Fortification of Acidophilus-bifidus-thermophilus (ABT) Fermented Milk with Heat-Treated Industrial Yeast Enhances Its Selected Properties

The improvement of milk dairy products’ quality and nutritional value during shelf-life storage is the ultimate goal of many studies worldwide. Therefore, in the present study, prospective beneficial effects of adding two different industrial yeasts, Kluyveromyces lactis and Saccharomyces cerevisiae pretreated by heating at 85 °C for 10 min to be inactivated, before fermentation on some properties of ABT fermented milk were evaluated. The results of this study showed that the addition of 3% and 5% (w/v) heat-treated yeasts to the milk enhanced the growth of starter culture, Lactobacillus acidophilus, Bifidobacteria, and Streptococcus thermophilus, during the fermentation period as well as its viability after 20 days of cold storage at 5 ± 1 °C. Furthermore, levels of lactic and acetic acids were significantly increased from 120.45 ± 0.65 and 457.80 ± 0.70 µg/mL in the control without heat-treated yeast to 145.67 ± 0.77 and 488.32 ± 0.33 µg/mL with 5% supplementation of Sacch. cerevisiae respectively. Moreover, the addition of heat-treated yeasts to ABT fermented milk enhanced the antioxidant capacity by increasing the efficiency of free radical scavenging as well as the proteolytic activity. Taken together, these results suggest promising application of non-viable industrial yeasts as nutrients in the fermentation process of ABT milk to enhance the growth and viability of ABT starter cultures before and after a 20-day cold storage period by improving the fermented milk level of organic acids, antioxidant capacity, and proteolytic activities.

How to characterize a strain? The neglected influence of clonal heterogeneity on the phenotypes of industrial Saccharomyces

Populations of microbes are constantly evolving heterogeneity that selection acts upon, yet heterogeneity is non-trivial to assess methodologically. The practice of isolating single cell colonies for establishing, transferring, and using a strain results in single-cell bottlenecks with a generally neglected effect on the characteristics of the strain. We used six industrial yeasts to assess the level of heterogeneity in clonal populations, especially in terms of stress tolerance. First, we uncovered the existence of genome structure variants in available sequenced genomes of clonal lineages of thes strains. Subsequent phenotyping of strains and their newly isolated subclones showed that single-cell bottlenecks during isolation can considerably influence the observable phenotype. Next, we decoupled fitness distributions on the level of individual cells from clonal interference by plating single cell colonies. We used the obtained data on colony area for statistical modeling of the heterogeneity in phenotypes. One strain was further used to show how individual subclonal lineages are remarkably different not just in phenotype, but also in the level of heterogeneity. Thereby we call attention to the fact that choosing an initial clonal lineage from an industrial yeast strain may vastly influence downstream performances and observations on geno- and phenotype, and also on heterogeneity.

Gastronomia e turismo: panificação tradicional em São Gotardo, Caxias do Sul-RS, Brasil./Gastronomy and tourism: Traditional breadmaking in São Gotardo, Caxias do Sul-RS, Brazil

Nas décadas finais do século XIX, imigrantes oriundos da Itália chegaram ao Sul do Brasil em busca de novas perspectivas de vida. Dentre as tradições culinárias trazidas por eles, estão os modos de panificação, pois o pão é um alimento culturalmente importante nos modos de vida deste e de ouros grupos étnicos. Neste contexto, o presente artigo propõe registrar os processos tradicionais de panificação na localidade de São Gotardo, no distrito de Vila Seca, Caxias do Sul-RS, onde ítalo-descendentes ainda utilizam forno de barro e fermentos não industriais. Considera-se que a localidade situa-se na região turística da Serra Gaúcha, e que a oferta gastronômica baseado em tradições locais pode vir a ser um diferencial. A metodologia teve como suporte a observação participativa, com entrevista, registro fotográfico e anotações em diário de pesquisa, além da realização de oficinas de panificação, para demonstração e registro de receitas e técnicas de preparos, das quais participaram quatro senhoras da comunidade que ainda produzem o próprio fermento, para utilização na panificação doméstica. Como resultados, tem-se que há uma permanência de tradições associadas às práticas alimentares de famílias ítalo-brasileiros de São Gotardo, através da feitura do pão com o fermento de batata, e aos rituais que o envolvem. Deste modo, entende-se que o patrimônio material e simbólico presente no pão pode se constituir um produto de consumo turístico pautado na identidade gastronômica. ABSTRACTIn the final decades of the nineteenth century, immigrants from Italy arrived at southern Brazil in search of new perspectives of life. Among culinary traditions brought by them are ways of baking, since bread is a culturally important food in the ways of life of this and other ethnic groups. Considering this context, present article proposes to register traditional processes of baking in São Gotardo, Caxias do Sul, Brazil, where Italian-descendants still use clay oven and non-industrial yeasts. It’s important to consider that São Gotardo is located in the tourist region of the Serra Gaucha, and gastronomic offer can turn out to be a differential in the dispute to attract tourists to this place. Methodology was supported by participant observation, with interview, photographic record and notes in research diary, as well as baking workshops for demonstration and registration of recipes and bread preparation techniques, attended by four old women from the community who still produce the yeast itself, for use in domestic baking. As a result, it is possible to note that there is permanence of traditions associated with the eating habits of Italian-Brazilian families of São Gotardo, through making of bread with potato and apple yeast, and the rituals that surround it. In this way, it is understood that the material and symbolic patrimony present in bread can constitute a product of tourist consumption based on the local gastronomic identity.Keywords: Food Tourism; Breadmaking; São Gotardo, Vila Seca, Caxias do Sul-RS, Brazil.