Search Results (704)

The aim of this study was to evaluate the feasibility of inducing non-enzymatic browning using enzymatic collagen hydrolysates from turkey knee cartilage and chondroitin sulfate disaccharides derived from turkey and shark cartilage. Glycation was carried out in aqueous solutions at 60–120 °C for 3 h. After glycation, furosine content and browning intensity were determined as indicators of intermediate and final Maillard reaction products. FTIR spectra, color parameters, and antioxidant properties were also analyzed. The results showed that chondroitin sulfate disaccharides were more reactive with collagen hydrolysates than glucose and produced glycation products with higher antioxidant activity. The sulfation site on the N-acetylgalactosamine residue linked to glucuronic acid influenced the characteristics of the Maillard reaction products, including higher antioxidant activity and increased redness in products derived from turkey chondroitin sulfate disaccharides compared with those derived from shark cartilage, despite very similar FTIR spectral characteristics. Full article

Fish allergy, mainly caused by Parvalbumin (PV), is a worldwide health issue with few effective mitigation options. This study investigated Maillard conjugation using chitosan (CS) and various saccharides to modify the structural, functional, and allergenic properties of turbot (Scophthalmus maximus) PV. Structural analyses, including SDS-PAGE, Western blotting, FTIR spectroscopy, and Circular dichroism, confirmed successful conjugation and significant changes in secondary structure, including decreases in α-helical content and increases in β-sheet and random-coil fractions. Glycation significantly boosted antioxidant activity, with total phenolic content (TPC) increasing up to 10.3 times and DPPH radical scavenging reaching 74.5% in the CS–xylose–PV conjugate (CXTPV). Indirect ELISA revealed notable (p < 0.05), sugar-dependent reductions in IgE-binding capacity, with reductions of up to approximately 72% for CXTPV. RBL-2H3 cell assays showed decreased β-hexosaminidase release (about 75% reduction), lowered IL-6 secretion, and strong inhibition of IL-4 production, indicating reduced allergenic potential and immune regulation. CXTPV demonstrated the best overall performance. These findings suggest that CS–saccharide Maillard conjugation is an effective approach for creating hypoallergenic marine ingredients with improved bioactive properties. Full article

Sorghum (Sorghum bicolor L.) is an environmentally friendly crop known for its nutritional and bioactive properties. This study investigated the effects of sorghum on the antioxidant properties and consumer acceptance of nurungji, a traditional Korean snack. To understand the antioxidant contribution of ferulic acid in sorghum during non-enzymatic browning, the antioxidant activity of ferulic acid was evaluated using a sugar (glucose or fructose)–lysine Maillard reaction model system. Nurungji samples were prepared with varying sorghum blending ratios (SN0, SN25, SN50, SN75, and SN100) and heating durations (0, 1, 3, and 5 min). The total polyphenol and total flavonoid contents of nurungji increased significantly in a sorghum concentration- and heating duration-dependent manner. Antioxidant activities, including DPPH and ABTS radical scavenging activities, ferric reducing antioxidant power (FRAP), and reducing power, exhibited trends similar to those of the antioxidant components. In the isolated model system, the addition of ferulic acid significantly enhanced the antioxidant capacity of the Maillard reaction products (MRPs), with the fructose–lysine–ferulic acid solution exhibiting the highest activity. These results support the proposed mechanism that during the thermal processing of nurungji, complex polymeric phenolic compounds within the sorghum are degraded, releasing free ferulic acid that actively boosts the overall antioxidant properties of the resulting MRPs. Although the antioxidant properties of nurungji increased with higher sorghum concentration, the consumer acceptance evaluations indicated that SN0 and SN25 received significantly higher scores for overall acceptance, taste acceptance, and purchase intention (p < 0.05). Full article

In this study, a novel combination strategy of sodium trimetaphosphate (STMP) phosphorylation and dextran (DX) glycosylation was employed to modify soy protein isolate (SPI). The phosphorylated protein–dextran conjugate (TSPI-DX) was successfully prepared and then was used as an emulsifier to prepare the astaxanthin emulsion, with the aim to enhance the emulsion delivery performance. Structural analysis revealed that phosphorylation and glycosylation altered the microenvironment of the side chains, leading to changes in protein secondary structure, which consequently loosened the protein architecture and enhanced molecular flexibility. The functional properties of TSPI-DX, including its solubility, emulsifying activity (EAI) and emulsifying stability (ESI), were markedly enhanced. Furthermore, the concurrent modification through phosphorylation and the Maillard reaction yielded a synergistic effect, boosting the DPPH radical scavenging rate by 86.5% and increasing the ferric-ion reducing power nearly fourfold. The astaxanthin emulsion prepared by modified SPI also exhibited several advantages. The TSPI-DX emulsion exhibited a markedly smaller mean particle size and a larger absolute Zeta-potential value. Consequently, with the higher electrostatic repulsion and steric hindrance among the droplets, the astaxanthin emulsion prepared by TSPI-DX demonstrated superior encapsulation efficiency and stability across various conditions, including storage, oxidation, thermal, and pH challenges. Moreover, in vitro digestion experiments revealed that the modified SPI emulsion facilitated a higher extent of lipolysis and astaxanthin bioaccessibility. Therefore, this work proposes a novel strategy for constructing plant-protein emulsion systems with enhanced delivery and release capabilities. Full article

The synergistic effects of glucose (Glu) concentration and clay mineral type (kaolinite [Kao], montmorillonite [Mon]) on abiotic humification via the polyphenol-Maillard reaction remain poorly understood. To address these scientific challenges, a series of controlled, sterile batch experiments was conducted. Specifically, a glucose concentration gradient (0, 0.03, 0.06, 0.12, and 0.24 mol/L) was established; Kao and Mon were separately introduced as mineral catalysts; and the Maillard reaction was facilitated in the presence of catechol and glycine under strictly abiotic conditions to preclude any potential biological interference. Comprehensive analyses were performed on the reaction products—namely, the supernatant and the dark-brown residue generated during the reaction process. These analyses included: the E₄/E₆ ratio and total organic carbon (TOC) content of the supernatant; the carbon-based ratio of humic-like acid to fulvic-like acid (C_HLA/C_FLA); and the structural characteristics of humic-like acid (HLA) isolated from the dark-brown residue. Results showed dynamic E₄/E₆ ratio and TOC changes in the supernatant were accurately described by the Logistic function. Kao favored soluble organic C accumulation and enhanced retention of early-stage, low-molecular-weight intermediates in the dark-brown residue, while Mon promoted humic-like substances (HLS) polymerization and aromatic condensation. FTIR spectroscopy analysis identified optimal Glu thresholds for maximal HLS formation—0.03 mol/L for Kao and 0.06 mol/L for Mon—indicating non-linear, rather than monotonic, dependence on Glu dosage. Comparative pre- and post-reaction Fourier-transform infrared (FTIR) spectroscopy further demonstrated that Mon, owing to Mg–OH octahedral sites arising from isomorphic substitution, formed more stable Cat chelates than Kao. These chelates effectively stabilized surface-bound hydroxyl-associated water molecules and modulated the electron cloud distribution around Si–O bonds. Collectively, this study clarified the dual regulatory role of Glu concentration and clay mineral identity in abiotic humification pathways, advanced mechanistic understanding of clay mineral-mediated polyphenol-Maillard reactions, and established a scientific foundation for optimizing humification efficiency in both engineered and natural systems. Full article

Severe browning often occurs in Multivitamin Iron Oral Solution during storage, which directly leads to the decline of product quality. To clarify the main mechanism of browning in this preparation, the contents of 5-hydroxymethylfurfural (5-HMF) and carbohydrates, as well as the relevant characteristic parameters such as color and fluorescence, were determined at different storage times in this study. Subsequently, four reaction models, namely sucrose-lysine, sucrose-citric acid, sucrose-niacin, and sucrose-folic acid, were constructed according to the formulation of the preparation to systematically investigate the effects of each system on browning. The results showed that the sucrose-lysine model was the main color-forming reaction system of the preparation. Citric acid could significantly promote the hydrolysis of sucrose to produce two reducing sugars, glucose and fructose, which not only provided sufficient substrates for the Maillard reaction (MR), but also led to the massive accumulation of 5-HMF. Further analysis revealed that heating temperature and heating time were significantly positively correlated with the contents of 5-HMF, browning index (BI), color density (CD), and reducing sugars in the solution, while significantly negatively correlated with sucrose content (p < 0.05). Two fractions, P1 and P2, were isolated by Sephadex LH-20 column chromatography. Among them, P1 with a molecular weight of 61,660 Da was identified as the key fluorescent color-forming component, whose ultraviolet and fluorescence characteristics were basically consistent with those of Multivitamin Iron Oral Solution. Ultra-performance liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) analysis confirmed that P1 contained characteristic fragments of conjugated unsaturated structure, which was the key chromophore responsible for its fluorescence properties. In summary, this study explored the main browning mechanism of Multivitamin Iron Oral Solution. It was found that after citric acid catalyzed the hydrolysis of sucrose, the generated reducing sugars underwent Maillard reaction with lysine to produce fluorescent color-forming substances, and heat treatment significantly aggravated the browning process. The results of this study not only provide a solid theoretical basis for optimizing the preparation process and improving the storage stability of Multivitamin Iron Oral Solution, but also offer an important reference for the research on the browning mechanism and stability of other sugar-containing liquid preparations. Full article

The current understanding of microbiota–flavor correlations in Chinese sourdough steamed bread is predominantly derived from the central provinces, with comparatively limited investigation in northeastern and northwestern regions. This study bridges this gap by analyzing traditional starters from Heilongjiang (HLJ) and Ningxia (TX) versus an industrial starter (JM) through integrated metagenomics and untargeted metabolomics. HLJ was dominated by Limosilactobacillus fermentum (14.75%), while TX featured a synergistic Lactiplantibacillus plantarum–Fructilactobacillus sanfranciscensis consortium. Metabolic pathway analysis revealed enhanced glycolysis, amino acid metabolism, and glycerophospholipid transformation driving flavor biosynthesis and dough rheology improvement, supported by nitrogen-metabolizing Bradyrhizobium spp. (6.00–6.61%). Core pathway enrichment established molecular foundations for region-specific flavors: HLJ generated sulfury/pungent notes via the enzymatic conversion of pentyl glucosinolate to isothiocyanates, whereas TX developed caramel–roasted aromas through stachyose/xylose-derived Maillard reactions forming 2-(methylthiomethyl)furan. Both consortia exhibited higher bitterness and lower umami than JM, with HLJ showing marginally higher umami and lower bitterness than TX. These findings elucidate the microbial mechanisms underlying regional flavor differentiation. Full article

Literature suggests that umami, Maillard reaction, and flavor complexity could contribute to sensorial acceptability of plant-based alternatives, but that was yet to be tested. Two field studies with 612 paying customers evaluating a complete meal were conducted in an operating restaurant in Sweden. In the first study, a gray pea burger (Control) was compared to burgers with added monosodium glutamate (MSG) (Umami), grilled (Maillard), or both grilled and added MSG (Complex). In the second study, a simplified gray pea burger (Control 2) was compared to a grilled burger with MSG and aromatics (Complex 2). Check-all-that-apply (CATA) tests show that participants perceived sensory differences between the samples, but their effects in hedonic ratings were inconclusive; only the Maillard sample was significantly more liked than Control and Complex burgers in Study 1. Although limited to their variables and context, these two experiments indicate that umami, Maillard reaction, and complexity, per se, are not key factors to improve liking and willingness to buy (WTB) of plant-based dishes. These results suggest that rather than trying to emulate sensory characteristics considered associated with meat, future research could prioritize addressing cultural barriers to vegetarian food. Full article

This study investigates the effects of roasting pre-treatment on Lupinus angustifolius protein isolate (LPI) and the resulting structure–function relationships relevant to food applications. Lupin seeds were roasted for 0, 10, 20, and 30 min prior to protein extraction, and the resulting LPI was characterized using circular dichroism (CD), Fourier-transform infrared (FT-IR) spectroscopy, intrinsic fluorescence spectroscopy, and SDS-PAGE. Unroasted LPI exhibited compact native conglutin structures with low solubility (58.64%), surface hydrophobicity (43.34 μg BPB), emulsifying activity (30.71 m²/g), and in vitro protein digestibility (IVPD, 82.84%). Roasting pre-treatment induced a biphasic structural response. Partial conformational changes increased solubility (up to 97.84%), exposed hydrophobic sites (peak 55.79 μg BPB), enhanced emulsifying activity (45.37 m²/g), doubled foaming capacity (210%), and improved IVPD (90.85%), likely due to structural changes that facilitated digestion. CD analysis showed a modest increase in α-helical content (3.43 → 6.74%) with minor fluctuations in β-sheet content, while fluorescence quenching indicated conformational loosening and partial reorganization. SDS-PAGE revealed the formation of soluble oligomers and high-molecular-weight aggregates, consistent with heat-induced association. Prolonged roasting reduced emulsion and foam stability because of aggregation, but maximized antioxidant capacity, likely associated with Maillard reaction products despite the observed depletion of amino acids. Overall, controlled roasting pre-treatment systematically modulates lupin protein structure and functionality, highlighting LPI as a competitive high-performance plant protein ingredient for food applications. Full article

Royal jelly, a nutrient-rich bee product characterized by high water content and active components, is particularly susceptible to quality deterioration during storage. While temperature effects have been extensively documented, the specific role of light exposure in quality degradation remains largely unexplored. despite its relevance during production, handling, transportation, and display. This study systematically investigated the volatile organic compounds (VOCs) of royal jelly under different storage conditions using gas chromatography-ion mobility spectrometry (GC-IMS) combined with fingerprint analysis. Results from dual-column validation demonstrated that even short-term light exposure at 25 °C induced pronounced alterations in VOC profiles, triggering the accumulation of off-flavor aldehydes (e.g., hexanal, nonanal) and ketones, along with 2-furfural generated via Maillard reaction. Concurrently, characteristic fresh-aroma esters and alcohols were significantly depleted. Multivariate statistical analysis confirmed light exposure as the predominant factor driving quality deterioration, with temperature variation under dark conditions producing comparatively minor effects within the same short timeframe. This work provides the first systematic evidence establishing insights into early volatile changes in royal jelly and identifies key VOC markers that offer valuable insights for optimizing storage strategies and developing rapid quality monitoring protocols. Full article

Deciphering the coupling mechanisms between post-harvest precursor shaping and roasting thermochemistry is pivotal for precise coffee flavor modulation. This study aimed to investigate the regulation mechanisms of in vitro biomimetic fermentation (BF) on the precursor-roasting reaction network. Integrated multi-omics characterization and sensory evaluation reveal that the BF protocol achieves targeted substrate enrichment, notably amplifying free amino acids—particularly leucine and phenylalanine—by 1.89-fold while accumulating lactate and succinate buffering salt systems. This reconfiguration constructs a matrix with superior thermal buffering capacity (ΔpH 0.17), which optimizes the thermal reaction kinetic window during roasting. Consequently, BF drives a 3.08-fold surge in esterification flux, significantly increasing the abundance of key fruity markers such as ethyl acetate and ethyl isovalerate. It also enhances the diversity of Maillard products, specifically elevating nutty-associated alkylpyrazines (e.g., 2,3,5-trimethylpyrazine). Concurrently, BF improves the thermal stability of bioactive compounds, including 5-caffeoylquinic acid (5-CQA) and trigonelline. Multi-scale molecular dynamics and quantum chemical calculations elucidate that BF-derived organic acid–salt complexes exert a ‘pseudo-catalytic effect,’ lowering activation free energy barriers for critical aroma-generating reactions by approximately 8.5 kcal/mol. This study demonstrates high sensory predictability (predictive model R² = 0.98) and provides a quantitative theoretical framework to advance coffee processing from empirical observation to rational flavor design. Full article

This study focuses on the storage process of coffee beans, employing electron beam irradiation (EBI) to investigate the comprehensive effects of different irradiation doses on coffee beans and their storage process, including physicochemical indicators, microbial abundance, and flavor compounds. The results showed that a 2 kGy dose of EBI could effectively reduce the total number of bacteria, molds, and yeasts in green coffee beans (GCBs), while a dose of 4 kGy can completely inactivate the bacteria and maintain this effect for one month. Compared with the control sample that has not undergone processing by EBI (CK), the crude fat content of the irradiated samples decreased, accompanied by a significant increase in acid value. After 30 days of storage, compared with the CK-30 sample, EBI treatment significantly reduced both the moisture content and overall brightness value of GCB. The analysis of aroma compounds in roasted coffee beans (RCBs) revealed that substances related to Maillard reaction, caramelization reaction and sugar degradation, such as 2-Furanmethanol and acetic acid, changed in the irradiated samples, but had no significant effect on the characteristic components like caffeine and the aroma detected by the electronic nose. The obtained results provide a scientific basis for applying irradiation technology to the preservation of coffee beans. Full article

High-temperature Daqu (HTD)’s quality determines the characteristics and yield of the Chinese sauce-aroma baijiu. However, winter production frequently encounters challenges such as fermentation instability and metabolic fluctuations, primarily stemming from complex, unmonitored microenvironmental changes within the HTD pile. This study established a closed-loop system linking the microenvironment, HTD quality, microbiome, and metabolome. Through continuous monitoring of the winter fermentation pile’s microenvironmental conditions and integrating multi-omics analyses, we revealed that CO₂ concentration within fermentation piles is the core factor causing quality variations in HTD. By breaking the respiratory bottleneck formed by carbon dioxide (CO₂) accumulation through the turning anaerobic stress can be alleviated, thereby driving metabolic succession. The study found that vertical CO₂ concentration heterogeneity severely restricts the enrichment of aerobic core functional microbial communities such as the Bacillus species. This directly blocks key metabolic pathways including amino acid metabolism and energy supply via ABC transporters. Moreover, the specific accumulation of Amadori products further confirms that this low-temperature environment under CO₂ stress causes the Maillard reaction to stall at intermediate stages. Consequently, this study proposes a steady-state control strategy centered on oxygen and CO₂ gas characteristics. By actively regulating the gaseous microenvironment to eliminate metabolic heterogeneity, it provides theoretical support for standardizing traditional fermentation processes. Full article

This study investigated how harvest timing within the growing season and lactic acid bacterial fermentation influence the phytochemical composition and biological activities of mountain-cultivated ginseng sprouts (MCGS). Various nutritional and bioactive constituents were examined, and in vitro assays were conducted before and after lactic acid bacterial fermentation. Although all samples were derived from 5-year-old plants grown under the same cultivation conditions, differences in harvest timing within the same season may be associated with progressive environmental variation rather than plant age. Nevertheless, harvest timing exerted a relatively limited effect on overall metabolite variation, whereas fermentation significantly enhanced functional properties across all harvest stages. Fermentation increased total phenolic content (4.27 → 7.21 mg/g), total flavonoid content (0.47 → 1.38 mg/g), and Maillard reaction products (2.02 → 2.84 OD_420nm), contributing to enhanced antioxidant capacity and increased inhibitory activities against pancreatic lipase and α-glucosidase. Notably, the levels of bioactive ginsenosides Rg3 and compound K increased markedly after fermentation (0.67 → 1.62 mg/g and 0.68 → 3.37 mg/g, respectively), despite a decrease in total ginsenoside content, indicating selective bioconversion during fermentation. Overall, these findings suggest that fermentation serves as the primary driver of functional enhancement in MCGS, while harvest timing within the growing season may play a secondary modulatory role. Full article

Although concentrate feeds supply most carbohydrates and proteins, the protein component represents the most expensive fraction. A substantial portion of concentrate protein can be replaced with more economical protein sources from forages, particularly from legumes such as pea (Pisum sativum ssp. arvense L.), combined with cereals like oat (Avena sativa L.). Mixtures of these annual legumes and cereals generate a synergistic effect, where oats contribute yield stability and energy, while peas enhance protein concentration and improve forage preservation quality. Assessing protein quality requires understanding the distribution of individual protein fractions classified according to the Cornell Net Carbohydrate and Protein System (CNCPS), which categorizes proteins from PA (non-protein nitrogen) to PC (undegradable proteins bound to lignin, tannins, or Maillard products). This study investigated the influence of pea–oat seed ratios—SR (80:20, 60:40, 40:60, and 20:80) and developmental stages—S (early flowering and pod filling) on the dynamics of protein fractions in green biomass. Results showed that soluble protein fractions (PA, PB₁) decreased during maturation due to nitrogen translocation to developing grains, while structural and undegradable fractions (PB₂, PB₃, PC) increased, particularly in mixtures with higher oat proportions. The 60:40 pea:oat ratio produced the most balanced protein profile, maximizing the proportion of moderately degradable proteins (PB₂), which are crucial for efficient microbial protein synthesis in the rumen. This ratio also optimized the synergy between legume nitrogen fixation and cereal energy supply, enhancing sustainable ruminant nutrition. Statistical analysis confirmed significant differences between growth stages and mixture compositions. Overall, pea–oat mixtures represent a key component of economically viable and ecologically sustainable forage production for ruminant livestock systems. Full article