Can instrumental characterization help predicting sour taste perception of wheat sourdough bread?

Sourdough bread is known to have a characteristic sour taste. To guarantee consumer acceptability, sour taste should be monitored to assure constant bread quality. However, little is known about bread sour taste perception, especially how it evolves during tasting, neither if some simple measurements could help predict it. The aims of this study were to characterize the evolution of sour taste perception during bread tasting and to determine which bread instrumental variables can be correlated to it. For that purpose, eight types of bread were made with different sourdoughs and baking processes to obtain wide ranges of acidity, density and Fermentation Quotient. Bread were characterized by instrumental methods (i.e. pH, Total Titratable Acidity, organic acid content and density measurements) and their sour taste was determined by Quantitative Descriptive Analysis and a dynamic method called Progressive Profiling. As a result, it appeared that breads were perceived as significantly different throughout tasting. The "sour taste profile" was globally similar among breads with the highest intensity reached at the swallowing point. Progressive Profiling seemed then an efficient and simple method to evaluate the intensity of food organoleptic properties as well as the persistence after swallowing. Surprisingly, bread acetic acid content and Fermentation Quotient showed no effect on sour taste perception. Conversely, from all the physicochemical characteristics monitored, bread pH correlated with sour taste the most, explaining up to 97% of sour taste variations. Measuring bread pH could therefore constitute a quick and easy way to predict bread sour taste perception in research and industry.

The effect of organic wheat flour by-products on sourdough performances assessed by a multi-criteria approach.

In this study, we determined the effect of organic (i) flour ash content (1%-1.4%) and (ii) flour by-product addition (bran, shorts and germ) on sourdough performances. After five consecutive back-sloppings, sourdough was used for bread-making and its bread-related properties were assessed. No effect of flour composition factors (i & ii) on sourdough lactic acid bacteria and yeasts were highlighted. Nonetheless, they greatly altered lactic acid and acetic acid sourdough contents from 6.9 to 17.4 g/kg and from 0.9 to 2.2 g/kg, respectively. The flour ash content (i) had a significant and positive effect on sourdough acidity and CO2 production. Bread made with sourdough with a high ash content had a significantly higher acidity and specific volume. These physicochemical differences between breads were perceived by sensory evaluation in a significant way. Sourdough supplemented (ii) with germ had higher lactic acid and carbon dioxide contents than sourdough supplemented with bran and shorts. Hence, flour composition, combining ash content and flour by-products, appears to be an effective factor to obtain a better control of sourdough performances.

How organic farming of wheat may affect the sourdough and the nutritional and technological features of leavened baked goods.

Organic farming is gaining broad recognition as a system that complies well with sustainability, an overarching principle that should drive agriculture now and in the coming year. Different cultivars and products can harbour different abundances of specific bacterial groups, farming system may influence the composition and abundances of microbial communities found on food product. Despite the growing interest towards organic foods, we still have a limited understanding of the diversity of food-associated microbial communities and the factors that influence the composition of these communities. Consumers in developed nations are commonly exposed to differences in farming practices through their choice between organic and conventionally farmed foods. Organic farming practices can differ from conventional farming practices in a variety of ways, including the types of fertilizer and pesticides that are used. This review aiming to gather current knowledge on chemical, technological, toxicological and functional properties and microbiota composition of wheat flours originating from organic and conventional farming systems and how the use of these may affect the sourdough fermentation and breadmaking. Sourdough fermentation is the most natural and best-performing process to ensure optimal sensory and functional characteristics. It fits perfectly into the processing chain that starts with the organic farming, especially for old wheat varieties with weaker technological properties. Recently, organic and sourdough microbiota diversity was investigated and in some case a comparison between organic and conventional microbial ecosystem was also carried out. Opposites evidences arise. Once a higher diversity of lactic acid bacteria species was found in conventional wheat sourdoughs, while when the diversity of Firmicutes was investigated, organic sourdoughs showed the highest complexity. When occurring, the differences between conventional and organic sourdough microbiota and their effects on bread properties are difficult to be identified and categorized due to the extremely large variability in baker's practices. Besides, this review would provide a critical view of this topic in order to avoid the speculation that in this field unavoidably arise.