Effect of Pediococcus acidilactici and mango seed polyphenols on the fermentative profile of the indigestible fraction of yam bean

Yam bean is an important source of dietary fiber and other components that comprise the total indigestible fraction (TIF), which can be fermented by the colonic microbiota and produce metabolites with beneficial health effects. Therefore, the objective of this study was to evaluate the in vitro colonic fermentation of yam bean TIF and the changes caused by the addition of a polyphenolic extract of mango seed and the lactic acid bacteria Pediococcus acidilactici. The mango seed extract was obtained by ultrasound-assisted extraction, and the microbial growth rate and viability of P. acidilactici were determined using a Neubauer chamber. Yam bean TIF was isolated by triple enzymatic hydrolysis and subjected to in vitro colonic fermentation in combination with treatments with mango seed extract and P. acidilactici suspensions. Changes in pH, total soluble phenols (TSP), and antioxidant capacity (AOX) were evaluated. Furthermore, the production of metabolites was quantified by HPLC-DAD-MS and GC-MS. The Growth rate of P. acidilactici was 0.1097 h-1 with 97.5 % viability at 7 h of incubation. All TIF treatments showed a high capacity of fermentation, and the addition of mango seed extract increased the TSP content and AOX in DPPH and FRAP assays. A total of Forty-six volatile metabolites were detected, with highlighting the presence of esters, benzenes, aldehydes, and short-chain fatty acids. Five phenolic compounds associated with mango by-products were quantified during all fermentation process, despite the concentration of the extract. P. acidilactici did not substantially modify the fermentative profile of TIF. However, further studies such as the evaluation of the abundance of microbial communities may be necessary to observe whether it can generate changes during colonic fermentation.

Design of Experiments for Optimizing Ultrasound-Assisted Extraction of Bioactive Compounds from Plant-Based Sources

Plant-based materials are an important source of bioactive compounds (BC) with interesting industrial applications. Therefore, adequate experimental strategies for maximizing their recovery yield are required. Among all procedures for extracting BC (maceration, Soxhlet, hydro-distillation, pulsed-electric field, enzyme, microwave, high hydrostatic pressure, and supercritical fluids), the ultrasound-assisted extraction (UAE) highlighted as an advanced, cost-efficient, eco-friendly, and sustainable alternative for recovering BC (polyphenols, flavonoids, anthocyanins, and carotenoids) from plant sources with higher yields. However, the UAE efficiency is influenced by several factors, including operational variables and extraction process (frequency, amplitude, ultrasonic power, pulse cycle, type of solvent, extraction time, solvent-to-solid ratio, pH, particle size, and temperature) that exert an impact on the molecular structures of targeted molecules, leading to variations in their biological properties. In this context, a diverse design of experiments (DOEs), including full or fractional factorial, Plackett-Burman, Box-Behnken, Central composite, Taguchi, Mixture, D-optimal, and Doehlert have been investigated alone and in combination to optimize the UAE of BC from plant-based materials, using the response surface methodology and mathematical models in a simple or multi-factorial/multi-response approach. The present review summarizes the advantages and limitations of the most common DOEs investigated to optimize the UAE of bioactive compounds from plant-based materials.

A standardized method for genus Colletotrichum characterization by isothermal microcalorimetry using thermokinetic parameters

A new standardized method, using isothermal microcalorimetry (IMC), was established to determine thermokinetic parameters from heat flow curves and to demonstrate the reproducibility and repeatability of the parameters of five Colletotrichum species on different days. Measurements on IMC were made at different periods and by two operators. Repeatability and reproducibility (R&R) measurement system analysis was performed on the technique used to measure the heat flow of Colletotrichum strains. The results showed that the %GageR&R was found to be within the acceptable ranges of a measurement system. Also, the parameters obtained from the curves were subjected to a combination of Principal Component Analysis (PCA) and Clustering, the data showed that the total heat (H_t) and maximum growth rate (μ_max) are probably the most specific distinguishing characteristic of the strains evaluated in this study. This study demonstrates, for the first time, the usefulness of IMC in obtaining heat flow curves and thermokinetic parameters, providing repeatable and reproducible measurements over a period and under controlled conditions, for future identifications of phytopathogenic fungi.

What we know about protein gut metabolites: Implications and insights for human health and diseases

Gut microbiota is a complex ecosystem of symbiotic bacteria that contribute to human metabolism and supply intestinal metabolites, whose production is mainly influenced by the diet. Dietary patterns characterized by a high intake of protein promotes the growth of proteolytic bacteria's, which produce metabolites from undigested protein fermentation. Microbioal protein metabolites can regulate immune, metabolic and neuronal responses in different target organs. Metabolic pathways of these compounds and their mechanisms of action on different pathologies can lead to the discovery of new diagnostic techniques, drugs and the potential use as functional ingredients in food. This review discusses the potential mechanisms by which amino acid catabolism is involved in microbial protein metabolites. In addition, results from several studies on the association of products from the intestinal metabolism of indigestible proteins and the state of health or disease of the host are revised.

In vitro human colonic fermentation of indigestible fraction isolated from lunch menus: impact on the gut metabolites and antioxidant capacity

The indigestible fraction (IF) isolated from three lunch menus: Modified Mexican Lunch (MM-L), Traditional Mexican Lunch (TM-L) and Alternative Mexican Lunch (AM-L), was studied in terms of antioxidant capacity (AOX) and metabolites produced through fermentation by human intestinal microbiota. IFs were isolated after withstanding in vitro gastrointestinal digestion and total soluble polyphenols (TSP), condensed tannins (CT), hydrolysable polyphenols (HP) and AOX (DPPH, FRAP) were evaluated. AOX, pH and bacterial metabolites profile changes were also monitored during in vitro colonic fermentation. Lunch menus showed differences in IF, TSP, CT and FRAP values (p<.05). TM-L had the highest TSP and CT contents (0.84 and 1.89 g/100 g DW, respectively). Changes in pH and AOX during fermentation were time-dependent and substrate-dependent (p<.05). Butyric acid production was not significantly modified by the IFs (p>.05). Fifty-seven microbiota-produced volatile compounds were detected by SPME-GC-MS. This study shows the potential effects of food habits on bacterial metabolite production.

Microbial metabolites profile during in vitro human colonic fermentation of breakfast menus consumed by Mexican school children

The nutrition transition promotes the development of childhood obesity. Currently, Mexico is affected by this serious public health problem. The nutritional and functional characterization of a whole menu has a number of advantages over the study of single nutrients. Since breakfast is considered the most important meal of the day, this study aimed to evaluate the metabolite profile produced by in vitro human colonic fermentation of the isolated indigestible fraction (IF) from three different Mexican breakfast (M-B) menus (Modified "MM-B", traditional "TM-B", and alternative "AM-B"), previously identified as commonly consumed by Mexican schoolchildren in Nayarit State, Mexico. The M-B's consist of egg, corn tortilla, beans (higher in TM-B), sugar and chocolate powder (higher in AM-B) and milk, combined in different proportions. The IF in all breakfasts was about 4.7-5.6g/100g FW, with a relatively high content of protein (≈21%), which might have negative physiological implications. Fermentation of IF from TM-B resulted in the largest pH decrease after 72h (pH=6.07), with a low short chain fatty acid (SCFA) production (0.75 to 47.23mmol/L), but greater relative concentration of other fatty acids (FA) (C7, C8, C9). Besides, 55 volatile compounds were detected in the fermentation media by SPME-GC-MS and three principal components (PC) were identified. PC1 was influenced by SCFA production, low FA esters production (<8C), and low volatile organic acids production. PC2 was influenced by the decrease in pH and an increase in antioxidant capacity (p<0.0001). These results suggest that the production of different metabolites in the luminal medium may affect the pH and antioxidant status in the colon. Fermentation of IF from TM-M, assessed after 48 and 72h, showed the highest correlation for PC2; the metabolic pattern registered for this IF maybe considered beneficial.