Degree Of Glycation Research Articles

The effect of polysaccharide type on dielectric barrier discharge (DBD) plasma glycosylation of sodium caseinate-part I: Physicochemical, structural and thermal properties

This study aimed to investigate the impact of polysaccharide type on the physicochemical, structural, and thermal properties of dielectric barrier discharge (DBD) plasma glycosylated sodium caseinate (SC). The polysaccharides Quince seed gum (QSG), carboxymethyl cellulose (CMC), and maltodextrin (MD) were mixed with SC and treated with DBD plasma at 18 kV for 10 min. The grafting degree, electrophoresis pattern, FTIR, XRD, carbonyl, sulfhydryl, and di-tyrosine content, FE-SEM, color, and thermal properties of SC and its polysaccharide mixtures before and after plasma treatment were analyzed. Results showed that the SC-QSG conjugate had the highest glycation degree and color change after plasma treatment. The SC-CMC and SC-QSG conjugates exhibited disappearance of distinct SC bands in electrophoresis pattern compared to SC. Also, significant changes in functional group and crystallinity were occurred in SC-CMC conjugate. Plasma treatment caused oxidation of SC, but the presence of polysaccharides offered protection against oxidation. The microstructure of SC was altered by mixing with polysaccharides and exposure to plasma. Also, the mixtures indicated higher thermal stability after plasma treatment. Results confirmed that the generation of protein-polysaccharide conjugates through DBD plasma technique was depended on with SC-MD conjugate unable to form through this method.

Oil in water emulsion stabilized by glycated rice bran protein aggregates: Effect on interfacial behavior and in vitro digestion of emulsion

To investigate the effect of molecular weight of saccharides and heating time on interfacial behavior of protein, glycated rice bran protein aggregates (gRBPAs) were obtained by incubating rice bran protein (RBP) with glucose (Glu), maltose (Mal) and dextran (Dex) via acid-heat treatment (pH 2.0, 90 °C). Subsequently, the stability and in vitro simulated digestion properties of oil in water (O/W) emulsion stabilized by gRBPAs were analyzed. Structural analysis (circular dichroism and fluorescence spectra) proved that the tertiary structure and secondary structure of RBP changed after glycation, and the contents of β-sheet structure of gRBPAs increased significantly. Besides, the glycation improved the interfacial activity and emulsification of protein obviously. Compared with Glu or Mal, the grafting of Dex could produce larger steric hindrance, which better inhibited the aggregation of emulsion droplets. Furthermore, glycation enhanced the pancreatic lipase (PL) inhibitory activity of gRBPAs obviously, and the emulsions stabilized by gRBPAs exhibited higher anti-digestion ability (62.12–75.00%) compared with RBP (95.27%). Moreover, the free fatty acid (FFA) rate of O/W emulsion was closely related to the surface hydrophobicity, degree of glycation, PL inhibitory activity and interfacial behavior of gRBPAs. Therefore, these findings would be enlightening to intuitively tailor the physicochemical stability and digestibility of O/W emulsion system according to heating time and molecular weight of saccharides. Meanwhile, this work would facilitate the application of O/W emulsion stabilized by glycated protein aggregates in functional foods.

Effects of glycation treatment on the structural, physicochemical, and in vitro digestible properties of tartary buckwheat protein

Tartary buckwheat protein (TBP) has a balanced amino acid composition and multiple health benefits, but it has not been fully utilized in the food industry because of its insufficient functional characteristics. Glycation is an effective strategy to enhance the function of food-derived proteins. This study was to investigate the effects of glucose and its ratio on the structure, physicochemical properties and in vitro digestibility of TBP during moist heat glycation. The results showed that glycation degree increased with glucose proportions, which facilitated the formation of TBP-glucose conjugates through hydrogen bonding, thus reducing tryptophan exposure. Moreover, glycation led to reduced aggregation between proteins and formation of more amorphous structures due to steric hindrance introduced by glucose. Notably, glycation significantly improved solubility (from 67.20% to 80.01%), foaming capacity (from 20.00% to 26.64%), and emulsifying activity (from 3.49 m2/g to 4.12 m2/g). Conversely, glycation reduced free sulfhydryl groups, surface hydrophobicity, turbidity, as well as gastric and intestinal digestibility of proteins. Considering the functional and digestive properties, the best results were obtained with TBP:glucose = 5:3. This study will help to elucidate the mechanism of TBP modification under glycation conditions and provide a theoretical basis for the development of TBP-related products.

Stability and lipid oxidation of oil-in-water emulsion stabilized by Maillard conjugates of soybean phosphatidylethanolamine with different polysaccharides

Lipid oxidation and instability in oil-in-water (O/W) emulsion are the main challenges in emulsion-based foods. Polysaccharide-induced Maillard conjugation of soybean phosphatidylethanolamine (SP) holds great potential in improving physicochemical stability of emulsions. This work applied tamarind gum, pectin, inulin and maltodextrin to conjugate with SP to obtain the four Maillard conjugates (MCs), and investigated their difference in interface and anti-oxidant abilities in emulsions. Results showed that lower polymerization degree of polysaccharide moieties (tamarind gum＞pectin＞maltodextrin＞inulin) caused higher glycation degree in MC: inulin-SP-MC＞maltodextrin-SP-MC＞pectin-SP-MC ≈ tamarind gum-SP-MC, which corresponded their color changes. Compared with unconjugated mixtures, interface activity and anti-oxidant abilities of MCs were strengthened. Among the four MCs, tamarind gum-SP-MC (7.77 mN/m) and pectin-SP-MC (8.42 mN/m) could decrease interfacial tension more largely. It was due to the faster interface saturation benefited from broader steric network of tamarind gum and pectin moieties, and stable interfacial absorption facilitated by improved zeta potential and lipophilicity. Pectin-SP-MC also exhibited the highest anti-oxidant ability (DPPH scavenging ability of 97.81% and ferric-reducing antioxidant power of 2.742 A). It was attributed to the combined effects of grafting degree, interface activity and chain length of pectin moiety. As a result, emulsions stabilized by pectin-SP-MC had less water loss, smaller droplet sizes, and lower contents of oxidation products. Maillard reaction between SP and pectin was favorable to produce MCs with higher potential for the improvements of physical and oxidative stability of O/W emulsions.

Modification techno-functional properties of spirulina protein concentrates (Arthrospira Platensis) as O/W emulsifier by conjugation and electrostatic complexations

Spirulina (Arthrospira platensis) is an intriguing but underutilized protein source in the food industry. This study aims to investigate the effect of electrostatic complexation and conjugation on the techno-functional properties of the protein spirulina and its benefits as an emulsifier in oil-in-water (O/W) emulsion in order to broaden its application as food ingridients. The Spirulina protein concentrate (SPC) interacted with carrageenan via electrostatic and conjugation (Maillard reactions). The properties of the complexes and conjugates were then evaluated. The results showed that the turbidity, browning index, and thermal stability of the solution were influenced by the protein: polysaccharides ratios and pH conditions. The best conjugates (MR) were obtained at a ratio of 2:1 with a pH of 7.0 based on confirmation of the degree of glycation, browning index value, emulsion activity index (EAI) value, and emulsion stability index (ESI). The best electrostatic complexes (EI) were obtained at a ratio of 2:1 with a pH of 2. SPC-carrageenan conjugates and complexes exhibited different functional properties based on conformation structure by FTIR and thermal properties by DSC. Conjugation and Electrostatic Interaction increased the denaturation temperature of SPC, which were reflected in the emulsions stabilized by maillard reaction (MR), electrostatic interaction (EI), and simple mixed (SM) SPC-carrageenan. The emulsion stabilized by MR had smaller droplet sizes, was more evenly distributed, and had better stability towards heating than those stabilized by Native SPC, SM, and EI. This study provides valuable basic information for the development of spirulina protein as a green emulsifier and other type of novel food.

Glycated Walnut Meal Peptide-Calcium Chelates: Preparation, Characterization, and Stability.

Finding stable and bioavailable calcium supplements is crucial for addressing calcium deficiency. In this study, glycated peptide-calcium chelates (WMPHs-COS-Ca) were prepared from walnut meal protein hydrolysates (WMPHs) and chitosan oligosaccharides (COSs) through the Maillard reaction, and the structural properties and stability of the WMPHs-COS-Ca were characterized. The results showed that WMPHs and COSs exhibited high binding affinities, with a glycation degree of 64.82%. After glycation, Asp, Lys, and Arg decreased by 2.07%, 0.46%, and 1.06%, respectively, which indicated that these three amino acids are involved in the Maillard reaction. In addition, compared with the WMPHs, the emulsifying ability and emulsion stability of the WMPHs-COS increased by 10.16 mg2/g and 52.73 min, respectively, suggesting that WMPHs-COS have better processing characteristics. After chelation with calcium ions, the calcium chelation rate of peptides with molecular weights less than 1 kDa was the highest (64.88%), and the optimized preparation conditions were 5:1 w/w for WMPH-COS/CaCl2s, with a temperature of 50 °C, a chelation time of 50 min, and a pH of 7.0. Scanning electron microscopy showed that the "bridging role" of WMPHs-COS changed to a loose structure. UV-vis spectroscopy and Fourier transform infrared spectrometry results indicated that the amino nitrogen atoms, carboxyl oxygen atoms, and carbon oxygen atoms in WMPHs-COS chelated with calcium ions, forming WMPHs-COS-Ca. Moreover, WMPHs-COS-Ca was relatively stable at high temperatures and under acidic and alkaline environmental and digestion conditions in the gastrointestinal tract, indicating that WMPHs-COS-Ca have a greater degree of bioavailability.

Enhancing the functionality of pea proteins by conjugation with propylene glycol alginate via transacylation reaction assisted with ultrasonication

Pea proteins lack the desirable functional characteristics for food and beverage applications. In this study, transacylation reaction assisted with ultrasonication was used to glycate pea proteins with propylene glycol alginate to enhance their functional properties. The reaction was carried out at pH 11.0 for different pea protein isolate: propylene glycol alginate mass ratios and time durations in a sonic bath at 40 °C. Glycation was confirmed in gel electrophoresis, and ultrasonication enhanced the glycation, with optimal degrees of glycation observed at 45 min reaction time and mass ratios of 2:1 (37.73%) and 1:1 (35.96%). The transacylation reaction increased random coil content of pea proteins by 28% and enhanced their solubility by 2.02 times at pH 7.0, water holding capacity by >50% at pH 7.0, foaming properties, emulsifying properties, and heat stability. This study offers a novel approach that can enhance functionality and applicability of pea proteins.

Effects of fibrillation combined with glycation by different chain length sugars on structural and functional properties of soybean protein

The key objective of this study was to investigate the effects of fibrillation combined with glycation of soybean protein isolate (SPI) on the protein structure and functional properties. SPI fibrils alone, glycated proteins and glycated fibrils with different chain lengths (glucose–G, maltose–M and dextran–D) were prepared and characterized by spectroscopy and microscopy methods. The results of the O-phthalaldehyde assay, ultraviolet–visible spectroscopy and fluorescent advanced glycation endproducts indicated the degree of glycation. The thioflavin T fluorescence assay, transmission electron microscopy (TEM) and Fourier-transform infrared (FTIR) spectroscopy results demonstrated that the fibril morphology improved, and more flexible and aggregated fibrils were produced after glycation, further improving the protein functional properties. With EAI and ESI values of 37.31 m2/g and 33.80%, respectively, the emulsifying properties of SPI fibrils glycated by dextran were higher than the others. Foam properties and antioxidant activity were highest for the fibrils glycated by glucose. These results are of scientific significance for in-depth understanding and reasonable regulation of protein functional properties for industrial production in a complex food system.

An unfolding/aggregation kinetic instructed rational design towards improving graft degree of glycation for myofibrillar protein

Glycation is an effective strategy for the application of myofibrillar protein (MP) in beverage formulas by improving water solubility. In conventional glycation, the efficiency was limited as MP-saccharides conjugates mostly produced at low temperature due to thermosensitivity. This study was aimed to explore unfolding/aggregation kinetics of MP, including aggregate behavior, structural characteristics, and micromorphology, which guided the selection of temperature for glycation. It was shown that 40 °C/47.5 °C were critical temperature for MP unfolding/aggregation, respectively. Accordingly, an innovative technology of glycation (cyclic continuous glycation, CCG) was established by combining such temperatures. The results confirmed that cyclic continuous heating (CCH) inhibited excessive exposure of sulfhydryl and hydrophobic groups impeding protein aggregation. Importantly, it was revealed that rational designed CCG promoted covalent binding of MP to glucose by regulating unfolding-aggregation balance, exhibiting higher glycation degree. Overall, CCG-modified MP is expected to motivate the application of meat proteins in food formulations.

Sour cherry seed proteins devoted to covalently bonded carbohydrate moieties: efficacy of transaction and carbohydrate type on amino acid distribution and emulsifier behavior

This paper handled the Maillard reaction under controlled conditions to conjugate sour cherry seed protein isolate (SCPI) with gum Arabic (GA), carboxymethyl cellulose (CMC), and pectin (P) polysaccharides. Characteristic investigations for conjugates were conducted by browning intensity, glycation degree, amino acid, FTIR, SEM, and TGA analyses. After glycation, the level of lysine and arginine declined. Conjugation process displayed beneficial efficacy on techno-functional attributes, namely solubility, water holding capacity, oil holding capacity, foaming capacity/stability and emulsion activity/stability of SCPI but maximum values in terms of these attributes were variable according to conjugate type. Stability index of emulsions stabilized by using conjugates including SCPI-GA (0.87 R), SCPI-CMC (0.94 R), and SCPI-P (0.95 R) was superior than that of SCPI alone (0.60 R). Centrifugal precipitation rate was 59.17, 36.04, 32.61, and 30.92% for emulsions prepared in the presence of SCPI, SCPI-GA, SCPI-CMC, and SCPI-P, respectively. Resilience to freeze-thawed, pH-shifting, various salt concentrations, and different temperature applications of emulsions were investigated to evaluate emulsifier behavior of protein and conjugates in food systems. Findings showed that emulsifying properties of the conjugates prepared using P and CMC came to the fore compared to SCPI alone and SCPI-GA.

Structural and functional characterization of mung bean protein-peach gum conjugate through the Maillard reaction as a novel encapsulation agent

This study used peach gum (PG) and mung bean protein isolate (MBPI) as an encapsulation agent. This study used peach gum (PG) and mung bean protein isolate (MBPI) as an encapsulation agent. The present investigation was undertaken to examine and refine the conjugation process of MBPI-PG, while concurrently evaluating the impact of Maillard modification on functional properties through the wet heat method. Through the analyses of SDS-PAGE, glycation degree, SEM micrographs, and FT-IR spectroscopy, it was ascertained that optimal glycosylation conditions were achieved at a pH of 8.5 and a temperature of 90 °C for a duration of 1 h. Conjugation resulted in the enhanced of solubility, emulsifying properties, and DPPH radical scavenging activity of MBPI. In comparison to their un-conjugated one, the observed improvements in thermal stability and solubility of proteins were attributed to the process of glycation. Collectively, the findings imply that the conjugation with PG imparts additional functional attributes to MBPI, thereby potentially enhancing its applicability in the food industries as a novel encapsulation agent.

Enhanced functional properties of pea protein isolate microgel particles modified with sodium alginate: Mixtures and conjugates

Protein microgels are emerging as versatile soft particles due to their desirable interfacial activities and functional properties. In this study, pea protein isolate microgel particles (PPIMP) were prepared by heat treatment and transglutaminase crosslinking, and PPIMP were non-covalently and covalently modified with sodium alginate (SA). The effects of polymer ratio and pH on the formation of PPIMP-SA mixtures and conjugates were investigated. The optimal ratio of PPIMP and SA was found to be 20:1, with the optimal pH being 7 and 10, respectively. PPIMP-SA conjugates were prepared by Maillard reaction. It was found that ultrasound (195 W, 40 min) enhanced the degree of glycation of PPIMP, with a highest value of 37.21 ± 0.71 %. SDS-PAGE, browning intensity and FTIR data also confirmed the formation of PPIMP-SA conjugates. Compared with PPIMP and PPIMP-SA mixtures, PPIMP-SA conjugates exhibited better thermal stability, antioxidant, emulsifying and foaming properties, which opens up opportunities for protein microgel in various food applications.

Effect of ultrasound on heated soybean isolate protein-soybean oligosaccharide glycation conjugate acid-induced emulsion gels and their applications as carriers of zeaxanthin

The acid-induced emulsion gels were prepared by heated soybean isolate protein (HSPI)-soybean oligosaccharide (SOS) glycation conjugates with ultrasonic treatment at 200 W for 10, 20 and 30 min, which were used as carriers of zeaxanthin. The structural characteristics of HSPI-SOS conjugates, the properties of conjugate emulsion gels and the delivery for zeaxanthin were investigated. The appropriate ultrasound increased glycation degree between HSPI and SOS, and inhibited the formation of browning products, leading to more disordered secondary structure and less compact tertiary conformation of conjugates, which promoted the exposure of hydrophobic groups, the reduction of free sulfhydryl groups and the enhancement of thermal stability. The ultrasonic HSPI-SOS conjugate emulsion gels exhibited smoother and denser microstructure with smaller and more evenly distributed oil droplets, which improved gel hardness, water holding capacity and rheological parameter, resulting in the reinforcement of physical stability of conjugate emulsion gels during heat and pH treatment. Furthermore, the ultrasonic treatment enhanced the chemical stability of zeaxanthin encapsulated in conjugate emulsion gels under light treatment and delayed the chemical degradation of zeaxanthin, which indicated that the ultrasonic treatment facilitated the protective effect of conjugate emulsion gels on zeaxanthin. The bioaccessibility of zeaxanthin encapsulated in conjugate emulsion gels was improved by ultrasonic treatment. Therefore, ultrasound-glycation treatment could be used to modify the structure of proteins to improve the physicochemical stability of conjugate emulsion gels, which exhibited excellent application potential in the encapsulation, protection and delivery for zeaxanthin.

Pulsed electric field enhances glucose glycation and emulsifying properties of bovine serum albumin: Focus on polarization and ionization effects at a high reaction temperature

Previous studies demonstrated that the non-thermal effects of pulsed electric fields can promote protein glycation below 40 °C, but it does not always enhance the emulsifying properties of proteins, such as in the bovine serum albumin/glucose model. Therefore, the aim of this study was to investigate the impact of non-thermal effects on the glucose glycation and emulsification properties of bovine serum albumin at 90 °C. The results of circular dichroism, surface hydrophobicity, and molecular dynamics simulations showed that the polarization effect increased the degree of glycation of bovine serum albumin-glucose conjugates from 12.82 % to 21.10 % by unfolding protein molecule, while the emulsifying stability index was increased from 79.17 to 100.73 compared with the control. Furthermore, the results of principal component analysis and Pearson correlation analysis indicated that the ionization effect and the free radicals generated by pulsed electric fields significantly (p < 0.05) inhibited browning and reduced free sulfhydryl content. This study demonstrated that pulsed electric fields combined with heating can prepare glycated proteins with good emulsifying properties in a short period of time and at temperatures lower than conventional heating while reducing energy consumption. This processing strategy has potential applications in improving the emulsifying performance of highly stable proteins.

Atmospheric cold plasma reduces Ara h 1 antigenicity in roasted peanuts by altering the protein structure and amino acid profile

Ara h 1 is the major allergen in peanuts. To enhance the unique flavor, peanuts are usually roasted at high temperatures. However, roasting can increase the allergenic potential, owing to glycation of allergens. Atmospheric cold plasma (ACP) is a non-thermal processing technology that generates reactive species, enabling protein structural changes. Herein, glucose was also added to the ACP-treated peanut protein before roasting. The content and antigenicity of the advanced glycation end products were measured. The antigenicity was evaluated by ELISA and in vitro digestion assays. The amino acid profile and secondary and tertiary protein structures were also assessed. The antigenicity of Ara h 1 decreased by 91 % and 76 % after 30 min of air and nitrogen plasma treatment, respectively. The glycation degree and thermal and digestive stabilities were also reduced. These results correlated with the structural changes, denaturation, and aggregation. Therefore, cold plasma may reduce the allergic effects of peanuts.

Sesame protein hydrolysate-gum Arabic Maillard conjugates for loading natural anthocyanins: Characterization, in vitro gastrointestinal digestion and storage stability

Protein-polysaccharide conjugates formed via Maillard reaction have the potential as a new type of encapsulation system. However, understanding the effects of the Maillard conjugates as carriers for anthocyanins (ANTs) is limited. The objectives of this study were to develop conjugation of sesame protein hydrolysate (SPH) and gum Arabic (GA) via a wet heating approach with variable times (1, 3, 6, and 12 h) and to investigate the ability of freshly prepared conjugates for encapsulation of Malva Sylvestris (common mallow) ANTs. Conjugate production was confirmed by the appearance of new properties, e.g., altered color, chemical interaction, and changed secondary and tertiary structures. The glycation degree of the conjugates increased to a maximum at 12 h. Conjugation with GA helped the partial unfolding of SPH, and improved its solubility and thermal stability. The ability of SPH, GA, and their conjugate as carriers were compared via the spray drying method. The encapsulation efficiency, morphology and simulated gastrointestinal conditions were investigated. The more homogeneous particles produced by the conjugate ensured greater retention and preservation of ANTs. The release of ANTs during in vitro simulated digestion was significantly slowed by encapsulation, particularly for encapsulated ANTs within the Maillard product. In storage for 90 days at 35 °C, the retention of ANTs was much higher within conjugates (93.13%) compared to nonencapsulated powder (39.76%). This research confirmed that the novel carrier prepared by the controlled Maillard reaction can be a proper wall material in the encapsulation of ANTs.

Comprehensive structural and functional characterization of a new protein-polysaccharide conjugate between grass pea protein (Lathyrus sativus) and xanthan gum produced by wet heating

The purpose of this work was to use a controlled wet-heating process to promote Maillard reaction (MR) between grass pea protein (GPPI) and xanthan gum (XG), and then analyse structural, functional and antioxidant properties of the conjugate (GPPI-XGCs). During heating, the degree of glycation of all conjugated samples was raised (up to 37.43 %) and, after heating for 24 h, the lightness of the samples decreased by 24.75 %. Circular dichroism showed changes in secondary structure with lower content of α-helix and random coil in conjugates. XRD patterns showed that MR destroyed the crystalline structure of the protein. In addition, Lys and Arg content of the produced conjugates decreased by 16.94 % and 6.17 %, respectively. Functional properties including foaming capacity and stability were increased by 45.17 % and 37.17 %, and solubility reached 98.88 %, due to the protein unfolding driven by MR. GPPI-XGCs showed significantly higher antioxidant activities with maximum ABTS-RS value of 49.57 %. This study revealed how MR can improve GPPI's properties, which can aid the food industry in producing a wide range of plant-based foods. Especially, among other characteristics, the foaming properties were significantly improved and the final product can be introduced as a promising foaming agent to be used in food formulation.

Water-soluble fraction of pea protein isolate is critical for the functionality of protein-glucose conjugates obtained via wet-heating Maillard reaction

Wet-heating Maillard reaction (MR) has been applied to improve the function of proteins by conjugating with soluble carbohydrates. However, the impact of soluble solutes particularly in plant protein on the degree of MR and the properties of the corresponding conjugates has yet to be discussed. In this study, high-intensity ultrasound (HIUS) was utilized to pretreat commercial pea protein isolate in order to improve its solubility. Two different fractions including soluble fraction (SUPPI) and whole solution (UPPI) of HIUS treated PPI were conjugated with glucose (G) to prepare SUPPI-G and UPPI-G, respectively, over a course of 24 h wet-heating at 80 °C. Conjugation was confirmed by the degree of glycation, SDS-PAGE, FTIR, and intrinsic fluorescence analysis. Color change and glucose content analysis showed that the degree of MR was greater when using SUPPI rather than UPPI. The solubility of SUPPI-G was further improved by 24 h of MR while it remained unchanged for UPPI-G. The emulsifying activity index and foaming capability of SUPPI-G were similar to those of UPPI-G. Interfacial properties determined by dynamic adsorption and dilatational rheology at both oil–water and air–water interface suggested that insoluble fraction of UPPI is essential to make stable emulsions and foams. In conclusion, the proportion of soluble protein in PPI is critical to its wet-heating MR based conjugation with glucose and the solubility of the conjugates.

Protective effect of thymoquinone on glycation of human myoglobin induced by d-ribose

Nonenzymatic glycation and the subsequent accumulation of advanced glycation end-products (AGEs) in proteins are factors underlying long-term pathogenesis in diabetes. The study of protein glycation is crucial for elucidating their relationship with diabetes mellitus and related disorders. This study explores the interaction between d-ribose and human myoglobin (HMb), as well as the protective effect of thymoquinone (TQ) on glycation. A time-dependent in-vitro glycation study was performed to investigate the mechanism of d-ribose-induced structural interference of HMb in the absence and presence of TQ. Spectroscopic and proteomic analysis indicated that the presence of TQ significantly reduced the total amount of AGEs while maintaining structural characteristics of HMb. 14 glycated sites on HMb were further identified via liquid chromatography-tandem mass spectrometry (LC-MS/MS) after incubation with d-ribose for 12 h, predominantly interacting with lysine residues. TQ was found to disrupt this interaction, reducing the glycated sites from 14 to 12 sites and the percentage of glycated peptides from 26.50 % to 12.97 %. Additionally, there was a significant decrease in the degree of glycation at the same sites. In summary, our findings suggest that TQ has the potential to act as an anti-glycation agent and provide a comprehensive understanding underlying the inhibition mechanism of glycation.

Investigation of structural and physicochemical properties of microcapsules obtained from protein-polysaccharide conjugate via the Maillard reaction containing Satureja khuzestanica essential oil

In this study, some common proteins including, whey protein isolate (WPI), soy protein isolate (SPI), and gelatin (G) conjugated with maltodextrin (MD) via Maillard reaction and were then used to encapsulate Satureja khuzestanica essential oil (SKEO). The higher glycation degree was obtained at a pH of 9 and 3 h of heating at 60 °C for SPI and WPI, and 90 °C for G. The results of FTIR and intrinsic fluorescence test showed the possibility of covalent binding formation between proteins and maltodextrin. The encapsulation efficiencies were obtained about 83.84 %, 88.95 %, and 89.27 % for MD-SPI, MD-G, and MD-WPI, respectively. Moreover, the Maillard reaction-based microcapsules had higher antioxidant activity than the physical mixture of protein-polysaccharide. The addition of SKEO to microcapsules improved antimicrobial activity. The results of this study demonstrated that MD-WPI and MD-G, as encapsulating materials, can be used to enhance the physiochemical properties of microcapsules loaded with SKEO.