Prebiotic effect of predigested mango peel on gut microbiota assessed in a dynamic <i>in vitro</i> model of the human colon (TIM-2)

Mango (Mangifera indica L.) peel (MP), is a by-product from the industrial processing to obtain juices and concentrates, and is rich in polyphenols and dietary fiber (DF). DF content of dried MP is about 40%. The aim of this study was to determine the prebiotic potential of this by-product submitting predigested mango ('Ataulfo') peel to a dynamic in vitro model of the human colon. Dried MPs were predigested following an enzymatic treatment and separating digestion products and undigested material by diafiltration. The predigested samples were fermented in a validated in vitro model of the colon (TIM-2) using human fecal microbiota and sampled after 0, 24, 48 and 72h. A carbohydrate mixture of standard ileal effluent medium (SIEM) was used as control. Production of short chain fatty acids (SCFA), branched chain fatty acids (BCFA) and ammonia profiles were determined in both lumen and dialysates. Microbiota composition was determined by sequencing 16S rRNA gene V3-V4 region. Principal component (PC) analysis of fermentation metabolites and relative abundance of genera was carried out. Fermentation of MP resulted in SCFA concentrations resembling those found in the SIEM experiments, with a 56:19:24 molar ratio for acetic, propionic and butyric acids, respectively. BCFA and ammonia were produced in similar concentrations in both samples. About 80 bacterial genera were identified after fermentation of MP, with an 83% relative abundance of Bifidobacterium at 24h. Three PC were identified; PC1 was influenced by a high Bifidobacterium abundance and low metabolites production. PC2 resulted in a decrease of other genera and an increase of metabolites studied. The relative abundance at 72h in MP was distributed over 4 genera Bifidobacterium, Lactobacillus, Dorea, and Lactococcus. Our results suggest MP as a potential prebiotic ingredient

Granola bars prepared with Agave tequilana ingredients: Chemical composition and in vitro starch hydrolysis

The stem of Agave tequilana is used to obtain: agave syrup (AS) and native agave fructans (NAF). Ground-agave-fiber is the by-product from fructans production. These ingredients were used to design a food ingredient: agave dietary fiber (ADF), containing NAF (30 g/100 g) as soluble dietary fiber (DF) and ground-agave-fiber (70 g/100 g) as an insoluble DF. The objective of this work was to evaluate the effect of the incorporation of A. tequilana ingredients (AS, NAP, ADF) on the proximate composition, in vitro starch hydrolysis (HI) and predicted glycemic index (pGI) of oat-based granola bars. Total DF (82.03 g/100 g) was the main component in ADF, with 22.8 g/100 g soluble DF. Granola bars were prepared by substituting honey and wheat flour by AS and ADF. A sensory test was used to select the level of sugar substitution by NAF, where 62 g NAF/100 g was the preferred one. The effect of each ingredient on the chemical composition was evaluated using a 2(3-1) fractional design. Soluble DF in a granola bar containing a combination of three agave ingredients (AS, NAP and ADF) was 23.35 g/100 g, with HI and pGI values of 74 and 72%, respectively, pointing this product as a moderate GI food. (C) 2013 Elsevier Ltd. All rights reserved

In Vitro Gastrointestinal Digestion and Colonic Fermentation of High Dietary Fiber and Antioxidant-Rich Mango (Mangifera indica L.) "Ataulfo"-Based Fruit Bars

Mango (Mangifera indica L.) is a tropical fruit which is considered to be a source of dietary fiber (DF) and phenolic compounds (PCs). In this study, high DF mango-based fruit bars were developed from whole mango (peel and pulp). The bars were evaluated for their nutritional composition, the bioaccesibility of PCs during gastrointestinal digestion, and the PCs metabolites profile after in vitro colonic fermentation. The amount of DF in a 30 g portion of mango bars was 9.5 g, i.e., 35% of the recommended daily intake. Phenolic acids such as gallic acid; cinnamic acids, such as ferulic, coumaric, and caffeic acids; flavonoids such as quercertin; and xanthones such as mangiferin and mangiferin gallate, were identified as the main PCs in the bars. The antioxidant capacity associated with the PCs profile, together with the high DF content are indicative of the potential functional features of these natural fruit bars. The bioaccesibility of PCs in the mango bar was 53.78%. During fermentation, the PCs were bioconverted mainly to hydroxyphenolic acids and the main short-chain fatty acid produced was acetic acid. The xanthone norathyriol was identified after 12 h of fermentation. This study on the digestion and colonic fermentation of mango-based bars using in vitro models provides hints of the potential physiological behavior of PCs associated with DF, which constitutes relevant information for further development of natural and health-promoting fruit-based bars

In Vitro Gastrointestinal Digestion Affects the Bioaccessibility of Bioactive Compounds in <i>Hibiscus sabdariffa</i> Beverages

Hibiscus sabdariffa possess great versatility to be used as an ingredient for a whole range of products with natural-based ingredients, which are growing in popularity due to the health benefits of bioactive compounds (BC). Therefore, the objective of this study was to characterize the BC content in Hibiscus beverages and to evaluate their in vitro bioaccessibility. Results showed significant differences (p Hibiscus beverage at the initial stage, while a maximum of 15 compounds were quantified in the different fractions of gastrointestinal digestion. After digestion, significant differences were found compared with the initial content of BC. That phenolic acids were the less bioaccessible group, while flavonoids were the most diverse. Principal components analysis showed different clusters and changes in the profiles of BC present at the initial stage and those bioaccessible, showing that intestinal digestion significantly affects the BC profile of the beverage

Nutritional properties and phenolic content of a bakery product substituted with a mango (Mangifera indica) 'Ataulfo' processing by-product

Wheat flour and cane sugar were partially substituted (50 and 75%) by a mango-processing by-product (MPB) as an added-value food ingredient in muffins. Their sensory analysis, chemical composition, antioxidant activity and in vitro starch hydrolysis properties were studied. Sensory analysis showed statistically significant difference (p < 0.05) between control and muffins 75% MPB substituted level (p < 0.05) with the highest score. Proximate analysis revealed that muffins substituted with MPB had significantly (p < 0.05) higher moisture, ash, soluble, insoluble and total indigestible fraction contents but lower total soluble carbohydrates and available starch contents than a non-substituted (control) muffin. Total soluble polyphenol (TSP) content increased about three times (from 1.86 to 5.36 g GAE/100 g dw) with MPB substitution. Chlorogenic, caffeic, gallic, hydroxycinnamic and ferulic acids were identified as major TSP. Muffins with MPB, exhibited better antioxidant properties (104.0 to 108.5 mu mol TE/g dw for DPPH assay and 34.1 to 19.1 mmol TE/g dw for FRAP assay) than the control formulation. The presence of high phenolic and insoluble indigestible fraction contents, which may be responsible of the lower rate of starch hydrolysis observed in muffins prepared with MPB, might modulate the postprandial glucose response in vivo. MPB may be used as an ingredient in foods with add-value with potential health-promoting features, besides providing a solution to the environmental problems associated with the disposal of mango by-products. (C) 2015 Elsevier Ltd. All rights reserved

Gut metabolites associated with pH and antioxidant capacity during in vitro colonic fermentation of Mexican corn products

Background and objectives: Food is the major factor driving the metabolism of the gut microbiota. In Mexico, nixtamalized corn products are widely consumed. Changes in antioxidant capacity (AOX) in 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and Ferric ion reducing antioxidant power (FRAP), pH values, short-chain fatty acid concentration, and relative metabolite production during in vitro colonic fermentation of indigestible fractions (IF) isolated from Istmo Totopos (ITs), baked corn tortillas (BCTs), and traditional corn tortillas (TCTs) were analyzed. Findings: The consumption of one piece (10 g) of any corn product may potentially maintain appreciable colonic antioxidant status (above 60 mmol TE) until 48 hr of fermentation. A portion of 10 g of corn products produces similar concentrations of acetic (3,050.43-4,181.47 mM), propionic (1,904.78-2,975.18 mM), and butyric acid (1,458.14-2,873.47 mM) at 12 hr of fermentation. Forty-six volatile compounds were also detected by solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS), and six principal components were identified. Positive correlations were found between DPPH, acetic acid, propionic acid, and butyric acid. Conclusions: Our results suggest the colonic fermentation potential to increase bioactive compounds and antioxidant activity hence suggesting improved gut health. Additional studies are required to evaluate their in vivo effects. Significance and novelty: The study of traditional corn products will facilitate a better understanding of the potential health-promoting impact of the interactions between indigestible components of the Mexican diet and the gut metabolites

Optimization of Ultrasound Treatment of Beverage from Mango and Carrot with Added Turmeric Using Response Surface Methodology

The effect of ultrasound treatment (UT) on a beverage from mango pulp and carrot juice with added turmeric powder on total soluble phenolic content (TSP), total carotenoid content (TC) and antioxidant capacity (AOC) was evaluated. Response surface methodology (RSM) was applied to obtain the optimal formulation of the beverage. The AOC was assigned as a response variable in addition to TSP and TC. Mathematical modeling showed that the formulation with 35% (v/v) of mango pulp, 10% (v/v) of carrot juice, and 0.7% (w/v) of turmeric powder, yielded the highest values of TSP, TC, and AOC. The beverages were subjected to different ultrasound conditions with varying exposure times (ET), sonication amplitudes (SA), and pulse cycles (PC) to obtain the highest values for response variables. Statistical modeling showed that a UT at 21 min ET, 100% SA, and 0.7 s PC, increased TSP, Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP) by 15.5%, 45.1%, and 15.9%, respectively. Seven phenolic acids, three curcuminoids, five flavonoids, and a xanthonoid were identified in the beverages. The quantities of 3,4-dihydroxybenzoic acid, gallic acid, chlorogenic acids, (+)-catechin, quercetin, kaempferol, (–)-gallocatechin gallate, and mangiferin were higher in the UT beverage compared to the control, suggesting their release from cell-wall structures as a result of UT