Microencapsulação por spray drying de leveduras epifíticas do café para inoculação no processo fermentativo
Data
2022-12-13
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Lavras
Resumo
A comercialização de leveduras na forma líquida não é indicada a longo prazo pois as células perdem a viabilidade. Além disso, há de risco de contaminação e maiores custos com transporte e armazenamento refrigerado. Assim, uma alternativa é a secagem por spray drying. Esta técnica pode ser utilizada de forma contínua e rápida, permitindo altas taxas de produção com baixos custos operacionais. Dito isto, o objetivo do trabalho foi avaliar a eficácia da microencapsulação por spray drying para promoção da secagem e revestimento de três leveduras epifíticas do café: Saccharomyces cerevisiae CCMA0543, Torulaspora delbrueckii CCMA0684 e Meyerozyma caribbica CCMA1738. O trabalho foi dividido em três etapas. A primeira etapa consistiu na avaliação da viabilidade celular das leveduras microencapsuladas em spray dryer de escala laboratorial. As leveduras (109 UFC mL−1 ) foram microencapsuladas separadamente com maltodextrina (15%), maltodextrina (15%) com sacarose (2%) ou maltose (2%). Os resultados indicaram que a viabilidade celular variou entre 94,06 e 97,97%. Após 6 meses, ambas as leveduras armazenadas a 7 °C e 25 °C apresentaram 107 e 10 2 UFC mL −1 , respectivamente. Esta etapa mostrou que foi possível microencapsular as leveduras epifíticas do café por spray drying e que a maltodextrina foi eficiente como material de parede. A segunda etapa consistiu na avaliação do efeito dos parâmetros operacionais no processo de secagem para obtenção de leveduras microencapsuladas em spray dryer de maior escala. A concentração do material de parede e a temperatura de entrada do ar de secagem foram investigadas por meio do Delineamento do Composto Central Rotacional (DCCR). Em seguida, a performance fermentativa das leveduras microencapsuladas foram avaliadas em meio de casca e polpa de café. As leveduras atingiram viabilidade celular e rendimentos de secagem acima de 90 e 50%, respectivamente. Soro de leite em pó manteve a viabilidade celular das três leveduras ao longo de 90 dias de armazenamento à temperatura ambiente (25°C) e foi selecionado como material de parede para as três leveduras. M. caribbica mostrou-se mais sensível à secagem por spray drying e menos resistente ao armazenamento. Algumas diferenças foram encontradas na fermentação, mas as leveduras microencapsuladas mantiveram suas características biotecnológicas. Por fim, a terceira etapa consistiu em comparar os desempenhos fermentativos de leveduras líquidas e microencapsuladas em café fermentados por anaerobiose autoinduzida (SIAF). Após 180 h de fermentação no processo natural, T. delbrueckii microencapsulada (MT) (7,97x107 cel/g) apresentou uma população maior do que T. delbrueckii líquida (FT) (1,76x107 cel/g). O estado da levedura influenciou na concentração dos compostos orgânicos e voláteis. Os cafés inoculados com S. cerevisiae microencapsulada (MS) apresentaram notas dominantes de frutado, caramelo e nozes no processamento natural. Já no café descascado, os cafés inoculados com MT apresentaram caramelo, mel e nozes. Considerando os parâmetros analisados, as leveduras mais indicadas para processamento natural e descascado seriam MS e MT, respectivamente. Como conclusão, as leveduras microencapsuladas por spray drying foram metabolicamente ativas e podem ser consideradas com potencial comercial, principalmente para produtores de café interessados em utilizar culturas iniciadoras durante SIAF.
The yeasts commercialization in the liquid form is not indicated in the long term as the cells lose viability. In addition, there is a risk of contamination and higher costs with transport and refrigerated storage. Thus, an alternative is spray drying. This technique can be used continuously and quickly, allowing high production rates with low operating costs. That said, the objective of this work was to evaluate the effectiveness of microencapsulation by spray drying to promote the drying and coating of three epiphytic coffee yeasts: Saccharomyces cerevisiae CCMA0543, Torulaspora delbrueckii CCMA0684 and Meyerozyma caribbica CCMA1738. The work was divided into three steps. The first step was evaluating of the cell viability of microencapsulated yeasts in a laboratory-scale spray dryer. The yeasts (109 CFU mL−1) were microencapsulated separately with maltodextrin (15%), maltodextrin (15%) with sucrose (2%), or maltose (2%). The results showed that cell viability varied between 94.06 and 97.97%. After six months, both yeasts stored at 7 °C and 25 °C showed 107 and 102 CFU mL−1, respectively. This step showed that it was possible to microencapsulate the epiphytic coffee yeasts by spray drying. Maltodextrin was efficient as a wall material. The second step evaluated the effect of operational parameters on the drying process to obtain microencapsulated yeasts in a larger-scale spray dryer. The wall material concentration and the drying air inlet temperature were investigated using the Central Rotational Composite Design (DCCR). Then, the fermentative performance of microencapsulated yeasts was evaluated in a coffee peel and pulp media. The yeasts reached cell viability and drying yields above 90 and 50%, respectively. Whey powder maintained the cell viability of the three yeasts over 90 days of storage at room temperature (25°C) and was selected as wall material for the three yeasts. M. caribbica was more sensitive to spray drying and less resistant to storage. Some differences were found in the fermentation, but the microencapsulated yeasts maintained their biotechnological characteristics. Finally, the third step compared the fermentative performances of liquid and microencapsulated yeasts in coffee fermented by self-induced anaerobiosis (SIAF). After 180 h of fermentation in the natural process, microencapsulated T. delbrueckii (MT) (7.97x107 cells/g) presented a larger population than liquid T. delbrueckii (FT) (1.76x107 cells/g). The state of the yeast influenced the concentration of organic and volatile compounds. Coffees inoculated with microencapsulated S. cerevisiae (MS) showed dominant notes of fruitiness, caramel, and nuts in natural processing. In the pulped coffee, the coffees inoculated with MT presented caramel, honey, and nuts. Considering the analyzed parameters, the most suitable yeasts for natural and pulped processing would be MS and MT, respectively. In conclusion, spray drying microencapsulated yeasts were metabolically active and may be considered with commercial potential, especially for coffee producers interested in using starter cultures during SIAF.
The yeasts commercialization in the liquid form is not indicated in the long term as the cells lose viability. In addition, there is a risk of contamination and higher costs with transport and refrigerated storage. Thus, an alternative is spray drying. This technique can be used continuously and quickly, allowing high production rates with low operating costs. That said, the objective of this work was to evaluate the effectiveness of microencapsulation by spray drying to promote the drying and coating of three epiphytic coffee yeasts: Saccharomyces cerevisiae CCMA0543, Torulaspora delbrueckii CCMA0684 and Meyerozyma caribbica CCMA1738. The work was divided into three steps. The first step was evaluating of the cell viability of microencapsulated yeasts in a laboratory-scale spray dryer. The yeasts (109 CFU mL−1) were microencapsulated separately with maltodextrin (15%), maltodextrin (15%) with sucrose (2%), or maltose (2%). The results showed that cell viability varied between 94.06 and 97.97%. After six months, both yeasts stored at 7 °C and 25 °C showed 107 and 102 CFU mL−1, respectively. This step showed that it was possible to microencapsulate the epiphytic coffee yeasts by spray drying. Maltodextrin was efficient as a wall material. The second step evaluated the effect of operational parameters on the drying process to obtain microencapsulated yeasts in a larger-scale spray dryer. The wall material concentration and the drying air inlet temperature were investigated using the Central Rotational Composite Design (DCCR). Then, the fermentative performance of microencapsulated yeasts was evaluated in a coffee peel and pulp media. The yeasts reached cell viability and drying yields above 90 and 50%, respectively. Whey powder maintained the cell viability of the three yeasts over 90 days of storage at room temperature (25°C) and was selected as wall material for the three yeasts. M. caribbica was more sensitive to spray drying and less resistant to storage. Some differences were found in the fermentation, but the microencapsulated yeasts maintained their biotechnological characteristics. Finally, the third step compared the fermentative performances of liquid and microencapsulated yeasts in coffee fermented by self-induced anaerobiosis (SIAF). After 180 h of fermentation in the natural process, microencapsulated T. delbrueckii (MT) (7.97x107 cells/g) presented a larger population than liquid T. delbrueckii (FT) (1.76x107 cells/g). The state of the yeast influenced the concentration of organic and volatile compounds. Coffees inoculated with microencapsulated S. cerevisiae (MS) showed dominant notes of fruitiness, caramel, and nuts in natural processing. In the pulped coffee, the coffees inoculated with MT presented caramel, honey, and nuts. Considering the analyzed parameters, the most suitable yeasts for natural and pulped processing would be MS and MT, respectively. In conclusion, spray drying microencapsulated yeasts were metabolically active and may be considered with commercial potential, especially for coffee producers interested in using starter cultures during SIAF.
Descrição
Tese de Doutorado defendida na Universidade Federal de Lavras
Palavras-chave
Otimização, Secagem, Culturas iniciadoras, SIAF, Optimization, Drying, Starter cultures
Citação
MARTINS, Pâmela Mynsen Machado. Microencapsulação por spray drying de leveduras epifíticas do café para inoculação no processo fermentativo. 2022. 168 p. Tese (Doutorado em Ciência dos Alimentos)–Universidade Federal de Lavras, Lavras, 2022.