Potential structure-function relationships of pectic polysaccharides from quinoa microgreens: Impact of various esterification degrees.

Pectic polysaccharides are one of the most vital functional ingredients in quinoa microgreens, which exhibit numerous health-promoting benefits. Nevertheless, the detailed information about the structure-function relationships of pectic polysaccharides from quinoa microgreens (QMP) remains unknown, thereby largely restricting their applications as functional foods or fortified ingredients. Therefore, to unveil the possible structure-function relationships of QMP, the mild alkali de-esterification was utilized to modify QMP, and then the correlations of esterification degrees of native and modified QMPs to their biological functions were systematically investigated. The results showed that the modified QMPs with different esterification degrees were successfully prepared by the mild alkali treatment, and the primary chemical structure (e.g., compositional monosaccharides and glycosidic linkages) of the native QMP was overall stable after the de-esterified modification. Furthermore, the results revealed that the antioxidant capacity, antiglycation effect, prebiotic potential, and immunostimulatory activity of the native QMP were negatively correlated to its esterification degree. In addition, both native and modified QMPs exerted immunostimulatory effects through activating the TLR4/NF-κB signaling pathway. These results are conducive to unveiling the precise structure-function relationships of QMP, and can also promote its applications as functional foods or fortified ingredients.

Impacts of ultrasound-assisted Fenton degradation and alkaline de-esterification on structural properties and biological effects of pectic polysaccharides from Tartary buckwheat leaves.

Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn) leaf has abundant rhamnogalacturonan-I enriched pectic polysaccharides, which exert various health-promoting effects. Nevertheless, the potential relationship between the chemical structure and the biological function of pectic polysaccharides from Tartary buckwheat leaves (TBP) remains unclear. Therefore, to bridge the gap between the chemical structure and the biological function of TBP, the impacts of ultrasound-assisted Fenton degradation (UFD) and mild alkaline de-esterification (MAD) on structural properties and biological effects of TBP were systematically studied. Compared with the native TBP (molecular mass, 9.537 × 104 Da), the molecular masses of degraded TBPs (TBP-MMW, 4.811 × 104 Da; TBP-LMW, 2.101 × 104 Da) were significantly reduced by the UFD modification, while their primary chemical structures were overall stable. Besides, compared with the native TBP (esterification degree, 22.73 %), the esterification degrees of de-esterified TBPs (TBP-MDE, 14.27 %; TBP-LDE, 6.59 %) were notably reduced by the MAD modification, while their primary chemical structures were also overall stable. Furthermore, the results revealed that both UFD and MAD modifications could significantly improve the antioxidant, antiglycation, and immunostimulatory effects of TBP. Indeed, TBP's biological effects were negatively correlated to its molecular mass and esterification degree, while positively linked to its free uronic acids. The findings demonstrate that both UFD and MAD modifications are promising techniques for the structural modification of TBP, which can remarkedly promote its biological effects. Besides, the present results are conducive to better understanding TBP's structure-bioactivity relationship.

Comparison of soluble dietary fibers from various quinoa microgreens: Structural characteristics and bioactive properties.

Quinoa (Chenopodium quinoa Willd.) microgreens are widely consumed as healthy vegetables around the world. Although soluble dietary fibers exist as the major bioactive macromolecules in quinoa microgreens, their structural characteristics and bioactive properties are still unclear. Therefore, the structural characteristics and bioactive properties of soluble dietary fibers from various quinoa microgreens (QMSDFs) were investigated in this study. The yields of QMSDFs ranged from 38.82 to 52.31 mg/g. Indeed, all QMSDFs were predominantly consisted of complex pectic-polysaccharides, e.g., homogalacturonan (HG) and rhamnogalacturonan I (RG I) pectic domains, with the molecular weights ranged from 2.405 × 104 to 5.538 × 104 Da. In addition, the proportions between RG I and HG pectic domains in all QMSDFs were estimated in the range of 1: 2.34-1: 4.73 (ratio of galacturonic acid/rhamnose). Furthermore, all QMSDFs exhibited marked in vitro antioxidant, antiglycation, prebiotic, and immunoregulatory effects, which may be partially correlated to their low molecular weights and low esterification degrees. These findings are helpful for revealing the structural and biological properties of QMSDFs, which can offer some new insights into further development of quinoa microgreens and related QMSDFs as value-added healthy products.

Glycosidic linkages of fungus polysaccharides influence the anti-inflammatory activity in mice.

INTRODUCTION: Over decades, the source-function relationships of bioactive polysaccharides have been progressively investigated, however, it is still unclear how a defined structure may conduce to the bioactivities of polysaccharides. OBJECTIVES: To explore the structure-function relationship of fungus polysaccharides, we employed a dextran sulfate sodium (DSS)-induced colitis mouse model to compare the anti-inflammatory activity of two fungus polysaccharides from Dictyophora indusiata (DIP) and Tremella fuciformis (TFP), which exhibit distinct glycosidic linkages. METHODS: The structures of DIP and TFP were characterized through molecular weight detection, molecular morphology analysis, methylation analysis, and NMR analysis. Subsequently, we employed a DSS-induced colitis model to assess the anti-inflammatory efficacy of DIP and TFP. The colitis symptoms, histological morphology, intestinal inflammatory cytokines, and the composition and function of gut microbiota before and after polysaccharides treatment in colitis mice were also investigated. RESULTS: DIP, l,3-ß-D-glucan with 1,4-ß and 1,6-ß-D-Glcp as branched chains, exhibited superior therapeutic effect than that of TFP consisted of a linear 1,3-α-D-mannose backbone with D-xylose and L-fucose in the side chains. Both DIP and TFP relieved DSS-induced colitis in a gut microbiota-dependent manner. Furthermore, metagenomics showed that DIP and TFP could partially reverse the bacterial function in colitis mice. Glycoside Hydrolase 1 (GH1) and GH3 were identified as being involved in hydrolyzing the glucose linkages in DIP, while GH92 and GH29 were predicted to be active in cleaving the α-1,3-linked mannose linkages and the glycosidic bonds of L-fucose residues in TFP. CONCLUSION: Our findings highlight the pivotal role of glycosidic linkages in anti-inflammatory activities of fungus polysaccharides and would promote the design and discovery of polysaccharides with designated activity to be used as functional foods and/or therapeutics.

Efficient and Selective Extraction of Rhamnogalacturonan-I-Enriched Pectic Polysaccharides from Tartary Buckwheat Leaves Using Deep-Eutectic-Solvent-Based Techniques.

Tartary buckwheat green leaves are considered to be among the most important by-products in the buckwheat industry. Although Tartary buckwheat green leaves are abundant in pectic polysaccharides, their potential applications in the food industry are quite scarce. Therefore, to promote their potential applications as functional or fortified food ingredients, both deep-eutectic-solvent-assisted extraction (DESE) and high-pressure-assisted deep eutectic solvent extraction (HPDEE) were used to efficiently and selectively extract pectic polysaccharides from Tartary buckwheat green leaves (TBP). The results revealed that both the DESE and HPDEE techniques not only improved the extraction efficiency of TBP but also regulated its structural properties and beneficial effects. The primary chemical structures of TBP extracted using different methods were stable overall, mainly consisting of homogalacturonan and rhamnogalacturonan-I (RG-I) pectic regions. However, both the DESE and HPDEE methods could selectively extract RG-I-enriched TBP, and the proportion of the RG-I pectic region in TBP obviously improved. Additionally, both the DESE and HPDEE methods could improve the antioxidant and anti-glycosylation effects of TBP by increasing its proportion of free uronic acids and content of bound polyphenolics and reducing its molecular weight. Moreover, both the DESE and HPDEE methods could partially intensify the immunostimulatory effect of TBP by increasing its proportion of the RG-I pectic region. These findings suggest that DES-based extraction techniques, especially the HPDEE method, can be promising techniques for the efficient and selective extraction of RG-I-enriched TBP.

A Polysaccharide from Ficus carica L. Exerts Immunomodulatory Activity in Both In Vitro and In Vivo Experimental Models.

Polysaccharides from Ficus carica L. (FCP) exert multiple biological activities. As a biological macromolecule, the available knowledge about the specific structures and mechanisms of the biological activity of purified 'Brunswick' fig polysaccharides is currently limited. In the present study, chemical purification and characteristics were identified via chemical and instrumental analysis, and then the impact of FCP on immunomodulation activity in vitro and in vivo was examined. Structural characteristics showed that the molecular weight of the FCP sample was determined to be 127.5 kDa; the primary monosaccharides present in the FCP sample were galacturonic acid (GalA), arabinose (Ara), galactose (Gal), rhamnose (Rha), glucose (Glc), and xylose (Xyl) at a ratio of 0.321:0.287:0.269:0.091:0.013:0.011. Based on the investigation of in vitro immunomodulatory activity, FCP was found to stimulate the production of NO, TNF-α, and IL-6, and increased the pinocytic activity of macrophages. Further analysis revealed that FCP activated macrophages by interacting with Toll-like receptor 4 (TLR4). Moreover, the in vivo test results indicate that FCP showed a significant increase in serum pro-inflammatory factors in immunosuppressed mice. Overall, this study suggests that FCP has the potential to be utilized as a novel immunomodulator in the pharmaceutical and functional food industries.

Efficient extraction of pectic polysaccharides from thinned unripe kiwifruits by deep eutectic solvent-based methods: Chemical structures and bioactivities.

To promote the potentially industrial applications of thinned unripe kiwifruits, two deep eutectic solvent-based methods, including deep eutectic solvent-assisted extraction (DAE) and microwave-assisted deep eutectic solvent extraction (MDE), were optimized for the extraction of polysaccharides from thinned unripe kiwifruits (YKP). Results showed that the yields of YKP-D prepared by DAE and YKP-DM prepared by MDE were extremely higher than YKP-H prepared by hot water extraction. Furthermore, YKP-H, YKP-D, and YKP-DM were mainly composed of pectic polysaccharides, including homogalacturonan (HG) and rhamnogalacturonan I (RG I) domains. Besides, both YKP-D and YKP-DM exhibited stronger antioxidant, anti-glycosylation, and immunomodulatory effects than those of YKP-H, and their higher contents of uronic acids and bound polyphenols as well as lower molecular weights could partially contribute to their bioactivities. Overall, these results revealed that the developed MDE method could be utilized as a promising method for highly efficient extraction of YKP with superior beneficial effects.

Evaluation of Lipidomics Profile of Quinoa Flour and Changes during Storage Based on Ultra Performance Liquid Chromatography Coupled with Quadrupole Exactive Orbitrap Mass Spectrometry.

Although quinoa is nutritious, its high fat content and lipase activity make it easily oxidized during storage. Meanwhile, quinoa's lipid composition and changes during storage are still unknown. Therefore, we stored fresh quinoa flour at low temperature and low humidity (LL), normal temperature and normal humidity (NN), and high temperature and high humidity (HH) conditions for 120 days to assess its oxidative stability and to monitor the changes in lipid composition. Herein, the contents of fatty acids, the peroxide values, the malondialdehyde values, and the lipase activity in quinoa flour during storage are determined to evaluate its oxidation stability. At LL and NN conditions, the contents of fatty acids, the peroxide values, the malondialdehyde values, and the lipase activity changed slowly. They were 3 (LL) and 5 times (NN), 2.7 (LL) and 4.7 times (NN), 1.4 (LL) and 2.3 times (NN), and 1.5 (LL) and 1.6 times (NN) the initial content at storage up to 120 d. However, with the prolongation of storage time under HH conditions, they all increased significantly to 8, 6.6, 3, and 2 times the original content. Moreover, during the storage of quinoa under LL, NN, and HH conditions for 120 days, we continuously monitored the lipid composition of quinoa grains with UPLC-Q-Exactive Orbitrap MS/MS. We identified a total of 14 subclasses of 229 lipids, including 90 significantly different lipid species. PCA and PLS-DA showed that quinoa lipids in HH conditions changed significantly with prolonged storage; among these, the TG and DG classes were the most susceptible to oxidation, which could distinguish fresh quinoa from oxidized quinoa. Simultaneously, we also found that lipase activity has a significant impact on lipid metabolism through correlation analysis, which also indicates that enzyme inactivation treatment can slow down lipid hydrolysis and oxidation during storage. To explore the mechanism of these changes, we also identified twelve important lipid metabolism pathways during quinoa storage. In conclusion, our study advances knowledge of the storage stability and lipid oxidation mechanisms of quinoa and provides a theoretical basis for setting the shelf life of quinoa.

Recent advances in the influences of drying technologies on physicochemical properties and biological activities of plant polysaccharides.

Plant polysaccharides, as significant functional macromolecules with diverse biological properties, are currently receiving increasing attention. Drying technologies play a pivotal role in the research, development, and application of various foods and plant polysaccharides. The chemical composition, structure, and function of extracted polysaccharides are significantly influenced by different drying technologies (e.g., microwave, infrared, and radio frequency) and conditions (e.g., temperature). This study discusses and compares the principles, advantages, disadvantages, and effects of different drying processes on the chemical composition as well as structural and biological properties of plant polysaccharides. In most plant-based raw materials, molecular degradation, molecular aggregation phenomena along with intermolecular interactions occurring within cell wall components and cell contents during drying represent primary mechanisms leading to variations in chemical composition and structures of polysaccharides. These differences further impact their biological properties. The biological properties of polysaccharides are determined by a combination of multiple relevant factors rather than a single factor alone. This review not only provides insights into selecting appropriate drying processes to obtaining highly bioactive plant polysaccharides but also offers a fundamental theoretical basis for the structure-function relationship of these compounds.

Structural properties and biological activities of soluble dietary fibers rich in pectic-polysaccharides from different buckwheat green leaves.

Buckwheat green leaves are commonly consumed as functional tea materials due to their various beneficial effects. Although buckwheat green leaves have abundant soluble dietary fibers (SDFs), the information about their structural properties and functional properties remains unknown, largely hindering their applications as functional/health products. Hence, to enhance the usage and application of SDFs from buckwheat green leaves as value-added health products, the structures and biological activities of SDFs derived from different buckwheat green leaves were investigated and compared. Results revealed that SDFs derived from Tartary buckwheat green leaves (TBSDF) and common buckwheat green leaves (CBSDF) were rich in complex pectic-polysaccharides, mainly composing of homogalacturonan (HG) and rhamnogalacturonan I (RG I) pectic domains. Besides, TBSDF had higher proportion of RG I pectic domains than that of CBSDF. Furthermore, the existence of a high content of complex pectic-polysaccharides in TBSDF and CBSDF could contribute to their various biological activities, such as antioxidant, antiglycation, fat/bile acid binding, anticancer, and prebiotic effects. These results can provide some new insights into further development of buckwheat green leaves and related SDFs as value-added health products.

Ultrasound-Assisted Deep Eutectic Solvent Extraction of Phenolic Compounds from Thinned Young Kiwifruits and Their Beneficial Effects.

Fruit thinning is a common practice employed to enhance the quality and yield of kiwifruits during the growing period, and about 30-50% of unripe kiwifruits will be thinned and discarded. In fact, these unripe kiwifruits are rich in nutrients and bioactive compounds. Nevertheless, the applications of thinned young kiwifruits and related bioactive compounds in the food and functional food industry are still limited. Therefore, to promote the potential applications of thinned young kiwifruits as value-added health products, the extraction, characterization, and evaluation of beneficial effects of phenolic compounds from thinned young fruits of red-fleshed Actinidia chinensis cv 'HY' were examined in the present study. A green and efficient ultrasound-assisted deep eutectic solvent extraction (UADE) method for extracting phenolic compounds from thinned young kiwifruits was established. A maximum yield (105.37 ± 1.2 mg GAE/g DW) of total phenolics extracted from thinned young kiwifruits by UADE was obtained, which was significantly higher than those of conventional organic solvent extraction (CSE, about 14.51 ± 0.26 mg GAE/g DW) and ultrasound-assisted ethanol extraction (UAEE, about 43.85 ± 1.17 mg GAE/g DW). In addition, 29 compounds, e.g., gallic acid, chlorogenic acid, neochlorogenic acid, catechin, epicatechin, procyanidin B1, procyanidin B2, quercetin-3-rhamnoside, and quercetin-3-O-glucoside, were identified in the kiwifruit extract by UPLC-MS/MS. Furthermore, the contents of major phenolic compounds in different kiwifruit extracts prepared by conventional organic solvent extraction (EE), ultrasound-assisted ethanol extraction (UEE), and ultrasound-assisted deep eutectic solvent extraction (UDE) were compared by HPLC analysis. Results revealed that the content of major phenolics in UDE (about 15.067 mg/g DW) was significantly higher than that in EE (about 2.218 mg/g DW) and UEE (about 6.122 mg/g DW), suggesting that the UADE method was more efficient for extracting polyphenolics from thinned young kiwifruits. In addition, compared with EE and UEE, UDE exhibited much higher antioxidant and anti-inflammatory effects as well as inhibitory effects against α-glucosidase and pancreatic lipase, which were closely associated with its higher content of phenolic compounds. Collectively, the findings suggest that the UADE method can be applied as an efficient technique for the preparation of bioactive polyphenolics from thinned young kiwifruits, and the thinned young fruits of red-fleshed A. chinensis cv 'HY' have good potential to be developed and utilized as functional foods and nutraceuticals.

A Comprehensive Review of Pea (Pisum sativum L.): Chemical Composition, Processing, Health Benefits, and Food Applications.

Pisum sativum L., commonly referred to as dry, green, or field pea, is one of the most common legumes that is popular and economically important. Due to its richness in a variety of nutritional and bioactive ingredients, the consumption of pea has been suggested to be associated with a wide range of health benefits, and there has been increasing focus on its potential as a functional food. However, there have been limited literature reviews concerning the bioactive compounds, health-promoting effects, and potential applications of pea up to now. This review, therefore, summarizes the literature from the last ten years regarding the chemical composition, physicochemical properties, processing, health benefits, and potential applications of pea. Whole peas are rich in macronutrients, including proteins, starches, dietary fiber, and non-starch polysaccharides. In addition, polyphenols, especially flavonoids and phenolic acids, are important bioactive ingredients that are mainly distributed in the pea coats. Anti-nutritional factors, such as phytic acid, lectin, and trypsin inhibitors, may hinder nutrient absorption. Whole pea seeds can be processed by different techniques such as drying, milling, soaking, and cooking to improve their functional properties. In addition, physicochemical and functional properties of pea starches and pea proteins can be improved by chemical, physical, enzymatic, and combined modification methods. Owing to the multiple bioactive ingredients in peas, the pea and its products exhibit various health benefits, such as antioxidant, anti-inflammatory, antimicrobial, anti-renal fibrosis, and regulation of metabolic syndrome effects. Peas have been processed into various products such as pea beverages, germinated pea products, pea flour-incorporated products, pea-based meat alternatives, and encapsulation and packing materials. Furthermore, recommendations are also provided on how to better utilize peas to promote their development as a sustainable and functional grain. Pea and its components can be further developed into more valuable and nutritious products.

Quality evaluation of citrus varieties based on phytochemical profiles and nutritional properties.

Introduction: China is one of the major producers and exporters of various kinds of citrus fruits. As one of China's major citrus planting bases, Sichuan has a citrus planting area that exceeds 400,000 hectares. Meanwhile, citrus cultivation has become one of the important agricultural pillar industries in the region. Citrus fruits are reported to show various health-promoting effects, especially antioxidant activity. However, reports on the functional, nutritional and qualitative characteristics of different citrus varieties in Sichuan are still scarce. Methods: The quality attributes (color parameters, shape, and size), juice properties (titratable acids and total soluble sugar), mineral elements, and health-promoting nutritional and functional components (protein, carbohydrates, fat, dietary fiber, ascorbic acid, phenolic acids, and flavonoids), as well as antioxidant properties of 10 typical citrus varieties cultivated in Sichuan, were systematically investigated and analyzed. Results and Discussion: Significant differences among different citrus varieties were found. In particular, the total soluble sugar content of Mingrijian was higher than that of other citrus, suggesting its potential for fresh consumption and food processing. Moreover, a total of five flavonoids and nine phenolic acids were identified and quantified. Yuanhong, with higher contents of ascorbic acid and phenolic acids, was considered to be a valuable variety with excellent antioxidant capacity and can be used for value-added processing in the food industry. Principal component analysis and hierarchical cluster heatmap analysis suggested that there were significant differences among the 10 citrus varieties. Correlation analysis confirmed the significant contribution of ascorbic acid and phenolic acids to antioxidant capacity in citrus. The results can provide some references for the cultivation and selection of nutritious citrus fruits.

Catabolism of Dictyophora indusiata Polysaccharide and Its Impacts on Gut Microbial Composition during In Vitro Digestion and Microbial Fermentation.

Dictyophora indusiata is one of the most famous edible mushrooms in China. D. indusiata polysaccharide (DP) has attracted increasing attention because of its multiple beneficial effects. In this study, the in vitro simulated digestion and microbial fermentation were designed to reveal the potential catabolic property of DP and its impacts on the modulation of gut microbial composition. The results showed that the reducing sugar content, total polysaccharides content, molecular weight, and rheological property of DP were not significantly altered under in vitro simulated digestive conditions. However, the molecular weight, apparent viscosity, and total polysaccharides content of indigestible DP (DPI) significantly decreased during in vitro fecal fermentation, and the reducing sugar content and the release of free monosaccharides notably increased, suggesting that DP could be degraded and used by gut microbiota. Additionally, the relative abundances of several beneficial bacteria, such as Bacteroides, Catenibacterium, Parabacteroides, and Megamonas, increased significantly, indicating that DP can regulate the composition and abundance of gut microbiota. Moreover, DP could also promote the production of SCFAs, thus changing the acid-base environment of the large intestine. The results of this study are beneficial for deeply clarifying the catabolic behavior of DP in the gastrointestinal tract, which can provide a theoretical basis for developing microbiota-directed products based on DP.

Genome-Wide Identification of Histone Deacetylases and Their Roles Related with Light Response in Tartary Buckwheat (Fagopyrum tataricum).

Histone deacetylases (HDACs), known as histone acetylation erasers, function crucially in plant growth and development. Although there are abundant reports focusing on HDACs of Arabidopsis and illustrating their important roles, the knowledge of HDAC genes in Tartary buckwheat (Polygonales Polygonaceae Fagopyrum tataricum (L.) Gaertn) is still scarce. In the study, a total of 14 HDAC genes were identified and divided into three main groups: Reduced Potassium Dependency-3/His-52 tone Deacetylase 1 (RPD3/HDA1), Silent Information Regulator 2 (SIR2), and the plant-53 specific HD2. Domain and motif composition analysis showed there were conserved domains and motifs in members from the same subfamilies. The 14 FtHDACs were distributed asymmetrically on 7 chromosomes, with three segmental events and one tandem duplication event identified. The prediction of the cis-element in promoters suggested that FtHDACs probably acted in numerous biological processes including plant growth, development, and response to environmental signals. Furthermore, expression analysis based on RNA-seq data displayed that all FtHDAC genes were universally and distinctly expressed in diverse tissues and fruit development stages. In addition, we found divergent alterations in FtHDACs transcript abundance in response to different light conditions according to RNA-seq and RT-qPCR data, indicating that five FtHDACs might be involved in light response. Our findings could provide fundamental information for the HDAC gene family and supply several targets for future function analysis of FtHDACs related with light response of Tartary buckwheat.

Changes in the Fruit Quality, Phenolic Compounds, and Antioxidant Potential of Red-Fleshed Kiwifruit during Postharvest Ripening.

Kiwifruit is very popular for its unique flavor and nutritional value, and for its potential health benefits, which are closely related to its richness in a variety of natural antioxidant substances, in which polyphenolics play a non-negligible role. This study investigated changes in the fruit quality, phenolic compounds, and antioxidant potential of Chinese red-fleshed kiwifruit "Hongshi No. 2" during postharvest ripening at room temperature (20 ± 1 °C). Results showed that the weight loss rate slowly increased, the firmness rapidly decreased, and the soluble solid concentration gradually increased during the postharvest ripening of red-flesh kiwifruit. In addition, the total phenolic (TPC), total flavonoid (TFC), and total proanthocyanidin (TPAC) contents gradually increased during postharvest ripening. The most abundant phenolic compounds in kiwifruit throughout postharvest ripening were catechin (CC), proanthocyanidin B1 (PB1), and proanthocyanidin B2 (PB2). Furthermore, the methanolic extracts of red-flesh kiwifruit exhibited remarkable antioxidant activities throughout postharvest ripening stages. Indeed, some phenolic compounds showed good correlations with antioxidant activities; for instance, chlorogenic acid (CHL) showed a significantly positive correlation with ferric reducing antioxidant power (FRAP), and isoquercitrin (IS) showed a significantly negative correlation with DPPH free radical scavenging ability. The findings from this study are beneficial to better understanding the quality profile of red-flesh kiwifruit "Hongshi No. 2" during postharvest ripening.

Physicochemical characteristics and biological activities of soluble dietary fibers isolated from the leaves of different quinoa cultivars.

Quinoa leaf is consumed as a promising value-added vegetable in the diet. Although quinoa leaf is rich in soluble dietary fibers, the knowledge regarding their chemical structures and biological activities is still limited, which astricts their application in the functional food industry. Thus, to improve the precise use and application of soluble dietary fibers (SDFs) isolated from quinoa leaves in the food industry, the physicochemical structures and bioactivities of SDFs isolated from different quinoa leaves were systematically investigated. Results indicated that quinoa leaves were rich in SDFs, ranging from 3.30 % to 4.55 % (w/w). Quinoa SDFs were mainly composed of acidic polysaccharides, such as homogalacturonan and rhamnogalacturonan I, which had the molecular weights in the range of 4.228 × 104 -7.059 × 104 Da. Besides, quinoa SDFs exerted potential in vitro antioxidant activities, lipid and bile acid-adsorption capacities, immunoregulatory activities, and prebiotic effects, which might be partially associated with their molecular mass, content of uronic acid, and content of bound polyphenol. Collectively, these findings are beneficial to better understanding the chemical structures and bioactivities of SDFs extracted from different quinoa leaves, which can also provide a scientific basis for developing quinoa SDFs into functional foods in the food industry.

Current extraction, purification, and identification techniques of tea polyphenols: An updated review.

Tea, as a beverage, has been reputed for its health benefits and gained worldwide popularity. Tea polyphenols, especially catechins, as the main bioactive compounds in tea, exhibit diverse health benefits and have wide applications in the food industry. The development of tea polyphenol-incorporated products is dependent on the extraction, purification, and identification of tea polyphenols. Recent years, many green and novel extraction, purification, and identification techniques have been developed for the preparation of tea polyphenols. This review, therefore, introduces the classification of tea and summarizes the main conventional and novel techniques for the extraction of polyphenols from various tea products. The advantages and disadvantages of these techniques are also intensively discussed and compared. In addition, the purification and identification techniques are summarized. It is hoped that this updated review can provide a research basis for the green and efficient extraction, purification, and identification of tea polyphenols, which can facilitate their utilization in the production of various functional food products and nutraceuticals.

Effects of various degrees of esterification on antioxidant and immunostimulatory activities of okra pectic-polysaccharides.

Pectic-polysaccharides are considered as one of the most abundant bioactive components in okra, which possess various promising health-promoting effects. However, the knowledge regarding the structure-bioactivity relationship of okra pectic-polysaccharides (OPP) is still limited. In this study, effects of various degrees of esterification (DEs) on in vitro antioxidant and immunostimulatory activities of OPP were analyzed. Results displayed that OPP with high (42.13%), middle (25.88%), and low (4.77%) DE values were successfully prepared by mild alkaline de-esterification, and their primary chemical structures (compositional monosaccharide and glycosidic linkage) and molecular characteristics (molecular weight distribution, particle size, and rheological property) were overall stable. Additionally, results showed that the notable decrease of DE value did not significantly affect antioxidant activities [2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and nitric oxide (NO) radical scavenging abilities as well as ferric reducing antioxidant power (FRAP)] of OPP, suggesting that the DE was not closely related to its antioxidant activity. In fact, the slight decrease of antioxidant activity of OPP after the alkaline de-esterification might be attributed to the slight decrease of uronic acid content. Nevertheless, the immunostimulatory effect of OPP was closely related to its DE, and a suitable degree of acetylation was beneficial to its in vitro immunostimulatory effect. Besides, the complete de-acetylation resulted in a remarkable reduction of immune response. The findings are beneficial to better understanding the effect of DE value on antioxidant and immunomodulatory activities of OPP, which also provide theoretical foundations for developing OPP as functional foods or health products.

Total saponins from quinoa bran alleviate high-fat diet-induced obesity and systemic inflammation via regulation of gut microbiota in rats.

In recent years, biologically active ingredients derived from natural plants or functional foods have raised considerable interests for its anti-obesity effect. Quinoa (Chenopodium quinoa Willd.) is a traditional staple food in the Andean regions of Peru which contains a variety of bioactive components. This study aimed to investigate the potential therapeutic effect of total saponins extracted from quinoa bran (TSQ) on obese rats and explore whether the underlying mechanism is related to intestinal microbiota. Results showed that TSQ could decrease the body weight gain and visceral fat accumulation in the obese rats. Moreover, trends in ameliorating insulin resistance and improved glucose tolerance were observed. Indeed, Pearson's correlations analysis revealed that the variation in gut microbial composition was highly correlated to insulin resistance, IL-6, and LPS levels. Collectively, these results suggest that the prevention of obesity and inflammation by TSQ may be mediated by the modulation of gut microbial composition.