Melanoidins produced by the Maillard reaction: Structure and biological activity

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.

Application of scoby bacterial cellulose as hydrocolloids on physicochemical, textural and sensory characteristics of mango jam

BACKGROUND

The scoby pellicle of symbiotic culture of bacteria and yeast is a by-product from kombucha fermentation. While a portion is used as starter culture, the remainder is often discarded, yet it can be a valuable source of bacterial cellulose.

RESULTS

Scoby from black, green and oolong tea kombucha fermentation was assessed for its hydrocolloid effects in mango jam-making through evaluation of physicochemical, textural and sensory characteristics. Quality of jam was significantly improved with water activity reduction up to 22.22% to 0.679, moisture content reduction up to 37.06% to 19.92%, and a pH drop up to 5.9% to 3.19 with the use of 20 to 100 g kg-1 scoby. In colour analysis, presence of scoby led to a brighter jam due to higherL * $$ {L}^{\ast } $$ values from 30.98 to a range of 31.82 to 40.83. Texture of jam with scoby gave higher gel strength and adhesiveness, with the most prominent effects from the black tea kombucha. Overall acceptability in sensory test scoring was above 70% on a nine-point hedonic scale with the 40 g kg-1 green tea kombucha scoby jam chosen as the most preferred.

CONCLUSION

Scoby gave significant contributions to jam stability, appearance and texture, showing potential as a clean-label food ingredient. © 2024 Society of Chemical Industry.

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.

Lipidomics and metabolomics reveal the molecular mechanisms underlying the effect of thermal treatment on composition and oxidative stability of walnut oil

Roasting walnut kernel significantly improves the oxidative stability and sensory properties of its oil. However, the effect of roasting temperatures on the molecular change of main components and micronutrients in walnut oil is still unclear. Herein, lipidomics and metabolomics were integrated to comprehensively profile the walnut oil obtained at different roasting temperatures (30 °C, 120 °C, 140 °C, 160 °C, and 180 °C). Lipidomics showed that the content of glycerolipids, sphingolipids, and glycerophospholipids decreased with roasting temperatures, while the oxidized fatty acids and triglycerides increased. Ratios of linoleic acid and linolenic acid varied with roasting temperatures and were most close to 4-6:1 at 140 °C, 160 °C, and 180 °C. Major classes of micronutrients showed a tendency to increase at the roasting temperature of 120 °C and 140 °C, then decrease at 160 °C and 180 °C. Liposoluble amino acids identified for the first time in walnut oil varied with roasting temperatures. Correlation analysis demonstrated that the higher contents of liposoluble amino acids and phenolics are positively associated with enhanced oxidative stability of walnut oil obtained at 140 °C. Furthermore, glutamine and 5-oxo-D-proline were expected to be potential biomarkers to differentiate the fresh and roasted walnut oil. The study is expected to provide new insight into the change mechanism of both major lipids and micronutrients in walnut oil during the roasting process.

Study of humic-like substances of dissolved organic matter using size exclusion chromatography and chemometrics

The study of dissolved organic matter (DOM) presents a significant challenge for environmental analyses and the monitoring of wastewater treatment plants (WWTPs). This is particularly true for the tracking of recalcitrant to biodegradation dissolved organic matter (rDOM) compounds, which is generated during the thermal pretreatment of sludge. This study aims to develop analytical and chemometric methods to differentiate melanoidins from humic acids (HAs), two components of rDOM that require monitoring at various stages of wastewater treatment processes due to their distinct biological effects. The developed method implements the separation of macromolecules through ultra-high-performance liquid chromatography size-exclusion chromatography (U-HPLC SEC) followed by online UV and fluorescence detection. UV detection was performed at 210, 254, and 280 nm, and fluorescence detection at six excitation/emission pairs: 230/355 nm, 270/355 nm, 240/440 nm, 270/500 nm, 330/425 nm, and 390/500 nm. Chromatograms obtained for each sample from these nine detection modes were integrated and separated into four molecular fractions: >40 kDa, 20-40 kDa, 10-20 kDa, and <10 kDa. To enhance analytical resolution and normalize the data, ratios were calculated from the areas of chromatographic peaks obtained for each detection mode. The results demonstrate the utility of these ratios in discriminating samples composed of HAs, melanoidins, and their mixtures, through principal component analysis (PCA). Low molecular weight fractions were found to be specific to melanoidins, while high molecular weight fractions were characteristic of HAs. For the detection modes specific to melanoidins, UV absorbance at 210, 254, and 280 nm were predominantly present in the numerators, with tryptophan-like fluorescence emissions in the denominators. Conversely, fluorescence emissions largely represented both numerators and denominators for HAs. This online method also enables the discrimination of pseudo-melanoidins, compounds revealing a nitrogen deficiency in their chemical structures.

Exploring Maillard reaction markers and melanoidins to investigate toxicological and antioxidant profiles of optimized expanded snacks from corn/common bean mixtures

BACKGROUND

Extrusion cooking of cereal-legume flour mixture is an innovative strategy to introduce nutrient-enriched ready-to-eat snacks to the market. However, this thermal process triggers the formation of compounds that could impact safety aspects of these products. Maillard reaction markers and the end products known as melanoidins were evaluated to assess the toxicological and bioactive profiles of extruded snacks from corn-plus-common-bean-flour combinations. Different molecular weight fractions were isolated and purified to analyze their antioxidant activity and to investigate the role of melanoidins.

RESULTS

The snack formulated with an 84:16 ratio of corn:common bean flours exhibited an enhanced toxicological profile. It displayed the lowest levels of acrylamide and furanic compounds, along with reduced blockage of lysine residues in the protein. Extrusion increased the antioxidant activity of uncooked flours (30 to 64%) and total phenolic compounds (26 to 50%), and decreased the available lysine (-72.7 to -79.5%). During the fractionation process, it was established that compounds within the range of 3-10 kDa made the greatest contribution to antioxidant activity. The fraction greater than 10 kDa, which included melanoidins, displayed 7 to 33% lower antioxidant activity. The purification of the fraction greater than 10 kDa revealed that pure melanoidins represented approximately one-third of the antioxidant activity in that fraction. Non-covalent adducts linked to the melanoidin core therefore had a relevant role in the antioxidant action of formulated snacks.

CONCLUSION

This investigation illustrates the importance of considering both potential risks and associated benefits of compounds formed during the Maillard reaction while developing new extruded snacks. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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.

Effects of the physical structure and surface charge of activated carbon on the reduction of biogenic amines in anchovy fish sauce

This study aimed to efficiently reduce a large number of biogenic amines in salt-fermented fish sauce while minimizing sensory reduction using various activated carbons. Aromatic amines, such as tryptamine and phenethylamine, were reduced by 86.1-100 % after treating with activated carbon. Histamine with a heterocyclic structure decreased by 13-42 %. No significant effects were observed on the levels of aliphatic amines, putrescine, cadaverine, spermine, and spermidine. The major taste component, amino acid nitrogen, was reduced to within 3 %, and brown color removal was reduced depending on the type of activated carbon used. Acid-modified AC-A and AC-B had rough surfaces, high total acidity, low point of zero charge (pHpzc), and rich surface functional groups. Owing to its smooth surface, low total acidity, high pHpzc, and few surface functional groups, AC-C exhibited a higher histamine elimination and less color reduction despite its lower surface area compared to other activated carbons.

Structure, spectral properties and antioxidant activity of melanoidins extracted from high temperature sterilized lotus rhizome juice

Melanoidins are complex macromolecular compounds closely associated with the browning phenomenon in high-temperature sterilized lotus rhizome juice (HTSL). This study aimed to preliminarily investigate the structural properties of melanoidins extracted from HTSL. Results showed that the average molecular weight of HTSL melanoidins ranged from 1.48 to 41.40 kDa. Medium and high molecular weight melanoidins were the main contributors to the brown color of HTSL. Sugars, proteins, and phenolics were present in HTSL, among which sugar was the most abundant, with glucose being the predominant monosaccharide in acid degradation products of melanoidins. Through fluorescence and ultraviolet spectral analysis, we found that the melanoidins contained carboxyl and carbonyl compounds, as well as furan and pyran heterocyclic compounds. The infrared spectra and nuclear magnetic resonance spectra revealed a prominent sugar absorption peak, indicating that sugar was the main component of the melanoidins of HTSL. Furthermore, in vitro antioxidant experiments showed that the antioxidant activity of melanoidins was significantly positively correlated with phenolic compounds. Our results indicated that there were differences in the structural properties of melanoidins fractions with different molecular weights. MW-H fraction significantly impacted the color and antioxidant activity of HTSL.

Exploring the formation pathway and antioxidant properties of the sugar-smoking pigment 5-GGMF

The present study aimed to elucidate the pathway of pigment formation and identify the source of antioxidant activity during sugar smoking. Building upon previous research, this investigation replicated the sucrose cleavage process involved in sugar-smoking through model reactions to obtain distinct model reaction products. The products were analyzed using various techniques such as ultraviolet-visible spectrometry, Fourier-transform infrared spectroscopy, high-performance liquid chromatography, and high-performance liquid chromatography-tandem mass spectrometry. The findings revealed that the pyrolysis of sucrose at 330 °C yielded glucose and fructose, with fructose pyrolysis producing significantly more 5-HMF than glucose. Moreover, the antioxidant capacity of 5-HMF was found to make a substantial contribution. The primary source of 5-HMF was identified as fructose resulting from the cleavage of sucrose at 330 °C, while the primary pathway for the formation of the sugar-smoking pigment 5-GGMF was attributed to the intermolecular dehydration of 5-HMF and glucose at 150 °C.

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

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

Effect of brewer's spent grain melanoidins on maillard reaction products during storage of whey protein model systems

Maillard reaction readily takes place in dairy products because of the association between thermal treatments, extended storage and the matrix composition. Along with the impairment of protein digestion, the formation of glycation and α-dicarbonyl compounds is a concern for quality attributes of whey proteins when used as ingredients. In this paper, we outline the capacity of brewer's spent grain melanoidins in reducing the accumulation of α-dicarbonyl compounds, thus controlling the formation of dietary advanced glycation end-products in accelerated shelf life at 35 °C. Results revealed that brewer's spent grain melanoidins targeted methylglyoxal and glyoxal reactivity leading to the reduction of N-ε-carboxymethyllysine and methylglyoxal-hydroimidazolone up to 27 and 60%, respectively. We here describe that the presence of melanoidins is instrumental in limiting the undesired effects of α-dicarbonyl compounds on whey proteins.

Effect of total solids content on anaerobic digestion of waste activated sludge enhanced by high-temperature thermal hydrolysis

Total solids (TS) content may provide a regulatory strategy for optimizing anaerobic digestion enhanced by high-temperature thermal hydrolysis, but the role of TS content is not yet clear. In this study, the effect of TS content on the high-temperature thermal hydrolysis and anaerobic digestion of sludge and its mechanism were investigated. The results showed that increasing the TS content from 2% to 8% increased the sludge solubility and methane production potential, reaching peak values of 26.6% and 336 ± 6 mL/g volatile solids (VS), respectively. With a further increase in TS content to 12%, the strong Maillard reaction increased the aromaticity and structural stability of extracellular polymer substances, decreasing sludge solubility to 18.6%. Furthermore, the decrease in sludge biodegradability and the formation of inhibitory by-products resulted in a reduction in methane production to 272 ± 4 mL/g VS. This article provides a new perspective to understand the role of TS content in the thermal hydrolysis of sludge and a novel approach to regulate the Maillard reaction.

Melanoidin-like carbohydrate-containing macromolecules from Shanxi aged vinegar exert immunoenhancing effects on macrophage RAW264.7 cells

Bioactive macromolecule mining is important for the functional chemome analysis of traditional Chinese vinegar. In this study, we isolated and characterized carbohydrate-containing macromolecules from Shanxi aged vinegar (CCMSAV) and evaluated their immunomodulatory activity. The isolation process involved ethanol precipitation, deproteinization, decolorization, and DEAE-650 M column chromatography, resulting in the acquisition of four sub-fractions. All sub-fractions exhibited a molecular weight range of 6.92 to 16.71 kDa and were composed of 10 types of monosaccharides. Comparative analysis of these sub-fractions with two melanoidins exhibited similarities in elemental composition, spectral signature, and pyrolytic characteristics. Immunological assays confirmed the significantly enhanced cell viability, phagocytic activity, and secretion of nitric oxide, tumor necrosis factor (TNF)-α and interleukin (IL)-6 in RAW264.7 cells by all four sub-fractions. Further investigation of the immunomodulatory mechanism revealed that SAV-RP70-X, the most potent purified sub-fraction, enhanced aerobic glycolysis in macrophages and activated Toll-like receptor 2 (TLR2), TLR4, mannose receptor (MR), scavenger receptor (SR), and the dendritic cell-associated C-type lectin-1 receptor (Dectin-1). Furthermore, the activation of macrophages was associated with the MyD88/PI3K/Akt/NF-κB signaling pathway. Methylation analysis revealed that 1,4-Xylp was the most abundant glycosidic linkage in SAV-RP70-X.

Influence of Roasting Temperature on the Detectability of Potentially Allergenic Lupin by SDS-PAGE, ELISAs, LC-MS/MS, and Real-Time PCR

Seeds of "sweet lupins" have been playing an increasing role in the food industry. Lupin proteins may be used for producing a variety of foods, including pasta, bread, cookies, dairy products, and coffee substitutes. In a small percentage of the population, lupin consumption may elicit allergic reactions, either due to primary sensitization to lupin or due to cross-allergy with other legumes. Thus, lupin has to be declared on commercial food products according to EU food regulations. In this study, we investigated the influence of roasting seeds of the L. angustifolius cultivar "Boregine" on the detectability of lupin by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), ELISAs, LC-MS/MS, and real-time PCR. Seeds were roasted by fluidized bed roasting, and samples were drawn at seed surface temperatures ranging from 98 °C to 242 °C. With increasing roasting temperature, the extractability of proteins and DNA decreased. In addition, roasting resulted in lower detectability of lupin proteins by ELISAs and LC-MS/MS and lower detectability of DNA by real-time PCR. Our results suggest reduced allergenicity of roasted lupin seeds used for the production of "lupin coffee"; however, this has to be confirmed in in vivo studies.

Bioactive compounds in coffee and their role in lowering the risk of major public health consequences: A review

This article addresses the bioactive components in coffee aroma, their metabolism, and the mechanism of action in lowering the risk of various potential health problems. The main bioactive components involved in the perceived aroma of coffee and its related health benefits are caffeine, chlorogenic acid (CGA), trigonelline, diterpenes, and melanoids. These compounds are involved in various physiological activities. Caffeine has been shown to have anticancer properties, as well as the ability to prevent the onset and progression of hepatocellular carcinoma and to be anti-inflammatory. CGA exhibits antioxidant action and is implicated in gut health, neurodegenerative disease protection, type 2 diabetes, and cardiovascular disease prevention. Furthermore, together with diterpenes, CGA has been linked to anticancer activity. Trigonelline, on the other side, has been found to lower oxidative stress by increasing antioxidant enzyme activity and scavenging reactive oxygen species. It also prevents the formation of kidney stones. Diterpenes and melanoids possess anti-inflammatory and antioxidant properties, respectively. Consuming three to four cups of filtered coffee per day, depending on an individual's physiological condition and health status, has been linked to a lower risk of several degenerative diseases. Despite their health benefits, excessive coffee intake above the recommended daily dosage, calcium and vitamin D deficiency, and unfiltered coffee consumption all increase the risk of potential health concerns. In conclusion, moderate coffee consumption lowers the risk of different noncommunicable diseases.

Characterization of melanoidins in thermal hydrolysis sludge and effects on dewatering performance

Thermal hydrolysis pretreatment (THP) of sludge can form the refractory brown melanoidins due to the occurrence of the Maillard reaction, which adversely involves the subsequent sludge anaerobic digestion (AD) process. However, details of the generation pattern of melanoidins and how they affect the sludge dewaterability remain largely unknown. This work aims to determine an approach to characterize and quantify the melanoidins created by THP of sludge. On this basis, the effect of melanoidins on sludge dewatering performance was revealed by adding synthetic melanoidins to the mixed sludge. Experimental results showed that three-dimensional fluorescence-region integration (3DEEM-FRI) could effectively distinguish melanoidins from other organic substances and achieve semi-quantitative characterization in sludge. The melanoidins significantly deteriorated the sludge dewaterability, and the lowest solids content of the filter cake (TS) was only 17.78% at the addition of 480 mg (g TS)-1, which was a drop of about 20% compared to the control group. The mechanism investigations indicated that the internal structure of sludge becoming particularly complicated and the opportunities for molecules to collide with each other enlarged because of the contribution of melanoidins, resulting in the increment of the sludge apparent viscosity and consistency coefficient (k), a decline of the flow behavior index (n) and a weakening of flowability. Melanoidins could capture massive water molecules and carry negative charges with the decrease of sludge particle size and zeta potential value, which enhanced the electrostatic repulsion between sludge particles and abated the flocculation ability, thus further aggravating the sludge dewatering performance.

Meat crust as a novel food ingredient to regulate lipid peroxidation and oxidative stress

Pan Fry (PF) is a common heating treatment however, there is limited data on meat oxidation after PF using direct contact with an uncoated iron pan. After PF, a crust is formed, and in this study, we aim to evaluate the potential anti-oxidation and anti-lipid peroxidation capacity of such crust. Ground beef and turkey meat were heat treated using PF or microwave. Lipid peroxidation was evaluated using malondialdehyde accumulation. PF meat generated lower lipid peroxidation levels versus microwave-heated meat. Iron PF has decreased lipid peroxidation versus Teflon pan heating. The crust significantly lowered lipid peroxidation and possessed millard reaction products (MRPs), strong reducing abilities, iodine removal capacity, and some iron chelation capacity. We demonstrated that the crust substantially decreases lipid peroxidation levels in various systems and can be used as a novel seminatural antioxidant ingredient, which may lead to extended shelf life and protects various food products.

Transforming 'Bonito del Norte' Tuna By-Products into Functional Ingredients for Nutritional Enhancement of Cereal-Based Foods

The fishing industry produces a significant number of by-products. This study explored two methods of transforming these by-products: fish protein hydrolysate (FPH) and Fishmeal (FM). Physicochemical characterization of these products was conducted and their potential inclusion in biscuits was investigated due to the lack of high biological value protein and polyunsaturated fatty acids of this product. The results identified colour disparities between FPH and FM, with FM displaying lower brightness and a more reddish hue. In FPH, there was also a noticeable decrease in polyunsaturated fatty acids, probably associated with the temperature reached in spray-drying. While the incorporation of these by-products in biscuits was feasible, there were challenges, particularly the fishy taste and rancid odour, which were more pronounced in FM biscuits due to the higher fat content. This correlated with the oxidation indexes, such as TBARS and acidity index. Nonetheless, FPH biscuit attributes like typical colour or flavour received positive feedback, attributed to the Maillard reaction. Scanning electron microscopy revealed microstructural differences, which correlated with the results of hardness and fracturability, probably due to the higher fat content in FM. This study revealed the possibility of nutritionally enriching cookies with ingredients derived from fish by-products. However, it would be necessary to go a step further and study alternatives that allow better preservation of saturated fatty acids.

Antioxidant activities of thermally treated Sesamum indicum L. leaf extracts and their inhibitory effects against growth and metastatic properties of human colon cancer cells

The study aimed to investigate antioxidant activities of two different thermally treated sesame (Sesamum indicum L.) leaf ethanol extract, steamed sesame leaf extract (SSLE) and roasted sesame leaf extract (RSLE), and their inhibitory effects on uncontrolled growth and increased metastatic properties in human colon cancer cell lines. Both SSLE and RSLE contained pedaliin as the major polyphenol and its aglycon, pedalitin, as a minor component and exhibited radical scavenging activities and ferric reducing antioxidant power. SSLE and RSLE decreased growth of HT29 and HCT116 colon cancer cells, which was attributed to the induction of apoptosis and cell cycle arrest at either G2/M (by SSLE in HCT116) or S phase (by RSLE in HCT116). Furthermore, SSLE and RSLE inhibited migration and adhesion in both cell lines. These results indicate that thermally treated sesame leaves retained pedaliin content and exhibited antioxidant activities and inhibitory activities against the growth and metastatic properties of colon cancer cells.

Physicochemical and functional property of the Maillard reaction products of soy protein isolate with L-arabinose/D-galactose

BACKGROUND

Soy protein isolate (SPI) is widely used in the food industry because of its nutritional and functional properties. During food processing and storage, the interaction with co-existing sugars can cause changes in the structural and functional properties of SPI. In this study, SPI-l-arabinose conjugate (SPI:Ara) and SPI-d-galactose conjugate (SPI:Gal) were prepared using Maillard reaction (MR), and the effects of five-carbon/six-carbon sugars on the structural information and function of SPI were compared.

RESULTS

MR unfolded and stretched the SPI, changing its ordered conformation into disorder. Lysine and arginine of SPI were bonded with the carbonyl group of sugar. The MR between SPI and l-arabinose has a higher degree of glycosylation compared to d-galactose. MR of SPI enhanced its solubility, emulsifying property and foaming property. Compared with SPI:Ara, SPI:Gal exhibited better aforementioned properties. The functionalities of amphiphilic SPI were enhanced by MR, SPI:Gal possessed better hypoglycemic effect, fat binding capacity and bile acid binding ability than SPI:Ara. MR endowed SPI with enhanced biological activities, SPI:Ara showed higher antioxidant activities, and SPI:Gal exhibited stronger antibacterial activities.

CONCLUSION

Our work revealed that l-arabinose/d-galactose exhibited different effects on the structural information of SPI, and further affected its physicochemical and functional property. © 2023 Society of Chemical Industry.

Microwaves affect the formation of volatile compounds in peper powder by changing the nucleophilic addition reactions in Maillard reactions

We explored the effect of microwave heating (MWH) and electric heating (ETH) on the volatile compounds (VCs) of pepper (Capsicum annuum L.). The spectral of the produced melanoidins by baking were used to screen samples with similar baking degrees. Mass spectrometry was used to detect the differences of VCs in samples. The results showed a dose-dependent effect between the intensity of absorption and fluorescence of melanoidins, which can be utilized as indicators for assessment baking degree. MWH samples produced larger variety of VCs than ETH. Changes in the variety and content of VCs infer changes in the flavor of pepper. According to the mechanism of Maillard reaction (MR) and MWH, it was deduced that MWH changes the type of chemical reaction in MR by affecting the distribution of valence electrons in the compounds. Therefore, MWH can be used as a novel method to modify the VCs and flavor of peppers.

Formation, Evolution, and Antioxidant Activity of Melanoidins in Black Garlic under Different Storage Conditions

Melanoidins (MLDs) are formed through the reaction of carbonyl compounds and amino compounds in the Maillard reaction (MR) during the heating or storage of food. In this study, the formation, chemical composition, and structural characteristics of black garlic (BG) MLDs stored at different temperatures (4 °C, 20 °C, and 35 °C) over a period of 6 months were investigated. The initial products of the MR formed more often at 4 °C and 20 °C, while higher temperatures (35 °C) promoted the reaction in the middle and late stages of the MR. The higher temperature promoted an increase in molecular weight and MLD content, which can be attributed to the increase in protein and phenolic content. Elemental analysis confirmed an increase in nitrogen (N) content and the continuous incorporation of nitrogen-rich substances into the skeleton. Amino acids, particularly aspartic acid and threonine, were the primary N-containing compounds involved in MLD formation. Additionally, the infrared analysis revealed that the changes in MLDs during storage were characterized by amide I and amide II groups. The MR enhanced the yields of heterocyclic compounds (from 56.60% to 78.89%), especially that of O-heterocyclic compounds, at the higher temperature according to Py-GC-MS analysis. Furthermore, the higher temperature enhanced the molecular weight, maximum height, and roughness of MLDs compared to the control. The antioxidant ability of MLDs was positively correlated with storage temperatures. In summary, temperature had an impact on the formation, evolution, and antioxidant activity of MLDs.

The potentials and challenges of using fermentation to improve the sensory quality of plant-based meat analogs

Despite the advancements made in improving the quality of plant-based meat substitutes, more work needs to be done to match the texture, appearance, and flavor of real meat. This review aims to cover the sensory quality constraints of plant-based meat analogs and provides fermentation as a sustainable approach to push these boundaries. Plant-based meat analogs have been observed to have weak and soft textural quality, poor mouth feel, an unstable color, and unpleasant and beany flavors in some cases, necessitating the search for efficient novel technologies. A wide range of microorganisms, including bacteria such as Lactobacillus acidophilus and Lactiplantibacillus plantarum, as well as fungi like Fusarium venenatum and Neurospora intermedia, have improved the product texture to mimic fibrous meat structures. Additionally, the chewiness and hardness of the resulting meat analogs have been further improved through the use of Bacillus subtilis. However, excessive fermentation may result in a decrease in the final product's firmness and produce a slimy texture. Similarly, several microbial metabolites can mimic the color and flavor of meat, with some concerns. It appears that fermentation is a promising approach to modulating the sensory profiles of plant-derived meat ingredients without adverse consequences. In addition, the technology of starter cultures can be optimized and introduced as a new strategy to enhance the organoleptic properties of plant-based meat while still meeting the needs of an expanding and sustainable economy.

Antibacterial Effect of Melanoidins Derived From Xylose and Phenylalanine Against Bacillus cereus and Clostridium perfringens

Melanoidins produced from the combination of D-xylose and L-phenylalanine have been reported to exhibit strong antibacterial effects. This study investigated the influence of environmental factors, such as temperatures (10, 15, 20, 25, 30, 35, 40, and 45°C), pH (5.5, 6.0, 6.5, 7.0, 7.5, and 8.0), and water activity (aw: 0.99, 0.96, and 0.93), on the antibacterial effect of the melanoidins produced from the combination of D-xylose with L-phenylalanine against Bacillus cereus and Clostridium perfringens in culture media. Furthermore, freeze-dried powdered melanoidin was used to determine the minimum concentration for growth inhibition, to compare the antibacterial effect of the melanoidin with conventional food preservatives. The liquid melanoidins significantly inhibited the growth of B. cereus (up to 4 log CFU/mL at the maximum) and C. perfringens (up to 6.5 log CFU/mL at the maximum) regardless of the incubation temperatures. However, the remarkable difference between the presence and absence of the melanoidins was demonstrated in the range of 20-35°C as 4 log-cycle lower in B. cereus and 2 log-cycle lower in C. perfringens than those without the melanoidins. The antibacterial effect of the melanoidin on B. cereus was not influenced by pH from 5.5 to 7.0, which exhibited 2-3 log-cycle lower viable counts than those without the melanoidin. Only one log-cycle difference between with and without the melanoidin was shown in C. perfringens growth under the pH range of 5.5-7.0. Although there was no significant difference in the growth of B. cereus between three aw conditions, the melanoidin exhibited a significant antibacterial effect at aw 0.99 demonstrating 4 log-cycle lower viable numbers than those without the melanoidin. Minimum inhibitory concentration of the melanoidin powder for B. cereus and C. perfringens was 7 mg/mL and 15 mg/mL, respectively, regardless of the kind of foods. Furthermore, the melanoidin exhibited comparable antibacterial effect on B. cereus and C. perfringens to potassium sorbate and sodium benzoate under the same concentration as the minimum inhibitory concentration of the melanoidin, demonstrating 2 log-cycle reduction during 3 days of incubation period at 25°C. The results presented here suggest that the xylose- and phenylalanine-based melanoidin demonstrates the possibility to be an alternative food preservative.

Long-term organic carbon preservation enhanced by iron and manganese

The balance between degradation and preservation of sedimentary organic carbon (OC) is important for global carbon and oxygen cycles1. The relative importance of different mechanisms and environmental conditions contributing to marine sedimentary OC preservation, however, remains unclear2-8. Simple organic molecules can be geopolymerized into recalcitrant forms by means of the Maillard reaction5, although reaction kinetics at marine sedimentary temperatures are thought to be slow9,10. More recent work in terrestrial systems suggests that the reaction can be catalysed by manganese minerals11-13, but the potential for the promotion of geopolymerized OC formation at marine sedimentary temperatures is uncertain. Here we present incubation experiments and find that iron and manganese ions and minerals abiotically catalyse the Maillard reaction by up to two orders of magnitude at temperatures relevant to continental margins where most preservation occurs4. Furthermore, the chemical signature of the reaction products closely resembles dissolved and total OC found in continental margin sediments globally. With the aid of a pore-water model14, we estimate that iron- and manganese-catalysed transformation of simple organic molecules into complex macromolecules might generate on the order of approximately 4.1 Tg C yr-1 for preservation in marine sediments. In the context of perhaps only about 63 Tg C yr-1 variation in sedimentary organic preservation over the past 300 million years6, we propose that variable iron and manganese inputs to the ocean could exert a substantial but hitherto unexplored impact on global OC preservation over geological time.

Bioaccessibility and Genoprotective Effect of Melanoidins Obtained from Common and Soft Bread Crusts: Relationship between Melanoidins and Their Bioactivity

Bread crust constitutes an important by-product of the bakery industry, and its utilization for the isolation of melanoidins to be used as a functional ingredient can enhance its added value and contribute to health. The aim of this study was to evaluate the bioaccessibility, bioactivity, and genoprotective effect of melanoidins derived from bread crust. Bioaccessibility was assessed in gastric, intestinal digestion, and colonic fermentation fractions. The results revealed a relationship between bioaccessible melanoidins and their type (common or soft bread). No cytotoxicity effects were observed for bioaccessible fractions, as assessed by MTT and RTA methods, and they did not affect the distribution of E-cadherin in Caco-2 cells, confirming their ability to maintain membrane integrity. Furthermore, our study demonstrated that the gastrointestinal and colonic fermentation fractions successfully transported across the intestinal barrier, without affecting cell permeability, and showed antioxidant activity on the basolateral side of the cell monolayer. Remarkably, both fractions displayed a significant genoprotective effect in Caco-2 cells. Our findings provide crucial insights into the relationship between the melanoidins and their bioactivity and genoprotective effect. These results demonstrated the potential of bioaccessible melanoidins as valuable bioactive compounds for the development of functional foods, without showing toxic effects on gastrointestinal cells.

Microbial Diversity of Anaerobic-Fermented Coffee and Potential for Inhibiting Ochratoxin-Produced Aspergillus niger

Coffee flavor considerably depends on the fermentation process, with contributing factors including fermentation temperature, oxygen concentration, and microbial diversity. Efficient controlling of the fermentation can improve the quality of coffee beverages. Therefore, several studies on coffee fermentation processes have been conducted in various regions. The objective of this study was to assess the microbial diversity of coffee beans undergoing anaerobic fermentation at various temperatures (4 °C or 37 °C) and fermentation durations (12 h or 36 h) using full-length 16S rRNA sequencing. This analysis aimed to evaluate the inhibitory effects of the fermented metabolites against ochratoxin-producing Aspergillus niger. From our results, Acetobacter was identified as the dominant microbial community at higher fermentation temperatures, whereas Leuconostoc and Gluconobacter were the dominant genera at lower temperatures. However, at lower temperatures, changes in microbial communities were relatively slow. This study expands our knowledge of the microbial diversity involved in the anaerobic fermentation of coffee beans in Taiwan. The findings of this study can be used in future research to cultivate microorganisms linked to the quality and improve the quality of coffee beverages through fermentation.

Widely targeted metabolomic approach reveals dynamic changes in non-volatile and volatile metabolites of peanuts during roasting

Roasting influences the color, flavor, and antioxidant activities of peanuts. However, the biochemical mechanisms that occur during roasting are not well known. In this study, the dynamic changes in non-volatile and volatile metabolites in raw, light, and dark roasted peanuts were investigated using ultra-performance liquid chromatography with a widely targeted metabolomic approach based on tandem mass spectrometry and gas chromatography-mass spectrometry. A total of 738 non-volatile metabolites (comprising 12 subclasses) and 71 volatile metabolites (comprising 14 subclasses) were identified in raw and roasted peanuts. Significantly different non-volatile and volatile metabolites were detected. Among them, amino acids, sugars, and lipids (lysophosphatidylethanolamines and oxidized fatty acids) were found to be highly linked to flavor formation. In addition, the enhanced color and antioxidant activities of peanuts were attributed to the Maillard reaction and sugar degradation. These results provide comprehensive insights into the quality improvements of peanuts during roasting.

Revalorization of Coffee Residues: Advances in the Development of Eco-Friendly Biobased Potential Food Packaging

One of the main limitations in the creation of bioplastics is their large-scale development, referred to as the industrial-scale processing of plastics. For this reason, bioplastic engineering emerges as one of the main objectives of researchers, who are attempting to create not only more environmentally friendly but also sustainable, low-cost, and less polluting materials. This review presents the advances in the development of biodegradable and compostable films/containers using eco-friendly components of by-products of the coffee industry, such as coffee flour (CF), coffee mucilage (CM), coffee husks (CH), coffee silverskin (CS), and spent coffee grounds (SCGs), and a brief review of the common industrial processing techniques for the production of food packaging, including extrusion, compression molding, injection molding, and laboratory-scale techniques such as solvent casting. Finally, this review presents various advances in the area that can be scalable or applicable to different products using by-products generated from the coffee industry, taking into account the limitations and drawbacks of using a biomaterial.

The formation and structural characteristics of melanoidins from fermenting and distilled grains of Chinese liquor (baijiu)

Chinese liquor (baijiu) is a typical fermented food. In which production, melanoidins are formed in fermenting grains during low-temperature fermentation with long-term, and in distilled grains with high-temperature distillation for short-term. Here, the formation and structural characterization of melanoidins in these two distinct stages were first investigated through chemical composition analysis and spectroscopic identification. Our research showed that proteins and phenols continuously participate in melanoidin formation during fermentation and distillation processes. Distillation could produce melanoidins with larger amounts, darker colors, higher molecular weights, and more stable states than fermentation. The chemical composition including 10 carbohydrates, 17 amino acids, 5 free phenolic acids, and 7 bound phenolic acids was successfully identified in melanoidins. Ion chromatography was proposed to be an efficient method to investigate carbohydrates in melanoidins. Moreover, the potential impact of microorganisms on melanoidins was first revealed to be the possible utilization of glucose in melanoidins.

Extracted dyes' stability as obtained from spent coffee grounds on silk fabrics using eco-friendly mordants

Spent coffee grounds (SCGs) are commonly known as a waste resource and a raw material useful for dyeing. SCG is a rich source of natural colorant from the class of flavonoids and anthocyanins. In this research, silk fiber dyeing with the dye which was extracted from SCGs with different metallic and natural mordants was done by applying pre-, meta-, and post-mordanting methods. Metal salts like tin chloride and copper sulfate as well as such natural materials as pinecone, tannic acid, and lemon peel were used to act as mordants. Color strength and color parameters of the dyed silk fabric samples were evaluated by applying a reflective spectrophotometer. Also, the evaluation of wash and light fastness was done based on ISO standards. The results indicated that in all methods, the metal samples had higher color strength when compared to the bio-mordant ones. Among the used methods and bio-mordants, the use of the pre-mordanting method and pinecone led to the highest amount of color strength. Also, the used bio-mordant could be a suitable substitute for metal mordants in terms of fastness parameters. Among the used methods and mordants, the post-mordanting method and pinecone mordant could provide the best washing and light fastness.

Effect of cereal bran phenolic profile on Maillard reaction products formation during hydrothermal treatment

Maillard reaction products (MRP) contribute to sensory quality of various foods. Whole grains (WG) are rich in phenols which may influence Maillard reaction pathways during thermal processing and impact WG product sensory attributes. This study investigated how WG phenolic profile affects MRP formation. Amylase-hydrolyzed wheat (white and red) and sorghum (white, red, tannin) brans were hydrothermally processed at 150 °C/6 min, and characterized for MRP using colorimetry, fluorescence spectroscopy, HPLC-MS/MS, and HS-SPME/GC-MS. Bran phenolic structure, and to a lesser extent content, had larger influence on MRP formation than protein/amino acid profile. Polymeric tannins (both in situ and when added to wheat brans) strongly inhibited volatile and non-volatile MRP intermediates and melanoidin formation, likely via their carbocation depolymerization intermediates trapping furans. Principle component analysis demonstrated clear segregation of volatiles formation based on bran phenolic profile. Phenolic composition should be considered in WG product formulation and processing to achieve desired MRP formation.

Impact- and Thermal-Resistant Epoxy Resin Toughened with Acacia Honey

High performance polymers with bio-based modifiers are promising materials in terms of applications and environmental impact. In this work, raw acacia honey was used as a bio-modifier for epoxy resin, as a rich source of functional groups. The addition of honey resulted in the formation of highly stable structures that were observed in scanning electron microscopy images as separate phases at the fracture surface, which were involved in the toughening of the resin. Structural changes were investigated, revealing the formation of a new aldehyde carbonyl group. Thermal analysis confirmed the formation of products that were stable up to 600 °C, with a glass transition temperature of 228 °C. An energy-controlled impact test was performed to compare the absorbed impact energy of bio-modified epoxy containing different amounts of honey with unmodified epoxy resin. The results showed that bio-modified epoxy resin with 3 wt% of acacia honey could withstand several impacts with full recovery, while unmodified epoxy resin broke at first impact. The absorbed energy at first impact was 2.5 times higher for bio-modified epoxy resin than it was for unmodified epoxy resin. In this manner, by using simple preparation and a raw material that is abundant in nature, a novel epoxy with high thermal and impact resistance was obtained, opening a path for further research in this field.

Maillard reaction-based conjugation of Spirulina protein with maltodextrin using wet-heating route and characterisation of conjugates

Spirulina protein concentrate (SPC) was extracted from Spirulina biomass and its structure and technofunctional properties were modified through Maillard reaction with maltodextrin (MD). Wet-heating route was adapted and Maillard reaction was controlled within initial to intermediate stage by avoiding or minimising the formation of melanoidins. A glycation degree of up to 29.1 % was achieved after reaction between SPC and MD, and molecular weight of the SPC increased accordingly. The solubility of SPC was improved only in the pH range around its isoelectric point after conjugation. The antioxidative property of the SPC-MD conjugate was also improved as the DPPH radical scavenging activity increased 19.7 to 30.2 %. Oil-in-water emulsion stabilised by SPC-MD conjugate produced at 6 h had significantly reduced droplet size, increased surface charge, and higher physical stability in temperature range 25-60 °C. The outcome of this research will help broaden the application of SPC in food as emulsifier and encapsulating shell material.

Hyperbranched polyethyleneimine-functionalised chitosan aerogel for highly efficient removal of melanoidins from wastewater

Melanoidins are hazardous dark-coloured substances contained in molasses-based distillery wastewater. Adsorption is an effective approach to eliminate melanoidins from wastewater. However, melanoidin adsorption capacities of available adsorbents are unsatisfactory, which seriously limits their practical application. A hyperbranched polyethyleneimine-functionalised chitosan aerogel (HPCA) was fabricated as an effective adsorbent for melanoidin scavenging. HPCA demonstrated superior melanoidin adsorption efficiency because of its high specific surface area, abundant amino functional groups, and high hydrophilicity. Melanoidin removal rate of HPCA was 94.95%, which remained at 91.45% after 5 cycles. Notably, using the Langmuir isothermal model, the maximum melanoidin adsorption capacity of HPCA was determined to be 868.36 mg/g, surpassing those of most of previously reported adsorbents. Toxicity experiments indicated that HPCA can be considered a safe adsorbent with excellent biocompatibility that hardly threatens aquatic organisms. The efficient melanoidin removal of HPCA was attributed to electrostatic attraction, H-bonding, and van der Waals force. However, the adsorption might be predominantly controlled by electrovalent interaction between protonated amino groups of HPCA and carboxyl/carboxylate groups of melanoidins. Two novel models, namely, external diffusion resistance-internal diffusion resistance mixed model and adsorption on active site model, were employed to describe the dynamic mass transfer characteristics of melanoidin adsorption by HPCA.

Preparation and antimicrobial mechanism of Maillard reaction products derived from ε-polylysine and chitooligosaccharides

Chitooligosaccharides can be combined with amino acids or polypeptide to form Maillard reaction products (MRPs) with the antibacterial characteristics through Maillard reaction. This research aims to clarify the structure, antimicrobial effect and mechanism against Shewanella putrefaciens (S. putrefaciens) of ε-polylysine and chitooligosaccharides Maillard reaction products (LC-MRPs). The results of intrinsic fluorescence (IF) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction, proton nuclear magnetic resonance (¹H NMR) spectra and scanning electron microscope (SEM) indicated Maillard reaction occurred between ε-polylysine and chitooligosaccharides. The observation of confocal laser scanning microscopy (CLSM), SEM and growth curves of S. putrefaciens evidenced that LC-MRPs have the strongest antibacterial effects. The leakage of alkaline phosphatase (AKP) and lactate dehydrogenase (LDH) implied that LC-MRPs sabotaged bacterial barrier (cell wall and cell membrane). The changes in content of nucleic acids, reactive oxygen species (ROS) level, lipid peroxidation content (LPO), succinate dehydrogenase (SDH) activity and adenosine triphosphate (ATP) content showed LC-MRPs will affect bacterial genetic gene transcription, material and energy metabolism. Therefore, the LC-MRPs were effective antibacterial agents to inhibit S. putrefaciens, which will help to preserve food with S. putrefaciens as the main spoilage bacteria.

Physical and Oxidative Stabilization of Oil-In-Water Emulsions by Roasted Coffee Fractions: Interface- and Continuous Phase-Related Effects

Emulsions fortified with polyunsaturated fatty acids are highly relevant from a nutritional perspective; however, such products are prone to lipid oxidation. In the current work, this is mitigated by the use of natural antioxidants occurring in coffee. Coffee fractions with different molecular weights were extracted from roasted coffee beans. These components were positioned either at the interface or in the continuous phase of emulsions where they contributed to emulsion stability via different pathways. Coffee brew as a whole, and its high-molecular-weight fraction (HMWF), was able to form emulsions with good physical stability and excellent oxidative stability. When added post-homogenization to the continuous phase of dairy protein-stabilized emulsions, all coffee fractions were able to slow down lipid oxidation considerably without altering the physical stability of emulsions, though HMWF was more effective in retarding lipid oxidation than whole coffee brew or low-molecular-weight fraction. This is caused by various effects, such as the antioxidant properties of coffee extracts, the partitioning of components in the emulsions, and the nature of the phenolic compounds. Our research shows that coffee extracts can be used effectively as multifunctional stabilizers in dispersed systems leading to emulsion products with high chemical and physical stability.

Food protein glycation: A review focusing on stability and in vitro digestive characteristics of oil/water emulsions

Recently, increasing studies have shown that the functional properties of proteins, including emulsifying properties, antioxidant properties, solubility, and thermal stability, can be improved through glycation reaction under controlled reaction conditions. The use of glycated proteins to stabilize hydrophobic active substances and to explore the gastrointestinal fate of the stabilized hydrophobic substances has also become the hot spot. Therefore, in this review, the effects of glycation on the structure and function of food proteins and the physical stability and oxidative stability of protein-stabilized oil/water emulsions were comprehensively summarized and discussed. Also, this review sheds lights on the in vitro digestion characteristics and edible safety of emulsion stabilized by glycated protein. It can further serve as a research basis for understanding the role of structural features in the emulsification and stabilization of glycated proteins, as well as their utilization as emulsifiers in the food industry.

Method development for the identification, extraction and characterization of melanoidins in thermal hydrolyzed sludge

Melanoidins, the brown late-stage Maillard reaction products, are responsible for color development and refractoriness in thermal hydrolyzed sludge (THS), causing negative effects on wastewater treatment. This study aimed to develop a methodology for the identification, isolation and preliminary characterization of the THS melanoidins. After thermal hydrolysis, the formation of melanoidins were confirmed by physicochemical indicators and excitation-emission matrix fluorescence analysis. The macroporous resin adsorption method was adopted to successfully extract melanoidins from THS with high recovery and selectivity. The main chemical components of the extracted melanoidins were carbohydrate (23.1 %), protein (43.8 %) and phenol (13.7 %), and the C/N was 4.5. In addition, furans, alcohols and sulfur-containing volatile substances were detected by pyrolysis-gas chromatography-mass spectrometry. Fourier transform infrared spectroscopy determined that functional groups such as CO, CN, NH, C-O-C, amide I and phenyl were present in the structure of THS melanoidins, and nuclear magnetic resonance spectroscopy indicated the formation of heterocyclic macromolecular structures. Their formation pathways were speculated to involve the cross-linkage of low-molecular-weight components (e.g. proteins, Amadori and Schiff base compounds) and the polymerization of heterocyclic units (e.g. furans, pyroles and pyrazines). The above results clarify the fundamental characteristics of the melanoidins formed during sludge thermal hydrolysis and will help improve subsequent research on melanoidins control.

Characterization and utilization of soy protein isolate-(-)-epigallocatechin gallate-maltose ternary conjugate as an emulsifier for nanoemulsions: Enhanced physicochemical stability of the β-carotene nanoemulsion

In this study, a ternary conjugate was prepared by covalent bonding of protein, polysaccharide, and polyphenol via ultrasound and the Maillard reaction. Subsequently, the β-carotene nanoemulsion was prepared with the soy protein isolate-(-)-epigallocatechin gallate-maltose (SPI-EGCG-maltose) conjugate as the emulsifiers via ultrasound. The SPI-EGCG-maltose conjugate showed superior solubility, emulsification and foaming properties at 4 h reaction time. Meanwhile, the retention rates of β-carotene in the nanoemulsion after 30 d of storage, 8 h of light, and 55 °C of heat were >60%, >75%, and >60%, respectively. Furthermore, ultrasound treatment at 500 W for 10 min produced an inhibitory effect on the degradation of β-carotene. This study indicates that the nanoemulsion based on the ternary conjugate can effectively inhibit the β-carotene degradation by the external environment and prevent the oxidation and degradation of β-carotene in the nanoemulsion.

(3-Chloro-2-hydroxypropyl) trimethylammonium chloride and polyethyleneimine co-modified pomelo peel cellulose-derived aerogel for remelt syrup decolorization in sugar refining

The crucial need for quality refined sugar has led to the development of advanced adsorbents, with a focus on the decolorization of remelt syrup. In this study, (3-chloro-2-hydroxypropyl) trimethylammonium chloride and polyethyleneimine co-modified pomelo peel cellulose-derived aerogel (CP-PPA) was fabricated, and synthetic melanoidins were used as model colorants of remelt syrup to evaluate the validity and practicality of CP-PPA for eliminating colored impurities. Integrating abundant amine-functionalized groups (quaternary ammonium and protonated amine) within the pomelo peel-derived aerogel directionally captured electronegative melanoidins via electrostatic interactions. Furthermore, the active sites, types, and relative strength of the weak interactions between CP-PPA and melanoidins were determined using density functional theory simulations. CP-PPA exhibited an excellent equilibration adsorbing capacity for capturing melanoidins of 749.51 mg/g, and a removal efficiency of 93.69 %. Additionally, the adsorption mechanism was thoroughly examined in an effort to improve the economy of the sugar refinement industry.

The Potential of Spent Coffee Grounds in Functional Food Development

Coffee is a popular and widely consumed beverage worldwide, with epidemiological studies showing reduced risk of cardiovascular disease, cancers and non-alcoholic fatty liver disease. However, few studies have investigated the health effects of the post-brewing coffee product, spent coffee grounds (SCG), from either hot- or cold-brew coffee. SCG from hot-brew coffee improved metabolic parameters in rats with diet-induced metabolic syndrome and improved gut microbiome in these rats and in humans; further, SCG reduced energy consumption in humans. SCG contains similar bioactive compounds as the beverage including caffeine, chlorogenic acids, trigonelline, polyphenols and melanoidins, with established health benefits and safety for human consumption. Further, SCG utilisation could reduce the estimated 6-8 million tonnes of waste each year worldwide from production of coffee as a beverage. In this article, we explore SCG as a major by-product of coffee production and consumption, together with the potential economic impacts of health and non-health applications of SCG. The known bioactive compounds present in hot- and cold-brew coffee and SCG show potential effects in cardiovascular disease, cancer, liver disease and metabolic disorders. Based on these potential health benefits of SCG, it is expected that foods including SCG may moderate chronic human disease while reducing the environmental impact of waste otherwise dumped in landfill.

Bread melanoidins as potential new sustainable bakery ingredients: a study using fat and fat-free bakery food models

Melanoidins isolated from bakery by-products are proposed as new sustainable ingredients for bakery products. The colour, odour profile, texture, water activity, and antioxidant capacity of two bakery food models, fat and fat-free, enriched with 2% and 4% soft bread and common bread melanoidins, were analysed. The colour of the bakery food models with melanoidins was darker than that of the respective control; the fat-free models with melanoidins showed higher values of hardness than the control, while no significant effect was observed in the fat models; the water activity did not change compared to the control; the odour profile was significantly modified with different effects depending on the type of melanoidin quantity added and the food model (fat or fat-free); and the antioxidant capacity increased proportionally to the quantity of melanoidin added. In general, melanoidins from soft bread exhibited a higher effect than the melanoidins from common bread. The melanoidins isolated from both fat and fat-free bakery food models did not show cytotoxicity nor did they modify the levels of reactive oxygen species in Caco-2 cells. Therefore, the results seem to indicate the favourable potential of bread melanoidins as new sustainable ingredients for bakery products.

Changes of polyphenols and antioxidants of arabica coffee varieties during roasting

Coffee is the most consumed beverage in the world after water. Multiple benefits are attributed to it in human health due to the presence of antioxidant compounds, whose content depends, among other factors, on the processing conditions of the coffee bean. The objective of this study was to determine the kinetics of polyphenols and antioxidants during the roasting of three varieties of arabica coffee. For this, we worked with varieties of coffee, Catimor, Caturra, and Bourbon, from the province of La Convencion, Cuzco, Peru. The samples were roasted in an automatic induction roaster, and 12 samples were taken during roasting (at 0, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, and 21 min of roasting) in triplicate. For green coffee beans, titratable acidity, total soluble solids, moisture and apparent density were determined. The change in polyphenol content was determined using the Folin-Ciocalteu method, and antioxidant activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis- (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS⁺) free radical capture technique during roasting. Polyphenol and antioxidant contents increased until minute 5 of roasting and then decreased until minute 20, and in some cases, there were slight increases in the last minute. The model that best described the changes in these bioactive compounds was the cubic model (R ² 0.634 and 0.921), and the best fits were found for the Bourbon variety, whose green grain had more homogeneous characteristics. The changes in the relative abundances of nine phenolic compounds were determined using high-performance liquid chromatography (HPLC). In conclusion, roasting modifies phenolic compounds and antioxidants differently in the coffee varieties studied. The content of some phenols increases, and in other cases, it decreases as the roasting time increases. The roasting process negatively affects the bioactive compounds and increases the fracturability of Arabica coffee beans, elements that should be taken into account at the moment of developing roasting models in the industry.

Bioactive compounds as an alternative for the sugarcane industry: Towards an integrative approach

Here, a comprehensive review of sugarcane industrialization and its relationship with bioactive compounds (BCs) detected in various products and by-products generated during its processing is presented. Furthermore, it is discussed how these compounds have revealed important antioxidant, antineoplastic, antidiabetic, and antimicrobial activities. From this bibliographic research highlights the significance of two types of BCs of natural origin (phenolic compounds (PCs) and terpenoids) and a group of compounds synthesized during industrial transformation processes (Maillard reaction products (MRPs)). It was found that most of the studies about the BCs from sugarcane have been conducted by identifying, isolating, and analyzing ones or a few compounds at a specific period, this being a conventional approach. However, given the complexity of the synthesis processes of all these BCs and the biological activities they can manifest in a specific biological context, novel approaches are needed to address these analyses holistically. To overcome this challenge, integrating massive and multiscale methods, such as omics sciences, seems necessary to enrich these studies. This work is intended to contribute to the state of the art that could support future research about the exploration, characterization, or evaluation of different bioactive molecules from sugarcane and its derivatives.

Different Regulatory Effects of Heated Products and Maillard Reaction Products of Half-Fin Anchovy Hydrolysates on Intestinal Antioxidant Defense in Healthy Animals

The oxidative state of intestinal tracts of healthy animals were investigated after short-term intake of half-fin anchovy hydrolysates (HAHp) and their thermal or Maillard reaction products (MRPs). After one month of continuous oral gavage of HAHp, HAHp-heated products (HAHp-H), the MRPs of HAHp with 3% of glucose (HAHp-3%G MRPs), and the MRPs of HAHp with 3% of fructose (HAHp-3%F MRPs) at a dose of 1.0 g/kg of body weight per day into healthy ICR male mice, the concentrations of serum low-density and high-density lipoprotein cholesterol did not significantly change compared to the control group (CK, gavage with saline). Similar results were found for the interleukin-6 concentrations of all groups. By comparison, HAHp-H, HAHp-3%G MRPs, and HAHp-3%F MRPs administration decreased serum tumor necrosis factor-α concentration as compared to the CK group (p < 0.05). No histological damage was observed in the jejunum, ileum, and colonic tissues of all groups. However, HAHp-H treatment induced higher upregulation of Kelch-like ECH-associated protein 1, transcription factors Nrf-2, associated protective phase-II enzymes of NAD(P)H: quinine oxidoreductase-1, and hemoxygenase-1 in colon tissue, as well as higher upregulation of endogenous antioxidant enzymes, including copper/zinc superoxide dismutase, manganese superoxide dismutase, catalase, and glutathione peroxidase 2 than other groups (p < 0.05). Additionally, increases in Nε-carboxymethyllysine expression in the colonic tissues of all groups were consistent with their increased oligopeptide transporter 1 expressions. Our results suggest that the thermal products of HAHp might have a broad application prospect in improving antioxidant defense in vivo in healthy animals.