Comparison of the antifungal effect of undissociated lactic and acetic acid in sourdough bread and in chemically acidified wheat bread

Sourdough is a very interesting natural preservation system to prolong mould free shelf-life of bread. Numerous studies have reported that the antifungal activity of sourdough is mainly correlated with the presence of lactic (LA) and acetic acid (AA), but very few information is available on the effect of undissociated acid concentrations in the aqueous phase of bread (C-HA; mmole/L). This study was conducted to provide additional information about the mode of action of the acids in sourdough bread, enabling a better shelf-life prediction. This study was divided into two parts. In part 1, three industrial biological sourdoughs were characterized (dough yield, pH, a(w), fermentation quotient, microbiota). During 7 weeks, a shelf-life test with natural flora was conducted with daily checks of visible mould growth (21 degrees C). In part 2, the effect of the acids present in the antifungal active sourdough breads was validated in chemically acidified wheat breads. Complete growth inhibition was observed in full-baked sourdough bread (30 g/100 g dough) containing Lactobacillus sanfranciscensis and Saccharomyces cerevisiae as dominant sourdough micro-organisms, whereas in control bread the shelf-life was limited to 4.4-9.2 days. These full-baked sourdough breads contained 36 mmole undissociated LA/L and 220 mmole undissociated AA/L. The data were used to make General Linear Regression models for shelf-life prediction and resulted in a fit of R-2 = 0.79 when expressing the shelf-life in function of C-HA,C- LA and C-HA,C-AA. In acidified breads, the role of lactic acid was not significant and only impacted shelf-life indirectly through acidification. No difference between antifungal activity of sourdough breads and chemically acidified bread with comparable C-HA,C- AA concentrations was observed. Shelf-life increased when 150-200 mmole undissociated AA/L aqueous phase in bread was present. To conclude, this study showed the importance of the undissociated acid fraction of acetic acid in relation to bread shelf-life, together with bread pH and moisture content

Perceived Teacher Discrimination and Depressive Feelings in Adolescents: The Role of National, Regional, and Heritage Identities in Flemish Schools

Adolescents' identities are multiple, yet there is very little research that investigates the importance of intersecting identities, especially in relationship to teacher ethnic/racial discrimination and mental health. Multiplicity is often approached bi-dimensional (heritage and national identities) yet this study highlights the importance of regional identity. Regions are distinct socio-political contexts in relation to migration and integration dynamics. Hence, this study investigates for different combinations of national, heritage and regional identities (i.e. Flemish, Belgian and Turkish or Moroccan) the relationship between students' experiences with teacher ethnic/racial discrimination and students' depressive feelings. Latent Class Analysis of survey data involving a sample of 439 adolescents (M age  = 18, SD = 0.93; Girls = 49%) with Turkish (41%) or Moroccan origin in Flanders, shows three identification classes: full integration (35%), national integration (40%) and (weak) separation (24%). All these identity profiles had in common that heritage identification was high, yet they were highly distinct due to variation in national and regional identification. Additional, multilevel modelling showed that nationally integrated adolescents were less depressed than fully integrated adolescents. This finding illustrates the importance of adolescents' identity multiplicity for understanding their resilience in relation to teacher discrimination

Students’ religious attitudes : the role of schools’ religious diversity and multicultural teaching in different Belgian policy contexts

This study examines how secondary school students perceive different (non-) religious groups. Very few studies in this area consider how students’ attitudes are informed by contextual differences in school policies and differences in their religious affiliations. We investigate the role of multicultural teacher culture, schools’ religious diversity as well as their specific association with the religious attitudes of students from different (non-) religious groups. In addition, we explore how these relationships differ between two different regional policy contexts (Francophone and Flemish education in Belgium). The analysis of a quantitative SIS-dataset involving 3,789 students selected from 62 Belgian secondary schools showed that a) students organize their religious attitudes hierarchically, b) the effect of multicultural teaching on students’ religious attitudes is rather limited and c) that non-believing students respond differently to schools’ religious diversity than religious students. Implications of these results for future research are discussed

Smith-Purcell Radiation from Electrons Moving Parallel to a Grating at Oblique Incidence to the Rulings.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel

School, identity and society survey

The aim of this survey is to study the relationship between different forms of collective identification and intercultural relationships of Belgian students inscribed in urban secondary schools situated both the Flemish and French educational system. A multi-stage sampling frame was developed to reach variation in school contexts: first multicultural urban areas were identified and second heterogeneous schools within each city were randomly selected. The survey contains information on 64 schools situated in Flanders, Brussels and Wallonia. The survey contains five main themes. The central theme is collective identity. In total six different identities were measured, namely the Belgian, regional and ethnic ones. Furthermore the connectedness with the religious identity was mapped as well as students’ identification with their school and track. A second central theme in the survey was the measurement of intergroup relationships. Four different aspects were mapped namely, stereotypes and prejudice towards ethnic outgroups, attitudes about language use at school and a comprehensive measure about school climate. Teaching practices from the point of view of students is the third central theme in the survey. A fourth central theme was mapping pupils experience and awareness of racism and discrimination. Lastly, psychological attributes such as students’ sense of futility, study involvement and self-esteem were included. (2020-12-16

Ethnic microaggressions and adolescents' self-esteem and academic futility : the protective role of teachers

The central focus of this study is the perceived frequency and consequences of ethnic microaggressions. Research in this area of adolescent literature on ethnic discrimination is underdeveloped. Evidence showing that microaggressions are not interchangeable with blatant forms of discrimination and can have a severe negative impact on well-being is scarce. This study focuses on (a) three subdimensions of microaggressions (denial of ethnic reality, emphasis on differences, and negative treatment, (b) differences in frequency based on Muslim affiliation, country of origin, and generational status, (c) the relationship of microaggressions with self-esteem and sense of academic futility, and (d) the protective role of teachers. We use a dataset of 2,763 students of immigrant descent from 64 Belgian secondary schools. The results show that a denial of ethnic reality and negative treatment are related to less self-esteem and more academic futility. The opposite is true for emphasis on differences

Entangled identities and acculturation : comparing majority and minority adolescents’ multiple identity profiles in Belgium

This study considers recent criticism levelled at Berry's acculturation model by (1) taking into account more complex expressions of belonging and by (2) testing the importance of regionalism (or the distinction between national and regional (/subnational) contexts) in understanding acculturation patterns. Data of the School, Identity and Society-survey, which contains information on 3510 adolescents from 64 schools selected from the three regions is employed to test specific hypotheses for the Belgian case. Three multiple identity profiles are selected for adolescents from migrant families, and four multiple identity profiles for adolescents from nonmigrant families. The findings show that multiple identification for adolescents from migrant families is more often a conflicting than integrated experience. This incompatibility is not present for adolescents from non-migrant families. Small but meaningful variations of these multiple identity profiles occur among the three regions. In Brussels adolescents have a higher chance to be in the integrated identity profile