Arabinoxylan supplemented bread: From extraction of fibers to effect of baking, digestion, and fermentation

Structural and quantitative changes in alkali-solubilized arabinoxylan throughout the breadmaking process

Arabinoxylan (AX) substantially impacts wheat dough and bread quality; however, the behavior of water-unextractable AX (WU-AX) during breadmaking is not fully understood. This study investigates WU-AX changes during breadmaking by treating it with various sodium hydroxide (NaOH) concentrations to produce alkali-solubilized AX (AS-AX). Higher NaOH concentrations (up to 2.0 M) increase the AS-AX ratio, reaching over 80 %. The release of ferulic acid also increases with NaOH concentration but plateaus at 0.5 M NaOH. Analysis with 50 mM NaOH revealed the AS-AX ratio decreased from 46.0 % in wheat flour to 30.5 % at the proof stage, indicating WU-AX conversion to water-extractable AX (WE-AX) through the cleavage of ferulic acid-mediated bonds. High and low molecular weight AS-AX exhibit different solubilization patterns; low molecular weight AX with weaker bonds solubilizes more readily and converts preferentially to WE-AX. Understanding these dynamic changes can enhance dough properties and bread quality through targeted WU-AX.

In vivo mechanism of the interaction between trimethylamine lyase expression and glycolytic pathways

Recent studies confirmed that host-gut microbiota interactions modulate disease-linked metabolite TMA production via TMA lyase. However, microbial enzyme production mechanisms remain unclear. In the present study, we investigated the impact of dietary and intervention factors on gut microbiota, microbial gene expression, and the interplay between TMA lyase and glycolytic pathways in mice. Using 16S rRNA gene sequencing, metagenomics, and metabolomics, the gut microbiota composition and microbial functional gene expression profiles related to TMA lyase and glycolytic enzymes were determined. The results revealed that distinct diets and intervention factors altered gut microbiota, gene expression, and metabolites linked to glycine metabolism and glycolysis. Notably, an arabinoxylan-rich diet suppressed genes linked to choline, glycine, glycolysis, and TMA lyase, favoring glycine utilization via pyruvate pathways. Glycolytic inhibitors amplified these effects, mainly inhibiting pyruvate kinase. Our findings underscored the crosstalk between TMA lyase and glycolytic pathways, regulating glycine levels, and suggested avenues for targeted interventions and personalized diets to curb choline TMA lyase production.

Investigation of Geographical Differences of Arabinoxylan in Wheat Grain and Gel Properties of Arabinoxylan/Starch Complexes and In Vitro Digestion

With an increasing number of people pursuing a healthy diet, people have gradually realized the significance of adequate dietary fiber in their diets. In this experiment, wheat bran was collected from eight regions in China with different longitudes and latitudes, different altitudes, and average temperatures during the filling period to study the differences in the Arabinoxylan (AX) of wheat bran. The higher the altitude of the wheat production area was, the higher the AX content in the wheat bran was. Therefore, wheat bran from high-altitude production areas was selected for extracting AX. Different proportions of AX were added to wheat starch (WS) to explore the influence of different concentrations of AX on the gelatinization of WS, including the solubility, swelling capacity, rheological properties, and microstructure of the gelatinized products. Among these eight kinds of wheat, the content of total AX accounted for 11.90-15.79% of their dry weight, with the highest content being in wheat from Wuwei, Gansu. Among them, the content of water-soluble AX accounted for approximately 0.85% of their dry weight content. After adding different concentrations of 0.05-2% AX to the WS system, the gel network structure was changed. The starch hydrolysis rate of bread with 2% AX added was the lowest, of which the contents of rapidly digestible starch and slowly digestible starch were 40.02% and 36.61%, and resistant starch was as high as 25.31%. The addition of AX to starch-based foods is helpful for controlling postprandial blood sugar and insulin levels.

Comparative study on structure, properties, functions, and in vitro digestion characteristics of dietary fiber from Chinese chestnut prepared by different methods

This study compared the effects of enzyme extraction (E-DF), enzyme-acid extraction (EAc-DF), enzyme-alkaline extraction (EAl-DF), ultrasonic-enzyme extraction (EU-DF), and microwave-enzyme extraction (EM-DF) on the yield, chemical composition, structural characteristics, physicochemical properties, physiological activities, and hypoglycemic activities of dietary fiber (DF) from Chinese chestnut. EAl-DF had the highest yield (25.44 ± 0.70%) among all five extraction methods. The structural analysis indicated that other extracts, particularly EAl-DF, had a more complex and porous structure than E-DF. Analysis of monosaccharide composition showed that the main sugars in Chinese chestnut DF included Ara, Gal, Glc, and Man. Notably, EAl-DF exhibited the highest water and oil retention ability and hypoglycemic activity. The DFs extracted by five methods can resist digestion in the digestive tract. These results indicate that enzymatic-alkaline method is a high-quality method for extracting DF from Chinese chestnut. And this study provides a theoretical basis for the efficient preparation and development of Chinese chestnut DF.

Green strategies for the valorization of industrial medicinal residues of Serenoa repens small (saw palmetto) as source of bioactive compounds

Serenoa repens is a medicinal plant well-known for its therapeutic potential in treating various urological disorders and prevention of prostatic cancer. However, the extraction process in the pharmaceutical industry leads to the generation of plant residues, typically discarded, wasting valuable resources. In this study, we aimed to explore a series of green extraction strategies to effectively valorize the residues of Serenoa repens fruits. Initially, we employed supercritical CO2 (1.2% yield on dry biomass) on the discarded biomass to identify and quantify residual fatty acids and polyprenols (1.6% of the extract dry weight), a class of unsaturated isoprenoid alcohols with promising biomedical applications. Subsequently, subcritical water extraction was utilized on the exhausted biomass to extract polar compounds. An increase in the extraction yield was observed with the rise in processing temperature up to 180 °C (yields were found higher than 26%). Phenolic compounds and carbohydrate macromolecules profiles were affected by the increased hydrolytic conditions. Polar extracts exhibited robust bioactivities, demonstrating significant antioxidant activity and antimicrobial efficacy against Gram-positive and Gram-negative bacteria strains. Extracts obtained at 180 °C demonstrated the highest efficacy. Furthermore, in vitro assessment of mannans-rich fraction provided a new perspective of potential applications in the cosmeceuticals field. Results underscore the potential of the sustainable extraction biorefinery for the residue of this medicinal plant and demonstrate that, harnessing these bioactive compounds, new sustainable and eco-friendly approaches for its complete utilization can be offered, thereby promoting near-zero waste practices and contributing to a more sustainable future.

Combination of legume proteins and arabinoxylans are efficient emulsifiers to promote vitamin E bioaccessibility during digestion

The emulsification potential of plant-based emulsifiers, that is, pea (PPI) and lentil (LPI) proteins (4%), corn arabinoxylans (CAX, 1%), and legume protein-arabinoxylan mixtures (4% proteins + 0.15 or 0.9% CAX), was evaluated by assessing: the surface tension and potential of emulsifiers, emulsifier antinutritional contents, emulsion droplet size, emulsion physical stability, and vitamin E bioaccessibility from 10% oil-in-water emulsions. Tween 80 (2%) was used as a control. All emulsions presented small droplet sizes, both fresh and upon storage, except 4% LPI + 0.9% CAX emulsion that exhibited bigger droplet sizes (d(4,3) of approximately 18.76 μm vs 0.59 μm for the control) because of droplet bridging. Vitamin E bioaccessibility from emulsions stabilized with the combination of 4% PPI and either 0.15% or 0.9% CAX (28 ± 4.48% and 28.42 ± 3.87%, respectively) was not significantly different from that of emulsions stabilized with Tween 80 (43.56 ± 3.71%), whereas vitamin E bioaccessibility from emulsions stabilized with individual emulsifiers was significantly lower.

The effects of a fibre-enriched bakery product on glucose, insulin values and appetite. A pilot randomised cross-over trial

Brewers spent grain (BSG) is a valuable source of arabinoxylans with potential beneficial effects on glucose values. This pilot randomised crossover double-blind trial compared the effects of panettone, a sweet baked-product, enriched with BSG-fibre (p-rich) to unenriched panettone (p-standard) on glucose and insulin blood values and appetite scores. Ten healthy volunteers consumed each food in a random order. Blood variables and appetite scores were assessed at fasting and at different intervals after each food consumption. Glucose values were significantly higher after p-standard intake at 90-min (89.9 ± 16.1 vs 74.6 ± 19.4 mg/dL) and 120-min (81.1 ± 9.85 vs 72.1 ± 14.0 mg/dL). The areas-under-the-curve (AUCs) were lower for both glucose (p = .043) and insulin values (p = .036) with p-rich. At 240-min, satiety was higher (p = .006), and desire-to-eat lower (p = .008) with p-rich; desire-to-eat AUC was lower with p-rich too (p = .029). The integration of a small amount of BSG-derived fibre into a sweet food led to improved glycaemic control and appetite regulation.

Unveiling the breadmaking transformation: Structural and functional insights into Arabinoxylan

To understand the changes in arabinoxylan (AX) during breadmaking, multi-step enzyme digestion was conducted to re-extract arabinoxylan (AX-B) from AX-fortified bread. Their structural changes were compared using HPSEC, HPAEC, FT-IR, methylation analysis, and 1H NMR analysis; their properties changes in terms of enzymatic inhibition activities and in vitro fermentability against gut microbiota were also compared. Results showed that AX-B contained a higher portion of covalently linked protein while the molecular weight was reduced significantly after breadmaking process (from 677.1 kDa to 15.6 kDa); the structural complexity of AX-B in terms of the degree of branching was increased; the inhibition activity against α-amylase (76.81 % vs 73.89 % at 4 mg/mL) and α-glucosidase (64.43 % vs 58.08 % at 4 mg/mL) was improved; the AX-B group produced a higher short-chain fatty acids concentration than AX (54.68 ± 7.86 mmol/L vs 44.03 ± 4.10 mmol/L). This study provides novel knowledge regarding the structural and properties changes of arabinoxylan throughout breadmaking, which help to predict the health benefits of fibre-fortified bread and achieve precision nutrition.