Advanced glycation end products (AGEs) are a class of heterogeneous compounds formed by the Maillard reaction between reducing sugars and free amino groups of proteins. Studies have found that dietary AGEs can be accumulated in the body, causing hazardous effects on human health. Therefore it is necessary to carry out detection and analysis of typical AGEs in foods. Currently, due to the wide variety and complex structure of dietary AGEs, there is a lack of general analytical methods for their detection. Therefore, this paper presents a review of the structure and types of dietary AGEs, their relationship with human health, and their state-of-the-art detection technologies. A specific focus is put on the immunoassays and instrumental methods used for the detection of dietary AGEs as well as their characteristics, advantages, and disadvantages. Furthermore, this paper provides an outlook on the future research directions in this field. We expect that this review will provide references for the development of new methods for the detection of dietary AGEs and the establishment of related research systems.

A method was developed for the simultaneous determination of seven Maillard reaction products (MRPs), namely N^ε-(carboxymethyl)-lysine (CML), N^ε-(carboxyethyl)-lysine (CEL), methyglyoxal-derived hydroimidazolones (MG-H1, MG-H2 and MG-H3), glyoxal-derived hydroimidazolone (G-H1) and furosine in prepackaged foods by ultra-high performance liquid chromatography-triple quadrupole-tandem mass spectrometry (UPLC-QqQ-MS/MS). The chromatographic separation was performed on a Kinetex C₁₈ column and quantification was performed in the multiple reaction monitoring (MRM) mode. The recoveries of the method ranged from 88.4% to 111.3% with relative standard deviations (RSDs) less than 9% in terms of precision, and the limit of detection and the limit of quantification were 2.1–14.2 and 7.4–41.2 ng/mL, respectively. The developed method was applied to 134 typical prepackaged foods, and the obtained data was analyzed by principal component analysis (PCA) and correlation analysis (CA). The results showed that CML, MG-H1/3, MG-H2 and G-H1 were the major MRPs in prepackaged foods, and they had significant positive correlations with each other and with protein, fat and total sugar contents. This method shows acceptable linearity, accuracy and precision and is suitable for the rapid determination of multiple MRPs in prepackaged foods.

This study aimed at the epitope mapping and allergencity reduction of the wheat non-gluten allergen α-amylase inhibitor. Its linear epitopes were predicted by using bioinformatic prediction tools DNAstar, IMED, and IEDB. Six candidate epitopes were obtained by comprehensive analysis, and four linear epitopes were verified by using indirect competition enzyme-linked immunosorbent assay (ic-ELISA). The allergenicity of the allergen was reduced by interaction with polyphenols, A non-covalent complex of α-amylase inhibitor and epigallocatechin gallate (EGCG) was prepared and characterized by fluorescence spectroscopy, circular dichroism (CD) spectroscopy and ultraviolet (UV) spectroscopy, and the efficiency of allergenicity reduction was investigated by ic-ELISA. Results showed that the complex with a molar ratio of α-amylase inhibitor to EGCG of 1:30 had the lowest IgE-binding capacity. The binding capacity was reduced by 22.7%. Molecular docking simulations by using Autodock software further demonstrated that the allergenicity reduction was due to the interactions of the linear epitopes of α-amylase inhibitor and their nearby residues with EGCG. This study can provide a reference for the epitope mapping of wheat non-gluten allergens and the preparation of polyphenols to reduce their allergenicity.

At present, the incidence of food allergy is increasing worldwide. Food allergy has become a food safety and public health issue of growing concern. In addition to genetic factors, dietary factors are important factors causing increased risks of food allergy, and the intestinal microbiota plays an important mediating role between diet and the immune system. In view of this, this article systematically reviews recent studies on dietary risk factors for food allergy by summarizing the immunological mechanisms of action of different risk factors and the results of cohort studies and intervention experiments and by providing an in-depth discussion on the role of the intestinal flora in this regard. This review will provide references and new ideas for researchers to develop strategies for the prevention and control of food allergy, as well as understand the mechanism of food allergy using the intestinal microbiota as a target and develop regulatory strategies.

Simple yet efficient detection methods for food allergens are in urgent need to help people avoid the risks imposed by allergenic food. In this work, a polydopamine (PDA)-based fluorescent aptasensor was developed to detect arginine kinase (AK), one of the major allergens in shellfish. The aptamer towards AK was firstly selected via systematic evolution of ligands by exponential enrichment method and labeled with fluorescein amidite (FAM) to build a fluorescence resonance energy transfer (FRET) system with PDA particles. Polyethylene glycol (PEG) was employed to construct an antifouling surface for the aptasensor to eliminate food matrix interferences. With the presence of AK, the PDA-based aptasensor exhibited elevated fluorescent signals as the FAM-labeled aptamer bound to AK and detached from the PDA particles. The aptasensor showed great stability and resistance to nonspecific interference of background proteins and had a limit of detection (LOD) of 0.298 μg/mL. The proposed aptasensor was further proved to be feasible for quantitative analysis of AK in nine species of shrimps and five commercial processed products, which indicated its high potential in tracing the presence of AK in complex aquatic products.

Porphyra polysaccharide is a special kind of nutrient showing multiple physiological functions including regulating cell proliferation, but the detailed mechanisms are not fully revealed, impairing its further development and applications. This work was to purify and characterize the Porphyra haitanensis polysaccharide (PH), investigate its physiological function, and demonstrate the underlying mechanisms. The purified PH was first characterized by Fourier-transform infrared spectroscopy. Then an intestinal epithelial cell model was established, in which PH significantly suppressed cell hyperplasia. Specifically, PH activated the Hippo/YAP pathway, which subsequently activated mTOR pathway, however mTOR activated Hippo in the absence of PH. Moreover, both the inhibition of Hippo by YAP1 knock-down and the suppression of mTOR by rapamycin impaired PH function. These results indicated that PH attenuated hyperplasia activity by remodeling the cross-talk between Hippo/YAP and mTOR pathways, which revealed potential targets and approaches for treating hyperplasia-related diseases and provided novel ways to utilize P. haitanensis as well as other related functional foods.

D-tryptophan is a special kind of nonprotein amino acid showing multiple physiological functions, but the detailed mechanisms are not fully revealed, impairing its further development and applications. This work was to investigate D-tryptophan physiological function and demonstrate the underlying mechanisms. D-tryptophan suppressed HaCaT cell proliferation but increased cell migration. Specifically, D-tryptophan decreased E-cadherin and increased Snail, Twist, and Slug expression, resulting in the development of an epithelial-mesenchymal transitions (EMT) phenomenon. Moreover, D-tryptophan promoted the expression of transforming growth factor-β (TGF-β) 1, and Smad4 knockout damages D-tryptophan's ability. These results indicated that D-tryptophan stimulated HaCaT cells to produce TGF-β1 and thus activated the TGF-β/Samd pathway, resulting in the triggering of EMT. This study revealed the molecular mechanisms of D-tryptophan activity, provided D-tryptophan as a potential approach for cancer treatment, wound healing, organ development and other relevant applications.