Purification, composition and activity of bound polyphenols from mung bean coat dietary fiber

The composition and bioactivity of bound polyphenols from coffee dietary fiber during in vitro Simulating digestion

Dietary fiber from coffee peel is rich in bound polyphenols good for human health due to the antioxidant activity. In this study, we evaluated the bound polyphenol release conditions and activities in coffee peel soluble dietary fiber (CPSDF) in the process of in vitro simulation digestion. The CPSDF structure became loose and porous due to simulated digestion but retained the polysaccharide backbone. Widely-targeted metabolomics analysis identified 550 metabolites, with phenolic acids and flavonoids being main differentially expressed metabolites in digested products (82.18% in total). The most significant increase in the 5,7,8,3',4'-pentamethoxyflavanone content and decrease in the 3,5-dihydroxyacetophenone content were observed after digestion (undigested vs S-intestine). Additionally, the changes in antioxidant and enzyme inhibitory activities followed the same pattern as that observed for total phenolic content. The enzyme inhibitory and antioxidant activities of gastric digestion products were greater than those of the oral and small intestinal digestion products. The present work provided the theoretical foundation for developing high-value CPSDF products and reusing coffee peel waste.

Enhancing stability and flavor of mung bean-based milk through ultrasound treatment: Impacts on physical-chemical properties and protein structure

Mung bean-based milk (MBM) is a novel plant-based milk that offers several benefits. However, being a legume, the biggest challenge of MBM is its instability and off-flavor. The present study investigated changes in physical-chemical properties and flavor compounds during the ultrasound treatment of MBM. Compared to the untreated and ultrasonic samples before enzyme hydrolysis (UBE), the ultrasonic samples after enzyme hydrolysis and before homogenization (UBH) exhibited a smaller average particle size, higher magnitude of zeta potential, a homogenous structure, and fewer fragments. Ultrasound treatment shifted the protein secondary structure from ordered to disordered. The sample treated by ultrasound after enzymatic hydrolysis for 25 min had the highest free SH group, the lowest surface tension and the highest surface hydrophobicity, preventing protein aggregation. The off-flavor compounds in MBM, including pentanol, hexanol, and hexanal were significantly reduced in UBH 25 min samples. In conclusion, ultrasonication impacted the physical-chemical properties and flavor compounds considerably to improve the stability and flavor of MBM.

Development of supercritical technology to obtain improved functional dietary fiber for the valorization of broccoli by-product

BACKGROUND

This research aimed to enhance the functional value of dietary fiber from broccoli leaves using supercritical fluid technology. By optimizing pressure, temperature, and time parameters through response surface methodology, the study sought to improve the bioactive properties of the fiber and develop a predictive model for its chemical composition and functional properties.

RESULTS

Structural analysis indicated that modified samples had a higher concentration of oligosaccharides than control samples did, with significant increases in galacturonic acid and neutral sugars after supercritical fluid technology treatment, highlighting enhanced pectin release due to cell wall degradation. Functional properties, such as water solubility, glucose absorption capacity, and antioxidant activity, improved significantly under optimized conditions (191 bar, 40 °C, 1 h). Multivariate analysis confirmed the effectiveness of supercritical fluid technology in enhancing the dietary fiber properties, achieving a global desirability value of 0.805.

CONCLUSION

These results underscore the potential of supercritical technology for valorizing broccoli leaf by-products, enhancing their health-promoting characteristics and functional applications in the food industry. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Extraction, phytochemicals characterization, in vivo and in vitro anti-diabetic ability of non-extractable polyphenols from Undaria pinnatifida

Undaria pinnatifida (Up) is an edible seaweed known for its abundant nutrients and active compounds. In this research, six different methods, including acid hydrolysis extraction (AHE), alkaline hydrolysis extraction (LHE), enzymatic hydrolysis extraction (EHE), as well as their combinations with ultrasonic assisted extraction (AHE-U, LHE-U, EHE-U), were applied to extract non-extractable polyphenols from Up (UNEPPs). Results revealed that LHE-U was the most effective way to extract UNEPPs, it gave the highest yield (1.26 %) and total phenolics content (29.88 μg GAE/mg E), as well as considerable antioxidant and in vitro hypoglycemic effects. HPLC-Q-TOF-MS/MS analysis revealed the identification of 36 compounds from ULNEPPs, ferulic acid, p-coumaric acid and ferulic acid 4-O-glucuronide were the major compounds. In vivo study found that ULNEPPs could reduce fasting blood glucose (FBG) level, ameliorate abnormal glucose metabolism and dyslipidemia, repair insulin resistance and pancreas islet damage in type 2 diabetes (T2D) mice. Additionally, RT-qPCR analysis revealed that ULNEPPs improved glucose metabolism through the up-regulation of gene expression levels of Pi3k, Glut4, Akt, Ampk and the down-regulation of gene expression levels of Foxo1, Pgc-1α, Gsk-3β, Glut4, and G6pc. These results evidence that has the potential as dietary ingredients for preventing and treating T2D.

Fermentation of millet bran with Bacillus natto: enhancement of bioactivity levels and the bioactivity of bran extract

BACKGROUND

Millet bran (MB), a byproduct of millet production, is rich in functional components but it is underutilized. In recent years, researchers have shown that fermentation can improve the biological activity of cereals and their byproducts. This study used Bacillus natto to ferment millet bran to improve its added value and broaden the application of MB. The bioactive component content, physicochemical properties, and functional activity of millet bran extract (MBE) from fermented millet bran were determined.

RESULTS

After fermentation, the soluble dietary fiber (SDF) content increased by 92.0%, the β-glucan content by 164.4%, the polypeptide content by 111.4%, the polyphenol content by 32.5%, the flavone content by 16.4%, and the total amino acid content by 95.4%. Scanning electron microscopy revealed that the microscopic morphology of MBE changed from complete and dense blocks to loosely porous shapes after fermentation. After fermentation, the solubility, water-holding capacity, and viscosity significantly increased and the particle size decreased. Moreover, the glucose adsorption capacity (2.1 mmol g-1), glucose dialysis retardation index (75.3%), and α-glucosidase inhibitory (71.4%, mixed reversible inhibition) activity of the fermented MBE (FMBE) were greater than those of the unfermented MBE (0.99 mmol g-1, 32.1%, and 35.1%, respectively). The FMBE presented better cholesterol and sodium cholate (SC) adsorption properties and the adsorption was considered inhomogeneous surface adsorption.

CONCLUSION

Fermentation increased the bioactive component content and improved the physicochemical properties of MBE, thereby improving its hypoglycemic and hypolipidemic properties. This study not only resolves the problem of millet bran waste but also encourages the development of higher value-added application methods for millet bran. © 2024 Society of Chemical Industry.

Purification, Characterization, and Anti-Inflammatory Potential of Free and Bound Polyphenols Extracted from Rosa roxburghii Tratt Pomace

Rosa roxburghii Tratt pomace (RRTP), an underutilized byproduct, is rich in polyphenol compounds. This study aimed to further explore the purification, characterization, anti-inflammatory activities, and underlying molecular mechanisms of free polyphenols (RRTP-FP) and bound polyphenols (RRTP-BP) from RRTP. The results indicated that AB-8 macroporous resin emerged as the preferred choice for subsequent separation and purification. The purities of purified RRTP-FP (P-RRTP-FP) and purified RRTP-BP (P-RRTP-BP) increased by 103.34% and 66.01%, respectively. Quantitative analysis identified epigallocatechin, epicatechin, and ellagic acid as the main phenolic compounds in P-RRTP-FP. In P-RRTP-BP, the primary phenolic compounds were ellagic acid, epicatechin, and gallic acid. In vitro antioxidant assays demonstrated the superior DPPH and ABTS radical scavenging activities of P-RRTP-FP and P-RRTP-BP compared to vitamin C. Treatment with P-RRTP-FP and P-RRTP-BP reduced nitric oxide (NO) and reactive oxygen species (ROS) production, mitigated the decline in cellular membrane potential, and significantly downregulated the mRNA expression of pro-inflammatory cytokines and inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Additionally, P-RRTP-FP and P-RRTP-BP inhibited the phosphorylation of pertinent proteins in the nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. This finding suggests potential utility of RRTP-derived polyphenols as anti-inflammatory agents for managing severe inflammatory conditions.

Precise evaluation of batch adsorption kinetics of plant total polyphenols based on a flow-injection online spectrophotometric method

Efficient evaluation of adsorption kinetics of plant total polyphenols is essential for the design of adsorption separation of bioactive compounds. The conventional method uses manual sampling with poor reproducibility. Here, we developed a new method for on-line determination of total polyphenol content (TPC) in plant extracts by applying the Folin-Ciocalteu method in flow-injection analysis (FIA). The FIA parameters were optimized and a standard curve with excellent linearity was established. Precise determination of TPC with a satisfactory sample throughput of 20 h-1 was achieved for the adsorption kinetic study. The pseudo-second-order kinetic model was found to better describe the kinetic parameters of the batch adsorption/desorption process. The developed method proved to be accurate compared with the conventional method. The FIA method holds significant promise for studying and monitoring adsorption processes, due to its automatic on-line nature, low consumption of reagents and samples, and the ability to generate large quantities of highly accurate adsorption data.