Navegando por Autor "Fernandez-Güimac, Samia Littly Jahavely"

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Exploring the diversity of microorganisms and potential pectinase activity isolated from wet fermentation of coffee in northeastern Peru
(Sociedade Brasileira de Ciência e Tecnologia de Alimentos, 2023-01-09) Fernandez-Güimac, Samia Littly Jahavely; Perez, Jhordy; Mendoza, Jani Elisabet; Bustamante, Danilo Edson; Calderon, Martha Steffany
In this study, the microbiota associated with coffee fermentation from two regions from northern Peru was evaluated. Bacteria and fungi were isolated from coffee farms in the Amazonas and Cajamarca regions and identified using molecular markers 16S rRNA and ITS. The potential pectinase activity was registered by the formation of a transparent halo around colonies. As a result, 29 and 09 species belonging to bacteria and fungi, respectively, were found. The bacterial genera Lysinibacillus and Stenotrophomonas and the fungal genus Aspergillus accounted for the highest number of species isolated from coffee ferments. Forty-one out of 71 isolates showed some type of pectinase enzyme activity, and they included 23 isolates from Cajamarca and 18 from Amazonas. Nevertheless, only three bacterial species registered the formation of transparent halos and showed relevant potential pectinase enzyme activity, namely, Lysinibacillus xylanilyticus, Stenotrophomonas maltophilia, and Stenotrophomonas pavanii, which were all from the Cajamarca region. These species could be further investigated by quantifying enzymes activity and performing other biochemical properties to prototype starter cultures. Accordingly, the study of indigenous microorganisms with biological potential will be essential to increase the coffee value chain and improve the incomes of farmers.
Variability of volatile compound profiles during two coffee fermentation times in northern Peru using SPME-GC/MS
(Instituto de Tecnologia de Alimentos – ITAL, 2023-05-15) Perez, Jhordy; Calderon, Martha Steffany; Bustamante, Danilo Edson; Caetano, Aline Camila; Mendoza, Jani Elisabet; Fernandez-Güimac, Samia Littly Jahavely
The time of the fermentation process of coffee from northern Peru is variable (9 to 48 hours) since coffee farmers do not use standardized processes, causing a variety of coffee qualities. This study aimed to identify volatile compounds in both short (9 hours) and long (32 hours) coffee fermentation processes from coffee farms in northern Peru using Solid-Phase Microextraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS) to associate the coffee quality and diversity of volatile compounds. Sensory analyses showed that the short fermentation process (SFP) scored 77.8 ± 0.39 and had chocolate, wood, cardboard, dry, fatty and rough notes, while the long fermentation process (LFP) showed higher punctuations 85.5 ± 3.16 and citrus, fruity, floral, caramel and chocolate sensory attributes. A total of 90 compounds were found in the SFP, whereas 141 compounds were identified in the LFP. Significant differences in the relative abundance of 14 chemical compounds were reported in the SFP and LFP (p < 0.05). From these results, the presence of benzaldehyde, methional, hexanal, 2-heptanone, pentadecane, 1-butanol-3-methyl-acetate, and benzene-acetic acid ethyl ester seems to impact the quality of coffee. The analysis of similarities showed that coffee samples (5 h and 9 h) during the SFP were very variable, whereas coffee samples from LFP showed some tendency to group, which may be related to the difference in altitude and temperature in coffee farms making comparison between them difficult. In addition, this study highlights the complex relationship between coffee fermentation and flavour and the influence of several factors and variables that may affect the composition of flavour and aroma precursors in green coffee beans obtained from wet fermentation.