Determination of ochratoxin A in coffee by ELISA method and its relationship with the physical, physicochemical and microbiological properties / Determinación de ocratoxina A en café mediante método ELISA y su relación con las propiedades físicas, fisicoquímicas y microbiológicas

Background: Coffee is one of the most consumed beverages in the world; however, it may contain toxic compounds such as ochratoxin A (OTA). Objectives: Determine the OTA's presence in different types of coffee, intended for beverage preparation and marketed in Colombia through the application of the enzyme-linked immunosorbent assay (ELISA) and analyze its relationship with the physical, physicochemical and microbiological properties. Methods: 8 samples of coffee commercialized in the Colombian market were selected, in which the OTA content was determined by applying the ELISA method. Likewise, a microbiological analysis was performed, and physicochemical properties were determined, such as moisture content, aw, percentage total dissolved solids (%TDS), and extraction yield (%EY). Physical properties such as free-flow densities, compacted bulk densities (CBD), porosity, average particle size (ASP), and color. The data were treated with multivariate analysis using Principal Component Analysis (PCA) and Cluster Analysis (CA) to quantitatively investigate the relationships between the coffee samples concerning their physical, physicochemical properties, and OTA content. LSD test was applied with a significance level of 95 % and Pearson correlation test. Results:All the samples had OTA content, but only 2 exceeded the limits allowed by the regulations, with a maximum value of 15.449 µg/Kg, which represents 31.449 % of the tolerable daily intake according to the parameters defined by Joint FAO/WHO Expert Committee on Food Additives (JECFA). According to the PCA and CA, the samples were grouped harmonically according to the type of coffee associated with its commercial presentation and industrial process, OTA content, and ASP. OTA content was significantly and positively correlated (p< 0.05) with %EY, %TDS, ASP, porosity, CBD and moisture. Conclusions: The coffees marketed in Colombia showed a variable range of OTA, where soluble coffees had higher OTA contents than roasted coffees, and 25 % of the coffees analyzed do not meet the levels defined by Colombian regulations. The OTA content in coffee is related to properties that define the ability to extract solutes from coffee

Antecedentes: El café es una de las bebidas más consumidas en el mundo, sin embargo, puede contener compuestos tóxicos como la ocratoxina A (OTA). Objetivos: Determinar la presencia de OTA en diferentes tipos de café destinados a la preparación de bebida y comercializados en Colombia mediante la aplicación del ensayo inmunoabsorbente ligado a enzimas (ELISA) y analizar su relación con las propiedades físicas, fisicoquímicas y microbiológicas. Métodos: Se seleccionaron 8 muestras de café comercializado en el mercado colombiano, en las cuales se determinó el contenido de OTA mediante la aplicación del método ELISA. Así mismo se realizó análisis microbiológico y se determinaron propiedades fisicoquímicas como contenido de humedad, aw, porcentaje de sólidos disueltos totales (%TDS) y rendimiento de extracción (%EY); y propiedades físicas como densidad por caída libre, densidad compactada (CBD), porosidad, tamaño promedio de partícula (ASP) y color. Los datos fueron tratados con análisis multivariado empleando análisis de componentes principales (PCA) y análisis de conglomerados (CA) para investigar cuantitativamente las relaciones entre las muestras de café con respecto a sus propiedades físicas, fisicoquímicas y contenido de OTA. Se aplicó prueba LSD con un nivel de significación del 95 % y prueba de correlación de Pearson. Resultados: Todas las muestras presentaron contenido de OTA, pero solo 2 sobrepasaron los límites permitidos por la normatividad, con un valor máximo de 15.449 µg/Kg, el cual representa un 31.449 % de la ingesta diaria tolerable según los parámetros definidos por el Comité Mixto FAO/OMS de Expertos en Aditivos Alimentarios (JECFA). De acuerdo al PCA y CA, las muestras se agruparon armónicamente de acuerdo al tipo de café asociado a su presentación comercial y proceso industrial, contenido de OTA y ASP; el contenido de OTA se correlacionó significativa y positivamente (p < 0.05) con el %EY, %TDS, ASP, porosidad, CBD y humedad. Conclusión: Los cafés comercializados en Colombia presentan un rango variable de OTA, en donde los cafés solubles presentan contenidos de OTA mayores que los cafés tostados y el 25 % de los cafés analizados no cumplen con niveles definidos por la normatividad colombiana. El contenido de OTA en el café está relacionado con propiedades que definen la capacidad de extracción de solutos del café

Characterization of Roasted Coffea arabica Species by the Relationship Between Caffeine and Diterpenes Contents

Abstract Commercial roasted and ground coffees are usually blends of Coffea arabica and Coffea canephora. Considering the differences in price and sensory characteristics between these two species, the identification of the presence of each species in commercial blends is of great interest. The aim of this study was to describe typical profiles of caffeine and diterpenes (kahweol and cafestol) contents and the ratios among these compounds to support the characterization of Coffea species in roasted coffees. 32 good cup quality Brazilian C. arabica coffees (from coffee quality contests) produced using different postharvest treatments were studied. All analysis were performed by HPLC. Higher ranges were observed in diterpene contents - kahweol varied from 1.75 to 10.68 g/kg (coefficient of variation of 510%) and cafestol from 1.76 to 9.66 g/kg (449%) - than caffeine, that varied from 5.1 to 16.2 g/kg (coefficient of variation of 218%). Wide ranges of the kahweol/cafestol ratio (0.63 to 2.77) and the caffeine/kahweol ratio (0.84 to 5.15) were also observed. Hence it was proposed the additional use of a new parameter, the ratio of caffeine/sum of diterpenes (kahweol + cafestol) that presents values from 0.54 to 2.39. The results indicated that the combined use of these parameters could be a potential tool for discriminating Coffea species in blends of roasted and ground coffee. It was proposed as potentially indicative of C. arabica: values of kahweol/cafestol ratio above 0.50, associated with caffeine/kahweol ratio lower than 5.50 and caffeine/sum of diterpenes ratio lower than 2.50.

Effect of Brewing Methods and Time on Secondary Metabolites, Total Flavonoid and Phenolic Content of Green and Roasted coffee Coffea arabica, Coffea canephora and Monsooned Malabar

Coffea arabica, Coffea canephora (robusta) and monsooned malabar are the three types of coffee which are well known and used by most of population in India and all over the globe. For consuming coffee various brewing methods are used worldwide, French press, Espresso, Turkish coffee, being the common. Eleven brewing methods are introduced in the paper for brewing of green coffee, some of which are common for brewing tea. Among all the mentioned brewing methods, Decoction method showed the best results, as maximum amount of Flavonoids and Phenols were found to be present in green coffee arabica, values being 69.24 mg QE/g of coffee and 108.67 mg QE/g of coffee respectively, whereas, for robusta it was found to be 47.47 mg QE/g of coffee and 93 mg QE/g of coffee respectively. Brewing time is also considered as one of the major factors for coffee brewing, as if the time is too short, all the flavours will not dissolve and if too long, it may dissolve undesirable components as well. An increasing trend was seen in flavonoid and phenolic content in both arabica (TPC up to 84.11 mg QE/g of coffee) and robusta (TPC up to 78 mg QE/g of coffee) along with monsooned malabar (TPC up to 84.88 mg QE/g of coffee) with increase in brewing time. Another factor considered is the solvent used for brewing. A comparison was made between water and alcohol. Both the coffees, green and roasted showed a significant difference in the values when brewed in ethanol and in water. Results indicate that the brewing methods given may be used along with a variant brewing time depending on its phenolic content. Also, green coffee can be proved a boon with more health benefits as compared to roasted one.

Comparison of High Performance Liquid Chromatography with Fluorescence Detector and with Tandem Mass Spectrometry methods for detection and quantification of Ochratoxin A in green and roasted coffee beans

Two analytical methods for the determination and confirmation of ochratoxin A (OTA) in green and roasted coffee samples were compared. Sample extraction and clean-up were based on liquid-liquid phase extraction and immunoaffinity column. The detection of OTA was carried out with the high performance liquid chromatography (HPLC) combined either with fluorescence detection (FLD), or positive electrospray ionization (ESI+) coupled with tandem mass spectrometry (MS-MS). The results obtained with the LC-ESI-MS/MS were specific and more sensitive, with the advantages in terms of unambiguous analyte identification, when compared with the HPLC-FLD.

Determinação quantitativa das principais substâncias utilizadas para fraudar o café torrado e moído / Quantitative determination of the main substances used to defraud ground roasted coffee

E descrita uma serie de métodos, elaborados na Seção do Café do Instituto Adolfo Lutz, São Paulo, SP, para identificação e determinação quantitativa das principais substancias (açúcar, caramelo, cevada, milho, cascas de cacau e de soja) utilizadas para fraudar o café torrado e moído. São métodos simples e rápidos, posto que ao Serviço de Fiscalização local interessa a resposta de analise no mais curto espaço de tempo possível. E descrito, ainda o aspecto das substancias da fraude, num exame a lupa (aum. 20 x) (AU).

Teores de cobre em café torrado e moído e em café bebida / Copper contents in roasted and ground coffee and in brewed coffee

Cem amostras de café torrado e moído (pó), de diferentes partes do Brasil, foram analisadas para determinação de cobre pelo método de espectrofotometria de absorção atômica. Foram analisados também os cafés bebida correspondentes. Os resultados encontrados mostraram um valor médio de 17,26 p.p.m. de cobre para os pós e de 1,19 p.p.m. para os cafés bebida. Como o café bebida foi preparado de modo a representar uma diluição de 1:5 do pó correspondente, os valores encontrados indicam uma extração de 34,9% do cobre existente nos pós. 5% das amostras de pós mostraram um nivel abaixo de 10p.p.m. de cobre. Neste pós, quase todo o cobre foi extraído quando o café bebida foi obtido. Não há correlação entre os valores de cobre obtidos no café bebida e o contidos no pó. Quando os cafés bebidas foram preparados do mesmo modo (na diluição de 1:5), todos mostraram um nivel de cobre de 1,0 p.p.m.+-0,26...

Determinação do sedimento, cascas e paus no café e moido / Determination of sediment, husks and sticks in coffee and ground

Neste trabalho foi descrito método para determinação do sedimento e cascas no café de consumo, torrado e moído. Consiste no desengorduramento parcial do material com solvente para separar o sedimento e deixar o pó solto, peneração para livrar a amostra do pó (que não é de interesse na observação para livrar a amostra do pó (que não é de interesse na observação á lupa), separação das impurezas e pesagem. No calculo final, usou-se o fator de conversão para reverter o peso encontrado em peso de impurezas no café verde (AU).