The use of mesophilic and lactic acid bacteria strains as starter cultures for improvement of coffee beans wet fermentation.

The use of starter cultures during food fermentation aims to standardize the process and to obtain a higher quality product. The objectives were to study mesophilic bacteria (MB) and lactic acid bacteria (LAB) isolated from wet coffee processing and evaluate their performance in a pulped coffee medium. Eighty-six bacteria isolates (59 MB and 27 LAB) were assessed for pectinolytic activity, metabolite production, and pH value decrease in coffee-based culture (CPM). Seven bacteria strains (3 MB and 4 LAB) were selected and used as starter cultures in the wet fermentation of pulped coffee. The MB and LAB populations varied from 4.48 to 8.43 log CFU g-1 for MB and 3.54 to 8.72 log CFU g-1 for LAB during fermentation. Organic acid concentration (ranged from 0.01 to 0.53 for succinic acid; 0.71 to 8.14 for lactic acid and 0.06 to 0.29 for acetic acid), and volatile compounds (44 compounds were detected in green beans and 98 in roasted beans) were evaluated during fermentation. The most abundant compounds found in roasted beans belong to furans [15], ketones and esters [14], pyridines [13], and pyrazines [12]). Leuconostoc mesenteroides CCMA 1105 and Lactobacillus plantarum CCMA 1065 presented volatile compounds important for coffee aroma. Isovaleric acid; 2,3-butanediol; phenethyl alcohol; ß-linalool; ethyl linoleate; and ethyl 2-hydroxypropanoate could improve cupping qualities.

Production of coffee (Coffea arabica) inoculated with yeasts: impact on quality.

BACKGROUND: The aim of this study was to evaluate the performance of yeasts Saccharomyces cerevisiae CCMA 0200 and Torulaspora delbrueckii CCMA 0684 in Mundo Novo and Catuaí varieties processed by the wet method and the impact on sensory quality and compounds profile. The microbiota was evaluated by surface plating, and the compounds were evaluated by high-performance liquid chromatography and gas chromatography-mass spectrometry. Sensorial analysis was performed using the cupping test (Specialty Coffee Association). RESULTS: T. delbrueckii CCMA 0684 was better adapted to the process and remained for up to 72 h of drying. Eighteen volatile compounds were detected in green coffee and 75 in roasted coffee. 2-Furanmethanol propanoate and 2-ethyl-3,5-dimethylpyrazine were identified only in the inoculated treatments, and these are important contributors to the coffee aroma. All treatments received scores greater than 80 in the sensory analysis. CONCLUSION: T. delbrueckii CCMA 0684 presented better results in relation to the sensorial analysis and is preferable for the varieties and processing method studied. The use of starter cultures is a viable method with which to obtain high-quality coffees with a distinct flavor and thus add to value to the product. © 2019 Society of Chemical Industry.

Behavior of yeast inoculated during semi-dry coffee fermentation and the effect on chemical and sensorial properties of the final beverage.

Pulped Mundo Novo and Ouro Amarelo coffee beans were inoculated with Saccharomyces cerevisiae (CCMA 0200 and CCMA 0543) during semi-dry coffee fermentation and compared with a non-inoculated control. Samples were collected throughout the fermentation process (12days) to evaluate the persistence of the inoculum by Real-Time quantitative PCR (qPCR). Also, the chemical composition of the beans was determined by HPLC and GC-MS and the roasted beans were sensorial evaluated using the cupping test. S. cerevisiae CCMA 0543 had an average population of 5.6logcell/g (Ouro Amarelo cultivar) and 5.5logcell/g (Mundo Novo cultivar). Citric, malic, succinic and acetic acid were found in all samples, along with sucrose, fructose, and glucose. There were 104 volatile compounds detected: 49 and 55 in green and roasted coffee, respectively. All coffee samples scored over 80 points in the cupping test, indicating they were specialty-grade. Inoculation with the CCMA 0543 strain performed better than the CCMA 0200 strain. This is the first time that qPCR has been used to assess the persistence of the inoculated strains populations during coffee processing. Strain CCMA 0543 was the most suitable as an inoculant due to its enhanced persistence during the process and number of volatile compounds produced.

Microbiological diversity associated with the spontaneous wet method of coffee fermentation.

The evaluation of the microbiota present during coffee wet fermentation was done in two distinct regions of Minas Gerais, Brazil: one farm in the South of Minas Gerais (Lavras=L) and another farm in the savannah region (Monte Carmelo=MC). The yeast population ranged from 2.48 to 4.92 log CFU/g and from 2 to 4.81 log CFU/g, the mesophilic bacteria population ranged from 3.83 to 8.47 log CFU/g and from 5.37 to 7.36 log CFU/g, and the LAB population ranged from 2.57 to 5.66 log CFU/g and from 3.40 to 4.49 log CFU/g in the L and MC farms, respectively. Meyerozyma caribbica and Hanseniaspora uvarum were the dominant yeasts in coffee wet fermentation at L farm, and Torulaspora delbrueckii was the dominant yeast at MC farm. The species Staphylococcus warneri and Erwinia persicina were the predominant bacteria at L farm, and Enterobacter asburiae and Leuconostoc mesenteroides were the dominant species at MC farm. Lactic acid was the principal acid detected, reaching 2.33 g/kg at L farm and 1.40 g/kg at MC farm by the end of the process. The volatiles composition was similar for roasted coffee from the two different regions and furans, acids, and alcohol were the main groups detected. Temporal Dominance Sensation (TDS) analyses showed that the coffee beverage from L farm was dominated by citrus and herbaceous sensory characteristics, while the coffee from MC farm was dominated by citrus, herbaceous, and nuts sensory characteristics. Evaluating the microbiota in these two regions was important in improving the knowledge of the microbial species present during coffee wet fermentation in Brazil.

Inoculation of starter cultures in a semi-dry coffee (Coffea arabica) fermentation process.

The aim of this study was to evaluate the use of yeasts as starter cultures in coffee semi-dry processing. Arabica coffee was inoculated with one of the following starter cultures: Saccharomyces cerevisiae UFLA YCN727, S. cerevisiae UFLA YCN724, Candida parapsilosis UFLA YCN448 and Pichia guilliermondii UFLA YCN731. The control was not inoculated with a starter culture. Denaturing gradient gel electrophoresis (DGGE) was used to assess the microbial population, and organic acids and volatile compounds were quantified by HPLC and HS-SPME/GC, respectively. Sensory analyses were evaluated using the Temporal Dominance of Sensations (TDS). DGGE analysis showed that the inoculated yeasts were present throughout the fermentation. Other yeast species were also detected, including Debaryomyces hansenii, Cystofilobasidium ferigula and Trichosporon cavernicola. The bacterial population was diverse and was composed of the following genera: Weissella, Leuconostoc, Gluconobacter, Pseudomonas, Pantoea, Erwinia and Klebsiella. Butyric and propionic acids, were not detected in any treatment A total of 47 different volatiles compounds have been identified. The coffee inoculated with yeast had a caramel flavor that was not detected in the control, as assessed by TDS. The use of starter cultures during coffee fermentation is an interesting alternative for obtaining a beverage quality with distinctive flavor.

Diversidade e resistência a antibióticos de bactérias psicrotróficas isoladas de tanques coletivos de resfriamento de leite / Diversity of psychotrophic bacteria isolated from the milk cooling collective tanks and antibiotics resistance profile of the microorganisms isolates

Bactérias psicrotróficas isoladas da parede, do fundo e da pá de homogeneização de tanques coletivos de resfriamento de leite, após o processo de higienização, foram identificadas e caracterizadas quanto à capacidade de produzir lipase, lecitinas e e protease, bem como determinada a sensibilidade dos isolados a antibióticos. Foram coletadas amostras de 32 tanques coletivos, localizados em diferentes cidades no sul do estado de Minas Gerais, por meio de swab de amostra da superfície, e analisadas pelas técnicas de diluições seriadas com plaqueamento em ágar triptona de soja e incubação das placas a 7 ºC por10 dias. As bactérias isoladas foram identificadas bioquimicamente pelos kits API 20NE (Biomérieux-Brasil) e Bactray I e II (Laborclin-Brasil). Foram identificados 197 isolados, os quais foram caracterizados quanto à produção de lipase, lecitinas e e protease. Para efetuar o teste de resistência a antibióticos, 21 isolados foram selecionados. Contagens entre < 1 e 108 UFC/cm2 foram observadas, com prevalência de Serratia sp., Klebsiela sp. e espécies do gênero Pseudomonas sp. Os isolados identificados apresentaram elevada atividade proteolítica e lipolítica, e a atividade de lecitinas e foi menos pronunciada. A multidroga resistência foi detectada em 54 por cento dos isolados analisados.

Composição centesimal da mucilagem do inhame (Dioscorea spp. ) liofilizado comparado a de um melhorador comercial utilizado na panificação e avaliação sensorial de pães de forma / Centesimal composition of lyophylized yam (Dioscorea spp. ) mucilage compared with a commercial improver used in breadmaking and sensorial evaluation of pan breads

O emprego de melhoradores na panificação vem expandindo a cada dia, porém há necessidade de estudos sobre a viabilidade de utilização de melhoradores naturais. O inhame é utilizado empiricamente como melhorador na panificação. Assim, conduziu-se o presente trabalho, com o objetivo de determinar a composição centesimal da mucilagem liofilizada do tubérculo do inhame (ML) e de um melhorador comercial (MC), utilizado como referencial, bem como a aceitação por meio de análise sensorial dos pães de forma elaborados com estes melhoradores. Na obtenção da mucilagem do inhame, os tubérculos foram triturados e a mucilagem foi separada por sistema de filtração em tecido de organza. Foram determinadas as composições centesimais, do ML e do MC. O MC apresentou maior teor de lipídios, fibra bruta, cinzas, valor calórico, que o melhorador natural. O ML apresentou teor de umidade, de proteínas, carboidratos totais maiores que o melhorador comercial. Quanto ao sabor, aroma e textura, os pães de forma acrescidos tanto com os melhoradores natural ou comercial alcançaram bons resultados.

The use of improvers in breadmaking has been increased, but there is a need for further studies on the viability of use of natural improvers.Yam is used empirically as an improver in bread making. Thus, the present work aimed to determine the centesimal composition of lyophylized mucilage of yam tuber (ML) and a commercial improver (MC), used as a referential, as well as the acceptance by means of sensorial analysis of pan bread manufactured with these improvers. In obtaining yam mucilage, the tubers were ground and mucilage was separated by an organza fabric filtering system. The centesimal compositions of the ML and MC were determined. The MC showed a higher content of lipids, crude fiber, caloric value than the ML. The ML presented higher contents of moisture, proteins, total carbohydrates than the MC. As to aroma, taste and texture, the pan bread added with the ML or MC reached good results.