Post-harvest processing and microbial fermentation of coffee fruits play an essential role in the metabolites formation that influence the nutritional and sensory quality of the beverage. Thus, the ...objective of this study was to analyze the effect of coffee cherries processing and fermentation conditions on the microbial communities and the chemical and sensory quality of the beverage. Induced fermentation changed in the bacteria and fungi communities (Treatments: T1, T3, and T7).
Klebsiella
sp. inoculation (T1) allowed an increase in richness of bacteria and 81 points in the sensory score over the fermentation time. However, there was a reduction in richness of microbial community in treatments with
Saccharomyces cerevisiae
(T3 and T7)
.
An increase in the indexes of microbial diversity was observed in 72 h in treatment with coffee pulp (T2). In treatment with coffee cherries and spontaneous fermentation (T4) had a higher sensory score than other treatments, indicating a sensory gain from 36 to 72 h. Coffee cherries with superficial disinfection (T5) had a reduction in microbial profile, but did not change the final score of the beverage over the 72 h. In T6 (floaters fruits) was observed an alteration in the fungal community (36–72 h) and the lowest sensory score. The impact of adding water on coffee fermentation was dependent on time (T3 and T7). Furthermore, 5-hydroxymethylfurfural has a positive correlation with the final score of the beverage. Thus, microbial profile and sensory score of beverages are dependent of conditions of processing of coffee fruits and fermentation.
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•Microbial richness increases depending on the condition of the fermentation.•Microorganisms actions could be correlated with sensory attributes.•Fermentation conditions promote ...sensory and chemical changes in coffee.
In view of the possibility of diversifying metabolic routes promoted by fermentation, this study proposed a new processing method for coffee, which consists of adapting a technique already consolidated in winemaking, carbonic maceration. The assay occurred under anaerobic conditions with different time and temperature fermentation. The aim of this study was to determine the differences in coffee characteristics (sensorial, chemical, and microbial) after carbonic maceration and fermentation. Specialty Coffee Association protocol, nuclear magnetic resonance, and denaturing gradient gel electrophoresis were used in these analyzes. A significant functional relationship between global score and temperature (38 °C), for the fermentation time of 96 h was observed. Bacterial diversity and sensory characteristics had a positive correlation. Furthermore, trigonelline, formic acid, hydroxymethylfurfural, lipids, and γ-butyrolactone also contributed to score and sensory quality of coffee beverage. Thus, our data show consistent factors to infer on the microbiological action on the sensory quality of coffee beverage.
Coffee is one of the most widely consumed beverages in the world. When compared to the arabica variety, robusta coffee has a lower market value due to several factors, especially those related to ...sensory analysis. Thus, this study examined fermentation processing techniques for Arabica and Robusta coffees using medium infrared analyzes to identify differences in their chemical compositions, which suggested specific fermentation routines for each variety. The samples of both varieties, collected in proper regions of the Brazilian state of Espírito Santo, were subjected to different wet-processing methods (Washed, Yeast fermentation, Dry fermentation, and Dry fermentation with yeast). The obtained spectra were divided into spectral regions, which were compared by specific statistical tests that revealed differences between them for the varieties and processing methods. Yeast Fermentation demonstrated to be the most recommendable processing technique for the robusta variety, considering the obtained secondary compounds associated with final coffee quality.
•Infrared spectroscopy and fermentation show similarities between arabica and conilon.•Statistical tests show differences in the structure of coffee varieties.•Secondary compounds generated by fermentation are related to coffee quality.•The induced fermentation approximates the quality of conilon to arabica coffee.
Edaphoclimatic conditions, planting altitudes, soil, the microbiome of plants and fruits, genotypes, and postharvest processing are variables that contribute to the chemical and sensory quality of ...the coffee. Thus, the objective of this study was to evaluate the impacts of planting altitude and fermentation of fruits on the chemical and sensory quality of the coffee using Nuclear Magnetic Resonance (NMR) and Linear Discriminant Analysis (LDA). Cherry coffees were harvested in eight points of altitudes between 826 and 1078.08 m. A completely randomized design with e planting altitudes, five fermentation processes, and five repetitions was performed. Lipids, trigonelline, citrate, and malate were the compounds that most contribute to the chemical discrimination of coffee in the altitudes below 969 m. While, in the high altitudes (> 1000 m), this discrimination was due to the HMF, quinic acid, caffeine, and formic acid, and the global notes of coffee beverages were higher than 80 points. In fermented coffee, the LDA of the chemical data indicates the formation of five clusters, showing how the compounds can suffer changes depending on the form of processing used in coffee. The best score of beverage was observed in samples of 1078.08 m under dry fermentation and only in samples of 969 m was observed a significant difference in the sensory score between spontaneous fermentation and induced fermentation. Thus, coffee sensory scores were dependent on planting and fermentation methods and NMR and LDA techniques proved important in chemical and sensory discrimination of coffees.
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•1H NMR and advanced data analysis methods for evaluating fermented coffees.•Starter fermentation with Saccharomyces cerevisiae provided better sensory quality.•The chemical and ...sensory profiles of fermented coffees are correlated.•Lipids are important markers for the quality of fermented conilon coffee.
The potential impact of fermentation on coffee quality has been the target of several scientific studies. In this perspective, we present a design of different fermentation processes applied to coffees of the Coffea canephora var. conilon. Thus, coffee samples were submitted to six fermentation methods, at five different times (24, 48, 72, 96, and 120 h). Sensory analysis and hydrogen nuclear magnetic resonance (1H NMR) were used in roasted coffees, to understand aspects of quality and chemical profile, respectively. Variable selection by Fisher discriminant (FD), and multivariate data analysis, including principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA), and support vector machine (SVM) were used to extract the main chemical information and establish direct relationships with coffee sensory quality. The results indicated chlorogenic acids, caffeine, γ-butyrolactone, lipids, sugars, and acetic acid as responsible for the discrimination of the different fermentation processes. In addition, lipids were characteristic in coffees with higher sensory scores, indicating they are an important marker for the quality of the beverage.
Coffee is one of the most widely consumed beverages in the world. The genetic variability of
Coffea canephora
has demonstrated significant differences in the chemical compositions of genotypes, ...resulting in different sensory profiles in the beverage. Fermentation can also affect the sensory quality of coffee beverage. Therefore, the objective of this study was to analyze the sensory profile and the chemical groups that contribute to the sensory qualities of the coffee beverage of
C. canephora
var. Conilon genotypes subjected to different fermentation processes. Fermentations were carried out with 4 L of cherry coffee or peeled cherry coffee for 36 h at 25 ℃. In the induced fermentation, the initial Colony Forming Unit (CFU/mL) was of 10
7
for S
accharomyces cerevisiae
,
Klebsiella
sp, and
Lactobacillus brevis
. There was no microbial inoculation in the washed fermentation and the natural process. The sensory quality and chemical groups of the coffee were determined using the Uganda Coffee Development Authority Sensory Analysis Protocol with 6 Q-Graders and mid-infrared spectroscopy, respectively. The sensory and spectrometry analyses were able to distinguish the genotypes, highlighting the separations of genotypes A1 and Verdim with the worst sensory results, and genotype 153 with the best result. Groups formation through the mean Euclidean distance reinforces the sensory differences between fermentations. Furthermore, the greatest chemical changes in coffee beans were promoted by fermentation induced by
S. cerevisiae
. Thus, the genotypes and the type of fermentation influence in the sensory quality demonstrating potential for optimizing fermentations to improve the sensory quality of conilon coffee.
VOLATILE PROFILE OF Coffea arabica AND Coffea canephora var. conilon BY SHS-GC-MS AND CHEMOMETRICS. The volatile composition of coffee exerts a substantial influence on its quality, as it defines the ...characteristics of the beverage. However, these compounds are influenced by factors within the coffee production chain, such as botanical origin, geography, processing methods, and roasting. Consequently, the identification of such compounds becomes a vital tool for characterizing coffees to these factors. In this context, gas chromatography with headspace extraction is widely used for aroma analysis, providing a composition closer to consumer perception. Headspace extraction offers speed, simplicity, minimal sample preparation, and no need for solvents. In this study, static headspace extraction (SHS) coupled with gas chromatography-mass spectrometry (SHS-GC-MS) was employed to establish the chemical profile of volatile compounds in Coffea arabica and Coffea canephora var. conilon and determine discriminants between the species. A total of 97 compounds, belonging to 17 chemical classes, were identified. The chemometric analysis highlighted furans, phenols, and carboxylic acids as key differentiating classes. Notably, furfuryl alcohol, acetic acid, 4-vinylguaiacol, N-acetyl-4(H)-pyridine, and N-furfurylpyrrole emerged as crucial volatile compounds. The variable selection using Fisher weight applied directly in the chromatograms, produced models consistent with relative area data, with furfuryl alcohol and 4-vinylguaiacol regions being particularly influential in differentiation.
The consumer market has a strong tendency to consume specialty coffees, making it essential to understand the influence of environmental conditions, such as solar radiation and altitude, on coffee ...quality. This study aimed to analyze the physical and sensory quality of Arabica coffee as a function of different altitudes and incident solar radiation on the coffee tree. The study was carried out in the city of Manhuaçu-MG, Brazil. Three altitudes (950, 1050 and 1150 m above mean sea level) and two sides of coffee exposure to solar radiation (east face: morning sun and west face: afternoon sun) were studied in two post-harvest processing (natural and peeled cherry). Sensory attributes, granulometry and occurrence of coffee defects were evaluated, in order to verify if there was variation in the physical and sensorial characteristics of the coffee. It was found that at an altitude of 1150mamsl, on the exposed face of the plant that received the afternoon sun, there was the formation of better-quality coffee, when compared to the face that received the morning sun. On the other hand, at lower altitudes, coffees from the face of the plant exposed to the morning sun showed a greater association with physical and sensory quality parameters.
•1H and 13C NMR for discrimination of asphaltenes from three different oils.•Aggregation of asphaltenes by diffusion-ordered NMR spectroscopy (DOSY).•Correlation between continental and archipelago ...model and asphaltene aggregation.
Nuclear Magnetic Resonance experiments were used to study the relationship between the structural type (continental or archipelago) and aggregation properties of three different asphaltenes (asph_A, asph_B and asph_C). Diffusion-ordered NMR spectroscopy (DOSY) was applied to investigate the diffusion coefficients. The self-diffusion of the asphaltene aggregates was investigated in the concentration range of 0.01–10% of each asphaltene in deuterated toluene. Data obtained from 1H and 13C NMR indicate that asph_B has a predominantly continental type of structure. This contributes to different properties of aggregation. DOSY shows the presence of three aggregates, with three different diffusion coefficients, called nanoaggregate, microaggregate and macroaggregate.
Among the different strategies adopted to improve the quality of Coffea canephora, fermentation is considered a promising technology to modulate the organoleptic characteristics of the beverage. ...Considering the possibility of providing a change in sensory profile through fermentation, this study aims to evaluate the chemical and sensory changes promoted by carbonic maceration in C. canephora whose effect is still unknown. The study was implemented in anaerobic conditions with different fermentation times (24, 48, 72, 96, and 120 h) and temperatures (18, 28, and 38 °C). The processed grains were subject to sensory analysis and medium infrared spectroscopy. Significant linear functional relationships were observed between total score and temperature for fermentation times of 24, 72, and 96 h and that the total score increased with fermentation temperature. Although a clear connection with sensory results was not observed, infrared analysis was able to point out important correlations with quality through stretches observed in infrared spectrum regions. Thus, there is feasibility of applying the carbonic maceration technique for grain processing of C. canephora.
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