruits [45]. ...
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Fruits and vegetables constitute a considerable amount of antioxidants and among them eggplant is a rich source of polyphenol compounds. This study investigated the bioactive and antimicrobial properties of eggplant under different degree of microwave cooking. The eggplant was cooked for 7 min (light cooked), 10 min (medium cooked), and 15 min (high cooked). The highest total polyphenol content was observed in the light cooked eggplant sample (27.35 mg gallic acid equivalent (GAE)/g dry weight (DW)) followed by high cooked sample (26.10 mg GAE/g DW), while the lowest total polyphenol content (2.79 mg GAE/g DW) was obtained for the uncooked (control) sample. The total polyphenol content of the samples ranged in the following order; light cooked > high cooked > medium cooked > uncooked. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging of eggplant ranged between 16.16% (control) and 47.88% (high cooked). The highest reducing power was exhibited by the light cooked (absorbance 1.708) eggplant sample followed by the high cooked (absorbance 1.597), while the lowest reducing power was shown by uncooked sample (absorbance 0.389). Moreover, antimicrobial studies showed that light cooked eggplant sample demonstrated broad-spectrum inhibition of growth in Gram-positive as well as Gram-negative bacteria and Candida albicans. Slightly lower antimicrobial potential was exhibited by medium cooked eggplant sample while no antibacterial or antifungal activity was recorded for the extract of high cooked eggplant sample. Microwave cooking might be a method to enhance the antioxidant and antimicrobial potential of eggplant.
... Tables 8 and 9 demonstrate that despite the physical (e.g., brittleness and grinding) and chemical differences of roasted pure and sugar-enriched coffee (Andueza et al., 2003;Baggenstoss et al., 2008), moisture can be measured successfully for both matrices. "Torrefacto" coffee is produced by a roasting process in which sugar is added to coffee, normally Robusta (Ludwig et al., 2013). A similar situation arise with powdered and evaporated milk. ...
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Method validation within food science is a not only paramount to assess method certainty and ensure results quality but a pennant in analytical chemistry. Proximate analysis is an indispensable requirement for food characterization. To improve proximate analysis, automated protein and thermogravimetric methods were validated according to international guidelines (including ISO 17095) and acceptance criteria of results based on certified reference materials and participation within international recognized proficiency schemes. Common food groups (including meat, dairy, and grain products) were included and at the end of validation, we obtained three rugged and accurate methods and z scores (−2 ≥ x ≤ 2) and recoveries (92–105%). During optimization, variables such as gas flows, subsample masses, and temperatures were varied and specific conditions (those that rendered the best results) were selected for each food group. For each validated method, a comparison (technical and economic) among the data obtained and the data extracted for its traditional counterpart were included: assays validated demonstrate to be more cost-effective labor-wise (ca. 9 and 16-fold) than their traditional alternatives. Specifically for combustion assay regression analysis (y = 0.9361x, y = 1.1001x, and y = 0.9739x, for meat, dairy and grain products, respectively) were performed to assess the factor, if any, which must be applied to the results to effectively match those obtained for Kjeldahl method. Finally, in the case of protein, samples can be analyzed under 5 min with no residue and a subsample mass below 400 mg. Moisture and ash analysis can be performed simultaneously using the same subsample. Data herein will also help harmonize and advance food analysis toward more efficient greener methods for proximate analysis.
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This study analysed the total content of phenolic compounds in roots and rhizomes extracts from two populations of Valeriana carnosa Sm. (Caprifoliaceae) at three phenological stages. Total phenolic content was determined through the Folin-Ciocalteu method, which ranged between individuals from 3.56 to 11.68 mg GAE/g of dry sample. Antioxidant activity was determined using the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), which showed a significant positive correlation between antioxidant activity and total phenolic content. We tentatively identified 18 phenolic compounds by HPLC-MS, mostly phenolic acids, one of which was present only in the Hoya population at the vegetative stage and one only in the Piltri population at the flowering and fruiting stages. Phenolic compounds in subterranean organs of V. carnosa vary qualitatively (between populations/stages) and quantitatively at intra-and inter-population level at different phenological stages. In both populations, on average a higher phenolic content and antioxidant activity were recorded at the flowering and fruiting stages.
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The present work evaluated the effect of microwave roasting on total polyphenol content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhyrazyl (DPPH) radical scavenging activity, some selected compounds, and the mineral content of coffee beans. Coffee bean powder was roasted at three microwave power levels (450, 720, and 900 W) and treatment durations (4, 6, and 8 min). The TPC, TFC, and DPPH radical scavenging activity were increased by increasing the microwave power and roasting duration, but detrimental effects were observed at higher power levels and longer treatment durations. The highest TPC, TFC, and DPPH radical scavenging activity were detected for the sample treated at 720 W for 6 min. The mineral content was only increased in the sample treated at 450 W for 4 min; all other treatments decreased the mineral content. Microwave power levels and treatment durations showed a significant increase in the browning intensity of the coffee bean extract. The selected coffee bean compounds as analysed by GC-MS were affected in different ways by microwave treatment. The relative percentage of caffeine was increased from 40.06 to 49.12% when treated at 450 W for 4 min, while n-hexadecanoic acid content was decreased from 33.86% in untreated coffee beans to 16.31% when treated at 450 W for 4 min. There was also the formation of new compounds such as octadecanoic acid-methyl ester, vitamin E, and stigmasterol upon microwave roasting of coffee beans. Based on the above results, microwave heating can be used as a roasting method for coffee beans.
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Brazilian arabica coffee is classified for trading according to the quality of the beverage obtained after roasting and brewing. In the present study, Brazilian green and roasted coffee beans were investigated for possible correlations between cup quality and the levels of sucrose, caffeine, trigonelline and chlorogenic acids, determined by HPLC analysis. Trigonelline and 3,4-dicaffeoylquinic acid levels in green and roasted coffee correlated strongly with high quality. To a lesser extent, caffeine levels were also associated with good quality. On the other hand, the amount of defective beans, the levels of caffeoylquinic acids (predominantly 5-caffeoyilquinic acid), feruloylquinic acids, and their oxidation products were associated with poor cup quality and with the Rio-off-flavor. The fact that similar correlations between cup quality and chemical attributes were observed in green and light roasted samples – the latter used for coffee cup classification – indicates that chemical analysis of green beans may be used as an additional tool for coffee quality evaluation.
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Publisher Summary This chapter discusses the analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. Analyses of the Folin-Ciocalteu (FC) type are convenient, simple, and require only common equipment and have produced a large body of comparable data. Under proper conditions, the assay is inclusive of monophenols and gives predictable reactions with the types of phenols found in nature. Because different phenols react to different degrees, expression of the results as a single number—such as milligrams per liter gallic acid equivalence—is necessarily arbitrary. Because the reaction is independent, quantitative, and predictable, analysis of a mixture of phenols can be recalculated in terms of any other standard. The assay measures all compounds readily oxidizable under the reaction conditions and its very inclusiveness allows certain substances to also react that are either not phenols or seldom thought of as phenols (e.g., proteins). Judicious use of the assay—with consideration of potential interferences in particular samples and prior study if necessary—can lead to very informative results. Aggregate analysis of this type is an important supplement to and often more informative than reems of data difficult to summarize from various techniques, such as high-performance liquid chromatography (HPLC) that separate a large number of individual compounds .The predictable reaction of components in a mixture makes it possible to determine a single reactant by other means and to calculate its contribution to the total FC phenol content. Relative insensitivity of the FC analysis to many adsorbents and precipitants makes differential assay—before and after several different treatments—informative.
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This paper summarises the occurrence in foods and beverages of the cinnamic acids, their associated conjugates and transformation products. Quantitative data are lacking for some commodities known to contain them, but it is clear that for many people coffee will be the major source. The daily dietary intake of total cinnamates may vary substantially from almost zero to perhaps close to 1 g. The data relating to their absorption and metabolism are presented along with a consideration of their possible in vivo effects. Data for true bioavailability are incomplete: in particular it is not clear whether availability differs markedly with the form of the conjugate, and whether as a consequence some dietary sources may be superior to others.
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 The time course of the formation of 1- and 3-deoxyosones, 2-osuloses, furan-2-aldehydes, as well as C2, C3 and C4α-dicarbonyl compounds, and hydroxycarbonyl compounds, upon the thermal treatment of aqueous solutions of glucose or xylose in the presence of l-alanine was investigated. 2-Osuloses and glyoxal were formed independently of the carbohydrate moiety, predominantly at the very beginning of the heating process, whereas the formation of 1- and 3-deoxyosones, 2-oxopropanal and hydroxy-2-propanone was favoured with increasing reaction times. In order to evaluate the role of these carbohydrate degradation products in the development of browning their activities as browning precursors were determined on the basis of a dosage/activity relationship by combining chemical/instrumental techniques and visual/sensory analysis. The browning precursors 3-deoxyosone, glyoxal and glycolaldehyde showed highest activities at the very beginning of heating carbohydrate/l-alanine solutions. In contrast to glucose, 2-oxopropanal was found to be an effective colour precursor even at the beginning of heating xylose in the presence of l-alanine. A prolongation of the reaction time led to a drastic decrease in the precursor activity of glyoxal, independently of that of the carbohydrate moiety, and, in parallel, to an increase in the participation of 2-oxopropanal and also furan-2-carboxaldehyde in browning reactions with l-alanine. In the present study, certain carbohydrate degradation products could be identified as browning precursors, and it could be demonstrated for the first time that the activity of these reaction intermediates in producing browning substances changes during the reaction time.
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The antiradical activities of various antioxidants were determined using the free radical, 2,2-Diphenyl-1-picrylhydrazyl (DPPH*). In its radical form. DPPH* has an absorption band at 515 nm which dissappears upon reduction by an antiradical compound. Twenty compounds were reacted with the DPPH* and shown to follow one of three possible reaction kinetic types. Ascorbic acid, isoascorbic acid and isoeugenol reacted quickly with the DPPH* reaching a steady state immediately. Rosmarinic acid and δ-tocopherol reacted a little slower and reached a steady state within 30 min. The remaining compounds reacted more progressively with the DPPH* reaching a steady state from 1 to 6 h. Caffeic acid, gentisic acid and gallic acid showed the highest antiradical activities with a stoichiometry of 4 to 6 reduced DPPH* molecules per molecule of antioxidant. Vanillin, phenol, γ-resorcylic acid and vanillic acid were found to be poor antiradical compounds. The stoichiometry for the other 13 phenolic compounds varied from one to three reduced DPPH* molecules per molecule of antioxidant. Possible mechanisms are proposed to explain the experimental results.
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The addition of sugar at the end of the torrefacto roasting process may influence the antioxidant and pro-oxidant properties of coffee because sugar is one of the main precursors the Maillard reaction. The aim of the work was to study and to compare the antioxidant and pro-oxidant properties of some commercial roasted coffees which are selected to represent conventional roasted arabica coffee and arabica/robusta blends, and torrefacto roasted blends. Higher antioxidant activity was observed in Colombian coffees than in conventional roasted coffee blends. On the other hand, when the percentage of torrefacto coffee was increased, an increase of the antioxidant activity and a slight tendency to decrease the pro-oxidant activity were observed. Moreover, principal component analysis allowed separation of: (a) brands by PC1 (46.9%), characterised by colour parameters defined by roasting degree and (b) torrefacto roasted blends by PC2 (33.7%), characterised by antioxidant/pro-oxidant activity.
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Due to the recognized toxicity of acrylamide, intensive efforts have been made to reduce the concentration of this undesired Maillard by-product in food. This work reports the results obtained from a series of experiments aimed at determining the concentration of acrylamide and the in vitro radical scavenging capacity in the same roasted and ground coffee samples, as it is well established that a significant part of the antioxidant activity in coffee is linked to the melanoidins, which are also considered as Maillard reaction products (MRPs). The radical scavenging capacity was measured using electroparamagnetic resonance (EPR). Coffee samples from the Robusta and Arabica varieties were roasted at 236 °C over different time periods to obtain very light, light, medium and dark roast. Color analyses were performed on all samples. Increasing the roasting degree led to a decrease in acrylamide concentration as well as radical scavenging capacity. The results of this work indicate that any mitigation efforts must also take into account the potential loss of desired food constituents and consequently changes to the risk/benefit characteristics of foods.
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A method, based on HPLC, described in our previous publication for the analysis of chlorogenic acids in instant coffee, was used in a study of the effect of roasting on the chlorogenic acid composition of Arabica and Robusta coffee. The degradation of seven chlorogenic acids was followed during roasting. Losses of about 60% were observed when mild roasting conditions were used and almost 100% after severe roasting. Considerable differences in degradation rates of individual isomers were observed so that the composition of chlorogenic acids changed throughout the roasting process. Thus the degree of roasting may have a direct influence on the final product flavour as the individual isomers have different sensory properties.
Article
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.
Article
Soluble high molecular weight fraction (>10 kDa, named melanoidins) was isolated from Maillard reaction model systems, coffee, beer and sweet wine by ultrafiltration. Deoxyribose method was adjusted for measuring the hydroxyl radical scavenging properties of melanoidins. The presence of competitive melanoidins with deoxyribose for OH decrease the rate of deoxyribose degradation. Possible interferences to the deoxyribose method have been evaluated. Most of isolated melanoidins exhibited a variable and measurable non-site-specific hydroxyl scavenging activity in a Fenton-type reaction system. The iron reducing properties of melanoidins at the reaction conditions were evaluated with ferrozine. It has established a kinetic approach to assess the second rate constants of hydroxyl radical scavenging reactions of melanoidins. This approach may be a valuable tool for addressing the structure–activity relationships of melanoidins in a future. There is no correlation between browning (absorbance at 420 nm) and efficiency for scavenging hydroxyl radicals in solution.
Article
Browning reactions represent an interesting research area for the implications in food technology, nutrition and health. The development of some non-enzymatic browning reactions, such as Maillard reaction, has been recently associated to the formation of compounds with strong antioxidant capacity. In this paper, the relation between colour changes due to non-enzymatic browning and the formation of compounds with antioxidant activity is discussed. Simple positive or complex correlation between colour and antioxidant properties can be found depending on composition and technological history of the product. Complex relations between these variables are generally obtained in multi-component and in formulated foods, where the simultaneous development of a number of reactions, interacting or prevailing Maillard reaction itself, can affect in opposite ways the overall antioxidant properties and colour of the product.
Article
The antioxidant properties of coffee were studied in relation to roasting degree. In particular, the extent of the chain-breaking activity and oxygen scavenging properties of Maillard reaction products contained in coffee brews were evaluated. Samples showed very high chain-breaking and oxygen consumption activities, which did not increase linearly with increasing roasting degree. In our experimental conditions, the highest antioxidant properties were found for the medium-dark roasted coffee brews.
Article
The production of soluble coffee starts with the selection of beans and is followed by roasting, grinding, extraction and drying. Lyophilised soluble coffees extracted by various methods from light, medium and dark-roasted arabica and robusta beans were evaluated for antioxidant activity (AA) using ABTS, Folin, DPPH and FRAP techniques. Caffeine, chlorogenic acid (5-CQA) and melanoidin content was also quantified. The data were analysed by principal component analysis. The AA values derived from the various methods used were correlated. Roasting resulted in the degradation of 5-CQA and formation of melanoidins, while AA was largely unaffected by roasting. The extraction of soluble coffee more prominently affected the AA of light-roasted coffee, mainly because it favoured the extraction of 5-CQA. The larger caffeine content in robusta coffee resulted in greater AA. All of soluble coffee products studied possessed antioxidant potential, which was conferred by their concentrations of phenolic compounds, caffeine and melanoidins.
Article
Roasting is a key step in the production of a high-quality coffee. Roasting degree is directly related to coffee chemical composition and may be determined objectively by weight loss after roasting. Chlorogenic acids (CGA) are thermally labile phenolic compounds that play an important role in the final cup quality and health benefits of coffee. Considering the interest in finding a reliable method to predict weight loss and CGA content in coffee, models have been developed to estimate these parameters during roasting. Weight loss was successfully modeled (r = 0.99) independent of the instant temperature. CGA degradation followed first-order Arrhenius-compliant kinetic models with good predictability (r = 0.98), especially for light to moderately dark samples. In both cases distinct models for Coffea arabica and Coffea canephora were calculated, because of differences in chemical composition and cell wall structure between these species. The proposed models may become important predictive tools in the coffee industry.
Article
The antioxidant capacity of coffee brews prepared with different coffeemakers (filter, plunger, mocha, and espresso) was measured by colorimetric (total phenolic compounds and ABTS) and electron spin resonance (ESR) spectroscopy techniques (Fremy's salt and TEMPO). The mocha coffeemaker had the highest yield in coffee antioxidant extraction per gram of ground roasted coffee, but espresso coffee was richest in terms of antioxidant intake (per milliliter of coffee brew) followed by mocha, plunger, and filter. Both Folin-Ciocalteu (total phenolic compounds) and ABTS assays reacted with standard solutions of chlorogenic acids (CGA) and melanoidins (MO-Ala and MO-Gly). However, Fremy's salt was mainly scavenged by chlorogenic acids, whereas the stabilized radical TEMPO was effectively scavenged by melanoidins, but not by chlorogenic acids. Thus, ESR spectroscopy allows distinguishing between phenolic and nonphenolic antioxidants. Moreover, the addition of pH-regulator agents to coffee, such as sodium carbonate (75 ppm) and bicarbonate (75 ppm), to extend its shelf life, slightly increases the pH, modifying the antioxidant capacity in those coffee brews with the highest capacity (mocha and espresso).
Article
The aim of this work was to obtain a black coffee brew to be consumed hot by extension of its shelf life, by addition of additives. Four pH-regulator agents (sodium and potassium carbonates and bicarbonates), one pH regulator and antioxidant (sodium citrate), three antioxidants [sodium ascorbate, ethylenediaminetetracetic acid (EDTA), and sodium sulfite], and lactoserum were tested by sensory analysis. Sodium carbonate and bicarbonate were selected for a study of the physicochemical (soluble and volatile compounds related to the sensory properties) and sensorial quality of coffee brew stored for 90 days at 4 degrees C. Although both additives extended the shelf life of the coffee brew up to 60 days, sodium carbonate was the chosen additive because it was the most useful in limiting the pH decrease and perception of sourness, which are some of the main factors involved in the rejection of stored coffee brews, and it better maintained the aroma and taste/flavor. Moreover, the application of multivariate analysis facilitated first the description of the global changes of the coffee brews with or without additives throughout the storage using principal component analysis and second the obtainment of a simple equation only with pH and caffeic acid parameters to discriminate the three types of coffee brews and simplify the analytical process, by means of the stepwise discriminant analysis.
Article
The effect of the roasting degree on coffee brew melanoidin properties and formation mechanisms was studied. Coffee brew fractions differing in molecular weight (Mw) were isolated from green and light-, medium-, and dark-roasted coffee beans. Isolated fractions were characterized for their melanoidin, nitrogen, protein, phenolic groups, chlorogenic acid, quinic acid, caffeic acid, and sugar content. It was found that the melanoidin level in all fractions correlated with both the nitrogen and the protein content. The melanoidin level also correlated with the phenolic groups' level and ester-linked quinic acid level. It was concluded that proteins and chlorogenic acids should be primarily involved in melanoidin formation. Initial roasting, from green to light-roasted beans, especially led to the formation of intermediate Mw (IMw) melanoidins when compared to high Mw (HMw) melanoidins. Indications were found that this IMw melanoidin formation is mainly due to Maillard reactions and chlorogenic acid incorporation reactions between chlorogenic acids, sucrose, and amino acids/protein fragments. Additionally, it was found that prolonged roasting predominantly led to formation melanoidins with a high Mw. Furthermore, arabinogalactans seem to be relatively more involved in melanoidin formation than galactomannans. It was hypothesized that chromophores may be formed or attached through the arabinose moiety of arabinogalactan proteins (AGP). Finally, it could be concluded that galactomannans are continuously incorporated in AGP-melanoidins upon roasting.
Article
The pro-oxidant activity of potent oxidants and foods was determined using the kinetic analysis of crocin bleaching. In its reduced form, crocin has an absorption band at 443 nm, which disappears upon oxidation by a generic radical species. Hydroxyl radicals generated by hydrogen peroxide, peroxyl radicals from ABAP, and the stable free radical DPPH(*) were allowed to react with crocin in an aqueous solution at 40 degrees C. Pro-oxidant activity was taken as the ratio between the decrease in crocin absorbance at 5 min and the relevant oxidant concentration. The test proposed was used to evaluate the pro-oxidant activity of widely consumed foods such as pasteurized skim milk and bread. They both exerted significant pro-oxidant activities, which were attributed to the early nonenzymatic browning products formed upon heat treatment.
Article
Colombian Arabica coffee beans were roasted to give light, medium, and dark samples. Their aqueous extracts were analyzed by gel filtration chromatography, UV-visible spectrophotometry, capillary electrophoresis, and the ABTS(*)(+) assay. A progressive decrease in antioxidant activity (associated mainly with chlorogenic acids in the green beans) with degree of roasting was observed with the simultaneous generation of high (HMM) and low molecular mass (LMM) compounds possessing antioxidant activity. Maximum antioxidant activity was observed for the medium-roasted coffee; the dark coffee had a lower antioxidant activity despite the increase in color. Analysis of the gel filtration chromatography fractions showed that the LMM fraction made a greater contribution to total antioxidant activity than the HMM components.
Article
To investigate the contribution of beverages to the intake of lipophilic and hydrophilic antioxidants in the Spanish diet. This includes the following (i) estimation of the daily intakes of beverages in Spain, from national food consumption data obtained from annual surveys of 5400 households, 700 hotels and restaurants and 200 institutions; (ii) determination of total antioxidant capacity in the selected beverages using two complementary procedures: ferric reducing ability of plasma (FRAP), which measures the ferric reduction capacity, and ABTS, which measures the radical scavenging capacity; (iii) determination of the antioxidant capacity in both lipophilic and hydrophilic extracts of the beverages; (iv) determination of the antioxidant efficiency of the lipophilic and hydrophilic phase of the beverages; and (v) estimation of the intake of dietary antioxidants from beverages in comparison with the daily requirements of antioxidant vitamins C and E. The contribution of beverages to the antioxidant intake in the Spanish diet is estimated at 1623 mg of vitamin E and 598 mg of vitamin C by FRAP, and 1521 mg of vitamin E and 556 mg of vitamin C by ABTS. Coffee is the main contributor (66 and 61% by FRAP and ABTS, respectively), followed by red wine (16 and 22%), fruit juices (6 and 5%), beer (4 and 5%), tea (3 and 5%) and milk (4 and 1%). Beverages account for a very high proportion of dietary antioxidant intake as compared to intake of antioxidant vitamins C and E. Although their metabolic effect must be affected by the bioavailability of the antioxidants, the significance of this intake for antioxidant status and health should be considered.
Article
A method involving fractionation in ethanol aqueous solutions, anion exchange chromatography, and immobilized copper chelating chromatography was developed to obtain high molecular weight anionic melanoidin populations from coffee infusions. Six anionic fractions with different physicochemical properties (ethanol solubility and chelating ability) and chemical composition regarding carbohydrate as well as protein nature and content were isolated. Fractions with similar chemical composition were obtained for light-, medium-, and dark-roasted coffee infusions. These melanoidin fractions accounted for 30-33% of the cold-water soluble high molecular weight material, independently of the degree of roast in coffee. The nature and abundance of the different polysaccharides in each fraction were dependent on their ethanol solubility. The 50% ethanol insoluble melanoidin populations contained mostly galactomannan-like carbohydrates, and the fractions obtained with 75% ethanol contained mostly arabinogalactan-like carbohydrates. The melanoidin populations with chelating properties presented significantly lower carbohydrate content and, from these, the 75% ethanol soluble fractions were almost devoid of carbohydrate material. The results obtained suggest that the chelating ability of these coffee melanoidins is modulated by their carbohydrates.
Article
Relationships between volatile and nonvolatile compounds and the antioxidant capacity of coffee brews prepared from commercial conventional and torrefacto roasted coffees, employing commonly used doses and prepared by four brewing procedures (filter, plunger, mocha, and espresso machine) were assessed. Significant correlations between volatile Maillard reaction products and antioxidant capacity (measured by both 2,2-diphenyl-1-picrylhydrazyl radical and redox potential methods) were not observed. Highly positive correlations between browned compounds and caffeine with both antioxidant capacity parameters were reported. Principal component analysis allowed coffee brews separation according to coffee roasting processes (PC1) and brewing procedures (PC2), showing that in all cases coffee brews from torrefacto roasted coffee were more antioxidant that those extracted from conventional ones; also, coffee brews extracted by an espresso machine were more antioxidant than those extracted by mocha, plunger, and filter machines.
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