•Sequential inoculation increases the formation of volatile compounds in the coffee.•Sequentially fermented coffees has as sensory descriptors the fruity and fermented.•Main volatile compounds found ...were furfuryl acetate, pyridine and 1-methylpyrrole.
Mixed starter cultures of lactic acid bacteria and yeasts used in the production of fermented foods, including coffee, can improve the sensory quality and food safety. The objective of this study was to evaluate the effects of fermentation of coffee with inoculation of Lactiplantibacillus plantarum followed by Saccharomyces cerevisiae and the effects of fermentation time on the aroma and flavor of the coffee beverage and on the volatile composition of the roasted coffee beans. The coffee was fermented for 48 h or 96 h after inoculation of Lactiplantibacillus plantarum followed by inoculation of Saccharomyces cerevisiae or the respective controls. The aroma and flavor of the coffee beverage fermented with sequential inoculation showed complexity, with a predominance of fruity and fermented sensory notes. Forty-seven volatile compounds were identified. In addition, the sequentially inoculated coffees had greater formation of volatiles and led to greater perception of fruity and fermented flavor and aroma.
Seeds from different coffee species and coffee from different continents or countries have very distinct chemical composition. However, the differences between genotypes grown at micro-regional ...levels with similar geographical characteristics are still unclear. In this study, we highlighted the need of using metabolite profiling instead of the usual targeted analysis as a more powerful tool to describe the slight differences between coffees of the same species grown in close origins. Thus, our study focused on finding potential metabolite markers to describe differences of Coffea arabica L. genotypes (Mundo Novo and Bourbons) grown in Brazilian coffee producing municipalities (Lavras, Santo Antônio do Amparo—SAA, and São Sebastião da Grama—SSG). Using the metabolomics approach, 44 metabolites were identified, and some showed great potential for origin and genotype differentiation. The Partial Least Square Discriminant Analysis — PLS-DA model showed that the SAA coffee samples had the most differentiated metabolite profile (approximately 95% accuracy) compared to the other municipalities. The samples from Lavras and SGG had similar profiles (model accuracy of approximately 50%). Potential metabolite markers for the SAA samples included galactinol, fructose, malic acid, oxalic acid, d-glucose, d-sorbitol, galactinol, and myo-inositol. The model used to differentiate the Bourbon and the MN genotype showed 100% accuracy indicating very different metabolite profiles. The features that were most influential in differentiating genotype were: 5-CQA, oxalic acid, galactinol, nicotinic acid, caffeine, and caffeic acid (Bourbon) and myo-inositol, quinic acid, malic acid, fructose, and d-glucose (MN). Enhancing subtle differences in the data by combining information from GC-Q/MS and multivariate analysis resulted in the identification of coffee origins and genotypes as well as the identification of potential markers.
•Metabolite profiling of coffee genotypes grown in different Brazilian regions•We used chemometric tools PCA and PLS-DA to assess the metabolite profiles.•GC-Q/MS ally to chemometric analysis is suitable to discriminate coffee samples.•Different regions have different metabolite profiles of coffee seeds.•Different genotypes have different metabolite profiles.
ABSTRACT Coffee sensory analysis is usually made by a sensory panel, which is formed by trained tasters, following the recommendations of the Specialty Coffee Association of America. However, the ...preference for a coffee is commonly determined by experimentation with consumers, who typically have no special skills in terms of sensory characteristics. Therefore, this study aimed at applying an intensive computational method to study sensory notes given by an untrained sensory panel, considering the probability distributions of the class of extreme values. Four types of specialty coffees produced under different processes and in varied altitudes in the mountainous region of Mantiqueira, Minas Gerais, were considered. We concluded that the generalized Pareto distribution can be applied to sensory analysis to discriminate types of specialty coffees. Furthermore, the method of importance sampling by Monte Carlo simulation showed greater variability considering a probabilistic model adjusted to identify specialty coffees.
The present study had the objective to evaluate the effect of blends of KCl and K
SO
fertilizers and their influence on the yield and the nutritional state of coffee plants, as well as on the ...chemical composition and quality of the coffee beverage. The experimental design was in randomized blocks with four repetitions and six treatments (T1: 100% KCl; T2: 75% KCl + 25% K
SO
; T3: 50% KCl + 50% K
SO
; T4: 25% KCl + 75% K
SO
; T5: 100% K
SO
; and a control, without application of K). The following analyses were performed: K and Cl content in the leaves and the soil, stocks of Cl in soil, yield, removal of K and Cl with the beans, cup quality of the beverage, polyphenol oxidase activity (PPO), electric conductivity (EC), potassium leaching (KL), the content of phenolic compounds, the content of total sugars (TS), and total titratable acidity (TTA). The stocks of Cl in the soil decreased as the proportion of KCl in the fertilizer was reduced. The fertilization with KCl reduces the cup quality and the activity of the polyphenol oxidase, probably due to the ion Cl. The increase in the application of Cl directly relates to the increase in potassium leaching, electric conductivity, and titratable acidity. Indirectly, these variables indicate damages to the cells by the use of Cl in the fertilizer. The activity of the polyphenol oxidase enzyme and the cup quality indicate that the ion Cl- reduces the quality of the coffee beverage. K content in the leaves was not influenced by the application of blends of K fertilizer while Cl content increased linearly with KCl applied. The application of KCl and K
SO
blends influenced coffee yield and the optimum proportion was 25% of KCl and 75% of K
SO
. The highest score in the cup quality test was observed with 100% K
SO
.
In Brazil, coffee beverage quality is classified according to technical recommendations of the Associação Brasileira da Indústria de Café (ABIC), which determines cutoff points to discriminate from ...non-recommended to gourmet coffees. Accordingly, this study aimed to propose the use of cluster analysis to evaluate coffee blends composed of coffees with different qualities and of different varieties regarding a few sensory properties, using continuous and binary scales obtained by a cutoff, which defines whether the coffee is recommendable or not according to the ABIC criteria. It is believed, therefore, that this technique can be used to analyze coffee beverage quality as it is easily accessible and implemented by researchers. In conclusion, a qualitative cluster analysis using the minimum cutoff value of the ABIC had more promising results. This is because blends whose composition contained high and moderate proportions of specialty coffees were more homogeneous in the clustering.
The identification and interpretation of discrepant observations in sensory experiments are difficult to implement since the external effects are associated with the individual consumer. This fact ...becomes more relevant in experiments that involve blends, which scrutinize coffees with different qualities, varieties, origins, and forms of processing and preparation. This work proposes a statistical procedure that facilitates the identification of outliers while also evaluating the discriminatory powers of a sensory panel concerning the differentiation of pure blends and coffees. For this purpose, four experiments were performed that tested coffees with different qualities and varieties. The results suggest that the statistical procedure proposed in this work was effective for discriminating the blends relative to the pure coffees and that the effects of the concentrations and types of processing did not interfere with the statistical evaluations.
The objective of this study was to evaluate the correlation between a group of physiological variables (electrical conductivity, potassium leaching, and germination percentage) and a group of drying ...kinetics variables (drying time and drying rate) in addition to verifying the relation between drying kinetics variables and coffee quality as a function of processing type, temperature, and drying airflow. Coffee drying was conducted in a fixed-layer dryer at two temperatures and two airflows. After drying, an evaluation of the physiological and sensorial quality was conducted. Based on the results obtained, the following conclusions were drawn: coffee that is processed via a dry method is more sensitive to mechanical drying with heated air than coffee processed via a wet method, resulting in poor physiological performance; airflow does not interfere with the physiological quality of pulped and natural coffees; a temperature increase from 40 to 45°C resulted in a decrease in the physiological quality only for pulped coffee; and an increase in the drying rate as a result of an increase in the drying temperature to 40°C had a negative effect on the sensorial quality of pulped coffee.
•Volatile compounds of roasted coffees identify chemical changes in green coffee.•Paper package allows more chemical changes on volatile compounds.•Natural coffee is more sensitive to chemical ...alteration then pulped natural coffee.
Studies of storage of green coffee often correlate sensory quality with chemical composition when chemical changes have already occurred irreparably and have affected the coffee flavor. This does not allow application of any technique to prevent the change in coffee flavor and aroma. The main aim of the present study was to identify chemical indicators of the aging of green coffee beans, through use of gas chromatography-mass spectrometry in roasted and ground coffee beans, before changes in the sensory attributes of the roasted coffee become perceptible. Green coffee beans of natural coffee and pulped natural coffee were packed and stored in bags permeable to water vapor and gases and in hermetic bags. Sensory analysis was carried out to be associated with the profiles of volatile compounds over 18 months of storage. The latent damage to sensory attributes is more pronounced in natural than pulped natural coffee. Green natural coffee beans packed in permeable packaging exhibit latent damage at 3 months of storage that will later be manifested, compromising sensory quality.
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