Sourdough Fermented Breads are More Digestible than Those Started with Baker’s Yeast Alone: An In Vivo Challenge Dissecting Distinct Gastrointestinal Responses

Abstract

As a staple food, bread digestibility deserves a marked nutritional interest. Combining wide-spectrum characterization of breads, in vitro nutritional indices, and in vivo postprandial markers of gastrointestinal function, we aimed at comparing the digestibility of sourdough and baker’s yeast breads. Microbiological and biochemical data showed the representativeness of the baker´s yeast bread (BYB) and the two sourdough breads (SB and t-SB, mainly differing for the time of fermentation) manufactured at semi-industrial level. All in vitro nutritional indices had the highest scores for sourdough breads. Thirty-six healthy volunteers underwent an in vivo challenge in response to bread ingestion, while monitoring gallbladder, stomach, and oro-cecal motility. SB, made with moderate sourdough acidification, stimulated more appetite and induced lower satiety. t-SB, having the most intense acidic taste, induced the highest fullness perception in the shortest time. Gallbladder response did not differ among breads, while gastric emptying was faster with sourdough breads. Oro-cecal transit was prolonged for BYB and faster for sourdough breads, especially when made with traditional and long-time fermentation (t-SB), whose transit lasted ca. 20 min less than BYB. Differences in carbohydrate digestibility and absorption determined different post-prandial glycaemia responses. Sourdough breads had the lowest values. After ingesting sourdough breads, which had a concentration of total free amino acids markedly higher than that of BYB, the levels in blood plasma were maintained at constantly high levels for extended time.

Physical properties, storage stability, and consumer acceptability for sourdough bread produced using encapsulated kombucha sourdough starter culture

“…The pH values of the EKSS (5.10 ± 0.01) and LTSS (5.16 ± 0.02) bread were not significantly ( P < 0.05) different but both of them showed significantly lower pH values compared to BY (6.06 ± 0.04) bread (Table 3). These results are in accordance to previous studies that showed sourdough bread gave lower pH values compared to yeast bread (Rizzello et al., 2019; Yezbick, Ahn‐Jarvis, Schwartz, & Vodovotz, 2013). This is due to the higher production of organic acids by LAB compared with yeast bread dough (Gamel, Abdel‐Aal, & Tosh, 2015).…”

“…The encapsulated sourdough starter culture requires rehydration before using it for bread making, as recommended in a previous study (Rizzello et al., 2019). The rehydration step helps to activate the microorganisms in the starter culture.…”

Nutritional, Functional, and Technological Characterization of a Novel Gluten- and Lactose-Free Yogurt-Style Snack Produced With Selected Lactic Acid Bacteria and Leguminosae Flours

“…As previously observed ( Rizzello et al, 2019 ), proteolysis occurring during fermentation affected level of protein digestibility, that resulted, in the novel yogurt-style snack, circa 18% higher than the unfermented matrix. Aiming at investigating the protein quality of the novel yogurt-style snack, the digestible protein fraction was used for the determination of the protein quality indexes ( Rizzello et al, 2014 ).…”

“…It resulted circa 54% higher than that found for a similar yogurt-like snacks made with quinoa, a pseudocereal overall known for the high quality of the protein fraction ( Lorusso et al, 2018 ). Accordingly, all the indexes elaborated based on the comparison of the essential amino acid ratio to the FAO reference protein ( Millward, 2012 ) resulted higher than those found for food products obtained from a single cereal, legume or pseudocereal matrix ( Lorusso et al, 2018 ; Rizzello et al, 2019 ; Sozer et al, 2019 ). Within the indexes that are used to evaluate the nutritional value of foods, the NI combines qualitative and quantitative factors and is considered a global predictor of the protein quality.…”

Metabolic and Gut Microbiota Responses to Sourdough Pasta Consumption in Overweight and Obese Adults

“…The increased rate of gastric emptying at these two time points likely reflects improved starch and protein digestibility. These results are in agreement with Rizzello et al ( 28 ) who tracked gastric emptying of various breads through ultrasound antral area measurements. In that study, the rate of half-emptying time (approximately 30 min post-consumption) was shortest in sourdough vs. baker's yeast bread.…”