Study on the interaction and functional properties of Dolichos lablab L. protein-tea polyphenols complexes

Sea buckthorn polyphenols on gastrointestinal health and the interactions with gut microbiota

The potential health benefits of sea buckthorn polyphenols (SBP) have been extensively studied, attracting increasing attention from researchers. This paper reviews the composition of SBP, the effects of processing on SBP, its interactions with nutrients, and its protective role in the gastrointestinal tract. Polyphenols influence nutrient absorption and metabolism by regulating the intestinal flora, thereby enhancing bioavailability, protecting the gastrointestinal tract, and altering nutrient structures. Additionally, polyphenols exhibit anti-inflammatory and immunomodulatory effects, promoting intestinal health. The interaction between polyphenols and intestinal flora plays a significant role in gastrointestinal health, supporting the composition and diversity of the gut microbiota. However, further research is needed to emphasize the importance of human trials and to explore the intricate relationship between SBP and gut microbiota, as these insights are crucial for understanding the mechanisms underlying SBP's benefits for the gastrointestinal tract (GIT).

An underutilized bean: hyacinth bean [Lablab purpureus (L.) sweet]: bioactive compounds, functional activity, and future food prospect and applications

Hyacinth bean [Lablab purpureus (L.) Sweet], a plant belonging to the leguminous family and traditionally used for medicinal purposes in China, is a valuable resource with a wide range of health benefits. This review examines the bioactive compounds, health-promoting properties and functional food potential of hyacinth bean, highlighting its role in protecting against metabolic diseases and the underlying molecular mechanisms. According to existing research, hyacinth bean contains a diverse array of bioactive compounds, Consumption of hyacinth beans and hyacinth bean-related processed food products, as well as their use in medicines, is associated with a variety of health benefits that are increasingly favoured by the scientific community. In light of these findings, we posit that hyacinth bean holds great promise for further research and food application. © 2024 Society of Chemical Industry.

Studies of the binding mechanism between liquid smoke from tea tree branches and proteins in dry-cured tenderloin using 4D-DIA proteomics, synergistic multispectral analysis, and molecular docking techniques

This research investigates the impact of various concentrations of tea branch liquid smoke (TLS) on the protein structure of dry cured pork tenderloin using multispectral techniques, molecular docking, and 4D-DIA proteomics. The results reveal that TLS enhances the solubility of myofibrillar protein, with varying effects on tryptophan exposure based on the concentration. Notably, at 5 mL/kg, TLS inhibits myofibrillar protein unfolding. Raman spectroscopy demonstrates that higher TLS concentrations mitigate disruptions in hydrogen bonding and hydrophobicity. Guaiacol and furfural in TLS engage in π-stacking interactions with myosin, heightening myosin interaction with its carrier. 4D-DIA proteomics has revealed that TLS can down-regulate the expression of cytoplasmic and mitochondrial proteins, metabolic enzymes, and ligases, playing pivotal roles in metabolism and genetic information processing. These proteins, featuring membrane linkers and phosphatases, potentially impact peptide and amino acid biosynthesis, thereby affecting meat quality modifications.

Effects of preheat treatment and syringic acid binding on the physicochemical, antioxidant, and antibacterial properties of black soybean protein isolate before and after in vitro digestion

This study investigated the effects of preheat treatment (70-100 °C) and syringic acid (SA) grafting on the antioxidant, antibacterial, and physicochemical properties of black soybean protein isolate (BSPI) before and after in vitro digestion. The results revealed that both preheat treatment and SA grafting increased the digestibility and the absolute zeta potential value of BSPI. However, as the preheating temperature increased, the antioxidant ability of BSPI decreased, which was improved by SA grafting. During in vitro digestion, the absolute zeta potential and antioxidant activities of preheated BSPI and preheated BSPI-SA complex followed the order: intestine > gastric > before digestion. Compared with before digestion, preheated BSPI with its SA complex after in vitro digestion exhibited excellent antibacterial activities. Importantly, the preheated BSPI-SA complex enhanced the SA recovery rate during digestion and SA stability, with the highest recovery rate observed for the SA-grafted BSPI with preheat treatment at 100°C (BSPI100-SA). The principal component analysis sufficiently distinguished preheated BSPI and preheated BSPI-SA complexes. There were partitions between BSPI and BSPI-SA treated at different preheating temperatures. This study contributes to expanding the potential applications of BSPI with its SA complex in food products and offers guidance for designing SA delivery systems. PRACTICAL APPLICATION: Preheated BSPI-SA complexes could serve as functional ingredients in food or health products. Besides, preheated BSPI has application potential as a carrier for SA delivery.

High internal phase emulsion stabilized by soy protein isolate-Rutin complex: Rheological properties, bioaccessibility and in vitro release kinetics

High internal phase emulsions (HIPEs) are promising carrier materials for encapsulating and delivering hydrophobic bioactive compounds. By strategically adjusting the composition, particle size, or charge of HIPEs, it is possible to enhance both their stability and the bioaccessibility of hydrophobic polyphenols encapsulated within them. In this study, different soy protein isolate (SPI)-rutin (SPI-R) complexes (formed under various preheating temperatures) were used to stabilize HIPEs, while the particle size, and charge of HIPEs was further adjusted through different homogenization rates. The results demonstrated that an optimal preheating temperature of 70 °C for the complex and a homogenization rate of 15,000 rpm for HIPEs enhanced the stability of the entire emulsion system by producing more uniform and smaller droplet distribution with improved rheological properties. Furthermore, in vitro digestion experiments showed that HIPEs stabilized by the SPI-R complexes (HSR) at optimal homogenization rate had better loading efficiency (98.68 %) and bioaccessibility compared to other groups. Additionally, fitting results from release kinetics confirmed that rutin encapsulated by HSR could achieve sustained release effect. Overall, these findings suggest that HSR has great potential as an effective vehicle for delivering hydrophobic bioactive compounds like rutin within the food industry.

Thermal-induced interactions between soy protein isolate and malondialdehyde: Effects on protein digestibility, structure, and formation of advanced lipoxidation end products

Thermally processed lipid- and protein-rich foods have sparked widespread concern since they may degrade food nutrition and even risk food safety. This study investigated soy protein isolate (SPI) alterations of digestibility and structure, as well as the formation of potentially hazardous chemicals, i.e., advanced lipoxidation end products (ALEs), after interacting with malondialdehyde (MDA, a lipid oxidation product) under high-temperature cooking conditions (100-180 °C, up to 60 min). In-vitro protein digestion of the SPI-MDA mixtures suggested that their room-temperature interactions damaged SPI digestibility, and increasing the temperature and the duration of the thermal treatment exacerbated the adverse effects. Protein oxidation, covalent aggregation of subunits, and changes in secondary and tertiary structures were revealed using thiol quantification, gel electrophoresis, fluorescence spectroscopy, and circular dichroism (CD) spectra, which could explain reduced protein digestibility. High-resolution mass spectrometry (HRMS) identified seven non-crosslinked ALEs and two crosslinked ALEs. Increased MDA concentrations promoted the generation of ALEs. Moreover, the acrolein-derived ALEs with reactive carbonyl groups were prone to further reacting into crosslinked ALEs, potentially responsible for the subunit aggregation.

Interaction between pea protein isolate and quercetin: Effects on protein conformation and quercetin activity

Comprehensive comprehension of the interaction between proteins and polyphenols is crucial for advancing their utilization in food processing. This study investigated no-covalent interaction between pea protein isolate (PPI) and quercetin (Que) through spectroscopic analysis and molecular simulation. Fourier transform infrared spectroscopy and circular dichroism spectrum showed that the interaction between PPI and Que changed the secondary structure of the protein due to a decrease in α-helix content and an increase in the random coil. Thermodynamic parameters indicated that the Quebound PPI via hydrogen bonds and hydrophobic interactions (ΔH > 0, ΔS > 0, and ΔG < 0), which was also confirmed by molecular docking. Particle size and ζ-potential showed that PPI and Que demonstrated effective interaction and binding capabilities, enhancing the stability. In addition, the antioxidant and bioaccessibility of complexes have also been enhanced. This study shed a light on the application of protein-polyphenol complexes for developing functional foods. PRACTICAL APPLICATION: Interaction between pea protein isolate and quercetin can change the protein conformation to maintain the stability of quercetin and is helpful to expand the market value and application value of plant protein. The research has important implications for using leguminous protein as embedded support to improve the stability of polyphenols compounds.

The Effect of Dihydromyricetin (DMY) on the Mechanism of Soy Protein Isolate/Inulin/Dihydromyricetin Interaction: Structural, Interfacial, and Functional Properties

The combination of proteins with polysaccharides and polyphenols is expected to improve their physicochemical and functional properties. In this study, a novel plant-based antioxidant emulsifier was formed by soybean protein isolate (SPI), inulin (INU), and dihydromyricetin (DMY). Based on the binary system of SPI/INU, we focused on exploring the effect of the DMY concentration (0.5 mg/mL~2.5 mg/mL) on the formation and properties of the ternary complex. The structure, interaction mechanism, and interfacial and functional properties of the ternary complex were investigated. The results indicate that compared to the SPI/INU binary complex, the SPI/INU/DMY ternary complex had a significant decrease in particle size (~100 nm) and a slight decrease in absolute zeta potential. The SPI/INU binary complex with DMY mainly interacted by hydrogen bonding and hydrophobic interactions. Due to the incorporation of DMY, the structure of SI was denser and more flexible. The ternary complex exhibited an ideal three-phase contact angle and demonstrated better foaming and antioxidant ability. Additionally, compared to SPI/INU, the ternary complex had a significant improvement in EAI. These results provide a strategy for polyphenols to modify the structure, interfacial properties, and functions of protein/polysaccharide complexes. This provides a potential reference for the preparation of more ternary complexes with excellent emulsifying and antioxidant properties for application in emulsions.

Incorporation of microencapsulated polyphenols from jabuticaba peel (Plinia spp.) into a dairy drink: stability, in vitro bioaccessibility, and glycemic response

This work incorporated bioactives extracted from jabuticaba peel in the form of concentrated extract (JBE) and microencapsulated powders with maltodextrin (MDP) and gum arabic (GAP) in a dairy drink, evaluating its stability, in vitro bioaccessibility, and glycemic response. We evaluated the pH, acidity, colorimetry, total phenolics and anthocyanins, antioxidant capacity, degradation kinetics and half-life of anthocyanins, bioaccessibility, and postprandial glycemic physicochemical characteristics response in healthy individuals. The drinks incorporated with polyphenols (JBE, GAP, and MDP) and the control dairy drink (CDD) maintained stable pH and acidity over 28 days. In color, the parameter a*, the most relevant to the study, was reduced for all formulations due to degradation of anthocyanins. Phenolic and antioxidant content remained constant. In bioaccessibility, we found that after the gastrointestinal simulation, there was a decrease in phenolics and anthocyanins in all formulations. In the glycemic response, we observed that the smallest incremental areas of glucose were obtained for GAP and JBE compared to CDD, demonstrating that polyphenols reduced glucose absorption. Then, the bioactives from jabuticaba peel, incorporated into a dairy drink, showed good storage stability and improved the product's functional aspects.

Modification mechanism of soybean protein isolate-soluble soy polysaccharide complex by EGCG through covalent and non-covalent interaction: Structural, interfacial, and functional properties

Soybean protein isolate was modified with polysaccharides and polyphenols to prepare a natural emulsifier with antioxidant capacity. Physicochemical, structural, interfacial, and functional properties of SPI-SSPS complex were investigated after covalent and non-covalent interacted with EGCG. SPI-SSPS-EGCG ternary complex with low EGCG concentrations (0.0625 and 0.125 mg/mL) showed a significant increase in absolute potential value and a decrease in turbidity. EGCG destroyed the original rigid structure of SPI-SSPS complex, and the covalent complexes had an ordered structure, while the non-covalent interaction resulted in disordered. The ternary complex with high EGCG concentrations (0.25 and 0.5 mg/mL) exhibited stronger EGCG binding capacity and lower surface hydrophobicity, which in turn affected its interfacial properties. The EAI and ESI of SPI-SSPS-EGCG covalent complex increased significantly, while the non-covalent complex had a significant change in EAI but no significant change in ESI with increasing EGCG concentration. The ternary complex showed significantly enhanced antioxidant capacity. The SPI-SSPS-EGCG ternary complex, with excellent antioxidant capacity and emulsifying property, making it suitable for emulsion delivery systems.

Study of four polyphenol-Coregonus peled (C. peled) myofibrillar protein interactions on protein structure and gel properties

The effects of four polyphenols-chlorogenic acid (CA), gallic acid (GA), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG) on the structure, gel properties, and interaction mechanisms of myofibrillar protein (MP) were studied. The changes in MP structure with polyphenols were analyzed using circular dichroism. The ultraviolet and fluorescence spectra and thermodynamic analysis indicated that the type of binding between the four polyphenols with the MP was static quenching of complex formation. GA had a more pronounced effect on improving MP gel properties. Finally, molecular docking determined that the affinity of the protein with the four polyphenols was in the order EGCG > ECG > CA > GA, with the main interaction force being hydrophobic interactions and hydrogen bonding, but hydrogen bonding dominates the interaction between GA and the protein. The findings illuminate the mechanism of MP binding to different polyphenols and facilitate the study of polyphenol-protein properties.