The Maillard reaction products as food-born antioxidant and antibrowning agents in model and real food systems

Characterization of the optical properties of soymilk with different pH values using excitation-emission matrix and multiple light scattering

Fluorescence spectroscopy was evaluated for non-destructive pH measurement in soymilk using excitation-emission matrix (EEM). EEMs of 110 soymilk samples with different pH levels were measured, showing two characteristic fluorescence peaks at excitation/emission wavelengths of 280/340 and 365/460 nm, attributed to aromatic amino acids and other fluorescent compounds, respectively. Both peaks showed increased intensity with elevated pH levels. Partial Least Squares Regression (PLSR) and Support Vector Machine (SVM) models were then constructed using various preprocessing methods. The SVM model using raw EEM achieved the highest accuracy with R2cv of 0.972 and RMSECV of 0.095, while the PLSR model performed best with logarithmically transformed EEM showing R2cv of 0.951 and RMSECV of 0.127. Complementary visible-near infrared transmission measurements suggested that the fluorescence changes were related to the changed in light scattering properties under alkaline conditions. These results demonstrate the potential of fluorescence spectroscopy as a tool for non-destructive pH measurement in soymilk.

Inhibition mechanism against hemoglobin oxidation of volatile pyrroles from Maillard reaction

This study aimed to investigate the antioxidant mechanisms of Maillard reaction-derived volatile pyrroles - 2-acetylpyrrole (2AP), N-methylpyrrole (NMP) and pyrrole-2-carboxaldehyde (2PC) on hemoglobin (Hb) oxidation. The findings revealed that during 4-days storage, the 2AP group showed lower carbonyl and dimerised tyrosine contents of Hb than the untreated Hb group, and 2AP preserved the conformation of heme porphyrin in Hb through microenvironmental polarity modulation. In stark contrast, NMP exhibited pro-oxidative properties with accelerated protein aggregation, while 2PC exhibited a biphasic effect - suppressing Hb oxidation initially but accelerating it subsequently - this late-stage oxidation was attributed to its enhanced Hb surface hydrophilicity. Generally, the inhibition activity of the three pyrroles is closely related to the position of the substituents in the pyrrole ring and the availability of electrons. This study provided a basis for investigating the antioxidant properties and applications of Maillard reaction-derived volatile small molecules in fresh meat preservation.

Preparation, identification and application of lipid-Maillard reaction products during the drying process of squid fillets

Squid fillets are susceptible to lipid oxidation and Maillard reaction during the drying process. In this study, a novel additive agent lipid-Maillard reaction products (L-MRPs) was optimized by response surface methodology, then the main antioxidant components of L-MRPs were identified. Finally, L-MRPs was applied to the drying process of squid fillets (LMSF) by comparing with the control group. The results showed that the optimal reaction conditions were pH 10.90, lipid content 1.70 %, reaction temperature 104 °C, reaction time 105 min. The DPPH radical scavenging activity of final L-MRPs was 89.78 %. The main antioxidant components of L-MRPs were Fru-Arg (19.31 μg/g), pyrroles (762.04 μg/g) and other HCCs (293.97 μg/kg). Besides, compared to the control group, LMSF group showed lower thiobarbituric acid reactive substances value (4.58 mg/kg) and formaldehyde content (17.00 mg/kg), but more flavor compounds (455.78 μg/kg) and higher sensory scores. Finally, the potential antioxidant and flavor-enhancing mechanism of L-MRPs was proposed.

Maillard reaction products derived from xylose-phosphatidylethanolamine: Potential anti-oxidative substances from hot-pressed flaxseed oil

Hot-pressed flaxseed oil is favored in Northwest China as cooking oil due to its flavor and oxidative stability. The mechanism of enhancing oxidation stability of hot-pressed flaxseed oil by neoformed Maillard reaction products (MRPs) remains mysterious. Maillard model reaction between phosphatidylethanolamine (PE) and reducing sugar of flaxseed, glucose (Glu)/fructose (Fru)/xylose (Xyl), was conducted to investigate the antioxidant characteristics of products. MRPs of PE-Xyl had a superior reactivity and anti-oxidative capabilities, which could improve the oxidative stability of flaxseed oil and inhibited the formation of aldehydes in the accelerated oxidation. Phosphatidylethanolamine-linked pyrrolecarbaldehyde (PLP) was the main antioxidant component in MRPs of Xyl-PE by MS and NMR analysis and verification of antioxidant activity. Furthermore, the results of quantum chemical calculation show that the antioxidant activity center of PLP is the pyrrole group. The findings of this study provide insights into the chemical basis underlying the improved oxidative stability of hot-pressed oils.

Insights into the mechanism of ameliorative antioxidant activity and hydration characteristics in cold plasma-induced glycosylated peanut protein products

To achieve the high-value application of high-denatured peanut protein isolate (HPPI), cold plasma (CP) was employed to modify its surface structure through covalent binding with sesbania gum. Compared to HPPI, the water-binding capacity and antioxidant activity of glycosylated products, containing DPPH and ABTS•+ free radical scavenging activities, as well as lipid peroxidation inhibition, were significantly enhanced. CP-induced covalent binding was confirmed by a degree of grafting (15.57 % ± 0.38 %), the formation of large molecular weight complexes, and the presence of glucosidic bonds. The loose tertiary structure of the glycosylated product facilitated the formation of hydrogen bonds between hydrophilic groups (-OH) and water molecules and also promoted the enhancement of the antioxidant activity of aromatic amino acids via electron transfer. Given the strong correlation between water retention and antioxidant activity, CP-induced glycosylated products can find applications in diverse fields, such as functional supplements.

Novel comprehensive perspective on Amadori compounds: preparation, multiple roles and interaction with other compounds

Amadori compounds are pivotal intermediates in the Maillard reaction. Amadori compounds serve as flavor enhancers, browning precursors and bioactive components, so they are promising versatile food additives. Comprehensive reviews on multiple roles of Amadori compounds are scarce. Furthermore, there is a lack of reviews on green, efficient and commercially prospective preparation techniques of Amadori compounds and their interactions with other components. This paper reviewed preparation, multiple roles and interactions with other components in foods. Spray drying, microwave heating, natural deep eutectic solvents and vacuum dewatering were deemed as green, efficient and commercially prospective preparation techniques for Amadori compounds. Amadori compounds broadened the application field of Maillard reaction-obtained additives compared to final-products, enabling their uses not only in dark-colored foodstuffs but also in light-colored. Peptide-derived Amadori compounds showed greater potency for flavor generation compared to amino acid-derived. Amadori compounds presented eleven physiological activities. Amadori compounds exerted synergistic effect with essential nutrients (lipids, exogenous amino acids and carbohydrates), functional ingredients (polyphenols, carotenoids, glycosides) as well as several drugs. More preparation approaches of Amadori compounds and their synergistic effects with other ingredients await investigation. This review provided comprehensive theoretical guidance for industrial preparation and application of Amadori compounds as versatile additives.

Metabolomics, E-tongue and HS-SPME-GC-MS reveal the smoking process of Prunus mume: Changes in flavor and chemical compositions

Smoked Prunus mume (SPM), known as Wumei, experiences remarkable alterations in flavor and chemical composition. However, no research has reported on the smoking process. In this study, the changes of flavor and chemical compositions were analyzed via E-tongue, metabolomics, and HS-SPME-GC-MS during the smoking process. Results showed that significant changes in the basic parameters and electronic sense were observed during the smoking process. 85 volatile organic compounds (VOCs) were identified, and 124 metabolites were significantly differentially regulated during the smoking process. Metabolic pathway analysis showed that 20 pathways in SPM, especially phenylpropanoid biosynthesis, are related to smoking process. A number of key substances were identified by Mantel test that may have caused the electrosensory changes in SPM. These findings revealed that the changes characterization of flavor and chemical compositions in SPM during the smoking process, which will help to better understand the formation mechanism of flavor and metabolites.

Characteristics and functional properties of soybean peptides-Hawthorn pectin Maillard conjugates synthesized/obtained under controlled temperature conditions

In the study, soybean peptide-Hawthorn pectin Maillard conjugates (SBP-HP-MC) were first obtained through the Maillard reaction at different temperature (50 °C, 70 °C, 90 °C) and were investigated using a series of characterization methods. UV, Intrinsic fluorescence, Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared spectroscopy (FT-IR) analyses confirmed that SBP and hawthorn pectin (HP) formed high-molecular-weight conjugates. The results demonstrated that the degree of the grafting (DG) (43.37 ± 0.05 % to 49.53 ± 0.05 %) of the product exhibited an initial increase with rising temperature. The conjugation of HP significantly enhanced the gelling ability, rheological properties (viscosity up to 301.68 mPa· s), emulsifying activity (14.79-28.09 m2/g), and antioxidant capacity (53.04-72.31 %) of soybean peptides (SBP). Notably, these improvements were positively correlated with the DG. Texture analysis indicated an increase in hardness (up to 3085.16 ± 2.08 N/m2), cohesiveness, and adhesiveness in SBP-HP-MC/Ca complex gels at 12.5 %. Furthermore, the liquid viscosity (Viscosity at 50 1/S of 10 % SBP-HP-MC70: 301.68 ± 0.32 mPa·s) of SBP-HP-MC varied from "nectar type" (51-350 mPa·s) to "honey type" (351-1750 mPa·s). SBP-HP-MC demonstrates significant potential as a texture modifier in the food industry.

Flavor enhancement pathways and mechanisms of cold-pressed walnut oil based on defatted cold-pressed walnut meal hydrolysates

The present study aimed to investigate the effect and underlying mechanism of Maillard reaction products (MRPs) derived from defatted cold-pressed walnut meal hydrolysates (DCWMH) on the aroma enhancement of cold-pressed walnut oil (CWO). Nineteen key aroma-active compounds were identified in CWO, hot-pressed walnut oil (HWO), and flavored walnut oil (FWO) using gas chromatography-olfactory-mass spectrometry (GC-O-MS) and odor activity values (OAVs). Principal component analysis (PCA) based on quantitative descriptive analysis (QDA) showed that the "roasted flavor" was positively correlated with FWO. Correlation analysis of free amino acids identified aspartic acid (Asp) as a key aroma precursor. Additionally, a novel pathway for furfural formation via Schiff base intermediates was proposed from the free radical cleavage process of the Maillard reaction in the [13C5]Xylose-Asp model system. Overall, this study provides valuable insights into the control of flavor quality during walnut oil production and supports the potential for the comprehensive utilization of walnut by-products.

Changes in chemical composition, volatile compound, and bioactive compounds retention in shallots (Allium ascalonicum L.) under different drying methods

Shallots (Allium ascalonicum L.) are widely used in culinary and medicinal applications due to their rich bioactive compounds and health benefits. This study examines the effects of freeze drying, sun drying, and hot air drying at 40, 60, and 80 °C on chemical and bioactive compounds in shallots. Hot air drying at 80 °C had the highest total phenolic and flavonoid contents. Freeze drying increased syringic, p-coumaric, protocatechuic, vanillic, and ferulic acids. Quercetin was highest in freeze drying. Apigenin increased in samples that was dried by hot air drying at 80 °C. Proline was the major amino acid; arginine increased by 34 % in sun drying. Fourier Transform Infrared Spectroscopy (FTIR) revealed polysaccharides, lipids-proteins, and amino acids. Eucalyptol was the predominant volatile component in fresh shallot and most preserved by freeze drying. The results underscore the significance of choosing suitable drying methods to preserve shallot bioactive compounds and antioxidant properties.

Structural and functional modifications of quinoa protein via hyaluronic acid-induced Maillard reaction

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.

An imidazo-pyridin derivative as fluorescent probe for the peroxynitrite detection in pulmonary permissive hypercapnia

The physiological and pathological processes in lungs indicated that ONOO- acted as an informative indicator for pulmonary functioning status with the corresponding dynamics, especially in permissive hypercapnia. Herein, for the peroxynitrite (ONOO-) detection and imaging in living lung cells, an imidazo-pyridin derived fluorescent probe IDPD-ONOO was developed. IDPD-ONOO recognized ONOO- to exhibit a corresponding fluorescence response at 490 nm with the excitation wavelength at 355 nm. The advantages of the developed probe included practical linear range (0-100 μM), high sensitivity (Limit of Detection 0.005 μM), rapid response (within 15 min), pH tolerance (7.0-9.0), high selectivity, and low cyto-toxicity. Furthermore, IDPD-ONOO achieved the pulmonary intracellular imaging of both the exogenous and endogenous ONOO- level, which was meaningful for the research on the pulmonary physiological and pathological mechanism with optimized optical implements.

Effect of lysine on the cysteine-xylose Maillard reaction to form flavor compounds

To understand flavor formation mechanisms in complex meat-like Maillard systems, effect of lysine on cysteine-xylose reaction to form flavors was studied. GC-MS and GC-O analyses found lysine of 1 times cysteine concentration led to the greatest amount of sulfur-containing meaty compounds while more additional lysine caused more pyrazine compounds. LC-MS analysis showed lysine competed with cysteine to form the early-stage intermediate of Lys-Amadori compounds and accelerated conversion of 2-threityl-thiazolidine-4-carboxylic acids to Cys-Amadori compounds from the cysteine-xylose reaction. Reaction rates based on UV 294 and 420 nm absorbance, browning color, and consumption of cysteine and xylose suggested addition of lysine continuously accelerated the Maillard reaction at intermediate and final stages. Pearson correlation analysis revealed less reaction rates and Lys-Amadori compounds formed could cause more meaty compounds and thereby exposed formation pathways of important aroma compounds. This work can provide guidance for optimizing meat or meat product composition to improve meat flavor.

Reduction of oil absorption and acrylamide content in banana slices by infrared frying

BACKGROUND

The crust characteristics of fried crisps determine their oil absorption. Starch structures, as the main components of fried starchy fruits and vegetables, influence their crust formation and properties. This study investigated the reduction of oil uptake and acrylamide content in infrared-fried (IF) banana slices by modifying starch structures at varying infrared power levels.

RESULTS

Infrared heating improved heat transfer and surface moisture removal in fried banana slices. It facilitated crust formation in the IF samples and produced increased crust uniformity, crust ratio, and hardness. Analysis of the porous properties showed that the volume fraction of pores sized 100-250 μm was reduced in IF samples but the proportion of pores with a diameter ranging from 0.02 to 10 μm was increased. Infrared frying reduced the total oil uptake, surface oil, and structural oil content in banana slices, and each of these measures decreased as infrared power levels increased. Characterization of the starch structures suggested that the damage to the crystalline structure was increased in IF samples and more starch-lipid complexes were generated, which would be responsible for the formation of a denser and thicker crust. The acrylamide content in the IF sample was reduced, as determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

CONCLUSION

Modifications to starch structures (crystalline structures and chemical structures) play a crucial role in oil absorption in fried starchy fruits and vegetables. Infrared frying can be used as an alternative method to produce low-fat fruits and vegetable crisps with reduced acrylamide content. © 2024 Society of Chemical Industry.

Characterization of astaxanthin-loaded Pickering emulsions stabilized by conjugates of pea protein isolate and dextran with different molecular weights

BACKGROUND

Pea protein isolate (PPI) is gaining increasing popularity in the food industry. It provides a diverse range of health benefits, such as hypoallergenic and gluten-free characteristics. However, the functional performance of PPI is hindered by its low solubility and poor stability. Therefore, in this article, PPI and dextran (DX) of different molecular weights were grafted to investigate the effects of grafting DX with different molecular weights on the interface properties and antioxidant properties of PPI. Additionally, the stability and digestive properties of the glycated PPI nanoemulsion system were explored.

RESULTS

The result showed that the grafting degree of PPI-DX conjugates (PPI-DC) decreased with an increase in the molecular weight of DX. Surface hydrophobicity, antioxidant activity and solubility of PPI-DC were significantly improved after grafting compared with PPI and PPI-DX mixtures (PPI-DM). Astaxanthin-loaded emulsions stabilized by grafted conjugates had smaller droplets and higher astaxanthin encapsulation rate compared to PPI emulsions. In vitro digestion demonstrated that the bioavailability of PPI-DC emulsions was higher than of PPI emulsion. Furthermore, after 24 days of storage, retention rate of astaxanthin-loaded emulsions prepared by conjugates remained above 70%, surpassing that of PPI emulsion.

CONCLUSION

These results indicated that DX grafting can improve the emulsion properties of PPI. In addition, the DX with a molecular weight of 5 kDa showed the most significant improvement. This study contributes to the advancement of natural emulsifiers by modifying PPI through glycation, and furnishes a valuable reference for its utilization in functional foods. © 2024 Society of Chemical Industry.

The Formation and Change of Volatile Flavor Compounds During the Cooking of Sheep Bone Soup

To investigate the formation of flavor compounds in sheep bone soup, E-nose, gas chromatograph (GC), and gas chromatography-mass spectrometry (GC-MS) were used to determine the changes in lipid oxidation, Maillard reaction, and volatile flavor compounds during the slow cooking process of 4 h. The thiobarbituric acid reactive substances (TBARS) value began to increase significantly (p < 0.05) after 2 h of cooking, reaching its peak in the third hour before significantly decreasing. The intensity of the Maillard reaction significantly increased after 2 h of cooking and subsequently stabilized. Thirty-nine flavor compounds were identified, primarily comprising aldehydes, ketones, alcohols, esters, aromatic compounds, and heterocyclic compounds. The formation of volatile flavor compounds in sheep bone soup was associated with lipid oxidation, particularly the oxidation of unsaturated fatty acids, and the Maillard reaction. Lipid oxidation produced a large number of volatile flavor compounds, such as aldehydes and ketones. The Maillard reaction gave sheep bone soup a certain flavor. Aldehydes were mostly influenced by cooking time, becoming the main flavor compounds in the bone soup after 2.5 h of cooking, accounting for more than half of the total volatile flavor compounds. The highest content and richest profile of volatile flavor compounds were obtained in the soup cooked for 2.5 h and 3 h. This study provides a theoretical basis for the flavor regulation of sheep bone soup.

Novel technologies, effects and applications of modified plant proteins by Maillard reaction and strategies for regulation: A review

With an increase in awareness of health, environmental conservation and animal welfare, the market for plant proteins is expanding. However, the low solubility and poor functional properties of plant proteins near the isoelectric point limit their application in food processing. Glycosylation refers to the structural modification of proteins by introduction of polysaccharides to form protein-polysaccharide conjugates in the early stages of Maillard reaction. Glycosylation is a green and efficient method that has been proved to produce modified proteins with superior solubility, emulsifying and forming properties. Glycosylation and the application of protein-carbohydrate conjugates have become research hotspots in recent years. This paper presented a comprehensive review of the effects of glycosylation on the functional properties of plant proteins and the mechanisms of non-thermal physical treatments assisted glycosylation. It was demonstrated that glycosylation modified the structure of plant proteins and improved their functional properties. Non-thermal physical treatments assisted glycosylation increased the reactive sites of plant proteins and further improved their functional properties. Protein-carbohydrate conjugates could be applied in delivery systems, films, emulsifiers and other applications, which have significant research prospects in food applications.

Insight into the structural, interfacial and functional properties of soybean 11S globulin-debranched starch conjugates through alkaline Maillard reaction

This study examined the effects of the alkaline Maillard reaction on the structural, interfacial, and functional properties of soybean 11S globulin-debranched starch (DBS) conjugates. The results showed that the degree of DBS binding to 11S globulin was influenced by the polymer ratios, which in turn affected the structural, interfacial, and functional characteristics. The 11S-DBS conjugates with a 2:1 biopolymer ratio exhibited the highest grafting degree, largest zeta potential absolute value, smallest particle size, and greatest thermal stability. Conjugates with higher globulin content demonstrated superior interfacial and functional properties, including improved solubility, increased surface hydrophobicity, and reduced interfacial tension. 3D fluorescence scanning revealed a decrease in the signal of aromatic amino acid residues, while microstructural observation provided insights into the binding behavior of different 11S-DBS conjugates. Molecular docking simulations highlighted the key role of hydrogen bonding in the formation of these conjugates. This study enhances understanding of soybean globulin-polysaccharide interaction mechanisms, expanding their potential applications in the food, medical, and bioengineering industries.

Combining Sensory Analysis and Flavoromics to Determine How the Maillard Reaction Affects the Flavors of Golden Pomfret Hydrolysates

Enzymatic hydrolysis can enhance the flavor of aquatic products. Nevertheless, the strong fishy odor restricts its utilization in culinary applications. This study is centered on enhancing the flavor of golden pomfret samples by promoting the Maillard reaction (MR) between golden pomfret hydrolysate (GHES) and reducing sugars. The research results demonstrate that the Maillard reaction significantly improves the sensory characteristics of GHES. It prompts the formation of diverse volatile compounds, such as aldehydes, esters, and furans. Simultaneously, it reduces the relative amounts of substances associated with fishy odor, such as 1-Octen-3-ol and Hexanal. Moreover, the Maillard reaction increases the contents of amino acids contributing to umami and sweetness, as well as 5'-nucleotides in the samples, thus enriching their umami flavor profiles. After undergoing the Maillard reaction treatment, the antioxidant capacity of the samples is also significantly enhanced (p < 0.05). This research highlights the potential of the Maillard reaction in improving both the flavor and antioxidant properties of GHES, establishing a theoretical basis for elevating the quality of golden pomfret products.

Storage stability evaluation of chicken seasoning by accelerating oil oxidation under different storage conditions

The effects of temperature, humidity, and UV irradiation on the accelerated oil oxidation of chicken seasoning (CS) were investigated, aiming to establish a method for evaluating its storage stability. Key oxidation indicators, such as peroxide value (POV), fatty acid profile, and volatile aldehydes, were measured to assess the degree of oil oxidation. The results indicated that oil oxidation of CS is not significantly accelerated by temperatures of 50-80 °C due to the inhibitory effects of the Maillard reaction. The effect of humidity on accelerating oil oxidation of chicken seasoning was insignificant, either, due to the high barrier properties of the packaging material. The oil oxidation rate was greatly accelerated by UV irradiation. However, the mechanism of photosensitive oxidation reaction is inconsistent with that of auto-oxidation reaction under actual storage conditions. Ultimately, UV irradiation combined with constant temperature storage was used to induce auto-oxidation of CS, and the suitable accelerating conditions were 18 h of UV irradiation, followed by 50 °C of constant temperature storage. The storage stability of 6 commercially available CS was successfully evaluated using this method. The established method provides a reliable approach for assessing the storage stability and shelf life of CS.

Enhancing shelf-life of dried goji berry: Effects of drying methods and packaging conditions on browning evolution

Preservation and shelf-life extension are of paramount importance for dried goji berry, especially those dehydrated using pulsed vacuum drying (PVD), which are generally applied for the high-quality dried products in the markets. This study compared the storage stability of dried goji berry dehydrated using PVD versus conventional hot wind drying (HWD), focusing on the complex interactions between packaging conditions and physicochemical compounds during accelerated storage. The results showed that PVD-dried goji berry exhibited higher browning degree (2.65 to 4.69) compared to HWD-dried berry (1.48-2.32). This difference was contributed to enzymatic and non-enzymatic precursors such as carotenoids, phenolics, reducing sugar, and intermediate products including 5-hydroxymethylfurfural, which also affected by the cuticular waxes leading to uneven and wrinkled appearance. Structural equation modeling and Pearson's analysis identified that Maillard reaction products as the primary factor of color deterioration in PVD-dried goji berry, with path coefficient of 0.460 and 0.241, and also depended on the light atmosphere. In contrast, the browning in HWD-dried goji berry was mainly due to the quinones accumulation with path coefficient of 0.343, associated with phenolics and intermediate compounds. In conclusion, the findings suggest that the selection of drying methods is crucial for determining appropriate storage conditions for dried goji berry, which provides scientific guidance for the selection of appropriate drying and storage methods to improve the product quality and stability in future efforts.

Antioxidant Maillard Reaction Products from Milk Whey: A Food By-Product Valorisation

The Maillard reaction (MR) is a key process in food science, producing bioactive compounds with antioxidant properties. This study evaluates the antioxidant potential of MR products (MRPs) from different dairy byproducts-cow cheese whey, goat cheese whey, and cow yoghurt whey-highlighting their applicability in food preservation and waste valorisation. Whey samples were subjected to the MR at 140 °C for 90 min, showing significant amino acid and sugar consumption, particularly arginine, histidine, and lactose. Using a library of potential antioxidant MRPs (molecular weight < 250 Da), 28 key compounds, including 2-pyrrolecarboxaldehyde and maltol isomer, were identified, primarily in cow cheese whey. A complementary high-molecular-weight MRP library (≥250 Da) identified 72 additional antioxidant compounds, with distinct production patterns linked to whey type. Multivariate analyses confirmed that whey type strongly influences MRP profiles. These results highlight the potential of MR to transform whey by-products into valuable sources of natural antioxidants. This approach offers sustainable strategies for enhancing food preservation, reducing food waste, and supporting the targeted use of MRPs in the food industry.

Prediction of Pasta Colour Considering Traits Involved in Colour Expression of Durum Wheat Semolina

Colour plays an important role among the quality traits of durum wheat, attracting consumer attention for the pasta market. The traits involved in colour expression are affected by genotype, environment, and processing. In the present study, based on eighteen durum wheat genotypes grown in eight environments, the effects of different traits related to colour expression were evaluated. Carotenoid pigments, such as lutein and β-carotene content; yellow and brown indices; and lipoxygenase, peroxidase, and polyphenoloxidase activities were analysed in semolina. The effects of processing were evaluated by measuring both the content of carotenoid pigments and colorimetric indices in pasta. The genotype, the environment, and their interaction were significant for all traits, although with a strong prevalence of genotypic effects, except for the brown index. After processing, a decrease in carotenoid content and the yellow index (86.7% and 16.0%, respectively) was observed, while the brown index increased (8.2%). A multiple regression analysis was performed on semolina traits, and the yellow index emerged as the main predictor for pasta colour, strengthening this trait as a fast and reliable criterion of selection. A High-Performance Index tool was also used to identify the genotype and environment that better combine all traits, positively influencing colour expression. All this information can be used in durum wheat breeding programmes for the prediction of pasta colour.

Moisture Loss from Cheese During Baking: Influence of Cheese Type, Cheese Mass, and Temperature

This study examined how temperature, cheese mass and moisture content impact moisture loss rate in various cheeses during baking. Understanding these factors is essential for determining the browning properties of cheese during baking. Eight cheese types, differing in moisture content, were baked at 100-200 °C in a halogen moisture analyzer, and moisture loss over time was recorded. A mixed-effects model analysis showed that temperature had the most significant impact on moisture loss rate (F = 2008.54; p < 0.00001), followed by cheese mass (F = 1973.28; p < 0.00001) and time (F = 278.49; p < 0.00001). Higher temperatures and larger cheese mass accelerated moisture evaporation rate. The moisture content of cheese explained 21.8% of model variation, suggesting that other factors, such as cheese structure, also play a significant role. The cheese baking process involving moisture removal followed by distinct drying stages. Initially, the drying rate increased as the cheese reached the wet bulb temperature; this was followed by a steady rate, and finally, a reduction in dehydration rate as the moisture decreased, limiting further evaporation. Browning, assessed through changes in lightness (L*), was more noticeable at higher temperatures, particularly in Mozzarella and processed Cheddar, after approx. 30% moisture loss in all cheeses.

Effect of superheated steam on Maillard reaction products, digestibility, and antioxidant activity in β-Lactoglobulin-glucose system

This study analyzes the interactions among Maillard reaction products (MRPs), digestibility and antioxidant activity in a β-lactoglobulin-glucose (βlg-Glu) model system during superheated steam treatment at 120 °C for 1 to 5 min. With an increase in treatment duration, there were significant increases in glucose loss, grafting degree, browning, and the formation of intermediate products in βlg-Glu. Characteristic MRPs, including α-dicarbonyl compounds, 5-hydroxymethylfurfural, and advanced glycation end products (AGEs), were formed through the degradation of sugars and condensation reactions between carbonyls and amines, accompanied by an increase in oxidative products. These changes impacted the molecular weight distribution and conformational structure of βlg-Glu, resulting in decreased digestibility. βLg-Glu with the highest level of glycation exhibited superior antioxidant activity after in vitro digestion, which was closely associated with the increase in AGEs and oxidation products. Therefore, the protein-sugar system treated by superheated steam with different heating time can significantly affect the formation and activity of the products, providing theoretical basis for superheated steam processing nutritious and healthy food.

Changes in Ginsenoside Composition, Antioxidant Activity and Anti-Inflammatory Activity of Ginseng Berry by Puffing

The effects of puffing on the ginsenoside composition as well as antioxidant and anti-inflammatory activities of ginseng berry were investigated to increase the utilization of ginseng berry. There was no significant difference in extraction yield between the control and puffed samples at all moisture contents and pressure conditions (p < 0.05). Major ginsenosides of ginseng berry (especially ginsenoside Re) were degraded through deglycosylation and dehydration by heat and pressure, and new minor ginsenosides (Rg3, F2, Rh2 and Rb2) were produced after puffing. Puffed ginseng berries showed higher total phenolic content (TPC), total flavonoid content (TFC) and Maillard reaction products (MRPs) than those of the control group, and these contents were increased as puffing pressure increased. In addition, higher antioxidant activities were observed in puffed ginseng berries compared to the controls, possibly due to the increase in TPC and MRPs. Antioxidant activity increased with increasing puffing pressure at all moisture contents. Nitric oxide (NO) production showed no significant inhibitory effect between control and puffed ginseng berries (p < 0.05). In the case of inflammatory cytokines, IL-6 had an inhibitory effect, but TNF-α had no inhibitory effect. Consequently, puffing showed a positive effect on the composition and the transformation of ginsenosides as well as the antioxidant activity of ginseng berries, suggesting that puffed ginseng berries can be used as a high value-added food material.

Recent Trends in Advanced Glycation End Products in Foods: Formation, Toxicity, and Innovative Strategies for Extraction, Detection, and Inhibition

Advanced glycation end products (AGEs) are produced in foods during their thermal treatment through routes like the Maillard reaction. They have been linked to various health issues such as diabetes, neurodegenerative disorders, and cardiovascular diseases. There are multiple pathways through which AGEs can form in foods and the body. Therefore, this review work aims to explore multiple formation pathways of AGEs to gain insights into their generation mechanisms. Furthermore, this review work has analyzed the recent trends in the detection and inhibition of AGEs in food matrices. It can be highlighted, based on the surveyed literature, that UHPLC-Orbitrap-Q-Exactive-MS and UPLC-ESI-MS/MS can produce highly sensitive results with a low limit of detection levels for AGEs in food matrices. Moreover, various works on inhibitory agents like spices, herbs, fruits, vegetables, hydrocolloids, plasma-activated water, and probiotic bacteria were assessed for their capacity to suppress the formation of AGEs in food products and simulation models. Overall, it is essential to decrease the occurrence of AGEs in food products, and future scope might include studying the interaction of macromolecular components in food products to minimize the production of AGEs without sacrificing the organoleptic qualities of processed foods.

Anti-oxidant activity of 1-(1H-imidazo[4,5-c]pyridin-4-yl)ethenone, a Maillard reaction product derived from fructose and histidine

BACKGROUND

The Maillard reaction involves the interaction of various amino acids and reducing sugars, resulting in food browning. It often produces appealing aromas and flavors. The complexities of the reaction are such that it can be challenging to identify the often numerous and frequently volatile products formed by it. In the present study, we sought to identify and evaluate an unusual product with anti-oxidant activity arising from a fructose-histidine Maillard reaction model. The anti-oxidant profile of this product was assessed by computational means.

RESULTS

The fructose-histidine Maillard reaction products (FH-MRPs) were generated by heating a 2:1 mixture of the sugar and the amino acid at 140 °C for 2 h. Chromatographically separable fractions, labelled DM-1 to DM-8, were obtained using silica gel as the stationary phase and dichloromethane/methanol (DCM/MeOH) mixtures as the mobile one. Fraction DM-5 exhibited the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and further bio-assay guided fractionation led to isolation and identification of 1-(1H-imidazo[4,5-c]pyridin-4-yl)ethenone (IMPE) as the active principal, the structure of which was established by nuclear magnetic resonance (NMR) spectroscopic and mass spectral techniques. A mechanism for the formation of IMPE from its precursors is proposed. Density functional theory (DFT) calculations suggest this novel heterocyclic compound exerts its anti-oxidant effects by interacting with DPPH and 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals. Essentially, IMPE was non-toxic below 300 ug mL-1, showing a concentration-dependent free radical clearance capacity and reducing power within the 100-1000 μg mL-1 range, and moreover, exhibiting significant Fe2+ chelating abilities wihin the 50-200 μg mL-1 range.

CONCLUSION

This study identified the unique FH-MRP, IMPE, and found that it acts as food antioxidant through the chelation of metal ions. © 2024 Society of Chemical Industry.

A rich-nutritious cultured meat via bovine myocytes and adipocytes co-culture: Novel Prospect for cultured meat production techniques

Cultured meat, an emerging meat production technology, has reduced environmental burden as well as provide healthier and more sustainable method of meat culture. Fat in cultured meat is essential for enhancing texture, taste, and tenderness. However, current cultured meat production method is limited to single-cell type. To meet the consumer demands for cultured meat products, it is crucial to develop new methods for producing cultured meat products that contain both muscle and fat. In this study, cell viability and differentiation were promoted by controlling the ratio and cultivation conditions of myocytes and adipocytes. The total digestibility of cultured meat exceeded 37%, higher than that of beef (34.7%). Additionally, the texture, appearance, and taste of the co-cultured meat were improved. Collectively, this research has great promise for preparing rich-nutritious and digestion cultured meat.

Spectroscopy-based analysis of the effect of Maillard reaction products on oxidative stability of carp myoglobin

As a pro-oxidant, myoglobin (Mb) can induce lipid oxidation in meat. In this study, Fourier-transform infrared spectroscopy (FTIR), circular dichroism (CD), fluorescence spectroscopy, UV-vis spectrophotometry, and fluorescence microscopy were used to evaluate the impact of Maillard reaction products (MRPs) formed from glucose and lysine on the oxidative stability of carp Mb. MRPs were found to inhibit the auto-oxidation of Mb, reducing MetMb production by 8.45%. The static quenching of fluorescence indicated that MRPs interacted with Mb through hydrogen bonding and van der Waals forces, thereby enhancing the α-helical content by 11.57% and reducing the random coil content by 2.72%. The enhanced stability of this advanced structure helps to minimize the exposure of amino acid in the side chain and prevent the formation of MetMb. Fluorescence microscopy showed that MRPs reduce porphyrin ring degradation, consequently decreasing heme iron release. It is evident that MRPs play a crucial role in maintaining Mb structure stability and inhibiting its oxidation.

Preparation of high internal phase emulsions based on high-temperature glycation-modified egg white protein: Structural characteristics, stability, and β-carotene bioavailability under multi-parameter regulation

In recent years, freeze-thaw stability of high internal phase emulsions (HIPEs) has gained increasing attention. High-temperature glycosylation-modified proteins have shown to produce stable HIPEs. This study examines the effects of high-temperature glycosylation on egg white protein (EWP) and fructo-oligosaccharides (FO), focusing on how pH and EWP/FO ratios affect the structure of glycosylated EWPs (GEWPs) and HIPEs stability. Specifically, strong alkaline conditions promoted the glycosylation reaction, with the highest DG value at pH 11.0. At pH 5.0, close to the isoelectric point of EWP, GEWPs could not successfully stabilize HIPEs. However, they stabilized HIPEs under other pH conditions, with the best freeze-thaw stability and flocculation resistance when EWP ≥ FO. At pH 3.0, HIPEs had high viscosity and storage modulus, but phase transitions occurred after freeze-thaw when EWP ≤ FO. GEWPs-stabilized HIPEs formed gel structures with elastic properties upon thermal induction. Encapsulation experiments with β-carotene demonstrated that HIPEs prepared from GEWPs showed potential in DPPH and ABTS+ radical scavenging, improving β-carotene stability and bioavailability. Our findings show that GEWPs-stabilized HIPEs offer excellent stability, rheological properties, and carrier performance, with enhanced applications through optimized emulsifiers and preparation processes.

Effect of ultra-high pressure heat-assisted technology combined with L-cysteine on the color of ready-to-eat shrimp during storage

This study used ultra-high pressure processing (HPP) heat-assisted technology combined with L-cysteine (L-cys) to process ready-to-eat (RTE) shrimp. Subsequently, the effects of physical field and chemical modifications on the color of RTE shrimp were studied. The results showed that the RTE shrimp treated with HPP-Heat-L-cys showed better performance in terms of brightness value (65.25) and astaxanthin (AST) content (0.71 μg/g) during storage, maintaining the original color of RTE shrimp effectively. In addition, it was observed that the application of HPP-Heat-L-cys significantly delayed phenol oxidation, lipid oxidation, and Maillard reaction compared with traditional HPP or heat treatments. Specifically, the total phenolic content of RTE shrimp treated with HPP-Heat-L-cys was higher than that of other samples, but the TBARS and browning index were lower. Furthermore, HPP-Heat-L-cys could delay the production of dark products (such as 2-methylanthraquinone, p-benzoquinone, lipofuscin and melanin), ultimately safeguarding the color stability of RTE shrimp during storage.

Glycation of sunnhemp protein with dextran via dry heating: Thermal, micro-structural characterization, and amino acid profiling

This study aims to obtain sunnhemp protein isolate (SHPI) and dextran conjugates by dry heating method of Maillard conjugation. The effects of different incubation time (0, 1, 3, 5, 7, and 9 days) on the molecular flexibility, available lysine content, antioxidant properties, molecular structure, and thermal and micro-structural properties of conjugates were compared with SHPI (no conjugation) at 60°C and 79% relative humidity. The results indicated the formation of SHPI-dextran conjugates as confirmed by the change in molecular flexibility, lysine content, antioxidant activities, color, and water activity values. The molecular structure revealed the confirmation of covalent bonding between SHPI and dextran. Differential scanning calorimetry and thermo-gravimetric analysis results exhibited improvement in the thermal stability of SHPI when conjugated with dextran. The microstructural characterization showed that Maillard conjugation changed the surface structure of SHPI. The analysis of amino acid composition displayed that lysine, arginine, and phenylalanine were the dominant Maillard reaction sites of SHPI and dextran. Among all the conjugated samples, 5 days of incubation time was selected as an optimum condition for the development of SHPI-dextran conjugates on the basis of the aforementioned characterization. Overall, it was concluded that Maillard conjugation of sunnhemp protein with dextran via dry-heating technique could modify and improve its various attributes. PRACTICAL APPLICATION: The conjugation of plant proteins with polysaccharide through the Maillard reaction under dry heating conditions represents a natural and green technique for improving the techno-functional properties of proteins. The study has the potential to establish framework for the utilization of Sunnhemp protein isolate-dextran conjugates. This approach offers the potential for cost-effective production of emulsifiers and development of effective encapsulating matrices. The investigation expands on an underutilized plant protein source facilitating an alternative to animal-based proteins and contributing to the development of a sustainable circular bioeconomy.

Assessment of the Stability and Nutritional Quality of Hemp Oil and Pumpkin Seed Oil Blends

This study characterized the quality of hemp oil (HO) and pumpkin seed oil (PO) and their blends before and after 2 and 4 months of storage at refrigerated and room temperature, without access to light and oxygen. The analyses included determining the acid value, peroxide value, fatty acid (FA) composition, and FA distribution in triacylglycerol (TAG) molecules. Pressure differential scanning calorimetry (PDSC) was used to assess the oxidative stability of oils and their blends. This study also evaluated the nutritional potential of hemp oil and pumpkin seed oil blends, as atherogenicity, thrombogenicity, and health-promoting indices and hypocholesterolaemic/hypercholesterolaemic ratio were calculated. The tested samples differed in properties depending on the storage time and temperature. The optimal choice was a blend of 50% hemp oil (HO) and 50% pumpkin oil (PO). This mixture demonstrated the desired fatty acid composition, satisfactory acid and peroxide values, and a relatively good oxidation induction time during storage. Despite the unfavorable distribution of FAs in TAG molecules, it was characterized by a balanced ratio of n-3 to n-6 acids. It was also concluded that research on HO and PO mixtures should be continued due to the potential synergistic effect of their bioactive substances.

Cooking Alters the Metabolites of Onions and Their Ability to Protect Nerve Cells from Lead Damage

Onions (Allium cepa L.) are nutritious vegetables; however, variations in processing methods can influence their chemical composition and functional properties. Raw processing and cooking are the two main food-processing methods for onions, but it is not clear what kind of changes these two methods cause. In the present study, ultrahigh-resolution liquid chromatography-mass spectrometry (UHPLC-MS) was utilized to observe the changes in onion composition during cooking and to investigate the protective effects of raw and cooked onion extracts against lead damage in vitro and at the cellular level. Many compounds were identified, including amino acids, nucleosides, flavonoids, and organosulfur compounds. Cooking causes changes in the content of numerous amino acids (e.g., DL-glutamine) in onions and increases nucleoside content (e.g., 5'-S-methyl-5'-thioadenosine, adenine). Both raw and cooked onion extracts can reduce neuronal cell damage caused by lead exposure, but cooking increased the free radical scavenging (e.g., DPPH, ABTS, hydroxyl radicals) and chelating of lead ions (up to about 25%) of the onion extracts. In conclusion, cooking can cause changes in the chemical composition of onions and increase their antioxidant and lead chelating capacity.

Impact of Thermophysical and Biological Pretreatments on Antioxidant Properties and Phenolic Profile of Broccoli Stem Products

Fruit and vegetable industrialisation is a major contributor to food waste; thus, its integral transformation into functional powders has gained attention. Pretreatments can be incorporated into valorisation processes to generate structural or biochemical changes that improve powders' characteristics. This study deepens into the impact of biological (fermentation, FERM) and thermophysical (autoclaving, AUTO; microwaves, MW; ultrasound, US; and pasteurisation, PAST) pretreatments, combined with dehydration (hot air-drying, HAD; or freeze-drying, FD) on the characteristics of powdered products obtained from broccoli stems. The impact of pretreatments on physicochemical (moisture, water activity, total soluble solids) and antioxidant properties (phenols, flavonoids, antioxidant capacity by ABTS and DPPH) on residue and powdered products was studied, together with their impact on plant tissue structure (Cryo-SEM) and the powders' phenolic profile (HPLC). Probiotic viability was also determined on the fermented samples. The pretreatments applied, particularly the ultrasound, improved the antioxidant properties of the broccoli stems compared to the unpretreated samples, in line with microscopic observations. Dehydration did also improve the antioxidant attributes of the broccoli wastes, especially drying at 60 °C. However, pretreatments combined with dehydration did not generally lead to an improvement in the antioxidant properties of the powders. Probiotic properties were preserved in the freeze-dried products (>107 CFU/g). In conclusion, pretreatments may be applied to enhance the antioxidant attributes of broccoli wastes, but not necessarily that of dried powdered products.

Maillard reaction products inhibit lipid oxidation by regulating myoglobin stability in washed muscle model

Lipid oxidation significantly contributes to muscle deterioration, with heme protein oxidation playing a crucial role in this process. This study investigated the inhibition of heme protein oxidation by Maillard reaction products (MRPs) using a washed muscle model combining washed carp with myoglobin (Mb). Protein oxidation products, protein texture, and lipid oxidation levels were assessed. Results showed that metmyoglobin (MetMb) is a primary driver of lipid oxidation in meat, likely due to Mb oxidation, exposing hydrophobic groups that bind to lipids. MRPs at concentrations of 0.5% and 1% effectively inhibited Mb oxidation. Specifically, treatment with 1% MRPs reduced MetMb formation by 15.38%, protein carbonyl content by 6.53%, hydroxyl radical content by 20.37%, protein aggregation by 40.81%, and particle size by 36.95% during later storage stages, thereby preserving Mb stability. In the Mb-mediated oxidation model, 1% MRPs inhibited the formation of primary and secondary oxidative metabolites by 59.47% and 68.19%, respectively, while maintaining muscle tissue texture integrity. PRACTICAL APPLICATION: The antioxidation of Maillard reaction products (MRPs) improves the stability of common carp. By inhibiting the autoxidation of myoglobin and lipid, MRPs help preserve the texture and color of fish muscle while extending its shelf life. This study provides a valuable reference for effectively controlling lipid oxidation in refrigerated fish products and enhancing their overall quality.

Comparison of characterization and composition of melanoidins from three different dried apple slices

The composition of melanoidins in dried apple that affects quality remains unclear. The composition and structure of melanoidins in dried apple slices by hot air drying (HAAM), instant controlled pressure drop drying (DICAM), and vacuum freeze-drying (FDAM) were investigated. It showed that the melanoidins were highly heterogeneous mixtures with a light-yellow color and blue-green fluorescence, belonging to polysaccharide-type melanoidins. Specifically, HAAM had a large molecular weight (929.5 g/mol) and wide molecular weight distribution, with more double-bond conjugated systems. DICAM (610.9 g/mol), possessing the strongest fluorescence intensity, was mainly composed of compounds with fewer π-conjugated structures and more electron-donating groups. As a control, the low level of Maillard reaction in FDAM resulted in the formation of the smallest molecular weight (458.6 g/mol) with weak fluorescence intensity. Moreover, 10 compounds were tentatively identified in apple melanoidins. This study provides the foundation for the future functional preparation of apple melanoidins.

Screening of Antioxidant Maillard Reaction Products Using HPLC-HRMS and Study of Reaction Conditions for Their Production as Food Preservatives

The Maillard reaction (MR) involves interactions between reducing sugars and amino acids or proteins during heating, producing Maillard reaction products (MRPs) that influence food flavour, aroma, and colour. Some MRPs exhibit antioxidant properties, prompting interest in their potential as natural food preservatives. This study aimed to develop a method for detecting and identifying antioxidant MRPs using high-pressure liquid chromatography (HPLC) coupled with high-resolution mass spectrometry (HRMS). By improving chromatographic conditions, the separation of antioxidant MRPs was optimised using known antioxidant MRPs as reference signals. This work also examined the effects of pH, reaction time, and different sugar-amino acid combinations on the production and composition of antioxidant MRPs. Results indicated that neutral to basic pH facilitated faster reactions, with pH 7 selected as optimal. A library of 50 m/z signals for potential antioxidant MRPs was created, and the best combinations of amino acids and sugars for their production were identified. These findings pave the way for more precise analyses of antioxidant MRPs, with future research focusing on isolating and characterising specific MRPs to understand their structures and mechanisms, ultimately contributing to the development of functional foods with natural antioxidant properties.

Glucose addition and oven-heating of pork stimulate glycoxidation and protein carbonylation, while reducing lipid oxidation during simulated gastrointestinal digestion

In the present study, it was investigated if glucose addition (3 or 5%) to pork stimulates glycoxidation (pentosidine, PEN), glycation (Maillard reaction products, MRP), lipid oxidation (4-hydroxy-2-nonenal, 4-HNE; hexanal, HEX; thiobarbituric acid reactive substances, TBARS), and protein oxidation (protein carbonyl compounds, PCC) during various heating conditions and subsequent in vitro gastrointestinal digestion. An increase in protein-bound PEN level was observed during meat digestion, which was significantly stimulated by glucose addition (up to 3.3-fold) and longer oven-heating time (up to 2.5-fold) of the meat. These changes were accompanied by the distinct formation of MRP during heating and digestion of the meats. Remarkably, stimulated glyc(oxid)ation was accompanied by increased protein oxidation, whereas lipid oxidation was decreased, indicating these reactions are interrelated during gastrointestinal digestion of meat. Glucose addition generally didn't affect these oxidative reactions when pork was packed preventing air exposure and oven-heated until a core temperature of 75 °C was reached.

Mechanochemistry in Glycation Research

Mechanochemistry by milling has recently attracted considerable interest for its ability to drive solvent-free chemical transformations exclusively through mechanical energy and at ambient temperatures. Despite its popularity and expanding applications in different fields of chemistry, its impact on Food Science remains limited. This review aims to demonstrate the specific benefits that mechanochemistry can provide in performing controlled glycation, and in "activating" sugar and amino acid mixtures, thereby allowing for continued generation of colors and aromas even after termination of milling. The generated mechanical energy can be tuned under specific conditions either to form only the corresponding Schiff bases and Amadori compounds or to generate their degradation products, as a function of the frequency of the oscillations in combination with the reactivity of the selected substrates. Similarly, its ability to initiate the Strecker degradation and generate pyrazines and Strecker aldehydes was also demonstrated when proteogenic amino acids were milled with glyoxal.

Conversion of gingerols to shogaols in ginger (Zingiber officinale roscoe) by puffing

Effect of puffing on conversion of gingerols to shogaols, physicochemical properties as well as antioxidant and anti-inflammatory activities of puffed ginger was investigated. Puffing significantly increased extraction yield and the highest value was 12.52% at 980 kPa. The significant decrease in gingerols and increase in shogaols were occurred after puffing, respectively. Especially, 6-shogaol was dramatically increased from 4.84 to 99.10 mg/g dried ginger. Puffed ginger exhibited the higher antioxidant activities (analyzed by DPPH, ABTS, TPC, and TFC) than those of control, and they were significantly increased with increasing puffing pressure. In case of anti-inflammatory activity, puffed ginger did not inhibit NO production, but significantly inhibited TNF-α and IL-6 productions. Among gingerols and shogaols, 6-shogaol showed significantly strong correlations with both antioxidant and anti-inflammatory activities. Consequently, puffed ginger can be applied to functional food industry, which dramatically increased the contents of 6, 8, 10-shogaols, the main bioactive compounds in ginger.

Development and standardization of spectrophotometric assay for quantification of thermal hydrolysis-origin melanoidins and its implication in antioxidant activity evaluation

Melanoidins are brown recalcitrant polymers originating from the thermal hydrolysis pretreatment (THP) of organic solid waste (OSW). Owing to their various formation pathways and complex structures, there is currently no reliable method to quantify melanoidins. In this study, a spectrophotometric method was developed to determine melanoidins concentration in different OSW. Three typical model Maillard reaction systems (glucose-glycine, glucose/fructose-20 amino acids, and dextran-bovine serum albumin) were used to acquire the characteristic peaks and establish standard curves. The results showed that a standard curve using glucose/fructose-20 amino acids model melanoidins at 280 nm was the optimal quantification method, because it had the best correlation with the physicochemical indicators of melanoidins and semi-quantification results calculated by excitation-emission matrix fluorescence. In addition, the applicability of the proposed method was evaluated using multiple real melanoidins samples extracted from thermally pretreated OSW under different THP conditions and food-derived melanoidins as well, demonstrating its validity and advantages. This study is the first to provide a simple, effective, and accurate method for quantifying THP-origin melanoidins from different sources. Remarkably, as a specific and important application scenario, the proposed quantification method was employed to investigate the concentration dependence of melanoidins antioxidation in thermally pretreated OSW.

Structural and functional properties of whey protein isolate-inulin conjugates prepared with ultrasound or wet heating method

BACKGROUND

Whey protein isolate (WPI) generally represents poor functional properties such as thermal stability, emulsifying activity and antioxidant activity near its isoelectric point or high temperatures, which limit its application in the food industry. The preparation of WPI-polysaccharide covalent conjugates based on Maillard reaction is a promising method to improve the physical and chemical stability and functional properties of WPI. In this research, WPI-inulin conjugates were prepared through wet heating method and ultrasound method and their structural and functional properties were examined.

RESULTS

In conjugates, the free amino acid content was reduced, the high molecular bands were emerged at sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), new C-N bonds were formed in Fourier-transform infrared (FTIR) spectroscopy, and fluorescence intensity was reduced compared with WPI. Furthermore, the result of circular dichroism (CD) spectroscopy also showed that the secondary structure of conjugates was changed. Conjugates with ultrasound treatment had better structural properties compared with those prepared by wet heating treatment. The functional properties such as thermal stability, emulsifying activity index (EAI), emulsion stability (ES) and antioxidant activity of conjugates with wet heating treatment were significantly improved compared with WPI. The EAI and ES of conjugates with ultrasound treatment were the highest, but the thermal stability and antioxidant activity were only close to that of the conjugates with wet heating treatment for 2 h.

CONCLUSION

This study revealed that WPI-inulin conjugates prepared with ultrasound or wet heating method not only changed the structural characteristics of WPI but also could promote its functional properties including thermal stability, EAI, ES and antioxidant activity. © 2024 Society of Chemical Industry.

Comparison evaluation pretreatments on the quality characteristics, oxidative stability, and volatile flavor of walnut oil

In this study, we applied various thermal pretreatment methods (e.g., hot-air, microwave, and stir-frying) to process walnut kernels, and conducted comparative analysis of the physicochemical properties, nutritional components, in vitro antioxidant activity, and flavor substances of the extracted walnut oil (WO). The results indicated that, thermal pretreatment significantly increased the extraction of total trace nutrients (e.g., total phenols, tocopherols, and phytosterols) in WO. The WO produced using microwave had 2316.71 mg/kg of total trace nutrients, closely followed by the stir-frying method, which yielded an 11.22% increase compared to the untreated method. The WO obtained by the microwave method had a higher Oxidative inductance period (4.05 h) and oil yield (2.48%). After analyzing the flavor in WO, we found that aldehydes accounted for 28.77% of the 73 of volatile compounds and 58.12% of the total flavor compound content in microwave-pretreated WO, these percentages were higher than those recorded by using other methods. Based on the comprehensive score obtained by the PCA, microwave-pretreatment might be a promising strategy to improve the quality of WO based on aromatic characteristics.

The Interplay between Endogenous and Foodborne Pro-Oxidants and Antioxidants in Shaping Redox Homeostasis

Oxidative stress has been known about in biological sciences for several decades; however, the understanding of this concept has evolved greatly since its foundation. Over the past years, reactive oxygen species, once viewed as solely deleterious, have become recognized as intrinsic components of life. In contrast, antioxidants, initially believed to be cure-all remedies, have failed to prove their efficacy in clinical trials. Fortunately, research on the health-promoting properties of antioxidants has been ongoing. Subsequent years showed that the former assumption that all antioxidants acted similarly was greatly oversimplified. Redox-active compounds differ in their chemical structures, electrochemical properties, mechanisms of action, and bioavailability; therefore, their efficacy in protecting against oxidative stress also varies. In this review, we discuss the changing perception of oxidative stress and its sources, emphasizing everyday-life exposures, particularly those of dietary origin. Finally, we posit that a better understanding of the physicochemical properties and biological outcomes of antioxidants is crucial to fully utilize their beneficial impact on health.

The Maillard reactions: Pathways, consequences, and control

The century old Maillard reactions continue to draw the interest of researchers in the fields of Food Science and Technology, and Health and Medical Sciences. This chapter seeks to simplify and update this highly complicated, multifaceted topic. The simple nucleophilic attack of an amine onto a carbonyl group gives rise to a series of parallel and subsequent reactions, occurring simultaneously, resulting into a vast array of low and high mass compounds. Recent research has focused on: (1) the formation and transformation of α-dicarbonyl compounds, highly reactive intermediates which are essential in the development of the desired color and flavor of foods, but also lead to the production of the detrimental advanced glycation end products (AGEs); (2) elucidation of the structures of melanoidins in different foods and their beneficial effects on human health; and (3) harmful effects of AGEs on human health. Considering that MRs have both positive and negative consequences, their control to accentuate the former and to mitigate the latter, is also being conscientiously investigated with the use of modern techniques and technology.

Air-Assisted Electrospinning of Dihydromyricetin-Loaded Dextran/Zein/Xylose Nanofibers and Effects of the Maillard Reaction on Fiber Properties

Dihydromyricetin (DMY) has been encapsulated in delivery systems to address the solubility limitations of DMY in water and improve its bioavailability. Air-assisted electrospinning has been used as a novel technology to load DMY. To evaluate the impact of adding DMY to dextran/zein nanofibers and understand the effects of the Maillard reaction (MR) on the physical and functional properties of DMY-loaded nanofibers, dextran/zein/xylose nanofibers with 0%, 1%, 2%, 3%, and 4% DMY were fabricated, followed by MR crosslinking. Scanning electron microscopy (SEM) observations indicated that the addition of DMY and the MR did not affect the morphology of the nanofibers. X-ray diffraction (XRD) results indicated amorphous dispersion of DMY within the nanofibers and a decreased crystalline structure within the nanofibers following the MR, which might improve their molecular flexibility. The nanofibrous film formed after the MR exhibited both increased tensile strength and elastic modulus due to hydrogen bonding within the nanofibers and increased elongation at break attributed to the increased amorphization of the structure after crosslinking. The nanofibers were also found to exhibit improved heat stability after the MR. The antioxidant activity of the nanofibers indicated a dose-dependent effect of DMY on radical scavenging activity and reducing power. The maintenance of antioxidant activity of the nanofibers after the MR suggested heat stability of DMY during heat treatment. Overall, dextran/zein nanofibers with various DMY contents exhibited tunable physical properties and effective antioxidant activities, indicating that dextran/zein nanofibers offer a successful DMY delivery system, which can be further applied as an active package.

The potential meat flavoring derived from Maillard reaction products of rice protein isolate hydrolysate-xylose via the regulation of temperature and cysteine

Maillard reaction products (MRPs) derived from rice protein isolate hydrolysate and D-xylose, with or without L-cysteine, were developed as a potential meat flavoring. The combined impact of temperature (80-140 °C) and cysteine on fundamental physicochemical characteristics, antioxidant activity, and flavor of MRPs were investigated through assessments of pH, color, UV-visible spectra, fluorescence spectra, free amino acids, volatile compounds, E-nose, E-tongue, and sensory evaluation. Results suggested that increasing temperature would reduce pH, deepen color, promote volatile compounds formation, and reduce the overall umami and bitterness. Cysteine addition contributed to the color inhibition, enhancement of DPPH radical-scavenging activity and reducing power, improvement in mouthfulness and continuity, reduction of bitterness, and the formation of sulfur compounds responsible for meaty flavor. Overall, MRPs prepared at 120 °C with cysteine addition could be utilized as a potential meat flavoring with the highest antioxidant activity and relatively high mouthfulness, continuity, umami, meaty aroma, and relatively low bitterness.

The interaction between lipid oxidation and the Maillard reaction model of lysine-glucose on aroma formation in fragrant sesame oil

The formation mechanism behind the sophisticated aromas of sesame oil (SO) has not been elucidated. The interaction effects of the Maillard reaction (MR) and lipid oxidation on the aroma formation of fragrant sesame oil were investigated in model reaction systems made of l-lysine (Lys) and d-glucose (Glc) with or without fresh SO (FSO) or oxidized SO (OSO). The addition of OSO to the Lys-Glc model increased the MR browning at 294 nm and 420 nm and enhanced the DPPH radical scavenging activity greater than the addition of FSO (p < 0.05). The presence of lysine and glucose inhibited the oxidation of sesame oil, reduced the loss of γ-tocopherol, and facilitated the formation of sesamol (p < 0.05). The Maillard-lipid interaction led to the increased concentrations of some of the alkylpyrazines, alkylfurans, and MR-derived ketones and acids (p < 0.05) while reducing the concentrations of other pyrazines, lipid-derived furans, aliphatic aldehydes, ketones, alcohols, and acids (p < 0.05). The addition of FSO to the MR model enhanced the characteristic roasted, nutty, sweet, and fatty aromas in sesame oil (p < 0.05), while excessive lipid oxidation (OSO) brought about an unpleasant oxidized odor and reduced the characteristic aromas. This study helps to understand the sophisticated aroma formation mechanism in sesame oil and provides scientific instruction for precise flavor control in the production of sesame oil.