Natural biopolymer nanoparticles are widely used to enhance the stability and bioavailability of anthocyanidins. In this study, cyanidin (CY)-loaded nanoparticles were fabricated via electrostatic complexation between sodium carboxymethyl cellulose (CMC) and lactoferrin (LF). The effects of pH, CMC substitution degree, material addition sequence, and thermal pretreatment on the particle size and stability CY@CMC/LF NPs were systematically evaluated. Under optimal conditions (CMC substitution degree 0.9 pretreated at 40 °C, LF pretreated at 75 °C, pH 5.0, and CMC-CY-LF addition sequence), CY@CMC/LF NPs exhibited the spherical shape with a mean particle size of 142.0 ± 2.3 nm, low polydispersity, and high encapsulation efficiency (91.07 ± 0.12%). Compared with free CY, CY@CMC/LF NPs significantly improved thermal stability, storage stability, and gastrointestinal retention during simulated digestion. Enhanced bioaccessibility and antioxidant activity of CY@CMC/LF NPs were also observed after intestinal digestion. This study presents a robust protein-polysaccharide delivery system for enhancing anthocyanidin stability and functionality in food applications.

Although Tartary buckwheat sprout pectic polysaccharides (YM) have been reported to exhibit immunostimulatory activity, their structure-activity relationship remains poorly understood. We therefore compared the structural characteristics and immunostimulatory activities of three YM fractions to explore structure-activity associations. YM was enzymatically digested and partially acid-hydrolyzed to yield two derivatives, YME and YMA, with distinct structures. YME showed an increased proportion of the galactose-rich rhamnogalacturonan-I (RG-I) domain (from 68.66 to 72.65 mol%) and a moderate molecular mass reduction (from 1.26 × 105 to 0.85 × 105 Da), whereas YMA was completely depleted of arabinose-side chains in RG-I (from 16.97 to 0 mol%), with increased galacturonic acid (from 19.96 to 34.85 mol%) and a drastic molecular mass reduction (from 1.26 × 105 to 0.16 × 105 Da). Both YME and YMA showed higher immunostimulatory activity than YM. YMA significantly increased body mass, thymus and spleen indices, cytokines interleukin-6 (IL-6), interferon-γ, immunoglobulins (IgA, IgG), tight-junction proteins (ZO-1, occludin), and short-chain fatty acids (SCFAs), particularly butyrate, whereas YME only improved spleen index, IL-6, IgG, ZO-1, occludin, and butyrate (all p < 0.05). These results suggest that YM's immunostimulatory activity is closely associated with galactose-rich RG-I domains, unesterified uronic acids, and molecular mass. This enhanced efficacy is associated, at least in part, with an enrichment of beneficial bacterial taxa (e.g., Muribaculaceae, Bacteroides, Rikenellaceae_RC9_gut_group), leading to improved SCFAs and enhanced gut barrier function and immune responses. These findings advance the understanding of YM's structure-immunostimulatory activity relationship, highlighting the role of galactose-rich RG-I domains in determining its activity.

Quinoa microgreen pectic polysaccharides (QMP) exhibit promising in vitro immunoenhancing activity, which inversely correlates with their degree of esterification (DE). However, the in vivo efficacy and how the DE modulates the immune function via interactions with the gut microbiota remain unclear. Herein, we evaluated three QMP fractions with distinct DE values (28.49%, 16.8%, and 4.4%) in an immunosuppressed mouse model induced by cyclophosphamide (CTX). All QMP fractions effectively attenuated immunosuppression, an effect associated with the restoration of gut microbiota homeostasis, increased short-chain fatty acids (SCFAs) generation, reinforced gut barrier function, and improved systemic immune and hepatic antioxidant parameters. Notably, QMP with a lower DE (QMP-LDE, 4.4%) exhibited slightly better efficacy in enhancing immune responses in immunosuppressed mice than its highly esterified counterpart (QMP-HDE, 28.49%). Furthermore, all QMP treatment consistently enriched beneficial SCFA-producing bacteria (such as Ligilactobacillus, Bacteroides, and Rikenellaceae-RC9-gut-group) but inhibited microbial taxa linked to dysbiosis (such as Lachnospiraceae_NK4A136_group). Collectively, this study elucidates the impact of DE on the in vivo immunoenhancing activity of QMP, supporting its potential application as a functional food ingredient for maintaining host immunity.

Protein hydrogels (PHGs) have emerged as promising soft materials in food systems due to their tunable structures, high water-holding capacity, and biocompatibility. However, current studies often address molecular interactions, gelation strategies, and functional properties separately, limiting the development of unified design principles. This review provides a critical analysis of PHGs from an interaction-driven perspective. The fundamental crosslinking mechanisms are first summarized, including physical interactions, chemical crosslinking, and metal-ligand coordination. Engineering strategies that regulate gelation are then discussed to clarify how external stimuli control network formation. The relationships between hydrogel structure and functional properties are further analyzed, with emphasis on mechanical behavior, water retention, microstructure, and environmental responsiveness. Food applications, including bioactive delivery, texture modification, fat substitution, 3D food printing, and active packaging, are critically evaluated from a structure-function perspective. Overall, the integration of interaction-driven design with engineering strategies provides a rational framework for tailoring PHGs toward practical food applications.

Tartary buckwheat sprout pectic polysaccharides (TP) have demonstrated notable immunostimulatory activity in vitro. Nevertheless, the in vivo function and how structural features dictate its immunostimulatory activity through gut microbiota modulation are still unclear. To fill this gap in our understanding, we compared in vivo immunostimulatory effects of TP and its derivatives featuring key structural modifications: a lower esterification degree (TP-LDE: 4.72% vs. TP: 28.04%) or a lower molecular mass (TP-LMW: 0.957 × 104 Da vs. TP: 8.191 × 104 Da). Results demonstrated that TP and its derivatives (TP-LDE, TP-LMW) counteracted cyclophosphamide (CTX)-induced immunosuppression by restoring gut microbiota balance, short-chain fatty acid (SCFA) levels, intestinal barrier function, and systemic immunity. Notably, the derivatives, particularly TP-LMW, exhibited superior immunostimulatory activity to the native TP in enhancing serum cytokines (TNF-α and IFN-γ) and serum immunoglobulin IgA, promoting SCFA (propionic acid and butyric acid) production, and maintaining intestinal barrier function (enhanced expression of ZO-1 and occludin), confirming that reducing either the molecular mass or the esterification degree enhances TP's immunostimulatory potency. Furthermore, all treatments reversed CTX-induced dysbiosis by increasing Muribaculaceae while suppressing dysbiosis-linked genera (e.g., Lachnospiraceae_NK4A136_group, Colidextribacter, and Oscillibacter). In contrast, only TP-LDE uniquely and significantly enriched the beneficial genera Bacteroides, Prevotellaceae_UCG_001, and Parabacteroides. Taken together, this work elucidates how structural features govern the immunostimulatory activity of TP, which provides a foundation for developing TP and its derivatives into functional foods for improving and maintaining host immunity.

Tartary buckwheat leaf is a promising sustainable source of rhamnogalacturonan-I-rich pectic polysaccharides (TBP) with marked in vitro immunostimulatory activity. However, their in vivo efficacy and structure-activity relationships remain unknown. Here, we investigated TBP fractions differing in esterification degree, molecular mass, and branching in a murine immunosuppression model. All TBP fractions attenuated immunosuppression, an effect associated with modulating gut microbial homeostasis, enhancing levels of short-chain fatty acids (SCFAs), reinforcing gut barrier integrity, and improving systemic immune markers. Structural modifications augmented bioactivity; low-esterified TBP-D and low-molecular-mass, low-branching TBP-F outperformed native TBP. TBP-F had the strongest effects, significantly improving immune organ indices, cytokines, immunoglobulins, SCFAs, and tight-junction proteins. Microbiota analysis revealed that all TBPs enriched Muribaculaceae and decreased dysbiosis-associated taxa, with TBP-F most strongly suppressing detrimental bacteria. These results imply that TBPs with lower molecular mass, less branching, or reduced esterification possess superior immunostimulatory potency, supporting their development as immune-enhancing functional foods.

Discarded young fig fruits (DYFFs) are rich in polyphenols, polysaccharides, and other active substances, and fig polysaccharides (FPs) extracted from DYFFs using different methods vary in structure, processing characteristics, and biological activities, which are of great research value. The polysaccharides extracted from DYFFs using different extraction methods were used to compare the structures, processing characteristics, and biological activities of FPs, and to research the conformational relationships. The yield of MDP (6.45% ± 0.03%) prepared by microwave-assisted deep eutectic solvent extraction was nearly double that of HWP (2.59% ± 0.01%) prepared by hot water extraction. The FPs extracted by different methods were free of other impurities, with molecular weights (Mw) ranging from 16.78 to 102.20 kDa, and were mainly composed of xylose, arabinose, glucose, galactose, and glucuronide. MDP exhibited significantly higher processing characteristics (water-holding capacity = 5.17 ± 0.50g/g; oil-holding capacity = 3.88 ± 0.54), antioxidant capacity (ABTS radical scavenging rates [10.41 ± 0.06 mg/g]; ferric-reducing antioxidant powers [51.73 ± 1.23 mg/g]; the reducing powers [37.35 ± 0.11 mg/g]), and hypoglycemic activity compared to other polysaccharides, whose inhibitory effect on α-amylase of MDP (IC50 = 1.48 mg/mL) was higher than 10 times that of HWP. FP structures affect processing characteristics and biological activities. MDP has a higher extraction rate, better processing characteristics and biological activities, and MDP has a better potential to be developed as a natural antioxidant and α-amylase inhibitor.

Plant milks are considered to be nutritious, sustainable, and vegetarian food products, and they have been the fastest growing beverages in the past decade in China. However, few studies have investigated consumers’ demands and purchase behaviors with respect to plant milks. Through an online questionnaire (n = 1052 valid responses), this study identified the factors that influenced individuals’ purchase intentions, purchase behaviors, attitudes, and demands with respect to current and future plant milk products. Through descriptive analysis and PCA, this study revealed that nutritional value (63.6%), taste (56.3%), and calories (42.8%) were the top three factors that Chinese consumers most cared about regarding plant milks. In the current Chinese market, coconut milk is the most popular plant milk with the highest purchase rate (61.2%), followed by soymilk (53.9%). Male consumers preferred plant milk with higher protein content and fortified with antioxidants, while female consumers preferred plant milk low in calories and enriched with collagen, dietary fiber, and probiotics. Chinese consumers are willing to pay higher prices for plant milks with enhanced nutritional value, improved product quality, and strengthened safety assurances. Innovative forms of plant milk, such as bean milk, rice milk, and quinoa milk, may be developed to satisfy the diversified needs of consumers.

Pectic polysaccharides are the mainly bioactive components in Lithocarpus litseifolius (sweet tea) leaves. Nevertheless, owing to their diverse and complex chemical structures, the detailed structure-function relationships (SFR) of pectic polysaccharides from sweet tea (STP) are still unclear. Herein, the influence of STP's esterified degree on its diverse biological functions was uncovered. The results showed that the de-esterified STPs with a middle-esterified degree (33.53 %) and a low-esterified degree (7.66 %) were successfully prepared when compared with the original high-esterified STP (47.01 %), and their primary structural features were almost stable after the controllable de-esterification treatment. Furthermore, the findings inferred that STP's antioxidant, anti-diabetic, and immunostimulatory functions showed inverse correlations with the esterified degree. Moreover, the de-esterified STP with a lower-esterified degree could be more easily utilized by intestinal microorganisms to positively regulate the gut microbial composition. Overall, these findings can provide valuable insights for elucidating STP's precise SFR.

In this study, the insufficient ability of tartary buckwheat protein (TBP) to stabilize Pickering emulsions was addressed by preparing TBP–sodium alginate (SA) composite particles via cross-linking and systematic optimization of the preparation parameters. The results showed that at a pH of 9.0 with 1.0% (w/v) TBP and 0.2% (w/v) SA, the zeta potential of the prepared TBP–SA composite particles was significantly more negative, and the particle size was significantly larger, than those of TBP, while emulsifying activity index and emulsifying stability index increased to 53.76 m2/g and 78.78%, respectively. Scanning electron microscopy confirmed the formation of a dense network structure; differential scanning calorimetry revealed a thermal denaturation temperature of 83 °C. Fourier transform infrared spectroscopy and surface hydrophobicity results indicated that the complex was formed primarily through hydrogen bonding and hydrophobic interactions between TBP and SA, which induced conformational changes in the protein. The Pickering emulsion prepared with 5% (w/v) TBP–SA composite particles and 60% (φ) oil phase was stable during 4-month storage, at a high temperature of 75 °C, high salt conditions of 600 mM, and pH of 3.0–9.0. The stabilization mechanisms may involve: (1) strong electrostatic repulsion provided by the highly negative zeta potential; (2) steric hindrance and mechanical strength imparted by the dense interfacial network; and (3) restriction of droplet mobility due to SA-induced gelation.

Polysaccharides, the primary bioactive compounds found in Ganoderma, are responsible for a multitude of biological activities. The bioactivity of Ganoderma polysaccharides (GPs) closely correlates to their physicochemical properties. Consequently, the accurate characterization and quantification of GPs are essential for the quality control of these compounds. Regrettably, the complex structural features of GPs have limited research on the relationships between their structures and bioactivities. In addition, a lack of appropriate quality assessment methods has impeded the regulation and application of GPs and related products. Therefore, it is essential to conduct extensive studies to develop reliable for quality control methods based on their pharmacological activities. This review aims to comprehensively and systematically outline the structural features, structure-activity relationships and quality control methods of GPs, thereby supporting their potential value in pharmaceuticals and functional foods. The insights presented in this review will significantly contribute to the research and potential applications of GPs.

In recent years, quinoa protein (QP) has attracted attention for its balanced amino acids composition, but its limited techno-functional properties continue to pose challenges for its utilization. Non-enzymatic Maillard glycation is considered as a promising strategy to expand the utilization of plant proteins in food processing due to its cost-effectiveness, spontaneous nature, and the lack of need for additives to initiate the reaction. Furthermore, the use of hyaluronic acid (HA) as an ingredient in food products is becoming increasingly accepted and popular. Therefore, the present study aims to prepare QP-HA glyconjugates by wet heating and to investigate the effects of sugar/protein ratios and reaction times on the structural features and functional properties of QP. The results showed that heating time and sugar/protein concentration ratio obviously affected the degree of grafting, structure and hydrophobicity of the conjugates. The random coil content of QP-HA increased significantly, resulting in a more flexible structure after Maillard glycation. After 3 h of glycation reaction, the QP-HA conjugates showed better emulsification, solubility, thermal stability and antioxidant activity compared to QP. Accordingly, these results indicate that polysaccharide-induced Maillard reaction is a potentially attractive approach for selective functionality enhancement and nutraceutical development of QP, which provides a new way to expand the application range of QP.

The intestinal microbiota plays a critical role in maintaining human health and can be modulated by dietary interventions and lifestyle choices. Fructans, a dietary carbohydrate, are selectively utilized by the intestinal microbiota to confer health benefits. However, the specific effects of different fructan types on microbial changes and functions remain incompletely understood. Here, we investigated how the intestinal microbiota responds to fructans with varying degrees of polymerization in the context of gut dysbiosis. Both low molecular weight fructo-oligosaccharides and high molecular weight levan suppressed intestinal inflammation in a colitis mouse model, mitigating intestinal fibrosis and dysbiosis. Although both the effects of fructo-oligosaccharides and levan are microbiota-dependent, distinct modulation patterns of the intestinal microbiota were observed based on the molecular weight of the fructans. Levan had a more pronounced and persistent impact on gut microbiota compared to fructo-oligosaccharides. Levan particularly promoted the abundance of Dubosiella newyorkensis, which exhibited preventive effects against colitis. Our findings highlight the importance of polymerization levels of dietary fructans in microbiota alterations and identify Dubosiella newyorkensis as a potential probiotic for treating inflammatory diseases.

Sausages are a globally cherished food item due to their rich texture, distinctive flavor, and cultural significance. However, the high fat content in traditional sausages, particularly the elevated levels of saturated fatty acids, poses significant health risks, such as cardiovascular disease, obesity, and certain types of cancer. To address these challenges, fat replacers have been introduced as viable alternatives to maintain the sensory and structural properties of sausages while reducing fat and saturated fatty acid content. This review comprehensively examines the application of lipid-based, carbohydrate-based, and protein-based fat replacers in sausages, focusing on their physicochemical properties, sensory impact, antioxidant activity, microbiological safety, and biological effects. Recent advancements, including composite fat replacers and nanotechnology, have demonstrated promising potential in enhancing sausage quality and consumer acceptability. Despite these advancements, challenges remain in replicating the flavor and texture of traditional sausages and optimizing storage stability. This review provides theoretical insights and practical guidance for developing healthier sausage products, addressing the growing demands for low-fat and health-oriented foods.

Thinned unripe kiwifruit, a significant byproduct of commercial kiwifruit production, contains abundant pectic polysaccharides comparable to mature kiwifruit. Although acidic heteropolysaccharides from mature kiwifruit exhibit potent anti-inflammatory activity, the protective effects of unripe kiwifruit-derived pectic polysaccharides against ulcerative colitis (UC) remain unclear, ultimately limiting their potential utilizations. Therefore, to bridge this knowledge gap and facilitate their utilization, the chemical structures and anti-UC effects of two pectic polysaccharides, TKP (from unripe kiwifruit) and MKP (from mature kiwifruit), were systematically studied and compared. Results demonstrated that TKP and MKP share nearly identical primary chemical structures, predominantly comprising homogalacturonan (HG) and rhamnogalacturonan I (RG-I) domains. Particularly, TKP exhibited a longer side chain length (14.37 vs. 8.21) and higher RG-I content (73.62 mol % vs. 50.02 mol%) than MKP. Furthermore, both TKP and MKP significantly alleviated dextran sulfate sodium (DSS)-induced UC in mice. Notably, TKP exhibited superior effects to MKP in several aspects, such as enhanced butyrate production, more effective restoration of goblet cell populations, enhanced upregulation of tight junction protein ZO-1, and greater reduction in pro-inflammatory cytokines (IL-1 beta, IL-6, and TNF-alpha). Both TKP and MKP effectively suppressed pathogenic bacteria (e.g., Escherichia-Shigella and Oscillibacter) while promoted beneficial bacteria (e.g., Akkermansia and Bacteroides). Notably, TKP significantly and selectively enhanced Paraprevotella growth, an effect not observed within MKP. These differential effects between TKP and MKP may be linked to their structural differences. Collectively, these findings provide valuable insights to develop TKP as a promising functional food or ingredient for preventing and ameliorating intestinal inflammatory disorders.

Quinoa microgreen, as a nutrient-dense and health-promoting vegetable, contains abundant rhamnogalacturonan-I enriched pectic polysaccharides. However, their protective effects against ulcerative colitis (UC) and the influence of structural features like degree of esterification (DE) are poorly understood. Consequently, to overcome this gap in understanding, we systematically assessed the anti-UC activity of quinoa microgreen pectic polysaccharides (QMP) exhibiting distinct DE levels: QMP-HDE (28.49 %), QMP-MDE (16.8 %), and QMP-LDE (4.4 %). Results demonstrated that all these pectic polysaccharides significantly mitigated dextran sulfate sodium-induced UC through upregulating tight junction proteins, suppressing intestinal proinflammatory cytokines, promoting short-chain fatty acid production, and resorting gut microbiota homeostasis. Notably, low-DE QMP-LDE demonstrated superior efficacy to high-DE QMP-HDE in restoring intestinal barrier integrity (enhanced upregulation of tight junction proteins and reduced serum lipopolysaccharide) and in elevating anti-inflammatory cytokine interleukin-10. Although all pectic polysaccharides suppressed pathogenic genera (Escherichia-Shigella, Klebsiella, and Helicobacter), they differentially modulated beneficial bacteria (Lactobacillus and Muribaculaceae). QMP-HDE selectively enhanced Lactobacillus abundance, whereas QMP-LDE specifically enriched Muribaculaceae. These differential effects among QMP-HDE and QMP-LDE are closely linked to their DE levels. Collectively, our findings shed light on the structure-anti-UC activity relationship of QMP pectic polysaccharides, supporting their potential application as functional foods to prevent intestinal inflammatory disorders.

Buckwheat, a nutrient-rich pseudocereal, is known for its various biological properties, but its antinutritional factors, such as phytic acid and tannins, can hinder nutrient absorption. Fermentation improves buckwheat's nutritional profile by enhancing bioactive compounds, increasing digestibility, and reducing antinutritional factors. This review comprehensively examines the effects of fermentation and microbial strains on the nutritional composition and functional properties of buckwheat, highlighting their impact on health benefits and potential applications in diverse food products. Fermentation significantly boosts essential nutrients, including amino acids, vitamins, minerals, and bioactive compounds, while reducing antinutritional factors like phytic acid and protease inhibitors. It also enhances antioxidant, antidiabetic, hypolipidemic, anti-inflammatory, and gut microbiota-regulating properties. However, there are notable gaps in research, including limited understanding of fermentation process control, heavy metal transformation, and pathogenic microorganism effects during fermentation. Addressing these gaps is crucial for optimizing the functional properties and ensuring the safety of fermented buckwheat in the food industry. Overall, fermented buckwheat holds significant potential as a functional ingredient for gluten-free foods, nondairy beverages, and other health-promoting products that cater to specific dietary needs.

Pectic polysaccharides are well-recognized as the mainly functional components in jujube fruits, which have garnered considerable attentions to be exploited into functional food products. Nevertheless, the knowledge about the influence of the producing area on their fine structural features and biological functions is still scarce, which may restrict their rational use in the functional food sector. Therefore, the structural and biological properties of pectic polysaccharides from jujube fruits (JP) collected from different producing areas were compared. The results showed that JP's physicochemical properties (e.g., total uronic acids, total bound polyphenols, molecular mass distributions, and ratios of constituent monosaccharides) varied significantly depending on the producing area. However, the primary chemical structures of JPs obtained from various producing areas were largely similar, predominantly composing of homogalacturonan and rhamnogalacturonan-I regions. Furthermore, JP's antioxidant and immunostimulatory effects also varied remarkedly depending on the producing area, primarily attributed to variations in their physicochemical properties. Particularly, JP's antioxidant activity demonstrated a significantly positive correlation with the levels of total uronic acids and total bound polyphenols, and similarly, its immunostimulatory activity was highly dependent on the level of total uronic acids. Moreover, mechanistic investigations revealed that JP could enhance immune responses via activating the Toll-like receptor 4 mediated nuclear factor-kappa B signaling pathway in RAW 264.7 macrophages. Collectively, the current findings could provide valuable insights for the rational application of jujube fruits and JP in the functional food sector.