Starches acylated with specific short-chain fatty acids (SCFAs) have the potential to provide specificity in SCFA delivery. It is well documented that SCFAs are involved in lipid metabolism, but the underlying mechanism is still unclear. For characterizing the fermentation properties of acylated starches with various SCFAs in terms of SCFA production, three different acylated starches were prepared following the esterification of high amylose maize starch (HAMS) using acetic anhydride, propionic anhydride and butyric anhydride, respectively. Compared with HAMS, the gut microbiota fermentation of acetylated, propionylated and butylated starches specifically increased the production of acetic acid, propionic acid, and butyric acid, respectively, indicating that the introduced acyl group can be effectively released during the fermentation process. Furthermore, the utilization of these starches generated more total SCFAs, suggesting that they can be effectively fermented by the microbiota as a carbohydrate substrate. Study on an in vitro model of cultured rat hepatocytes indicated that either mixed SCFAs or butyrate play an important role in regulating lipid metabolism via activating AMPK and PPAR signaling pathways, implying the importance of butyrate in the improvement of lipid metabolism and accumulation. This study may provide further understanding of the individual function of the corresponding SCFA.

• The molecular weight of polysaccharide obtained from Helvella leucopus was 7.34 × 10⁴ Da. • Helvella leucopus polysaccharide attenuated high-fat-diet-induced high blood cholesterol. • Helvella leucopus polysaccharide regulated expression of lipid metabolism genes in vivo.

This study investigated the impact of in situ-formed exopolysaccharides (EPS) in red bean (Vigna angularis) sourdough fermented by Weissella confusa QS813 on dough rheo-fermentation properties, bread-making quality and aroma characteristics of red bean sourdough bread. The EPS formed in red bean sourdough and sourdough-induced acidification improved the maximum dough fermentation height, gas retention coefficient and viscoelastic properties of dough. Doughs had a lower increase rate of total SDS-soluble gluten proteins, a low decline in GMP content and similar free sulfhydryl content to wheat dough. Resultantly, breads showed declines in baking loss and hardness, increase in specific volume and lower moisture loss and staling rate after 7 days of storage. Finally, despite a reduction in the total content of aroma compounds, new aroma compounds such as acetic acid and higher contents of 3-methyl-1-butanol and 2,3-butanediol were enriched in red bean sourdough bread. Sourdough acidification probably promoted interaction of EPS with gluten or red bean proteins through bond interactions to form structures which stabilized gluten in dough and increased water-binding ability in red bean sourdough bread. This study provided a better understanding of the role of EPS in sourdough in improving bread quality and of promising strategies to address consumer demand for nutritious and clean-label products.

The objective of this study was to investigate the suitability of incorporating pitaya fruit fermented by antifungal LAB strains Lactiplantibacillus plantarum and Pediococcus pentosaceus at 1: 30 °C for 24h or 2: 31 °C for 19.5h as an ingredient with respect to bread making performance and bio-preservation effect. Underlying mechanisms related to gluten protein hydrolysis, starch hydrolysis, and yeast activity in dough were explored. The antioxidant activity, antifungal activity and bread making performance of the resulted breads were analyzed. Also, the antifungal phenolic acids in the breads were identified and quantified. Incorporation of fermented substrates in dough increased yeast activity and gas production capacity, but decreased gas retention capacity. This was attributed to increased dough acidity after incorporating fruit substrates. As a result, reducing sugar and free sulfhydryl (SH) groups increased in these doughs which indicated higher starch and gluten protein hydrolysis, respectively. However, SH groups increased at lower rate in presence of substrates fermented by L. plantarum and P. pentosaceus at condition 2 than 1. This could be due to improvement of gluten network as revealed by decreased α-helix (%) and increased β-turn (%) in secondary gluten structures in these doughs which subsequently resulted in more homogeneous microstructural properties than in presence of unfermented substrate compared to wheat dough. Subsequently, bread specific volume increased (6.6–20.0%) in presence of fermented substrates, especially fermented by L. plantarum at (2). Moreover, bread incorporated with fermented substrates (P. pentosaceus than L. plantarum at 1 than 2) had enhanced antioxidant activities, lower fungal growth rates based on challenge tests and mold free shelf life. Antifungal phenolic acids such as gallic acids, caffeic acid, protocatechuic acid were only detected in bread incorporated with fruit substrates, and their total content higher in fermented substrates.