Navegando por Autor "Freitas, Valdeir Viana"

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Avaliação da fermentação do café arábica com uso de culturas starters
(Universidade Federal de Viçosa, 2018-07-13) Freitas, Valdeir Viana; Eller, Monique Renon
O objetivo deste estudo foi avaliar o uso de leveduras e bactérias láticas como culturas starters em processamento de café por via úmida. O café arábica foi colhido em duas propriedades rurais na cidade de Venda Nova do Imigrante no Estado do Espírito Santo, e foi inoculado com as seguintes culturas starters: Saccharomyces cerevisiae JP14 (FML) e Pediococcus acidilactici CCT 1622 (FBL). O controle (FN) não foi inoculado. A contagem da população microbiana, as atividades de enzimas hidrolíticas em espectrofotômetro e a avaliação dos ácidos orgânicos, etanol e glicose, quantificados por HPLC, foram realizadas para verificar as diferenças que ocorrem neste tipo de processamento. As análises sensoriais foram realizadas utilizando a Escala Hedônica de 9 pontos. No perfil dos microrganismos, as leveduras e mesófilos aeróbios estavam presentes durante toda a fermentação com contagens até 10 4 e 10 7 respectivamente, e houve predominância de leveduras em FML devido ao número de células inoculado. As atividades de enzimas amilolíticas, celulolíticas e pectinolíticas sofreram descréscimo no decorrer do período fermentativo. Etanol e os ácidos málico, propiônico e succínico não foram detectados em nenhum dos tratamentos, enquanto ácido cítrico e ácido lático foram identificados em todos os tratamentos em ambas as propriedades, tanto nos mostos quanto nos grãos de cafés torrados e moídos. O café inoculado com P. acidilactici CCT 1622 (FBL) apresentou um sabor mais acentuado e agradavél em relação a FN (controle) e FML, e obteve escore entre gostei moderadamente a gostei muito, tal como avaliado pelos testes de aceitação utilizando provadores não treinados. O estudo evidenciou que o uso de culturas starters durante a fermentação do café contribuiu para a obtenção de uma bebida de qualidade com características sensoriais agradavéis.
Chemical and sensory composition of arabica and robusta coffee in response to modifications in the roasting process
(Universidade Federal de Viçosa, 2023-10-11) Freitas, Valdeir Viana; Stringheta, Paulo Cesar; Santos, Marcelo Henrique dos; Vidigal, Márcia Cristina Teixeira Ribeiro
In recent years, the coffee market has experienced remarkable growth, driven by its expansion and production on a global scale. South America, in particular, stands out as one of the main coffee-producing regions, led by Brazil, and is also the largest exporter of this agricultural commodity. Furthermore, it is relevant to emphasize that coffee is one of the most widely consumed beverages worldwide, attracting an increasingly discerning consumer audience regarding product quality. An essential element in the process of transforming green coffee beans into an aromatic and flavorful cup of coffee is the roasting stage. This operation plays a fundamental role in creating the distinctive flavors and aromas found in the final beverage. In this context, the purpose of this study was to investigate the complexity of roasting by conducting a thorough analysis of the physicochemical and sensory changes that occur during this process. For this purpose, six different roasting profiles were employed, where temperature and roasting time were carefully considered and adjusted. The results unveiled intriguing information. It was found that the highest levels of total phenolics, compounds endowed with beneficial antioxidant properties for health, were identified in coffees subjected to specific temperatures, such as 135 °C/20.20 min and 210 °C/9.02 min. These findings not only provide valuable insight into the nutritional profile of roasted coffee but also emphasize the influence of different roasting profiles on these characteristics. Surprisingly, C. canephora, known for its more robust and full-bodied character, exhibited superior antioxidant activity compared to C. arabica in many of the evaluated roasting profiles. This finding may redefine the traditional view that C. arabica always surpasses C. canephora in terms of quality. The results showed that roasting profiles, as well as the species, strongly influenced all investigated parameters, particularly the concentration of sugars, organic acids, and melanoidins. Succinic acid was the organic compound with the highest concentrations, with the highest concentration observed in C. canephora at 210 °C/11.01 min (224.24 mg/g), with the highest concentrations of organic acids found in this same roasting profile and species (430.39 mg/g). Fructose was the sugar with the highest concentration, particularly in the 210 °C/11.01 min roast, which exhibited 17.14 mg/g. The highest melanoidin content was also found in this same roasting profile and species. Sensory evaluation, conducted by both experts and consumers, has revealed significant differences in flavor, aroma, and overall quality properties among coffee varieties and various roasting profiles. C. arabica has received higher ratings compared to C. canephora, particularly with better scores for roasting profiles at 135 °C/20.20 min and 230 °C/17.43 min. These conclusions offer a deeper understanding of the nuances present in the roasting process and its impact on the coffee experience for enthusiasts of this beverage. Therefore, as we delve deeper into the coffee market, it becomes evident that roasting represents an operation that not only transforms the beans but also influences flavor, nutritional value, and consumer perception. Keywords: Coffea arabica L. Coffea canephora. Roasting. Chemical composition. Coffee quality.
Sensory Q-Grader evaluation of fermented arabica coffees by yeast (Saccharomyces cerevisiae) and lactic bacteria (Pediococcus acidilactici) cultures
(Editora UFLA, 2020) Rodrigues, Sandy Dias; Coelho, Vinicius Serafim; Freitas, Valdeir Viana; Brioschi, Alessandra; Brioschi Júnior, Dério; Guarçoni, Rogério Carvalho; Pereira, Lucas Louzada; Eller, Monique Renon; Cardoso, Wilton Soares
The objective of this study was to evaluate sensorially, by professional Q-Grader, the beverage coffee from fermentation natural and fermentation with the use of yeasts and lactic acid bacteria as starter cultures in wet coffee processing. The Arabica coffee was harvested at two different altitudes in Espírito Santo State. Both coffees went through 04 treatments: inoculated with starter cultures Saccharomyces cerevisiae (YML) or Pediococcus acidilactici CCT 1622 (LAF), natural fermentation (NF) (not inoculated) and Control, without fermentation (WF). The coffee was processed by just the wet process. After process and roasting, the sensorial analysis was performed to understand the impact of fermentation processing in the coffee quality, and was performed by 6 Q-Graders, following SCA protocol. The study evidenced that the use of natural fermentation or starter cultures during post-harvest coffee contributed to obtain a quality beverage with pleasurable sensorial characteristics, punctuated by the tasters in the overall score obtained and also by the high sensory scores in attributes such as fragrance, acidity, aftertaste and the different perceived aromas. This work demonstrates for coffee growers that fermentation technology is not intuitive but requires an understanding of the relationship of the microorganisms with the coffee and the environment. In addition to the other chemical aspects of roasting and brew coffee.