Demonstration of antioxidant and anti-inflammatory bioactivities from sugar-amino acid maillard reaction products

Exploring the bioactive potential of algae residue extract via subcritical water extraction: Insights into chemical composition and biological activity

Gelidium sesquipedale is valued in the Spanish agar industry, but its production generates substantial waste, often discarded despite its nutritional and bioactive content. Subcritical water extraction (SWE) at 175 °C and 50 bar for 130 min was performed on this waste after agar extraction, comparing it to conventional ethanol extraction. The SWE extract exhibited superior nutritional profile, including proteins (170.6 ± 1.0 mg/gfreeze-dried-extract), essential amino acids (18.1%), carbohydrates (148.1 ± 0.3 mg/gfreeze-dried-extract), total phenolic content (57 ± 7 mg-EqGA/gfreeze-dried-extract), and also containing Maillard reaction compounds, such as 5-hydroxymethylfurfural, furfural, 2-furanmethanol, 1-(2-furanyl)-ethanone, and 5-methyl-2-furfural, influencing color, aroma and flavor. This extract showed better antioxidant and anti-inflammatory properties than the conventional extract, and higher xanthine oxidase, tyrosinase, and acetylcholinesterase inhibition activities. Toxicological assessment on human cells indicated the safety of the SWE extract. Therefore, SWE technology offers a promising method to valorize G. sesquipedale residue, yielding a bioactive and nutrient-rich extract suitable for food and nutraceutical applications.

Glycation of tilapia protein hydrolysate decreases cellular antioxidant activity upon in vitro gastrointestinal digestion

Changes in structural characteristics and antioxidant activity of tilapia hydrolysate glycated with glucose, fructose, or xylose at 90 °C for 12 h, and following in vitro gastrointestinal (GI) digestion were investigated. Fourier-transformed infrared (FTIR) band between 1,800 and 1,400 cm-1 confirmed the structural modifications of hydrolysate under glycations. Glycation drastically increased ATBS · + and ONOO - scavenging activities (p < 0.05) as well as ferric-reducing antioxidant power (FRAP). Xylose was the most effective sugar for glycation, yielding the highest chemical antioxidant activities (p < 0.05). However, glycated hydrolysates exhibited lower cellular antioxidant activity (CAA) on HepG2 cell when compared to hydrolysates. The extensive glycation of hydrolysates resulted in lower GI digestibility as confirmed by the FTIR spectra of C[bond, double bond]O, C-N, N-H, C-C, C-O, and C-H stretching vibrations. Glycation of tilapia hydrolysates only improved chemical antioxidant activities, but alleviated CAA, especially upon simulated GI digestion.

Antioxidant and antibrowning properties of Maillard reaction products in food and biological systems

Oxidative damage refers to the harm caused to biological systems by reactive oxygen species such as free radicals. This damage can contribute to a range of diseases and aging processes in organisms. Moreover, oxidative deterioration of lipids is a serious problem because it reduces the shelf life of food products, degrades their nutritional value, and produces reaction products that could be toxic. Antioxidants are effective compounds for preventing lipid oxidation, and synthetic antioxidants are frequently added to foods due to their high effectiveness and low cost. However, the safety of these antioxidants is a subject that is being discussed in the public more and more. Synthetic antioxidants have been found to have potential negative effects on health due to their ability to accumulate in tissues and disrupt natural antioxidant systems. During thermal processing and storage, foods containing reducing sugars and amino compounds frequently produce Maillard reaction products (MRPs). Through the chelation of metal ions, scavenging of reactive oxygen species, destruction of hydrogen peroxide, and suppression of radical chain reaction, MRPs exhibit excellent antioxidant properties in a variety of food products and biological systems. Also, the capacity of MRPs to chelate metals makes them as a potential inhibitor of the enzymatic browning in fruits and vegetables. In this book chapter, the methods used for the evaluation of antioxidant activity of MRPs are provided. Moreover, the antioxidant and antibrowning activities of MRPs in food and biological systems is discussed. MRPs can generally be isolated and used as commercial preparations of natural antioxidants.

Effect of Conventional Humid-Dry Heating through the Maillard Reaction on Chemical Changes and Enhancement of In Vitro Bioactivities from Soy Protein Isolate Hydrolysate-Yeast Cell Extract Conjugates

This study investigated the formation of soy protein isolate hydrolysate-yeast cell extract (SPIH-YCE) conjugates through a humid-dry heating process and their impact on bioactivity. The incubation of SPIH-YCE samples at 60 °C and ~75% humidity for varying durations (0, 5, 10, 15, and 20 days) resulted in a significant decrease in reducing sugars and free amino acids, while the degree of glycation increased by approximately 65.72% after 10 days. SDS-PAGE analysis and size exclusion chromatography revealed the presence of peptides and glycoprotein molecules, with an increase in the distribution of larger peptide size chains. The conjugated SPIH-YCE (10 days) exhibited the highest antioxidant capacity compared to the other samples at different incubation times. A comparative study between SPIH-YCE (day 0) and SPIH-YCE after 10 days of incubation showed significantly higher anti-inflammatory and ACE inhibitory activities for the conjugates subjected to the humid-dry heating process. This suggests that SPIH-YCE conjugates could serve as an alternative substance with the potential to provide health benefits by mitigating or preventing non-communicable diseases (NCDs). This research highlights the importance of the Maillard reaction in enhancing bioactivity and offers insights into the alterations of the chemical structure of these conjugates.

Investigation of Cox-2 inhibition of Laportea decumana (Roxb). Wedd extract to support its analgesic potential

ETHNOPHARMACOLOGICAL RELEVANCE

Itchy leaves Laportea decumana (Roxb). Wedd is an indigenous plant in Maluku, Indonesia, and is used traditionally to treat complaints such as fatigue and joint and muscle pains.

AIM OF THE STUDY

To provide scientific proof of the analgesic effect of L. decumana ethanolic extract tested in in vivo assays while investigating its bioactive phytochemicals using liquid chromatography tandem high-resolution mass spectrometry (LC-HRMS) profiling and Cox-2 inhibition assay.

MATERIALS AND METHODS

To investigate the analgesic activity of the ethanolic extract, assays were conducted on male mice Balb/c strain by chemical induction using acetic acid (i.p.) and heat induction (hotplate). Mice were divided into six groups consisting of six mice, i.e., the baseline group; positive control group (paracetamol 80 mg/kg BW); groups treated with extracts in dosages of 100, 200, and 400 mg/kg bodyweight (BW); and negative control group (acetic acid 0.6%, i. p.). The crude extract was partitioned with liquid-liquid fractionation to yield hexane, ethyl acetate, and water fractions. The extract and fraction were assayed for Cox-2 enzyme inhibition, and the chemical profiles were analyzed using untargeted LC-HRMS.

RESULTS

The analgesic assays revealed the dose-dependent effect of the extracts, of the effect of treatment with 400 mg/kg BW was not significantly different with that of paracetamol (p < 0.05). The ethyl acetate fraction showed IC50 of 19.25 μg/mL on Cox-2 inhibition (IC50 celexocib 18.48 μg/mL). LC-HRMS showed a distinctive profile of the ethyl acetate fraction compared with those in the extract and other fractions.

CONCLUSIONS

This study presents scientific evidence of the analgesic activity of the L. decumana ethanol extract given orally to experimental animals. Inflammatory inhibition plays a role in the overall analgesic mechanism by Cox-2 inhibition of the extract and all fractions. This finding is also supported by the phytochemical profiles of the extract and fractions, showing the presence of compounds reported elsewhere as anti-inflammatory activity.

Dietary effect of grape (Vitis vinifera) seed extract mitigates hepatic disorders caused by oxidized fish oil in rainbow trout (Oncorhynchus mykiss)

The major goal of this study was to determine the effect of grape seed extract (GSE) on liver damage in rainbow trout (Oncorhynchus mykiss) that was caused by the consumption of dietary oxidized fish oil (OFO). Rainbow trout were fed six different experimental diets coded OX-GSE 0 (OFO diet), OX-GSE 1 (OFO and 0.1% GSE), OX-GSE 3 (OFO and 0.3% GSE), GSE 0 (fresh fish oil and 0.0% GSE), GSE 1 (fresh fish oil and 0.1% GSE), and GSE 3 (fresh fish oil and 0.3% GSE) for 30 days. The lowest % hepatosomatic index (HSI) result was calculated in fish fed with OX-GSE 0 and the highest HSI was determined in fish fed with GSE 1 diets (p < 0.05). Histopathologically, hydropic degeneration in hepatocytes significantly increased OX-GSE 0 and GSE 3 compared to GSE 1 diets (p < 0.05). Deposition of lipid droplets in hepatocytes was significantly increased in OX-GSE 0 and OX-GSE 3 groups than others (p < 0.05). Liver biochemistry parameters such as superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) were significantly affected by OX and GSE treatments (p < 0.05). There were significant differences in alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) among the liver enzymes analyzed in serum in OX and GSE (p < 0.05), meanwhile no difference was observed in lactate dehydrogenase (LDH) values between groups (p > 0.05). In conclusion, liver biochemistry and histopathology of rainbow trout consuming diets containing oxidized fish oil were negatively affected. However, it was determined that the supplementation of 0.1% GSE to the diet had a significant ameliorative role in these adverse effects.

Synergic Effect of Honey with Other Natural Agents in Developing Efficient Wound Dressings

Honey has been used for therapeutic and nutritional purposes since ancient times. It was considered one of the essential medical assets in wound healing. According to research, honeybees have significant antibacterial, antioxidant, anti-inflammatory, antitumor, and wound-healing properties. Lately, scientific researchers have focused on apitherapy, using bee products to protect and strengthen the immune system. Since honey is the most important natural product rich in minerals, proteins, and vitamins, it has been intensively used in such therapies. Honey has gained significant consideration because of the beneficial role of its antioxidant compounds, such as enzymes, proteins, amino and organic acids, polyphenols, and carotenoids, but mainly due to flavonoids and phenolic acids. It has been proven that phenolic compounds are responsible for honey's biological activity and that its physicochemical properties, antioxidants, and antimicrobial potential are significant for human health. The review also presents some mechanisms of action and the medical applications of honey, such as wound healing dressings, skin grafts, honey-based nanofibers, and cochlear implants, as the most promising wound healing tools. This extensive review has been written to highlight honey's applications in medicine; its composition with the most important bioactive compounds also illustrates its synergistic effect with other natural products having remarkable therapeutic properties in wound healing.

Physicochemical Profile, Antioxidant and Antimicrobial Activities of Honeys Produced in Minas Gerais (Brazil)

Honeys can be classified as polyfloral or monofloral and have been extensively studied due to an increased interest in their consumption. There is concern with the correct identification of their flowering, the use of analyses that guarantee their physicochemical quality and the quantification of some compounds such as phenolics, to determine their antioxidant and antimicrobial action. This study aims at botanical identification, physicochemical analyses, and the determination of total polyphenols, chromatographic profile and antiradical and antimicrobial activity of honey from different regions of Minas Gerais. Seven different samples were analyzed for the presence of pollen, and color determination. The physicochemical analyses performed were total acidity, moisture, HMF, reducing sugar, and apparent sucrose. The compound profile was determined by UHPLC/MS, the determination of total phenolics and antiradical activity (DPPH method) were performed by spectrophotometry, and minimum inhibitory and bacterial concentrations were determined for cariogenic bacteria. All honey samples met the quality standards required by international legislation, twenty compounds were detected as the main ones, the polyfloral honey was the only honey that inhibited all of the bacteria tested. Sample M6 (Coffee) was the one with the highest amount of total polyphenols, while the lowest was M4 (Cipó-uva). Regarding the antioxidant activity, M5 (Velame) had the best result and M4 (Cipó-uva) was the one that least inhibited oxidation. Of the polyfloral honeys, there was not as high a concentration of phenolic compounds as in the others. Coffee, Aroeira, Velame and Polyfloral have the best anti-radical actions. Betônica, Aroeira, Cipó-uva and Pequi inhibited only some bacteria. The best bacterial inhibition results are from Polyfloral.

A review on ethnobotany, phytochemistry, and pharmacology of the genus Didymocarpus wall. (Gesneriaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal plants have been extensively used to treat various illnesses since the dawn of civilization. The genus Didymorcapus Wall. comprises 100 species widely distributed in the tropical regions of Asia, with a few found scattered in Africa and Australia. Species in this genus have long been used in folk medicine to treat various illnesses, including wounds, kidney stones, inflammations, asthma, flu, eczema, dysentery, fractures, colic etc. Some species have applications as weight loss agents, laxatives, and protective medication after childbirth.

AIM

To provide comprehensive information on the current knowledge of the ethnobotanical uses, phytochemical compounds, pharmacological applications, and toxicology of genus Didymocarpus to reveal its therapeutic potential, offering insights into future research opportunities.

MATERIALS AND METHODS

Data were systematically obtained from books and online databases such as PubMed, Web of Science, Scopus, Sci Finder, Google Scholar, Science direct, ACS Publications, Elsevier, Wiley Online Library.

RESULTS

Seventeen Didymocarpus species have applications in traditional medicine in different Asian countries. A total of 166 compounds have been isolated from the genus Didymocarpus including terpenoids, flavonoids, phenolic compounds, fatty acids, chalcones, steroids, and others. Among these constituents, terpenoids, flavonoids, chalcones, and phenolics are the significant contributors to pharmacological activities of the genus Didymocarpus, possessing wide-reaching biological activities both in vivo and in vitro. The crude extracts and isolated phytochemical compounds from this genus have been shown to exhibit various pharmacological activities, including antiurolithiatic, nephro-protective, antimicrobial, anticancer, antidiabetic, cytotoxic, wound healing, and antioxidant activities.

CONCLUSIONS

Traditional uses and scientific evaluation of Didymocarpus indicate that Didymocarpus pedicellata is one of the most widely used species in some parts of the world. Although substantial progress on the chemical and pharmacological properties of Didymocarpus species has been made, further studies on the pharmacology and toxicology of these species are needed to ensure safety, efficacy, and quality. Also, further research on the structure-activity relationship of some of the isolated phytocompounds may improve their biological potency and scientific exploitation of traditional uses of the Didymocarpus taxa.

Maillard Reaction Products with Anti-Tobacco Mosaic Virus Activities Generated in Processed Thermopsis lanceolata R. Br. Seed Extract

Six novel Maillard reaction products (MRPs) (1-6) were isolated from the processed Thermopsis lanceolata R. Br. seed extract, along with one biogenetically related intermediate (7). Compounds 1-4 possessed three rare dimerization patterns constructed by cytisine, whereas compounds 5 and 6 represented the first example of the addition products of cytisine and 5,6-dihydroxy-4-hexanolide. Their structures were elucidated by comprehensive spectroscopic data analysis and quantum chemistry calculations including GIAO ¹³C{¹H} NMR and ECD calculation, combined with single-crystal X-ray diffraction analysis. Biologically, compound 3 displayed significant anti-tobacco mosaic virus activity compared with the positive control ningnanmycin.

Comparative effect of dietary supplements on the performance and severity of experimental Eimeria tenella infection in broiler chickens

The effect of the dietary supplements, sugarcane molasses (prebiotic), Antox® (probiotic) and Enflorax® (synbiotic), on gut health, performance and severity of infection with Eimeria tenella in broiler chickens was evaluated in this study. Ninety-day-old broiler chicks were divided into six groups (A, B, C, D, E and F). Groups B to F were challenged with Eimeria tenella (2.0 × 10⁴ oocysts/chick). Groups C, D and E were supplemented from day old with prebiotic, probiotic and synbiotic, respectively, while F was administered amprolium. Groups A and B served as negative and positive controls, respectively. Feed intake and performance parameters were assessed weekly for each group. After infection clinical signs, morbidity and mortality rates were monitored alongside oocyst output, gross and microscopic caecal lesions. Infected chickens exhibited clinical signs 4 days post infection (dpi) with 100% morbidity in all infected groups. Infected groups showed significant (P < 0.05) drop in feed intake and weight gain from 3 to 5 weeks of age. Feed conversion ratio was highest in B but lower in the supplemented groups. Oocyst output in faeces were significantly lower (P < 0.05) in the supplemented groups compared with B. Macroscopic lesion scores 7 dpi were significantly lower in the supplemented groups compared with B, though group F had the lowest mean score. Histopathological examination of caeca tissues showed milder lesions in the supplemented groups. In conclusion, the supplements prebiotic, probiotic and synbiotic ameliorated the consequences of caecal coccidiosis in broiler chickens and therefore recommended for use in broiler production.

Antidesma thwaitesianum Müll. Arg. fruit extract rich in 5-hydroxymethylfurfural exhibits anti-inflammatory effects in lipopolysaccharide-stimulated RAW264.7 macrophages

Introduction: Antidesma thwaitesianum Müll. Arg is a tropical fruit, which has been commonly used for healthy food and traditional herbal medicine. This study aimed to investigate the anti-inflammatory effects of A. thwaitesianum fruit extract (AFE) rich in 5-hydroxymethylfurfural (5-HMF) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Methods: The chemical composition of AFE was analysed by gas chromatography/mass spectrometry (GC/MS). RAW264.7 cells were used as an in vitro inflammatory response model. RAW264.7 cells were pre-treated with various concentrations of AFE or 5-HMF and subsequently treated with LPS. Cell viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The production levels of pro-inflammatory cytokines and mediators, including nitric oxide (NO), interleukin (IL)-1β, and tumour necrosis factor (TNF)-α were determined by the Griess assay and enzyme-linked immunosorbent assay. The protein expression of inducible nitric oxide synthase (iNOS) was examined by western blot analysis. Results: AFE had a high content of 5-HMF (61.03% ± 0.49%). Pre-treatment with AFE and 5-HMF markedly reduced LPS-induced pro-inflammatory mediators and cytokines, namely NO, IL-1β, and TNF-α, in RAW264.7 cells; this reduction correlated with downregulation of iNOS expression. Conclusion: This study suggests that A. thwaitesianum fruit extract containing 5-HMF could modulate the LPS-induced inflammatory response by inhibiting NO, IL-1β, and TNF-α production and iNOS expression. A. thwaitesianum fruit extract rich in 5-HMF could be considered a potential therapeutic agent for the prevention of inflammation.

Effects of Osthole on Inflammatory Gene Expression and Cytokine Secretion in Histamine-Induced Inflammation in the Caco-2 Cell Line

Hyperactivity of the immune system in the gastrointestinal tract leads to the development of chronic, inflammation-associated disorders. Such diseases, including inflammatory bowel disease, are not completely curable, but the specific line of treatment may reduce its symptoms. However, the response to treatment varies among patients, creating a necessity to uncover the pathophysiological basis of immune-mediated diseases and apply novel therapeutic strategies. The present study describes the anti-inflammatory properties of osthole during histamine-induced inflammation in the intestinal Caco-2 cell line. Osthole reduced the secretion of cytokines (CKs) and the expression level of inflammation-associated genes, which were increased after a histamine treatment. We have shown that the secretion of pro-inflammatory CKs (IL-1β, IL-6, IL-8, and TNF-α) during inflammation may be mediated by NFκB, and, after osthole treatment, this signaling pathway was disrupted. Our results suggest a possible role for osthole in the protection against inflammation in the gastrointestinal tract; thus, osthole may be considered as an anti-inflammatory modulator.

Antioxidant and Functional Activities of MRPs Derived from Different Sugar-Amino Acid Combinations and Reaction Conditions

The Maillard reaction (MR), or non-enzymatic browning, involves reducing sugars reacting with amino acids, peptides, or proteins when heated to produce an abundance of products that contribute to sensory, nutritional, and functional qualities of the food system. One example of an important functional quality of MR relates to antioxidant capacity, which has relevance to preserve food quality and also to extend a potential role that may promote gastrointestinal health. The addition of Alphacel (10%), a non-reactive polysaccharide, to MR reactants produced small significant (p < 0.05) reductions in yield of soluble Maillard reaction products (MRPs), sugar loss, and color change of products formed respectively, for reducing sugars. A similar effect was also noticed for different free-radical scavenging capacity (p < 0.05), using chemical (e.g., 2,2-diphenyl-1-picrylhydrazyl (DPPH)), Trolox equivalent antioxidant capacity (TEAC), and oxygen radical absorbance capacity (ORAC) assays. An inflamed Caco-2 cell model revealed nitric oxide (NO) inhibitory activity for Glu-amino acid MRPs, which contrasted the NO stimulatory activity obtained with Fru-amino acid MRPs, especially when glycine was used as the amino acid. Pre-treating Caco-2 cells with Fru-glycine MRPs protected against loss in trans-epithelial resistance (TEER) (p < 0.05) and reduced (p < 0.05) disruption of Caco-2 intestinal epithelial tight-junction (TJ) protein cells when exposed to 7.5% ethanol. A low molecular weight Fru-glycine (e.g., <1 kDa) fraction contributed to the protective effect, not observed with the corresponding high molecular weight MRP fraction. The presence of Alphacel had minimal effect on generating MRPs with relative modified protection against intestinal dysfunction in cultured Caco-2 cells. Rather, different types of sugar-amino acid combinations used to generate MRPs contributed more to mitigate injury in stress-induced Caco-2 cells. With the growing evidence that MRPs have a wide range of bioactive activities, this study concludes that specificity of substrate precursors that produce MRPs in heated foods is a critical factor for antioxidant and related cellular functions that represent a healthy gut.

5-Hydroxymethylfurfural Enhances the Antiviral Immune Response in Macrophages through the Modulation of RIG-I-Mediated Interferon Production and the JAK/STAT Signaling Pathway

5-Hydroxymethylfurfural (5-HMF) exists in a wide range of sugar-rich foods and traditional Chinese medicines. The role of 5-HMF in antiviral innate immunity and its mechanism have not been reported previously. In this study, we reveal for the first time that 5-HMF upregulates the production of retinoic acid-inducible gene I (RIG-I)-mediated type I interferon (IFN) as a response to viral infection. IFN-β and IFN-stimulated chemokine gene expressions induced by the vesicular stomatitis virus (VSV) are upregulated in RAW264.7 cells and primary peritoneal macrophages after treatment with 5-HMF, a natural product that appears to inhibit the efficiency of viral replication. Meanwhile, 5-HMF-pretreated mice show enhanced innate antiviral immunity, increased serum levels of IFN-β, and reduced morbidity and viral loads upon infection with VSV. Thus, 5-HMF can be seen to have a positive effect on enhancing type I IFN production. Mechanistically, 5-HMF upregulates the expression of RIG-I in macrophages, resulting in an acceleration of the RIG-I signaling pathway activation. Additionally, STAT1 and STAT2 phosphorylations, along with the expression of IFN-stimulated chemokine genes induced by IFN-α/β, were also enhanced in macrophages cotreated with 5-HMF. In summary, these findings indicate that 5-HMF not only can induce type I IFN production but also can enhance IFN-JAK/STAT signaling, leading to a novel immunomodulatory mechanism against viral infection. In conclusion, our study reveals a previously unrecognized effect of 5-HMF in the antiviral innate immune response and suggests new potential of utilizing 5-HMF for controlling viral infection.

Dietary advanced glycation end-products elicit toxicological effects by disrupting gut microbiome and immune homeostasis

The aging immune system is characterized by a low-grade chronic systemic inflammatory state ("inflammaging") marked by elevated serum levels of inflammatory molecules such as interleukin (IL)-6 and C-reactive protein (CRP). These inflammatory markers were also reported to be strong predictors for the development/severity of Type 2 diabetes, obesity, and COVID-19. The levels of these markers have been positively associated with those of advanced glycation end-products (AGEs) generated via non-enzymatic glycation and oxidation of proteins and lipids during normal aging and metabolism. Based on the above observations, it is clinically important to elucidate how dietary AGEs modulate inflammation and might thus increase the risk for aging-exacerbated diseases. The present narrative review discusses the potential pro-inflammatory properties of dietary AGEs with a focus on the inflammatory mediators CRP, IL-6 and ferritin, and their relations to aging in general and Type 2 diabetes in particular. In addition, underlying mechanisms - including those related to gut microbiota and the receptors for AGEs, and the roles AGEs might play in affecting physiologies of the healthy elderly, obese individuals, and diabetics are discussed in regard to any greater susceptibility to COVID-19.

Chemical-free recovery of crude protein from livestock manure digestate solid by thermal hydrolysis

Protein is becoming an increasingly important resource for a variety of commercial applications. Yet, a large volume of protein is being wasted. Notably, livestock manure solids have a significant content of protein which is not only underutilized, but prone to runoff and eventual breakdown to reactive nitrogen compounds, contributing to eutrophication. It would be desirable to remove protein before it causes environmental hazards and then convert it to value-added commercial applications. We have developed a novel thermal hydrolysis process (THP) to extract crude protein from livestock manure solid, or manure digestate solid (MDS) in particular, without the use of any chemical. We demonstrate the versatility of our new process to control the molecular weight (MW) distribution of the extracted protein hydrolysate (PH). The antioxidant activity of the crude protein hydrolysate (CPH) has been examined through Oxygen Radical Absorbance Capacity Assay. The results have shown that our CPH had its antioxidant capacity against the peroxyl radical similar to that of vitamin E and exhibited almost 7 times as strong inhibition against the hydroxyl radical as vitamin E. We also evaluated the nutritional value of our PH by analyzing its amino acid composition and the MW distribution through amino acid analysis, SDS-PAGE, and MALDI-TOF mass spectroscopy. The characterizations have revealed that the PH recovered from MDS had 2.5 times as much essential amino acids as soybean meal on dry matter basis, with the MW distribution ranging from over a 100 Da to 100 KDa. Finally, the protein powder was prepared from the extracted CPH solution and its composition was analyzed.

Electrochemical Determination of the "Furanic Index" in Honey

5-(hydroxymethyl)furan-2-carbaldehyde, better known as hydroxymethylfurfural (HMF), is a well-known freshness parameter of honey: although mostly absent in fresh samples, its concentration tends to increase naturally with aging. However, high quantities of HMF are also found in fresh but adulterated samples or honey subjected to thermal or photochemical stresses. In addition, HMF deserves further consideration due to its potential toxic effects on human health. The processes at the origin of HMF formation in honey and in other foods, containing saccharides and proteins—mainly non-enzymatic browning reactions—can also produce other furanic compounds. Among others, 2-furaldehyde (2F) and 2-furoic acid (2FA) are the most abundant in honey, but also their isomers (i.e., 3-furaldehyde, 3F, and 3-furoic acid, 3FA) have been found in it, although in small quantities. A preliminary characterization of HMF, 2F, 2FA, 3F, and 3FA by cyclic voltammetry (CV) led to hypothesizing the possibility of a comprehensive quantitative determination of all these compounds using a simple and accurate square wave voltammetry (SWV) method. Therefore, a new parameter able to provide indications on quality of honey, named “Furanic Index” (FI), was proposed in this contribution, which is based on the simultaneous reduction of all analytes on an Hg electrode to ca. −1.50 V vs. Saturated Calomel Electrode (SCE). The proposed method, validated, and tested on 10 samples of honeys of different botanical origin and age, is fast and accurate, and, in the case of strawberry tree honey (Arbutus unedo), it highlighted the contribution to the FI of the homogentisic acid (HA), i.e., the chemical marker of the floral origin of this honey, which was quantitatively reduced in the working conditions. Excellent agreement between the SWV and Reverse-Phase High-Performance Liquid Chromatography (RP-HPLC) data was observed in all samples considered.

Supercritical CO2 treatment reduces the antigenicity of buttermilk β-lactoglobulin and its inflammatory response in Caco-2 cells

β-Lactoglobulin (β-LG) is believed to be a common allergen in bovine milk. Buttermilk (BM) powder has abundant contents of milk fat globule membrane and phospholipid, both of which have been demonstrated to have positive effects on brain and cognitive development during early infancy. This study focused on modifying β-LG in BM via supercritical CO2 (ScCO2) treatment to modify its reactivity to antibodies and thus reduce its antigenicity. Buttermilk powder was treated in a supercritical fluid extraction system with food-grade CO2 at 100, 150, 200, 250, 350, and 400 bar at 2 temperatures, 50 and 75°C. All analyses were completed in a 10% BM suspension (wt/vol). The BM proteins were examined using sodium dodecyl sulfate (SDS)-PAGE, Western blot, ELISA, and periodic acid staining methods. Semi-purified β-LG was used to evaluate the cytotoxicity, viability, and inflammatory response in the Caco-2 cell line by means of the lactate dehydrogenase assay, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium] assay, and IL-8 production, respectively. The SDS-PAGE showed that the signal intensity of β-LG bands was reduced by up to 50% after being processed at 250 bar and 75°C for 30 min. Lighter and more diffuse signals were found by Western blot, indicating modification of the protein structure. The ELISA demonstrated that ScCO2 treatment could significantly change β-LG antigenicity in BM. Sugar moieties in bands corresponding to β-LG were revealed by periodic acid staining, indicating glycosylation only in samples treated with ScCO2. Caco-2 cells treated with whey proteins had high viability, 24.9% lower inflammation, and no evidence of cytotoxicity compared with untreated cultures. These results showed that reduced antigenicity of β-LG was caused by lactosylation, which has been reported as a possible pathway to reduce the allergenicity in foods. The denaturation of β-LG by supercritical fluid processing is a promising way to address milk allergy, which remains a problem requiring more attention and further research.

Modulatory Effects of Osthole on Lipopolysaccharides-Induced Inflammation in Caco-2 Cell Monolayer and Co-Cultures with THP-1 and THP-1-Derived Macrophages

Lipopolysaccharydes (LPS) are responsible for the intestinal inflammatory reaction, as they may disrupt tight junctions and induce cytokines (CKs) secretion. Osthole has a wide spectrum of pharmacological effects, thus its anti-inflammatory potential in the LPS-treated Caco-2 cell line as well as in Caco-2/THP-1 and Caco-2/macrophages co-cultures was investigated. In brief, Caco-2 cells and co-cultures were incubated with LPS to induce an inflammatory reaction, after which osthole (150-450 ng/mL) was applied to reduce this effect. After 24 h, the level of secreted CKs and changes in gene expression were examined. LPS significantly increased the levels of IL-1β, -6, -8, and TNF-α, while osthole reduced this effect in a concentration-dependent manner, with the most significant decrease when a 450 ng/mL dose was applied (p < 0.0001). A similar trend was observed in changes in gene expression, with the significant osthole efficiency at a concentration of 450 ng/μL for IL1R1 and COX-2 (p < 0.01) and 300 ng/μL for NF-κB (p < 0.001). Osthole increased Caco-2 monolayer permeability, thus if it would ever be considered as a potential drug for minimizing intestinal inflammatory symptoms, its safety should be confirmed in extended in vitro and in vivo studies.

Antioxidant and Anti-Inflammatory Potential of Peptides Derived from In Vitro Gastrointestinal Digestion of Germinated and Heat-Treated Foxtail Millet (Setaria italica) Proteins

This study aimed at identifying antioxidant and anti-inflammatory peptides derived from the in vitro gastrointestinal digestion of germinated and heated (microwave and boiling) foxtail millet. The protein digest fraction containing low-molecular-weight peptides (<3 kDa) and the most hydrophobic subfraction (F4) abundant in random coil structure were responsible for the bioactivity. Then, seven novel peptides were identified using liquid chromatography with tandem mass spectrometry (LC-MS/MS) from the most potent F4 subfraction derived from boiled germinated millet. All seven synthesized peptides significantly (p < 0.05) reduced reactive oxygen species production and increased glutathione content and superoxide dismutase activity in Caco-2 cells, whereas two peptides (EDDQMDPMAK and QNWDFCEAWEPCF) were superior in inhibiting nitric oxide, tumor necrosis factor-α (reduced to 42.29 and 44.07%, respectively), and interleukin-6 (reduced to 56.59 and 43.45%, respectively) production in a RAW 264.7 cell model. This study is the first to report about the potential role of germinated and heated foxtail millet as a source of dual antioxidant and anti-inflammatory peptides.

HMF causes anaphylactic symptoms by acting as a H1 receptor agonist

5-Hydroxymethylfurfural (HMF) can readily form by acid-catalyzed transformations of various sugars such as fructose, sucrose and to a lesser degree glucose, and is known to widely exist in various sugar-containing consumer products. Thus the potential health effect of HMF has been a subject of intensive studies. There have been earlier reports of HMF's undesirable effects at or above high micromolar concentrations. In this study, HMF is found to stimulate the H₁ receptor in vivo and in vitro. When assessed in cell culture and animal models, HMF was found to cause deformation of in cell culture studies of HUVECs at 50 μM, to increase the vascular permeability of paw skin at 1.0 mg/mL, and trigger symptoms of anaphylaxis in animal models at 32.5 μg/kg. At the molecular level, HMF was found to induce the release of NO and related cytokines, and trigger H₁ receptor-mediated inflammatory responses. Mutation studies also suggest the binding sites for HMF on the H₁ receptor. The findings described suggest the need for close monitoring of HMF contents in consumer products and their related side effects.

Formation and Antioxidant Activity of Maillard Reaction Products Derived from Different Sugar-amino Acid Aqueous Model Systems of Sesame Roasting

This investigation was carried out to offer insight into the formation and antioxidant activity of Maillard reaction products (MRPs) derived from various sugar-amino acid model systems active in the roasting of sesame seeds. Reducing sugars (glucose, fructose, and xylose) and amino acids (serine, cystine, arginine, and lysine) present in sesame seeds were used to prepare the MRPs at various reaction times, and then the effect of reaction time on the MRPs derived from the various model systems was investigated. Within the first 15 min, the amounts of free amino groups decreased around 40% remaining amino groups of Lys-sugar model and around 75% remaining amino groups of Arg-sugar model. Results indicated that reducing sugar and free amino groups decreased obviously in Lys- and Arg-model systems. Based on correlation coefficient of antioxidant activities assessment and MRP formation in the Lys- and Arg-model systems above 0.978 and an extremely significant correlation in Pearson test exists, a conclusion could be made that these model systems are critical contributing factors in MRP formation during the roasting of sesame seeds. These findings offer insight into the formation and antioxidation of MRPs during the sesame seeds roasting.

Maillard Reaction Products of Stir Fried Hordei Fructus Germinatus Are Important for Its Efficacy in Treating Functional Dyspepsia

Hordei Fructus Germinatus (HFG) has been used as a traditional medicine to treat functional dyspepsia (FD) in China. Stir fried HFG (F-HFG) containing Maillard reaction products (MRPs) is used more widely than the raw HFG (R-HFG). However, the exact mechanisms in its functionality remain unclear. This article investigated the effect of R-HFG, F-HFG, and MRPs on brain-gut peptides, gut microbiota, and digestive enzymes using an FD animal mode. After administration of R-HFG, F-HFG, and MRPs, higher mRNA expression level of gastrin (GAS) and lower mRNA expression level of vasoactive intestinal peptide (VIP) were exhibited in F-HFG and MRPs rats than R-HFG rats (P < .05). Furthermore, compared with the R-HFG group, the contents of motilin (MTL) and GAS showed an upward tendency, whereas the contents of VIP and chokcystokinin (CCK) showed a downward tendency in the F-HFG group. In addition, bacterial communities in the control, F-HFG, and MRPs groups clustered closely to one another, and bacterial communities in the model and recovery groups clustered together, whereas the bacterial communities in the R-HFG group were clustered into a category. Moreover, there were no apparent differences in brain-gut peptides and gut microbiota between the F-HFG and MRPs groups. However, after the oral administration of R-HFG, F-HFG, and MRPs, the level of digestive enzyme did not show a significant change as compared with the recovery group. These results indicated that the stronger effect of F-HFG could be attributed to the MRPs produced during stir frying, and MRPs possessed the effect of regulating brain-gut peptides and gut microbiota.

Remarkable impact of amino acids on ginsenoside transformation from fresh ginseng to red ginseng

Background

Amino acids are one of the major constituents in Panax ginseng, including neutral amino acid, acidic amino acid, and basic amino acid. However, whether these amino acids play a role in ginsenoside conversion during the steaming process has not yet been elucidated.

Methods

In the present study, to elucidate the role of amino acids in ginsenoside transformation from fresh ginseng to red ginseng, an amino acids impregnation pretreatment was applied during the steaming process at 120°C. Acidic glutamic acid and basic arginine were used for the acid impregnation treatment during the root steaming. The ginsenosides contents, pH, browning intensity, and free amino acids contents in untreated and amino acid–treated P. ginseng samples were determined.

Results

After 2 h of steaming, the concentration of less polar ginsenosides in glutamic acid–treated P. ginseng was significantly higher than that in untreated P. ginseng during the steaming process. However, the less polar ginsenosides in arginine-treated P. ginseng increased slightly. Meanwhile, free amino acids contents in fresh P. ginseng, glutamic acid-treated P. ginseng, and arginine-treated P. ginseng significantly decreased during steaming from 0 to 2h. The pH also decreased in P. ginseng samples at high temperatures. The pH decrease in red ginseng was closely related to the decrease in basic amino acids levels during the steaming process.

Conclusion

Amino acids can remarkably affect the acidity of P. ginseng sample by altering the pH value. They were the main influential factors for the ginsenoside transformation. These results are useful in elucidating why and how steaming induces the structural change of ginsenoside in P. ginseng and also provides an effective and green approach to regulate the ginsenoside conversion using amino acids during the steaming process.

5-Hydroxymethylfurfural Mitigates Lipopolysaccharide-Stimulated Inflammation via Suppression of MAPK, NF-κB and mTOR Activation in RAW 264.7 Cells

5-Hydroxymethylfurfural (5-HMF) is found in many food products including honey, dried fruits, coffee and black garlic extracts. Here, we investigated the anti-inflammatory activity of 5-HMF and its underlying mechanisms in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. 5-HMF pretreatment ranging from 31.5 to 126.0 μg/mL reduced the production of nitric oxide (NO), prostaglandin E2 (PGE2) and pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) in a concentration-dependent manner in LPS-stimulated cells. Moreover, 5-HMF-pretreated cells significantly down-regulated the mRNA expression of two major inflammatory mediators, nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and suppressed the production of pro-inflammatory cytokines, as compared with the only LPS-stimulated cells. 5-HMF suppressed the phosphorylation of extracellular regulated protein kinases (ERK1/2), c-Jun N-terminal kinase (JNK), IκBα, NF-κB p65, the mammalian target of rapamycin (mTOR) and protein kinase B (Akt). Besides, 5-HMF was proved to inhibit NF-κB p65 translocation into nucleus to activate inflammatory gene transcription. These results suggest that 5-HMF could exert the anti-inflammatory activity in the LPS-induced inflammatory response by inhibiting the MAPK, NF-κB and Akt/mTOR pathways. Thus, 5-HMF could be considered as a therapeutic ingredient in functional foods.

Contribution of Chemical Modifications and Conformational Epitopes to IgE Binding by Ara h 3

Roasting is known to change the allergenic properties of peanuts. To study these observations at a molecular level, the relationship of IgE binding to the structure of Ara h 3 from raw and roasted peanuts was assessed. Ara h 3 (A3) was purified from raw (R), light roast (LR) and dark roast (DR) peanuts, the purity was assessed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the secondary structures were compared with circular dichroism (CD) spectroscopy. In order to understand the contribution of structure to IgE binding, the R A3 was partially denatured (PD) by heat treatment (65 °C for 2 h), subjected to CD spectroscopy and IgE spot blot analysis with sera from peanut- allergic individuals. While we observed that the secondary structure of purified A3 from R and LR peanut in solution was affected by the reduction of disulfide bonds and heat treatment when purified from the peanut following the roasting process, only small alterations were seen in the secondary structure. The purified LR A3 bound higher levels of IgE than the RA3. CD spectroscopy of PD A3 revealed a reduction in the percentage of alpha helices, and serum IgE binding. Therefore, while A3 purified from roasted peanuts did not show significant changes in secondary structure, it showed higher IgE binding than R A3. Therefore, the higher IgE binding to LR A3 was more likely to be due to chemical modifications than structural changes. However, a decrease in the IgE binding was seen if R A3 was deliberately unfolded, indicating that the structure played an important role in IgE binding to A3.

Effects on the quality and health-enhancing properties of industrial onion waste powder on bread

Industrial onion waste powder (IOWP) was used as an additive in wheat flour at different levels: 0, 1, 2, 3, 4 and 5%. The effect of onion waste addition on the mixing properties of the dough and quality of bread was investigated. The mixing properties of the dough were determined by farinograph. The bread were characterized and evaluated for crumb hardness, crumb porosity, sensory properties, dietary fiber, total phenolic content and total flavonoids. DPPH and FRAP assays were carried out to measure antioxidant activity in vitro. The results indicated that IOWP could be used as a potential health-enhancing functional ingredient up to 3% level to produce bread enriched with dietary fiber, total phenolic compounds and total flavonoids, and characterized by high antioxidant activity and acceptable quality.

A New Compound Isolated from the Reduced Ribose-Tryptophan Maillard Reaction Products Exhibits Distinct Anti-inflammatory Activity

In this study, a compound of 532.24 Da named BF-4 was separated from the ribose-tryptophan Maillard reaction products by solvent extraction and purified through reverse phase high performance liquid chromatography. The purified compound BF-4 was identified as 3-((1 H-indol-3-yl)methyl)-8-(5-((1 H-indol-3-yl)methyl)-6-oxomorpholin-2-yl)-9-hydroxy-1,7,4-dioxazecan-2-one in accordance with 1D- and 2D-NMR spectra and LC-ESI-MS/MS analysis. BF-4 significantly reduced the production of nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α) in lipopolysaccharide-stimulated RAW 264.7 cells. It inhibited nuclear factor κB (NF-κB) activation and mitogen-activated protein kinase (MAPK) phosphorylation through suppressing phosphorylation of IκBα, P65, P38 and c-Jun N-terminal kinase (JNK). The anti-inflammatory activity of BF-4 was comparable to dexamethasone, and more importantly, BF-4 showed less cytotoxicity than dexamethasone on the normal human liver cell LO2. The results indicate that BF-4 is a promising anti-inflammatory agent with pharmaceutical potential.

Comparative study of the physicochemical, nutritional, and antioxidant properties of some commercial refined and non-centrifugal sugars

Three refined and four unrefined branded commercial sugars available in Korea were investigated in terms of pH, soluble solids, moisture, ash content, turbidity, color values, microbial profile, reducing power, 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities, cellular antioxidant activity, and total phytoconstituent (i.e. phenolic, flavonoid, mineral, sucrose, glucose, and fructose) contents using standard analytical protocols such as high-performance liquid chromatography, gas chromatography-flame ionization detector/mass spectrometry, and inductively coupled plasma atomic emission spectroscopy. All tested physicochemical parameters were within the recommended standard levels. Significantly high nutritional and antioxidant properties were observed for the unrefined sugars, especially AUNO® sugar, whereas a high sucrose content was detected for the refined sugars. Hence, this study revealed that the degree of purification affects the nutritional values and antioxidant potentials of sugars. The present findings also indicate that unrefined sugars can be used as sweeteners in sugar-based cuisine to obtain nutritional and antioxidant-rich foodstuff.

5-Hydroxymethylfurfural (HMF) levels in honey and other food products: effects on bees and human health

An organic compound known as 5-hydroxymethylfurfural (HMF) is formed from reducing sugars in honey and various processed foods in acidic environments when they are heated through the Maillard reaction. In addition to processing, storage conditions affect the formation HMF, and HMF has become a suitable indicator of honey quality. HMF is easily absorbed from food through the gastrointestinal tract and, upon being metabolized into different derivatives, is excreted via urine. In addition to exerting detrimental effects (mutagenic, genotoxic, organotoxic and enzyme inhibitory), HMF, which is converted to a non-excretable, genotoxic compound called 5-sulfoxymethylfurfural, is beneficial to human health by providing antioxidative, anti-allergic, anti-inflammatory, anti-hypoxic, anti-sickling, and anti-hyperuricemic effects. Therefore, HMF is a neo-forming contaminant that draws great attention from scientists. This review compiles updated information regarding HMF formation, detection procedures, mitigation strategies and effects of HMF on honey bees and human health.

Fluorescent Carbon Dots Derived from Maillard Reaction Products: Their Properties, Biodistribution, Cytotoxicity, and Antioxidant Activity

Food-borne nanoparticles have received great attention because of their unique physicochemical properties and potential health risk. In this study, carbon dots (CDs) formed during one of the most important chemical reactions in the food processing field, the Maillard reaction from the model system including glucose and lysine, were investigated. The CDs purified from Maillard reaction products emitted a strong blue fluorescence under ultraviolet light with a fluorescent quantum yield of 16.30%. In addition, they were roughly spherical, with sizes of around 4.3 nm, and mainly composed of carbon, oxygen, hydrogen, and nitrogen. Their surface groups such as hydroxyl, amino, and carboxyl groups were found to possibly enable CDs to scavenge DPPH and hydroxyl radicals. Furthermore, the cytotoxicity assessment of CDs showed that they could readily enter HepG2 cells while causing negligible cell death at low concentration. However, high CDs concentrations were highly cytotoxic and led to cell death via interference of the glycolytic pathway.

Effect of Temperature on Flavor Compounds and Sensory Characteristics of Maillard Reaction Products Derived from Mushroom Hydrolysate

Maillard reaction products (MRPs) were prepared from mushroom hydrolysate (MH) by heating with d-xylose and l-cysteine at various temperatures (100 °C-140 °C) for 2 h at a pH of 7.4. The sensory characteristics of MH and MRPs were evaluated by panelists and volatile compounds were analyzed by GC/MS. Additionally, partial least squares regression (PLSR) was performed to analyze the correlation between quantitative sensory characteristics and GC/MS data. GC/MS results revealed that higher reaction temperature resulted in more nitrogen and sulfur containing compounds in MRPs while alcohols, ketones and aldehydes were the major flavor compounds obtained in MH. PLSR results showed that 3-phenylfuran and 2-octylfuran were the compounds responsible for the caramel-like flavor; 1-octen-3-ol, (E)-2-octen-1-ol and geranyl acetone were significantly and positively correlated to mushroom-like flavor, whereas, 2-thiophene-carboxaldehyde, 2,5-thiophenedicarboxaldehyde and 3-methylbutanal positively affected MRPs meat-like attribute. Overall, 125 °C was identified as the optimal temperature for preparing MRPs with abundant volatile compounds and favorable sensory characteristics; the concentration of free amino acids and 5'-GMP, which are associated with the umami taste, in MRPs derived under 125 °C were 3 to 4 times higher than those in MH.

Anti-inflammatory bowel effect of industrial orange by-products in DSS-treated mice

Pectin, phenolic compounds and/or Maillard reaction products present in orange by-products may exert an anti-inflammatory bowel effect in DSS-treated mice.

Rapid determination and conversion study of 5-hydroxymethylfurfural and its derivatives in glucose injection

5-HMF and two identified additional derivatives (II, III) in glucose injection were rapidly separated in less than 7 min for the first time by our normal phase high performance liquid chromatography. The results were more precise than the method adopted by pharmacopeias.

Anti-inflammatory effect of glucose-lysine Maillard reaction products on intestinal inflammation model in vivo

Inflammatory bowel diseases (IBDs) are chronic disorders that are characterized by intestinal epithelial inflammation and injury. Currently, the most employed therapies are antibiotics and anti-inflammatory drugs; however, the side effects limit long-term effectiveness. We evaluated the impact of glucose-lysine Maillard reaction products (Glc-Lys MRPs) on colitis, induced in rats by an administration of 5% dextran sulfate sodium (DSS) in drinking water. Glc-Lys MRPs ameliorate DSS-induced colitis, as determined by a decrease in disease index activity, colon weight/length ratio, nitric oxide levels in serum, recovery of body weight loss, colon length and serum lysozyme levels. Furthermore, Glc-Lys MRPs increase the glutathione content and the activity of glutathione peroxidase, superoxide dismutase and catalase, and inhibit lipid peroxidation and myeloperoxidase activity in colon tissues. In particular, Glc-Lys MRPs suppress the mRNA level of the inflammatory cytokines and nuclear factor-κB in colon tissues. This study suggests the potential of Glc-Lys MRPs in preventing or treating IBDs.

Hot water extracts of pressure-roasted dried radish attenuates hepatic oxidative stress via Nrf2 up-regulation in mice fed high-fat diet

This study investigated the effect of pressure-roasted dried radish (PRDR) against oxidative stress. To prepare PRDR extract, dried radish (DR) was pressure-roasted, boiled, and then freeze-dried. Mice fed a chow diet with oral administration of distilled water (DW) (normal group) or a high-fat diet with DW (control, CON group), DR (DR group, 237 mg/kg bw/day), or PRDR (PRDR group, 237 mg/kg bw/day) (n = 8 each group) for 12 weeks. Hepatic lipid peroxidation level in the DR and PRDR groups was lower than that in the CON group, whereas hepatic glutathione level in these groups was higher (p < 0.05). Hepatic expression of nuclear factor (erythroid-derived 2)-like 2 and its related antioxidant enzymes such as catalase, glutathione S-transferase, and peroxidases was the highest in the PRDR group (p < 0.05). It is apparent that radish attenuate oxidative stress and the process of pressure roasting might contribute positively to this effect.

Antioxidant and chelating capacity of Maillard reaction products in amino acid-sugar model systems: applications for food processing

BACKGROUND

Maillard reaction products (MRP) have gained increasing interest owing to their both positive and negative effects on human health. Aqueous amino acid-sugar model systems were studied in order to evaluate the antioxidant and chelating activity of MRP under conditions similar to those of food processing. Amino acids (cysteine, glycine, isoleucine and lysine) combined with different sugars (fructose or glucose) were heated to 100 and 130 °C for 30, 60 and 90 min. Antioxidant capacity was evaluated via ABTS and DPPH free radical scavenging assays, in addition to Fe²⁺ and Cu²⁺ ion chelating capacity.

RESULTS

In the ABTS assay, the cysteine-fructose model system presented the highest antioxidant activity at 7.05 µmol mL^-1 (130 °C, 60 min), expressed in Trolox equivalents. In the DPPH assay, the cysteine-glucose system presented the highest antioxidant activity at 3.79 µmol mL^-1 (100 °C, 90 min). The maximum rate of chelation of Fe²⁺ and Cu²⁺ was 96.31 and 59.44% respectively in the lysine-fructose and cysteine-glucose systems (100 °C, 30 min).

CONCLUSION

The model systems presented antioxidant and chelating activity under the analyzed temperatures and heating times, which are similar to the processing conditions of some foods. © 2017 Society of Chemical Industry.

Anti-inflammatory effect of sugar-amino acid Maillard reaction products on intestinal inflammation model in vitro and in vivo

The Maillard reaction is a nonenzymatic reaction between an amino acid and a reducing sugar that usually occurs upon heating. This reaction occurs routinely in cooking, generates numerous products, which are collectively referred to as Maillard reaction products (MRPs) contributing to aroma and color features. Advanced glycation end-products (AGEs) transformed from MRPs are participated in many types of inflammation reaction. In this study, various sugar-amino acid MRPs were prepared from three different amino acids (lysine, arginine, and glycine) and sugars (glucose, fructose, and galactose) for 1 h with heating at 121 °C. Treatment of lipopolysaccharide-stimulated RAW264.7 macrophages with the MRPs decreased nitric oxide (NO) expression compared to control without MRPs treatment. MRPs derived from lysine and galactose (Lys-Gal MRPs) significantly inhibited NO expression. The retentate fraction of Lys-Gal MRPs with cut-off of molecular weight of 3-10 kDa (LGCM) suppressed NO expression more effectively than did Lys-Gal MRPs. The anti-inflammatory effect of LGCM was evaluated using a co-culture system consisting of Caco-2 (apical side) and RAW264.7 or THP-1 (basolateral side) cells to investigate the gut inflammation reaction by stimulated macrophage cells. In this system, LGCM prevented a decreased transepithelial electrical resistance, and decreased both tumor necrosis factor-α production in macrophages and interleukin (IL)-8 and IL-1β mRNA expression in Caco-2 cells. In co-culture and in vivo dextran sulfate sodium (DSS)-induced colitis model study, we also observed the anti-inflammatory activity of LGCM.