Concept and health-related properties of nonextractable polyphenols: the missing dietary polyphenols

Phytochemical Profile and Bioactivity of Bound Polyphenols Released from Rosa roxburghii Fruit Pomace Dietary Fiber by Solid-State Fermentation with Aspergillus niger

This study aimed to investigate the phytochemical profile, bioactivity, and release mechanism of bound polyphenols (BPs) released from Rosa roxburghii fruit pomace insoluble dietary fiber (RPDF) through solid-state fermentation (SSF) with Aspergillus niger. The results indicated that the amount of BPs released from RPDF through SSF was 17.22 mg GAE/g DW, which was significantly higher than that achieved through alkaline hydrolysis extraction (5.33 mg GAE/g DW). The BPs released through SSF exhibited superior antioxidant and α-glucosidase inhibitory activities compared to that released through alkaline hydrolysis. Chemical composition analysis revealed that SSF released several main compounds, including ellagic acid, epigallocatechin, p-hydroxybenzoic acid, quercetin, and 3,4-dihydroxyphenylpropionic acid. Mechanism analysis indicated that the disruption of tight structure, chemical bonds, and hemicellulose was crucial for the release of BPs from RPDF. This study provides valuable information on the potential application of SSF for the efficient release of BPs from RPDF, contributing to the utilization of RPDF as a functional food ingredient.

The Effects of Different Drying Methods on the In Vitro Bioaccessibility of Phenolics, Antioxidant Capacity, and Morphology of European Plums (Prunes domestica L.)

Four different drying methods, hot-air-drying (HAD), vacuum-drying (VD), ultrasound-assisted vacuum-drying (US-VD), and freeze-drying (FD), were used to obtain dried plums (Prunes domesticaL.). These prunes were evaluated for their physical properties (such as color, rehydration ratio, and microstructural properties), phenolic compounds, and antioxidant activities before and after being subjected to in vitro digestion. TPC (total phenolic content) of plums ranged from 196.84 to 919.58 mg of GAE (gallic acid equivalent)/100 g of dw, and neochlorogenic acid was the most abundant phenolic compound. FD prunes had the highest levels of phenolics, whereas US-VD caused the most significant loss. During in vitro digestion, the phenolics were present at higher levels at the gastric medium but failed to maintain their stability at the small intestinal stage. Among the samples, FD along with HAD prunes exhibited a higher bioaccessibility index for most of the phenolic compounds. The ratios of TPC, TFC (total flavonoid content), and individual phenolics determined in the digested residues to the initial values of the undigested samples ranged from 0.23 to 31.03%. It could be concluded that the majority of the phenolics were extracted during digestion. Our findings showed that the different drying methods would alter the microstructure, which would affect the extractability and release of phenolics in the simulated digestion model.

The synergistic ramification of insoluble dietary fiber and associated non-extractable polyphenols on gut microbial population escorting alleviation of lifestyle diseases

Most of the pertinent research which aims at exploring the therapeutic effects of polyphenols usually misapprehends a large fraction of non-extractable polyphenols due to their poor aqueous-organic solvent extractability. These polymeric polyphenols (i.e., proanthocyanins, hydrolysable tannins and phenolic acids) possess a unique property to adhere to the food matrix polysaccharides and protein sowing to their structural complexity with high glycosylation, degree of polymerization, and plenty of hydroxyl groups. Surprisingly resistance to intestinal absorption does not hinder its bioactivity but accelerates its functionality manifolds due to the colonic microbial catabolism in the gastrointestinal tract, thereby protecting the body from local and systemic inflammatory diseases. This review highlights not only the chemistry, digestion, colonic metabolism of non-extractable polyphenols (NEPP) but also summarises the synergistic effect of matrix-bound NEPP exerting local as well as systemic health benefits.

Polyphenol-Dietary Fiber Conjugates from Fruits and Vegetables: Nature and Biological Fate in a Food and Nutrition Perspective

In the past few years, numerous studies have investigated the correlation between polyphenol intake and the prevention of several chronic diseases. Research regarding the global biological fate and bioactivity has been directed to extractable polyphenols that can be found in aqueous-organic extracts, obtained from plant-derived foods. Nevertheless, significant amounts of non-extractable polyphenols, closely associated with the plant cell wall matrix (namely with dietary fibers), are also delivered during digestion, although they are ignored in biological, nutritional, and epidemiological studies. These conjugates have gained the spotlight because they may exert their bioactivities for much longer than extractable polyphenols. Additionally, from a technological food perspective, polyphenols combined with dietary fibers have become increasingly interesting as they could be useful for the food industry to enhance technological functionalities. Non-extractable polyphenols include low molecular weight compounds such as phenolic acids and high molecular weight polymeric compounds such as proanthocyanidins and hydrolysable tannins. Studies concerning these conjugates are scarce, and usually refer to the compositional analysis of individual components rather than to the whole fraction. In this context, the knowledge and exploitation of non-extractable polyphenol-dietary fiber conjugates will be the focus of this review, aiming to access their potential nutritional and biological effect, together with their functional properties.

Grain Germination Changes the Profile of Phenolic Compounds and Benzoxazinoids in Wheat: A Study on Hard and Soft Cultivars

Pre-harvest sprouting is a frequent problem for wheat culture that can be simulated by laboratory-based germination. Despite reducing baking properties, wheat sprouting has been shown to increase the bioavailability of some nutrients. It was investigated whether wheat cultivars bearing distinct grain texture characteristics (BRS Guaraim, soft vs. BRS Marcante, hard texture) would have different behavior in terms of the changes in phytochemical compounds during germination. Using LC-Q-TOF-MS, higher contents of benzoxazinoids and flavonoids were found in the hard cultivar than in the soft one. Free phytochemicals, mainly benzoxazinoids, increased during germination in both cultivars. Before germination, soft and hard cultivars had a similar profile of matrix-bound phytochemicals, but during germination, these compounds have been shown to decrease only in the hard-texture cultivar, due to decreased levels of phenolic acids (trans-ferulic acid) and flavonoids (apigenin) that were bound to the cell wall through ester-type bonds. These findings confirm the hypothesis that hard and soft wheat cultivars have distinct behavior during germination concerning the changes in phytochemical compounds, namely the matrix-bound compounds. In addition, germination has been shown to remarkably increase the content of benzoxazinoids and the antioxidant capacity, which could bring a health-beneficial appeal for pre-harvested sprouted grains.

Upcycling Rocha do Oeste Pear Pomace as a Sustainable Food Ingredient: Composition, Rheological Behavior and Microstructure Alone and Combined with Yeast Protein Extract

This work explores the potential of Rocha do Oeste pear pomace to be used as a sustainable and healthy food ingredient. Moreover, the enrichment with yeast protein extract (YPE) may be useful to design innovative food products. The main goals of this study were to assess pear pomace concerning: (i) chemical composition and antioxidant capacity; (ii) rheology, texture, and microstructure characterization (alone or enriched with YPE), before and after heating. The results showed that pear pomace was a rich source of dietary fibers (74.5% DW), with phenolic compounds (3.9 mg chlorogenic acid equivalents/g dry weight), also presenting antiradical activity (3.90 μmol Trolox equivalents/g DW). Pear pomace showed a shear thinning behavior and a typical soft-gel behavior, which was not affected by YPE enrichment, thus suggesting that YPE did not affect pear pomace technological properties. Thermal treatment also did not alter pear pomace rheological properties. YPE addition induced a decrease in the apparent viscosity and a destabilizing effect, compared to the samples that were subjected to thermal processing. These results highlight the importance of pear pomace and the use of YPE for protein enrichment, opening new opportunities for their exploitation.

Chardonnay Marc as a New Model for Upcycled Co-products in the Food Industry: Concentration of Diverse Natural Products Chemistry for Consumer Health and Sensory Benefits

Research continues to provide compelling insights into potential health benefits associated with diets rich in plant-based natural products (PBNPs). Coupled with evidence from dietary intervention trials, dietary recommendations increasingly include higher intakes of PBNPs. In addition to health benefits, PBNPs can drive flavor and sensory perceptions in foods and beverages. Chardonnay marc (pomace) is a byproduct of winemaking obtained after fruit pressing that has not undergone fermentation. Recent research has revealed that PBNP diversity within Chardonnay marc has potential relevance to human health and desirable sensory attributes in food and beverage products. This review explores the potential of Chardonnay marc as a valuable new PBNP ingredient in the food system by combining health, sensory, and environmental sustainability benefits that serves as a model for development of future ingredients within a sustainable circular bioeconomy. This includes a discussion on the potential role of computational methods, including artificial intelligence (AI), in accelerating research and development required to discover and commercialize this new source of PBNPs.

In Vivo Evaluation of the Cardiometabolic Potential of Grape Pomace: Effect of Applying Instant Controlled Pressure Drop

Grape pomace (GP) is a source of polyphenols which may be present as free structures or associated with dietary fiber. Instant controlled pressure drop (DIC) is a technology which can modify the association of polyphenols with food matrixes, but how these modifications affect the health benefits associated with GP remains to be elucidated. In this study, in rats fed a high-fat-fructose diet (HFF), we evaluated the in vivo cardiometabolic effects of the modification of polyphenols in GP caused by DIC at 0.2 MPa for 60 s (DIC1) and 0.4 MPa for 120 s (DIC2). These treatments increased anthocyanin and total flavonoid contents, respectively, while all the supplementations caused significant improvements in insulin resistance and plasma triacylglycerols. Thus, the bioactive compounds present in GP (including a major fraction of non-extractable proanthocyanidins) caused these modifications independently of the specific polyphenol profiles which may have resulted from these DIC treatments. Additionally, only intact GP led to an increase in HDL cholesterol, while only DIC2-treated GP improved hepatic steatosis. In conclusion, GP always improves insulin sensitivity in this animal model of obesity, while the different compositions of GP modified by DIC may be associated with other cardiometabolic parameters.

Principle and Application of Steam Explosion Technology in Modification of Food Fiber

Steam explosion is a widely used hydrothermal pretreatment method, also known as autohydrolysis, which has become a popular pretreatment method due to its lower energy consumption and lower chemical usage. In this review, we summarized the technical principle of steam explosion, and its definition, modification and application in dietary fiber, which have been explored by researchers in recent years. The principle and application of steam explosion technology in the modification of food dietary fiber were analyzed. The change in dietary fiber structure; physical, chemical, and functional characteristics; the advantages and disadvantages of the method; and future development trends were discussed, with the aim to strengthen the economic value and utilization of plants with high dietary fiber content and their byproducts.

Free and Bound Phenolic Profiles of Rosa roxburghii Tratt Leaves and Their Antioxidant and Inhibitory Effects on α-Glucosidase

Rosa roxburghii Tratt (R. roxburghii) tea is a traditional Chinese beverage. This study aims to investigate and compare the phenolics in free and bound forms of two cultivars of R. roxburghii leaves, and their bioactivities. The total phenolic content of free and bound fractions was 72.71 and 17.75 mg GAE/g DW in Gui Nong No. 5 (GNN5) and 94.28 and 11.19 mg GAE/g DW in Seedless Cili (SC). A total of 37 phenolic compounds were characterized and quantified by UPLC-Q-Exactive Orbitrap/MS with ellagic acid, quercitrin, isoquercitrin, and quininic acid in free fraction, while gallic acid, ellagic acid, and hyperoside were main compounds in bound fraction. The free fraction with higher phenolic contents also showed excellent performances on antioxidant activities and α-glucosidase inhibitory potency than bound phenolics. Therefore, the results highlight that R. roxburghii leaves are a promising source enriched in phenolic constituents for functional beverages and nutritional foods.

In vitro evaluation of antioxidant activity and determination of total phenolic and flavonoids contents of ethanol-water extracts of Paeonia lactiflora and Calendula officinalis L. petals

In this study, the petals collected from peony hybrid Paeonia lactiflora "Bowl of beauty" and Calendula officinalis L. were extracted using ethanol-water mixture assisted with microwave and ultrasonic treatment. The isolation of Calendula officinalis L. essential oil was done by hydrodistillation as well. The total phenolic and flavonoids content in the extracts and oil were determined and their antioxidant activity was evaluated. The highest total phenolic content was found for the extracts of hybrid Paeonia lactiflora and Calendula officinalis L. obtained by ultrasound extraction (9.73 and 10.03 mg GA/mL RE, respectively), while the highest flavonoid content was obtained by microwave-assisted extraction (14.45 and 6.02 mg QE/mL RE, respectively). Antioxidant activity was assessed using standard antioxidant in vitro DPPH• and ABTS•+ assays. The highest antioxidant activity was obtained in DPPH• and ABTS•+ assay for the microwave-assisted extraction of hybrid Paeonia lactiflora (79% and 83%) and ultrasound-assisted extraction of Calendula officinalis L. (45% and 49%), respectively. In order to improve the antioxidative activity of both extract and essential oil the pectin films with gallic acid, using enzymatically assisted catalysis to attain covalent bonding to a carrier, were prepared. Optical microscopy and FTIR spectroscopy were used for the characterization of obtained materials. The films, with essential oil of Calendula officinalis L. and gallic acid, showed significantly increased percentage inhibition in DPPH• and ABTS•+ test (91% and 95%, respectively) after 10 minutes. The results, also, showed that all formulations of pectin biopolymer film, modified with gallic acid, can be successfully applied as a carrier for both types of ingredients.

In vitro evaluation of antioxidative activities of the extracts of petals of Paeonia lactiflora and Calendula officinalis incorporated in the new forms of biobased carriers

In this study, the petals collected from peony hybrid Paeonia lactiflora "Bowl of Beauty" and Calendula officinalis L. were extracted using an ethanol-water mixture assisted with microwave and ultrasonic treatment. The isolation of Calendula officinalis L. essential oil was done by hydrodistillation as well. The total phenolic and flavonoids content in the extracts and oil were determined and their antioxidant activity was evaluated. The highest total phenolic content was found for the extracts of hybrid P. lactiflora and C. officinalis L. obtained by ultrasound extraction (83.16 and 114.47 mg GA/g, respectively), while the flavonoid content obtained by microwave-assisted extraction was relatively high (123.48 and 65.29 mg QE/g, respectively). The highest antioxidant activity was obtained in DPPH• and ABTS•+ assay for the microwave-assisted extraction of hybrid P. lactiflora (79% and 83%) and ultrasound-assisted extraction of C. officinalis L. (45% and 49%), respectively. To improve antioxidant activity of both types of examined analytes (extracts and essential oil), the pectin biopolymer film (as a carrier) was prepared in the process of enzymatically assisted catalysis. Optical microscopy and FTIR spectroscopy were used for the characterization of obtained materials. The films, with essential oil of C. officinalis L. and gallic acid, showed significantly increased percentage inhibition in DPPH• and ABTS•+ test (91% and 95%, respectively) after 10 minutes. The results, also, showed that all formulations of pectin biopolymer film, modified with gallic acid, can be successfully applied as a carrier for both types of ingredients.

Extraction of the antioxidant phytocomplex from wine-making by-products and sustainable loading in phospholipid vesicles specifically tailored for skin protection

The present study is aimed at valorizing grape pomace, one of the most abundant winery-making by-products of the Mediterranean area, through the extraction of the main bioactive compounds from the skin of grape pomace and using them to manufacture innovative nanoformulations capable of both avoiding skin damages and promoting skincare. The phytochemicals were recovered through maceration in hydroethanolic solution. Catechin, quercetin, fisetin and gallic acid, which are known for their antioxidant power, were detected as the main compounds of the extract. Liposomes and phospholipid vesicles modified with glycerol or Montanov 82® or a combination of both, were used as carriers for the extract. The vesicles were small (~183 nm), slightly polydispersed (PI ≥ 0.28), and highly negatively charged (~-50 mV). The extract was loaded in high amounts in all vesicles (~100%) irrespective of their composition. The antioxidant activity of the extract, measured by using the DPPH (2,2-Diphenyl-1-picrylhydrazyl) test, was 84 ± 1%, and slightly increased when loaded into the vesicles (~89%, P < 0.05). The grape pomace extract loaded vesicles were highly biocompatible and able to protect fibroblasts (3T3) from the oxidative stress induced by hydrogen peroxide.

High-performance thin-layer chromatography and direct analysis in real time-high resolution mass spectrometry of non-extractable polyphenols from tropical fruit peels

Passiflora species, mangosteen, and cherimoya peels are a source of bioactive phenolic compounds. Nevertheless, a significant fraction of polyphenols, called non-extractable polyphenols (NEPs), are retained in the extraction residue after a conventional extraction. Thus, alkaline, acid, and enzymatic-assisted extractions to recover high contents of antioxidant NEPs from the extraction residue of fruit peels, were compared in this work. A high-performance thin-layer chromatography method with UV/Vis detection was developed in order to obtain the phenolic profile for the extracts. The most intense bands were further analyzed by direct analysis in real-time-high-resolution mass spectrometry to tentatively identified NEPs in fruit peel extracts. Total phenolic and proanthocyanidin contents and antioxidant capacity of the extracts were measured to carry out a multivariate statistical analysis. Alkaline hydrolysis was the most efficient treatment to recover NEPs from fruit peels as well as a promising treatment to obtain antioxidant extracts along with EAE. Cherimoya peel extracts were the richest in antioxidant NEPs. This work highlights that many NEPs remain on the extraction residue of fruit peels after conventional extraction and are not usually taken into account.

Phenolic profiles, bioaccessibility and antioxidant activity of plum (Prunus Salicina Lindl)

Plum (Prunus Salicina Lindl) is a rich source of phenolic compounds. However, the bound phenolics and its bioaccessibility and antioxidant activity remain unclear. Hence, the purpose of this study was to determine: 1) phenolic profiles of plum, including both free and bound phenolic fractions, 2) bioaccessibility of phenolic compounds in plum during simulated gastrointestinal digestions, 3) their antioxidant properties. A total of 17 phenolic compounds were identified by UPLC-Q-Exactive Orbitrap/MS with most epicatechin, neochlorogenic acid and procyanidin B2 in the free phenolics fraction, while catechin and epicatechin was the main compounds in the bound phenolics fraction. After the gastrointestinal digestion phase, the most bioaccessible phenolics were quercetin-pentoside (61.64%), cyanidin-3-O-glucoside (43.26%), and naringenin-7-O-β-D-glucoside (42.04%). The antioxidant capacity of both undigested plum and its digested fractions showed a positive correlation with the total phenolics, and with specific individual phenolic compounds such as neochlorogenic acid, epicatechin and procyanidin B2 in undigested plum whereas catechin, neochlorogenic acid, and epicatechin in digested one. The results confirm that bound fraction of plum contribution to the total phenolic content must be taken into account in the assessment of the improving human health effects of plum.

Protective Role of Polyphenols in Heart Failure: Molecular Targets and Cellular Mechanisms Underlying Their Therapeutic Potential

Heart failure (HF) is a leading cause of death in the United States, with a 5-year mortality rate of 50% despite modern pharmacological therapies. Plant-based diets are comprised of a diverse polyphenol profile, which lends to their association with reduced cardiovascular disease risk. Whether a polyphenol-rich diet can slow the progression of or reverse HF in humans is not known. To date, in vitro and in vivo studies have reported on the protective role of polyphenols in HF. In this review, we will discuss the major mechanisms by which polyphenols mitigate HF in vitro and in vivo, including (1) reduced cardiac inflammation and oxidative stress, (2) reduced mitochondrial dysfunction, (3) improved Ca²⁺ homeostasis, (4) increased survival signaling, and (5) increased sirtuin 1 activity.

Effects of Different Nitrogen Forms and Exogenous Application of Putrescine on Heat Stress of Cauliflower: Photosynthetic Gas Exchange, Mineral Concentration and Lipid Peroxidation

This study examines the effect of the exogenous application of polyamine putrescine together with the application of different ratios of nitrate/ammonium (NO₃⁻/NH₄⁺), on the physiology of cauliflower subjected to heat stress. The 50:50 NO₃⁻/NH₄⁺ ratio was the best ratio against heat stress. As a result of the joint application of these compounds, a higher photosynthetic rate, a higher accumulation of both photosynthesis-related compounds and pigments, total proteins, and a change in the status of nutrients were obtained. Particularly, the decrease in content of calcium, chloride and sulphate in plants under heat stress is ameliorated by the ammonium effect. Additionally, it is important to highlight that cauliflower waste contains a higher content of mineral nutrients than floret cauliflower. These effects were more marked in young leaves. Furthermore, a synergistic effect for coping with heat stress between the polyamine and the nutritional treatment was observed. For this, both the application of putrescine and the feeding of plants with a 50:50 NO₃⁻/NH₄⁺ ratio before heat stress is proposed for the first time as an agricultural practice for increasing the thermotolerance of cauliflower cv Moonshine. On the other hand, due to the lower lipid peroxidation rate obtained in cauliflower leaves, these plants could be used for health purposes as ointments or other nutraceutical products, making the cultivation of this kind of cruciferous more sustainable.

Extractable and Non-Extractable Antioxidants Composition in the eBASIS Database: A Key Tool for Dietary Assessment in Human Health and Disease Research

The antioxidant properties of foods are crucial in nutrition, food chemistry, and medicine studies but are often underestimated, with significant amounts of bioactive compounds containing physiological and biochemical properties remaining in the residue from extraction as non-extractable antioxidants. Over the last decade, extractable and non-extractable compounds have become key in the evaluation/determination of the antioxidant properties of food matrices because of their relevance in human health. This has led to the need to include extractable and non-extractable antioxidants in comprehensive and harmonized food composition databases for a wide range of applications within research, food, pharmaceutical, nutraceutical, and cosmeceutical areas. Additionally, the databases are invaluable as part of the health claims application process. eBASIS, (Bioactive Substances in Food Information System) a comprehensive database containing quality-evaluated scientific data, covering the composition of bioactive compounds present in foods, has flexible structures, allowing it to be extended to include newly emerging data on extractable and non-extractable compounds. Search criteria were developed and defined for compiling suitable peer-reviewed literature. Data quality assessment methods were established for the addition of composition data and antioxidant activity, with a focus on various parameters including: the extraction procedure, the antioxidant measurements, the expression of results. A total of 437 quality-evaluated datapoints on the composition of extractable and/or non-extractable compounds were entered into the database. This database update represents one of the first examples of building a database dedicated to antioxidant properties. This expansion of eBASIS provides a novel and unique tool for nutritionists, dietitians, researchers to use for a wide range of applications, such as dietary assessment, exposure studies and epidemiological studies, and may contribute to an increase in high-bioactive food consumption by consumers.

Antioxidant and α-glucosidase inhibitory capacity of nonextractable polyphenols in Mopan persimmon

This study was to evaluate and compare the polyphenols contents, antioxidant capacities, and α-glucosidase inhibitory abilities of extractable and nonextractable polyphenols (EP and NEP) in Mopan persimmon. The results showed that total phenols content of NEP was 5 times higher than that of EP, and the hydrolyzed NEP compounds displayed higher antioxidant capacity than EP in vitro by DPPH, ORAC assays. Meanwhile, NEP also exhibited inhibition capacity of α-glucosidase and were higher than that of acarbose. In addition, an in vitro model of gastrointestinal digestion was used for the release of NEP, the polyphenols content and ORAC values were obviously increased in gastric digestion stage. The result indicated that NEP in Mopan persimmon, which has often been overlooked and discarded in the past, possessed higher polyphenols content and antioxidant capacity than EP.

Acetic acid buffer as extraction medium for free and bound phenolics from dried blackcurrant (Ribes nigrum L.) skins

The aim of this study was to investigate the effects of different solvent and extraction temperatures on the free and bound phenolic compounds and antioxidant activity of dried blackcurrant skins (DBS). Apart from acetic acid buffer solution, different solvent systems, including water, methanol, and mixtures of methanol/water, were also employed and the effects of solvent and temperature (30 and 50 °C) on the free and bound forms of anthocyanins, hydroxycinnamic acids, and flavonols yield were assessed. The results showed that among all solvents, acetic acid buffer resulted in the highest free anthocyanin content (1,712.3 ± 56.1 mg/100 g) (P < 0.05) after 2 hr extraction at 50 °C from DBS, while lower amounts of bound anthocyanins and anthocyanidins were detected after acid hydrolysis. Acetic acid buffer extracts exhibited the highest free hydroxycinnamic acid content (268.0 ± 4.5 mg/100 g), total phenolic content (3702.2 ± 259.3 mg GAE/100 g), and DPPH activity (60.7 ± 2.0% of inhibition). However, their free flavonol content was slightly lower (60.2 ± 0.8 mg/100 g) compared to 100% methanol at 30 and 50 °C (71.4 ± 1.5 mg/100 g and 71.5 ± 6.2 mg/100 g, respectively). Two-way ANOVA indicated interactions between solvent and temperature (P < 0.05), which suggested that the relationship between solvent and phenolic compounds depends on the extraction temperature. PRACTICAL APPLICATION: Overall, acetic acid buffer is more environmental friendly, efficient, and cost effective than other solvents, thus, offering an improved extraction method for phytochemicals as valuable ingredients for nutraceutical applications, from underutilized dried blackcurrant skins (DBS).

Interactions between cell wall polysaccharides and polyphenols: Effect of molecular internal structure

Cell wall polysaccharides (CPSs) and polyphenols are major constituents of the dietary fiber complex in plant-based foods. Their digestion (by gut microbiota) and bioefficacy depend not only on their structure and quantity, but also on their intermolecular interactions. The composition and structure of these compounds vary with their dietary source (i.e., fruit or vegetable of origin) and can be further modified by food processing. Various components and structures of CPSs and polyphenols have been observed to demonstrate common and characteristic behaviors during interactions. However, at a fundamental level, the mechanisms that ultimately drive these interactions are still not fully understood. This review summarizes the current state of knowledge on the internal factors that influence CPS-polyphenol interactions, describes the different ways in which these interactions can be mediated by molecular composition or structure, and introduces the main methods for the analysis of these interactions, as well as the mechanisms involved. Furthermore, a comprehensive overview is provided of recent key findings in the area of CPS-polyphenol interactions. It is becoming clear that these interactions are shaped by a multitude of factors, the most important of which are the physicochemical properties of the partners: their morphology (surface area and porosity/pore shape), chemical composition (sugar ratio, solubility, and non-sugar components), and molecular architecture (molecular weight, degree of esterification, functional groups, and conformation). An improved understanding of the molecular mechanisms that drive interactions between CPSs and polyphenols may allow us to better establish a bridge between food processing and the bioavailability of colonic fermentation products from CPSs and antioxidant polyphenols, which could ultimately lead to the development of new guidelines for the design of healthier and more nutritious foods.

Composition of bound polyphenols from carrot dietary fiber and its in vivo and in vitro antioxidant activity

Qualitative analysis of bound polyphenols from carrot dietary fiber (CDF-PP) was performed by ultra-performance liquid chromatography equipped with an electrospray ionization and quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS/MS). Eleven organic acids, nine hydroxybenzoic acids and derivatives, six hydroxycinnamic acids and derivatives, four phenolic alcohols and derivatives, three flavonoids and derivatives, seven esters and derivatives, two other compounds, were detected by matching their retention times, secondary mass spectrometry fragment information with authentic standards or literature data. Furthermore, in vitro antioxidant activity was determined by different kinds of assays, including DPPH, ORAC, PSC, demonstrated that CDF-PP could scavenge radicals in a dose dependent manner. Moreover, CDF-PP exhibited significantly reactive oxygen species (ROS) scavenging activity in living Caenorhabditis elegans. To our knowledge, this is the first comprehensive research to investigate composition and in vitro/in vivo antioxidant activity of bound polyphenols in CDF, which implied that CDF-PP could be a promising source of antioxidants.

Non-Extractable Polyphenols from Food By-Products: Current Knowledge on Recovery, Characterisation, and Potential Applications

Non-extractable polyphenols (NEPs), or bound polyphenols, are a significant fraction of polyphenols that are retained in the extraction residues after conventional aqueous organic solvent extraction. They include both high molecular weight polymeric polyphenols and low molecular weight phenolics attached to macromolecules. Current knowledge proved that these bioactive compounds possess high antioxidant, antidiabetic, and other biological activities. Plant-based food by-products, such as peels, pomace, and seeds, possess high amount of NEPs. The recovery of these valuable compounds is considered an effective way to recycle food by-products and mitigate pollution, bad manufacturing practice, and economic loss caused by the residues management. The current challenge to valorise NEPs from plant-based by-products is to increase the extraction efficiency with proper techniques, choose appropriate characterising methods, and explore potential functions to use in some products. Based on this scenario, the present review aims to summarise the extraction procedure and technologies applied to recover NEPs from plant-based by-products. Furthermore, it also describes the main techniques used for the characterisation of NEPs and outlines their potential food, pharmaceutical, nutraceutical, and cosmetic applications.

The Protective Effect of Polyphenols for Colorectal Cancer

Colorectal cancer (CRC) is one of the most prevalent cancers that threaten people in many countries. It is a multi-factorial chronic disease caused by a combination of genetic and environmental factors, but it is mainly related to lifestyle factors, including diet. Plentiful plant foods and beverages are abundant in polyphenols with antioxidant, anti-atherosclerotic, anti-inflammatory, and anticancer properties. These compounds participate in host nutrition and disease pathology regulation in different ways. Polyphenolic compounds have been used to prevent and inhibit the development and prognosis of cancer, and examples include green tea polyphenol (-)epigallocatechin-3-O-gallate (EGCG), curcumin, and resveratrol. Of course, there are more known and unknown polyphenol compounds that need to be further explored for their anticancer properties. This article focuses on the fact that polyphenols affect the progression of CRC by controlling intestinal inflammation, epigenetics, and the intestinal microbe in the aspects of prevention, treatment, and prognosis.

(Poly)phenolic Content and Profile and Antioxidant Capacity of Whole-Grain Cookies are Better Estimated by Simulated Digestion than Chemical Extraction

It is widely recognized that the biological effects of phytochemicals cannot be attributed to the native compounds present in foods but rather to their metabolites endogenously released after intake. Bioavailability depends on bioaccessibility, which is the amount of the food constituent that is released from the matrix in the gastrointestinal tract. The use of chemical extraction to evaluate the content and profile of phytochemicals does not mirror the physiological situation in vivo, and their bioaccessibility should be considered while assessing their nutritional significance in human health. The current study was designed to compare the (poly)phenolic profile and content and antioxidant capacity of whole-grain (WG) cookies using chemical extraction and a more physiological approach based on simulated digestion. Three types of organic WG cookies (made with durum, Italian khorasan, or KAMUT^® khorasan wheat) were considered, either fermented by Saccharomyces Cerevisiae or sourdough. Although the flour type and the fermentation process influenced the release of phytochemicals from the cookie matrix, in almost all samples, the simulated digestion appeared the most efficient procedure. Our results indicate that the use of chemical extraction for evaluation of the phytochemicals content and antioxidant capacity of food could lead to underestimation and underline the need for more physiological extraction methods.

Modulation of the human gut microbiota by phenolics and phenolic fiber-rich foods

The gut microbiota plays a prominent role in human health. Alterations in the gut microbiota are linked to the development of chronic diseases such as obesity, inflammatory bowel disease, metabolic syndrome, and certain cancers. We know that diet plays an important role to initiate, shape, and modulate the gut microbiota. Long-term dietary patterns are shown to be closely related with the gut microbiota enterotypes, specifically long-term consumption of carbohydrates (related to Prevotella abundance) or a diet rich in protein and animal fats (correlated to Bacteroides). Short-term consumption of solely animal- or plant-based diets have rapid and reproducible modulatory effects on the human gut microbiota. These alterations in microbiota profile by dietary alterations can be due to impact of different dietary macronutrients, carbohydrates, protein, and fat, which have diverse modulatory effects on gut microbial composition. Food-derived phenolics, which encompass structural variants of flavonoids, hydroxybenzoic acids, hydroxycinnamic acids, coumarins, stilbenes, ellagitannins, and lignans can modify the gut microbiota. Gut microbes have been shown to act on dietary fibers and phenolics to produce functional metabolites that contribute to gut health. Here, we discuss recent studies on the impacts of phenolics and phenolic fiber-rich foods on the human gut microbiota and provide an insight into potential synergistic roles between their bacterial metabolic products in the regulation of the intestinal microbiota.

Anil Kumar N, Sharopov F, Ramírez-Alarcón K, Ruiz-Ortega A, Abdulmajid Ayatollahi S, Valere Tsouh Fokou P, Kobarfard F, Amiruddin Zakaria Z, Iriti M, Taheri Y, Martorell M, Sureda A, N. Setzer W, Durazzo A, Lucarini M, Santini A, Capasso R, Adrian Ostrander E, -ur-Rahman A, Iqbal Choudhary M, C. Cho W, Sharifi-Rad J. Antidiabetic Potential of Medicinal Plants and Their Active Components

Diabetes mellitus is one of the major health problems in the world, the incidence and associated mortality are increasing. Inadequate regulation of the blood sugar imposes serious consequences for health. Conventional antidiabetic drugs are effective, however, also with unavoidable side effects. On the other hand, medicinal plants may act as an alternative source of antidiabetic agents. Examples of medicinal plants with antidiabetic potential are described, with focuses on preclinical and clinical studies. The beneficial potential of each plant matrix is given by the combined and concerted action of their profile of biologically active compounds.

Isolation of Strong Antioxidants from Paeonia Officinalis Roots and Leaves and Evaluation of Their Bioactivities

Paeonia officinalis extracts from leaves and roots were tested for their antioxidant potential using in vitro chemical (Folin-Ciocalteu, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), oxygen radical absorbance capacity (ORAC), hydroxyl radical antioxidant capacity (HORAC), hydroxyl radical scavenging capacity HOSC)) and cellular antioxidant activity (CAA) assays. Leaf extracts were stronger antioxidants than root extracts, while methanol was a more effective solvent than water in chemical assays. However, the selected water extract of leaves was a stronger antioxidant in CAA than the methanol extract (0.106 vs. 0.046 µmol quercetin equivalents/mg). Twenty compounds were identified by ultra performance liquid chromatography-quadrupole-time-of-flight (UPLC-Q-TOF) mass spectrometer, while on-line screening of their antioxidant capacity by high performance liquid chromatography (HPLC) with a DPPH^•-scavenging detector revealed that gallic acid derivatives are the major peony antioxidants. Root water and leaf methanol extracts inhibited α-amylase in a dose dependent manner. The IC₅₀ value for the strongest inhibitor, the methanol extract of leaves, was 1.67 mg/mL. In addition, the cytotoxicity assessment of extracts using human Caco-2 cells demonstrated that none of them possessed cytotoxic effects.

The Influence of Vinification Methods and Cultivars on the Volatile and Phenolic Profiles of Fermented Alcoholic Beverages from Cranberry

This study investigated the effects of vinification techniques and cultivars (Stevens, Pilgrim and Bergman) on cranberry wine quality. Three winemaking technologies were conducted to prepare cranberry musts before fermentation, including traditional red and white vinifications (Red and White), and thermovinification (Thermo). In wine products, proanthocyanins (PACs) and anthocyanins (ANCs) are dominant in phenolics, while esters and alcohols are prevalent in volatiles, with phenylethyl alcohol, β-damascenone, benzyl alcohol, etc. as the main contributors to the aroma. The phenolic compositions of wines were in the same pattern with cultivars: the Stevens and Bergman wines contained the highest amount of ANCs and PACs, respectively, while the Pilgrim wines had the lowest total phenolic contents (TPC), and antioxidant capacities (AOC). Nevertheless, products from Pilgrim cultivar had a distinctive pattern of volatiles compared to Stevens and Bergman, especially for aromatic compounds. Considering vinification methods, Thermo demonstrated advantages on correlations with both phenolic and volatile (polymeric and monomeric) compositions.

Comparative Study of Phenolic Profiles, Antioxidant and Antiproliferative Activities in Different Vegetative Parts of Ramie (Boehmeria nivea L.)

Ramie (Boehmeria nivea L.) is usually cultivated as a fiber crop, but it is also well known for its potential use in animal feeding with viable commercial applications. In this study, the phenolics profile as well as cellular antioxidant and antiproliferative activities were investigated in free and bound fractions of six different vegetative parts from Boehmeria nivea L. The highest total phenolic content was observed in bud (4585 ± 320 mg GAE/100 g DW), whereas root and petiole had the lowest total phenolic contents, 442.8 ± 9.8 and 630.9 ± 27.0 mg GAE/100 g DW, respectively. Likewise, phloem had the most abundant total flavonoids (2755 ± 184 mg CE/100 g DW), whereas the lowest flavonoid contents was found in root and petiole, 636.9 ± 44.2 and 797.4 ± 87.6 mg CE/100 g DW, respectively. Xylem and bud depicted remarkable antioxidant and antiproliferative activities, which could be explained by their diverse phenolic composition, especially chlorogenic acid and epicatechin. The Boehmeria nivea L. plant might be a valuable resource for high value-added phenolic compounds used in food and non-food industries.

Abelmoschus esculentus (L.): Bioactive Components' Beneficial Properties-Focused on Antidiabetic Role-For Sustainable Health Applications

The main features of the okra, Abelmoschus esculentus (L.), are highlighted. The evaluation of interactions between biologically active compounds and other components of the food matrix can be considered as the first action in the investigation of potential benefits of this annual herb. Moreover, updated examples of current and innovative directions in an integrated and multidisciplinary approach are discussed, with particular attention to chemometrics. Among the main effects attributed to okra, its antidiabetic property is the focus. Finally, the use of okra in different fields will be discussed.

The Consumption of Beef Burgers Prepared with Wine Grape Pomace Flour Improves Fasting Glucose, Plasma Antioxidant Levels, and Oxidative Damage Markers in Humans: A Controlled Trial

Wine grape pomace flour (WGPF) is a fruit byproduct that is high in fiber and antioxidants. We tested whether WGPF consumption could affect blood biochemical parameters, including oxidative stress biomarkers. In a three-month intervention study, 27 male volunteers, each with some components of metabolic syndrome, consumed a beef burger supplemented with 7% WGPF containing 3.5% of fiber and 1.2 mg gallic equivalents (GE)/g of polyphenols (WGPF-burger), daily, during the first month. The volunteers consumed no burgers in the second month, and one control-burger daily in the third month. At baseline and after these periods, we evaluated the metabolic syndrome components, plasma antioxidant status (i.e., 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity (DPPH), vitamin E, vitamin C), and oxidative damage markers (i.e., advanced oxidation protein products (AOPPs), oxidized low-density lipoproteins (oxLDLs), malondialdehyde (MDA)). The WGPF-burger intake significantly reduced glycemia and homeostatic model assessment-based measurement of insulin resistance. Vitamin C increased and decreased during the consumption of the WGPF-burger and control-burger, respectively. The WGPF-burger intake significantly decreased AOPP and oxLDL levels. Vitamin E and MDA levels showed no significant changes. In conclusion, the consumption of beef burgers prepared with WGPF improved fasting glucose and insulin resistance, plasma antioxidant levels, and oxidative damage markers. Therefore, this functional ingredient has potential as a dietary supplement to manage chronic disease risk in humans.

Characterization of polyphenols in Australian sweet lupin (Lupinus angustifolius) seed coat by HPLC-DAD-ESI-MS/MS

Seeds of the legume lupin (Lupinus spp.) are becoming increasingly important as human food. The seed coat, at ~25% of the whole seed of Lupinus angustifolius (Australian sweet lupin, ASL), is the main by-product of lupin kernel flour production. The primary market for lupin seed coat is low value feed with very limited use in foods. In this study, seed coats of six ASL commercial varieties from two growing sites were sampled for identification and quantification of polyphenols using a high-performance liquid chromatography (HPLC) with diode array detector (DAD) and coupled with a triple quadrupole mass spectrometer which equipped with electrospray ionization source (ESI-MS/MS). Three flavones (apigenin-7-O-β-apiofuranosyl-6,8-di-C-β-glucopyranoside, vicenin 2, and apigenin-7-O-β-glucopyranoside), one isoflavone (genistein) and one dihydroflavonol derivative (aromadendrin-6-C-β-d-glucopyranosyl-7-O-[β-D-apiofuranosyl-(1 → 2)]-O-β-D-glucopyranoside), and several hydroxybenzoic and hydroxycinnamic acid derivatives were identified. Considerable variations in levels of individual polyphenols were found but apigenin-7-O-β-apiofuranosyl-6,8-di-C-β-glucopyranoside was the predominant polyphenol in all samples accounting for 73.08-82.89% of the total free polyphenols. These results suggest that ASL seed coat could be valuable dietary source of polyphenols.