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Summary: This current work presents a meta‐analysis to determine coffee bean specifications [types (Arabica and Robusta), roasting degree (light, medium and dark), roasting condition (time and temperature) and geographical origins by countries (Brazil, India and Thailand)] with the highest antioxidant activity. A total of 12 articles and 189 data points were employed for meta‐analysis of subgroups. The results showed that the Arabica coffee bean was reported to have the highest antioxidant activity as assessed by ferric reducing antioxidant power (FRAP) and 2,2‐azinobis‐3 ethyl benzothiazoline‐6‐sulfonic acid (ABTS). In addition, the light roasting degree of coffee beans produced the highest antioxidant activity as assessed by FRAP and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH). Roasting degree is a better parameter to obtain coffee beans with higher antioxidant activity compared to roasting conditions. Coffee from Brazil and India was found to have higher antioxidant activity compared with coffee from Thailand. This study concludes that Arabica coffee beans from Brazil or India with a light roasting degree are expected to have high antioxidant activity. [ABSTRACT FROM AUTHOR]

BACKGROUND This study was carried out in order to investigate the role of post‐harvest methods and roasting degree on the sensory profile of Turkish coffees and to compare the results between two sensory panels: Turkey and Brazil. Bourbon variety of Arabica coffee beans processed by three different post‐harvest methods (natural, pulped natural and fully washed) and roasted at three different roasting degrees (light, medium and dark). RESULTS: Ground coffee in powder size was heated with cold water and prepared in a Turkish coffee machine. Twenty assessors – ten Turkish and ten Brazilian – were selected and trained to assess 20 flavor attributes of nine Turkish coffee samples. Sensory evaluation results showed that the effects of roasting method on flavor development were perceived more dominantly than effects of post‐harvest methods. For the first time, this study highlighted the sensory analysis of Turkish coffees assessed by Turkish and Brazilian assessors. CONCLUSION: Turkish coffee flavor profiles were significantly influenced by roasting method and no significant effects of post‐harvest method were observed. Sensorial properties of Turkish coffee were affected by several factors, such as geographical origin and techniques used for preparation of coffee beans, cultural tradition, lifestyle, social behavior and habit. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The coffee strip-picking harvesting method, preferred in Brazil, results in high percentages of immature and overripe beans, as the fruits in a single tree branch do not reach ripeness at the same time. This practice, together with inappropriate processing and storage conditions, contribute to the production of high amounts of defective coffee beans in Brazil, which upon roasting will impart negative sensory aspects to the beverage. Therefore, the development of analytical methodologies that will enable the discrimination and quantification of defective and non-defective coffees after roasting is rather desirable. Given that infrared spectroscopy has been successfully applied to coffee analysis, the objective of this work was to evaluate and to compare the performances of Fourier transform infrared (FTIR) and near infrared (NIR) spectroscopies for the quantification of defective beans in roasted coffees. Defective and non-defective Arabica coffee beans were manually selected, roasted, ground and sieved. Mixtures of defective and non-defective roasted and ground coffees were produced and analyzed, with % defects ranging from 0% to 30%. FTIR and NIR spectra were recorded, respectively, within a range of 3100–800 cm −1 and 1200–2400 nm and submitted to mathematical processing. Quantitative models were developed by partial least squares regression (PLSR). Excellent predictive results were obtained indicating that defective coffees could be satisfactorily quantified. The correlation coefficients and the root mean squared errors of validation for the FTIR and NIR models developed to quantify the amount of defective roasted coffees mixed with non-defective ones were, respectively, as high as 0.891 and as low as 0.032, and as high as 0.953 and as low as 0.026. A comparison between the two techniques indicated that NIR provided more robust models. [ABSTRACT FROM AUTHOR]

Abstract: Coffee is an important commercial product to Brazil with its consumption distributed globally. The aim of this work was to evaluate the potential of yeast strains as starter cultures for dry fermentation of washed and non-washed coffee beans. Four yeast strains (Saccharomyces cerevisiae UFLA YCN727, S. cerevisiae UFLA YCN724, Candida parapsilosis UFLA YCN448 and Pichia guilliermondii UFLA YCN731) were inoculated separately in washed and non washed coffee cherries and in the control was not added any of the starter cultures. The fruits inoculated were spread on trays and placed on a terrace until the coffee beans reached 11% of moisture. Samples were collected for evaluation of the persistence of the inoculum by PCR-DGGE, and for chemical composition by HPLC and GC-FID. Sensory analysis was performed using the Temporal Dominance of Sensations (TDS) methodology. In all tests the yeasts persisted until the end of fermentation. There was no propionic and butyric acid production in concentrations that could compromise the final quality of the beverage. Forty-eight volatile compounds were identified, some were similar for green and roasted coffee. The most abundant class of compounds was alcohols (11–27%) followed by furan in roasted grains (~27%), and aldehydes (~13%) in green grains. The coffee inoculated with yeast showed sensations of flavors higher than the control coffee indicating increased sensory quality. The treatment with C. parapsilosis UFLA YCN448 showed dominance rate higher (near 1) for the sensation of caramel. In non-washed coffee those sensations were not pleasant in relation to the washed coffee, except when P. guilliermondii UFLA YCN731 was inoculated, suggesting that washing the fruit before the fermentation process positively influenced the final product quality. A coffee with special aroma of caramel, herbs and fruits could be produced using the starter cultures C. parapsilosis UFLA YCN448 and S. cerevisiae UFLA YCN727 in coffee processed by the dry method. [Copyright &y& Elsevier]

This work describes the use of near infrared spectroscopy (NIRS) and chemometric techniques calibration for the classification of coffee samples from different lots and producers acquired in supermarkets and roasting industries in some Brazilian cities. Seventy-three samples of finely ground roasted coffee were acquired in the market and 91 samples of roasted ground Arabica beans were analyzed in the full NIR spectral range (800–2500 nm) using a diffuse reflectance accessory coupled to an MB160 Bomem spectrophotometer. Two classification models were constructed: Soft Independent Modeling Class Analogy (SIMCA) and PLS Discriminant Analysis (PLS-DA). All findings reveal that NIR spectroscopy, coupled with either SIMCA or PLS-DA multivariate models, can be a useful tool to differentiate roasted coffee grains and to replace sensory tests. [ABSTRACT FROM PUBLISHER]

In this work, the potential of mid-infrared diffuse reflectance spectroscopy with Fourier transform for discrimination of 29 commercial Brazilian coffee samples with different industrial processing, i.e., caffeine extraction and roasting degree, was evaluated. The statistical treatments applied to pre-treated spectral data were principal component analysis and partial least squares – discriminant analysis (PLS-DA). The ordered predictors selection method was used for variable selection. The chemometric analyses of the mid-infra-red spectra allowed inferring on the lower carbohydrate, caffeine and chlorogenic acid concentration as well as on the higher water content in the decaffeinated coffee. The technique also allowed speculation on the higher lipid and lower water content in the dark roasted coffee compared with traditional roasted coffee. A clear discrimination of decaffeinated from medium and dark roasted coffees was observed in PC1. PLS-DA was used for the discrimination between medium and dark roasted coffees. A model with one latent variable correctly classified 100% of the external validation and prediction samples according to their roasting degree. PRACTICAL APPLICATIONS Diffuse reflectance mid infrared spectroscopy (DRIFTS), principal component analysis and partial least squares were successfully applied to discriminate decaffeinated coffees from nondecaffeinated coffees and to discriminate roasted coffees by their roasting degree. This study have shown that DRIFTS coupled with chemometrics consists in a simple and straightforward analytical method for monitoring the roasted coffee authenticity, and the results could help in developing an alternative and inexpensive method for quality control of coffee products. [ABSTRACT FROM AUTHOR]