Coupling effects of structure, oxygen availability and temperature on microbial growth in a pastry filling

The structure of real food is a key factor to be considered in order to control microbial growth. A pastry filling has been employed as model food to study the growth of Staphylococcus under different conditions. Additionally, the structure of the food system has been characterised by means of rheological measurements. Frequency sweeps showed that, in all cases, the elastic component determines the rheological behaviour of model pastry filling (G' > G''). Values obtained for the coordination number (z) and the proportional coefficient (A) indicated that the model food exhibits more aggregate structures and stronger links at lower temperatures. According to the maximum specific growth rates, the Staphylococcus growth in the model pastry filling was clearly conditioned by oxygen diffusion, which is limited by the food matrix, and also by the incubation temperature. In addition, the analysis of Staphylococcus growth at different temperatures suggested the influence of the pastry filling structure on microorganism behaviour.

Does Responsiveness to Basic Tastes Influence Preadolescents’ Food Liking? Investigating Taste Responsiveness Segment on Bitter-Sour-Sweet and Salty-Umami Model Food Samples

The objective of this study was to investigate the relationships between taste responsiveness and food liking in preadolescents. Model food samples of grapefruit juice (GF) and vegetable broth (VB) modified with four additions of sucrose and sodium chloride, respectively, were employed. Intensity perception for sweetness, sourness, and bitterness were measured in GF while saltiness and umami were measured in VB. The children (N = 148) also completed food choice, familiarity, stated liking and neophobia questionnaires. The test was conducted at school, with instructions provided remotely via video call. Four segments were defined differing in basic taste responsiveness. Segments and sucrose concentrations significantly affected liking for GF, while no significant effect of segments and sodium chloride concentrations occurred on liking for VB. An increasing sucrose concentration was positively associated with liking for GF only in the segment with low responsiveness to bitter and sour tastes. No significant differences across segments were found for food choice, familiarity, stated liking, and neophobia. Conclusively, relationships between taste responsiveness and liking are product and basic taste-dependent in addition to being subject-dependent. Strategies to improve acceptance by using sucrose as a suppressor for warning sensations of bitterness and sourness can be more or less effective depending on individual responsiveness to the basic tastes.