Subcritical water treatment to modify insoluble dietary fibers from brewer's spent grain for improved functionality and gut fermentability

Lactic acid (LA)-assisted subcritical water treatment (SWT) was applied to modify the insoluble dietary fiber (IDF) from brewer's spent grain (BSG) for enhancing its functionality and gut fermentability. Modified IDFs were thoroughly characterized for their chemical and structural properties. The results revealed that increasing the treatment temperature and LA concentration reduced hemicellulose content in IDFs from 38.4 % to 0.7 %, alongside a decreased yield (84.8 %-51.4 %), reduced particle size (519.8-288.6 μm), and more porous structure of IDFs. These modifications were linked to improved functionalities, evidenced by the highest water and oil holding capacity increasing by 36 % and 67 %, respectively. Remarkably, the highest glucose adsorption capacity increased by 6.5 folds. Notably, modified IDFs exhibited slower in-vitro fermentation, elevated short-chain fatty acids (SCFAs) production, and a higher proportion of butyrate in SCFAs. These findings highlight the potential of LA-assisted SWT in transforming BSG-derived IDF into a valuable functional food ingredient.

Sugarcane polyphenol and fiber to affect production of short-chain fatty acids and microbiota composition using in vitro digestion and pig faecal fermentation model

This study aimed to examine the effects of sugarcane polyphenol and fiber (Phytolin + Fiber) on gut microbiota, short-chain fatty acids (SCFAs) production and phenolic metabolites production using in vitro digestion and fermentation model. Microbial profiling by 16S rRNA sequencing was used to analyze the pig faecal microbiota profile. SCFAs were identified and quantified by GC-FID, and phenolic metabolites were characterized by LC-ESI-QTOF-MS/MS. The results showed that Phytolin + Fiber exert synergistic effects on the pig gut microbiota by increasing the relative abundances of Lactobacillus and Catenibacterium, and decreasing the relative abundances of Mogibacterium, Dialister, and Escherichia-Shigella. Phytolin + Fiber also significantly increased the total SCFAs production, particularly the propionic and butyric acids. Production of phenolic metabolites related to major polyphenols in Phytolin were tentatively identified. These results suggest that Phytolin + Fiber could be beneficial to human colon health given the similarities between pig and human intestine in terms of physiology and microbiome.

The effect of lactic acid fermentation with different bacterial strains on the chemical composition, immunoreactive properties, and sensory quality of sweet buttermilk

This paper describes the successful development of new low-immunoreactive buttermilk (BM)-based formulations which were fermented with 31 lactic acid bacteria (LAB) and Bifidobacterium strains. The aim of this study was to create a new formula, which can serve as potential candidates for the immunotherapy of allergy. Preparations were tested for their content of biologically active compounds, such as proteins, peptides, phospholipids, and short-chain fatty acids (SCFA), as well as for the survivability of LAB and sensory quality. The results showed that the BM was a matrix rich in nutritional components and displayed higher than expected susceptibility to the reduction of protein IgE-immunoreactivity (to 98%) and high bacterial-protecting capacity. The overall sensory quality of examined products was influenced by the profile of SCFA and free peptides, but two formulations fermented with Lactobacillus delbrueckii ssp. bulgaricus-151 and Lactobacillus casei-LcY were the most advantageous with desirable sensory, immunoreactive, and biochemical properties.

Dietary adzuki bean paste dose-dependently reduces visceral fat accumulation in rats fed a normal diet

The aim of this study was to evaluate the dose-dependent effect of adzuki bean (Vigna angularis) paste (ABP) on visceral fat accumulation in rats. ABP is a rich source of indigestible carbohydrates (18.5%) with fiber and resistant starch (RS) contents of 14.5% and 4.0%, respectively. Animals were fed one of the following diets, control (CON), 30% ABP or 58.9% ABP for 28 days. The daily dietary energy intake was lowered (p < 0.05) and reduced visceral fat accumulation and lower serum lipid levels were observed in ABP fed groups. ABP consumption dose-dependently increased (p < 0.05) the daily fecal lipid and fecal acidic sterol excretions. On the other hand, cecal content and fecal moisture content in the 58.9% ABP group were greater (p < 0.05) than the CON group, while there was no significant difference between the two ABP fed groups. Both 30% and 58.9% ABP diets had significantly (p < 0.05) higher contents of cecal acetic, propionic and n-butyric acids, and lowered cecal pH, independently of the ABP dose. Microbial community data of rats fed ABP diets exhibited higher alpha-diversities than the rats fed CON diet, based on the Shannon Index and the number of observed species index, where the two ABP groups exhibited a similar alpha diversity. The weighted UniFrac-based principal coordinate analysis plot of cecal microbial community data showed that the ABP had a substantial effect on the cecal microbial composition. Furthermore, cecal bacterial 16S rRNA gene sequencing revealed that the ABP supplemented diets decreased the ratio of Firmicutes to Bacteroidetes. These findings suggested that the cecal fermentation of fiber and RS in ABP, might have decreased the energy intake, altered the gut microbiota composition, increased fecal lipid output, and thereby reduced fat accumulation in rats.

Characterization of key odorants causing the roasted and mud-like aromas in strong-aroma types of base Baijiu

The roasted and mud-like aromas in Chinese strong-aroma types of base Baijiu (base SAB) and the interactions among the corresponding key compounds causing these two characteristic aromas were investigated. A total of 68 and 64 odorants were identified in the base and commercial SAB by comparative aroma extract dilution analysis. Furthermore, the complex matrix of Baijiu always pose a long-term challenge for quantitative accuracy and precision of target aroma compounds; thus, the odorants with flavor dilution (FD) ≥ 9 were further quantified by multiple quantitative techniques, including the direct injection combined with gas chromatography-flame ionization detector, the vortex-assisted surfactant-enhanced emulsification liquid-liquid microextraction (VSLLME) combined with GC-MS, and the derivatization method combined with VSLLME-GC-MS, and 37 and 26 odorants were shown to be important odorants as their OAVs ≥1. Among these components, 5 compounds, hexanoic acid, butyric acid, p-cresol, 3-methylindole, and 3-(methylthio)propanal showed higher OAVs in base than in commercial SAB, and based on aroma recombination and omission analysis, they were confirmed to be the key odorants responsible for the mud-like and roasted odors. The evaluation of the aforementioned five key odorants by the "addition" test showed that the roasted and mud-like aromas of base SAB were related, and the odors were mainly attributed to additive or masking effects among the compounds.

Gut microbiota, a new frontier to understand traditional Chinese medicines

As an important component of complementary and alternative medicines, traditional Chinese medicines (TCM) are gaining more and more attentions around the world because of the powerful therapeutic effects and less side effects. However, there are still some doubts about TCM because of the questionable TCM theories and unclear biological active compounds. In recent years, gut microbiota has emerged as an important frontier to understand the development and progress of diseases. Together with this trend, an increasing number of studies have indicated that drug molecules can interact with gut microbiota after oral administration. In this context, more and more studies pertaining to TCM have paid attention to gut microbiota and have yield rich information for understanding TCM. After oral administration, TCM can interact with gut microbiota: (1) TCM can modulate the composition of gut microbiota; (2) TCM can modulate the metabolism of gut microbiota; (3) gut microbiota can transform TCM compounds. During the interactions, two types of metabolites can be produced: gut microbiota metabolites (of food and host origin) and gut microbiota transformed TCM compounds. In this review, we summarized the interactions between TCM and gut microbiota, and the pharmacological effects and features of metabolites produced during interactions between TCM and gut microbiota. Then, focusing on gut microbiota and metabolites, we summarized the aspects in which gut microbiota has facilitated our understanding of TCM. At the end of this review, the outlooks for further research of TCM and gut microbiota were also discussed.

Cranberries attenuate animal-based diet-induced changes in microbiota composition and functionality: a randomized crossover controlled feeding trial

Cranberries have multiple health effects but their impact on gut microbiota has not been examined in randomized controlled feeding trials. We evaluated the relationship between the microbiota and cranberries in the context of an animal-based diet. In a randomized, double-blind, cross-over, controlled design trial, 11 healthy adults consumed for 5 days each a control diet (animal-based diet plus 30 g/day placebo powder) and a cranberry diet (animal-based diet plus 30 g/day freeze-dried whole cranberry powder). The animal-based diet included meats, dairy products, and simple sugars. Stool, urine, and blood samples were obtained before and after each intervention phase. As compared to the pre-control diet, control diet modified 46 taxonomic clades, including an increase in the abundance of Firmicutes and decrease in Bacteroidetes. Moreover, it increased bacteria-derived deoxycholic acid and decreased acetate and butyrate in stool. As compared to the post-intervention phase of control diet, the cranberry diet modified 9 taxonomic clades, including a decrease in the abundance of Firmicutes and increase in Bacteroidetes. Further, the cranberry diet attenuated control diet-induced increase in secondary bile acids and decrease in short-chain fatty acids (SCFA), and increased urinary anthocyanins and bacterially derived phenolic acids. No changes were found in fecal trimethylamine and plasma cytokines. In conclusion, an animal-based diet altered the microbiota composition to a less favorable profile, increased carcinogenic bile acids, and decreased beneficial SCFA. Cranberries attenuated the impact of the animal-based diet on microbiota composition, bile acids, and SCFA, evidencing their capacity to modulate the gut microbiota.

Deep sequencing reveals high bacterial diversity and phylogenetic novelty in pit mud from Luzhou Laojiao cellars for Chinese strong-flavor Baijiu

The pit mud (PM) in fermentation cellar is a complex ecosystem that hosts diverse microbial communities that contribute to the production of Chinese strong-flavor Baijiu (CSFB). However, the microbial ecology of PM, particularly the extent of their phylogenetic novelty remains poorly understood. Here we conducted Illumina MiSeq sequencing to explore the diversity and novelty patterns of PM bacterial communities from Luzhou Laojiao cellars in use for 40 and 400years. High diversity indices were found in the PM with 16 phyla and 105 genera. Interestingly, the compositions of dominant genera of the PM were significantly different than that reported previously for PM sampled from other geographic sites, suggesting greater microbial diversity of PM. The dominant genus of Caproiciproducens, a caproic acid-producing bacterium, is the first reported for Chinese Baijiu production. Our results demonstrate that the PM hosts a large number of novel taxa, with 26% of the total OTUs (operational taxonomic units) distant to cultured counterparts. The class Clostridia within Firmicutes presented the highest proportion of novel OTUs. Most novel OTUs were initially isolated from diverse environments, the most abundant of which came from Chinese Baijiu brewing ecosystems, highlighting the huge culturing gap within the PM, but at the same time suggesting the importance of these OTUs in CSFB production. The data presented in this study significantly increases the number of bacteria known to be associated with CSFB production and should help guide the future exploration of microbial resources for biotechnological applications.

In vitro evaluation of whole faba bean and its seed coat as a potential source of functional food components

In vitro studies were conducted to evaluate the particular nutritional benefits of whole faba bean seed (WFB) and fava bean seed coat (FBSC). Total dietary fiber contents of WFB and FBSC were 27.5% and 82.3%, respectively. FBSC were contained much higher total phenolic substances, condensed tannins, and total antioxidant activity than WFB. Bile acid (BA)-binding capacities of in vitro digested samples and nutritionally important products produced by in vitro fermentation of digestion residues were also studied. The BA-binding capacities of WFB and FBSC were 1.94 and 37.50μmol/100mg, respectively. Total BA bound by FBSC was even higher than the positive standard cholestyramine. Lignin and other constituents of the Klason residue were found to influence BA-binding properties. Moreover, the extent of the in vitro fermentation process showed that, fermentability of FBSC residue was significantly lower than that of WFB residue. Overall, faba bean, especially its seed coat, has great potential as a functional food.

Neuroprotective effects of the monoamine oxidase inhibitor tranylcypromine and its amide derivatives against Aβ(1-42)-induced toxicity

Monoamine oxidase (MAO) enzymes play a central role in the pathogenesis of Alzheimer's disease (AD) and MAO inhibitors (MAOIs) are antidepressant drugs currently studied for their neuroprotective properties in neurodegenerative disorders. In the present work MAOIs such as tranylcypromine [trans-(+)-2-phenylcyclopropanamine, TCP] and its amide derivatives, TCP butyramide (TCP-But) and TCP acetamide (TCP-Ac), were tested for their ability to protect cortical neurons challenged with synthetic amyloid-β (Aβ)-(1-42) oligomers (100 nM) for 48 h. TCP significantly prevented Aβ-induced neuronal death in a concentration-dependent fashion and was maximally protective only at 10 µM. TCP-But was maximally protective in mixed neuronal cultures at 1 µM, a lower concentration compared to TCP, whereas the new derivative, TCP-Ac, was more efficacious than TCP and TCP-But and significantly protected cortical neurons against Aβ toxicity at nanomolar concentrations (100 nM). Experiments carried out with the Thioflavin-T (Th-T) fluorescence assay for fibril formation showed that TCP and its amide derivatives influenced the early events of the Aβ aggregation process in a concentration-dependent manner. TCP-Ac was more effective than TCP-But and TCP in slowing down the Aβ(1-42) aggregates formation through a lengthening at the lag phase. In our experimental model co-incubation of Aβ(1-42) oligomers with TCP-Ac was able to almost completely prevent Aβ-induced neurodegeneration. These results suggest that inhibition of Aβ oligomer-mediated aggregation significantly contributes to the overall neuroprotective activity of TCP-Ac and also raise the possibility that TCP, and in particular the new compound TCP-Ac, might represent new pharmacological tools to yield neuroprotection in AD.

Proteomic and high-throughput analysis of protein expression and microbial diversity of microbes from 30- and 300-year pit muds of Chinese Luzhou-flavor liquor

Luzhou-flavor liquor is fermented based on the metabolism of special microbial communities in pit. In this study, total proteins and DNAs of microbes from 30- and 300-year pit muds were firstly extracted. Meanwhile, an efficient approach for protein extraction with increased protein content was optimized. iTRAQ-based proteomic was then applied to investigate the aroma-forming functional protein expression of microbes from the samples. Furthermore, high-throughput sequencing of 16S rDNA was employed to reveal microbial diversity. We comparatively identified 63 proteins of aroma-forming functional microbes in these samples, and found that 59 of these proteins were highly expressed in the 300-year pit mud. Those aroma-forming functional proteins were found to be involved in methanogenesis, as well as the formation of caproic acid and butyric acid during the liquor fermentation. High-throughput sequencing revealed that the microbes most commonly found in both samples were members of phylum Firmicutes (by 97% sequence similarity), both of which, along with another common Methanobacterium, were important components of aroma-forming functional colonies in the pit muds for the brewing of Chinese liquor. The findings in this study afford us new insight into the different protein expression levels and microbial communities in two pit muds.

Impact of different cocoa hybrids (Theobroma cacao L.) and S. cerevisiae UFLA CA11 inoculation on microbial communities and volatile compounds of cocoa fermentation

The aim of this work was to study the microbial communities and volatile compounds profile of different fermentations: using four different cocoa hybrids and adding Saccharomyces cerevisiae UFLA CA11 as starter culture. Each hybrid showed particular characteristics: size, peel, seed and pulp. The temperature of the cocoa mass increased during fermentations (24°C to 47°C). The hybrid FA13 inoculated with S. cerevisiae showed the lowest temperatures (26 to 37°C). The pulp's compositions were different between the hybrids, mainly regarding citric acid (0.5 to 3.2g/kg). The carbohydrates were more rapidly (60h) metabolized in inoculated fermentations than in spontaneous fermentations (84h). Thirty-nine volatile compounds were identified by GC-FID for all fermentation processes. Esters (14 compounds) and alcohols (12) were the most important groups. Yeast communities were similar among the different processes while bacterial communities were dependent on the hybrid and process. The inoculation accelerated the fermentation and the hybrid characteristics influenced on the fermentation requiring particular management.