Xiujin Chen

Small-molecule α-dicarbonyl compounds (α-DCs), including glyoxal, methylglyoxal and diacetyl, are electrophilic compounds characterized by two adjacent carbonyls. These compounds ubiquitously occur in various foods and food–medicine homologous herbs, generated via the Maillard reaction, caramelization, lipid peroxidation, and enzymatic reactions during thermal treatment and storage. Upon oral intake, small-molecule α-DCs are rapidly absorbed into systemic circulation, triggering protein and DNA damage, as well as inflammation. They also serve as important precursors to derive other hazards, such as advanced glycosylation end products possessing carcinogenic and genotoxic properties. Small-molecule α-DCs and their derived harmful products accelerate the progression of multiple metabolic diseases, e.g., cancer and diabetes. However, their pathological processes remain poorly elucidated, necessitating highly sensitive and accurate analytical methods. This review also systematically summarizes and discusses the current analytical techniques targeting small-molecule α-DCs. Chromatography and chromatography–mass spectrometry are still frequently used techniques. Given the polarity and weak ultraviolet absorption of small-molecule α-DCs, tedious pretreatment is necessary yet time-consuming. Novel rapid detection techniques such as mass spectrometry probes and direct ionization mass spectrometry have been proposed in recent years. Even so, developing rapid, eco-friendly, highly sensitive and accurate analytical methods remains a key priority for future research.

The instability of pigments and non-quantitative indication limit the application of intelligent labels in food freshness monitoring. Natural anthocyanins face challenges including photodegradation and difficulty in quantifying shrimp freshness. To solve these problems, this study prepared a colorimetric intelligent label with UV-shielding and real-time monitoring functions. Carbon-coated nano-TiO₂ (C-TiO₂) was synthesized by the hydrothermal method and combined with blueberry anthocyanins (BAs) in an agarose (AG)/gellan gum (GG)/glycerol matrix. The label properties were characterized and a remaining shelf-life prediction model was established based on the correlation between label color difference (ΔE) and shrimp total volatile basic nitrogen (TVB-N). The results demonstrated that C-TiO₂ could enhance compatibility and color stability, and maintain mechanical properties. After 24 h of ultraviolet irradiation, the BA degradation rate was 98.4% in the GAB group and 62.8% in the GABT-0.05 group, representing a reduction of 35.6% compared to the former. This indicates that the addition of C-TiO₂ significantly enhanced photostability. The predictive model demonstrated an error below 10% at both 10 °C and 20 °C conditions, indicating its potential for shelf-life prediction applications. This dual-functional label provides a reliable method for visual and quantitative evaluation of shrimp freshness.

In this work, a ratiometric fluorescent method for carbaryl detection is reported. We found that the combination of rapid hydrolysis of carbaryl and cetyltrimethylammonium bromide (CTAB) emulsification could significantly enhance the intrinsic weak blue fluorescence of carbaryl. By using red fluorescent glutathione-gold nanoculsters (GSH-Au NCs) as a reference signal, ratiometric detection of carbaryl within 3 min was successfully achieved. The method exhibited high sensitivity, with a linear response to carbaryl in the range from 1.0 to 70 ng/mL and an LOD of 0.05 ng/mL. The method was applied for detection of carbaryl in apple and cabbage samples, and recovery rates of 90~101% and 93~110%, respectively, were obtained. These results show that the proposed method for carbaryl detection has great potential for application in food sample monitoring.

With the increasingly serious problem of aminoglycoside antibiotic residues, it is imperative to develop rapid, sensitive and efficient detection methods. This article reviews the detection methods of aminoglycoside antibiotics in animal-derived foods, including enzyme-linked immunosorbent assay, fluorescent immunoassay, chemical immunoassay, affinity sensing assay, lateral flow immunochromatography and molecular imprinted immunoassay. After evaluating the performance of these methods, the advantages and disadvantages were analyzed and compared. Furthermore, development prospects and research trends were proposed and summarized. This review can serve as a basis for further research and provide helpful references and new insights for the analysis of aminoglycoside residues. Accordingly, the in-depth investigation and analysis will certainly make great contributions to food safety, public hygiene and human health.

Ochratoxin A (OTA) is a widely distributed mycotoxin that often contaminates food, grains and animal feed. It poses a serious threat to human health because of its high toxicity and persistence. Therefore, the development of an inexpensive, highly sensitive, accurate and rapid method for OTA detection is imperative. In recent years, various nanomaterials used in the establishment of aptasensors have attracted great attention due to their large surface-to-volume ratio, good stability and facile preparation. This review summarizes the development of nanomaterial-based aptasensors for OTA determination and sample treatment over the past 5 years. The nanomaterials used in OTA aptasensors include metal, carbon, luminescent, magnetic and other nanomaterials. Finally, the limitations and future challenges in the development of nanomaterial-based OTA aptasensors are reviewed and discussed. Graphical abstract

The aptasensors have received extensive attention and been widely used in various targets, however, the development of aptamer based LFA (Apt-LFA) is still far behind, especially for small molecule targets detection. The shortcoming of long response time severely hindered the Apt-LFA strip application in on-site detection of small molecules contaminants in environment and foods. Herein, we introduce bivalent triple helix aptamer (BTHA) and nanozyme yielding an accelerated and signal amplified LFA for acetamiprid detection. We obtained a BTHA with two 10 nt arms, which could shorten the response time between the aptamer and acetamiprid by 6 times, thus dramatically accelerating the detection of acetamiprid. Moreover, we integrate Au@Pt nanozyme to further amplify the detection signal by catalyzing the color development of substrate. In conjunction with smartphone-based analytical device, the Apt-LFA strip enabled the on-site quantitative detection of acetamiprid residue. It is believed that our strategy will facilitate the development of Apt-LFA against small molecule contaminants.

Simple immuno-magnetic separation tandem fluorescent probes based on quantum dots-antibody (QDs-Ab) were developed to detect Salmonella with sensitivity of 500 cfu mL⁻¹. With two monoclonal antibodies, which recognize different antigenic determinant on the surface of Salmonella, we prepared antibody-coated magnetic nanoparticles (MNPs) and conjugates of QDs-Ab. The immune-magnetic beads were verified with high enrichment efficiency for Salmonella (90%). A sandwich structure formed if the Salmonella solution was mixed together with immune-beads and QDs-Ab, and the fluorescent single from QDs was related to the amount of Salmonella. A linear response between fluorescence intensity and various concentrations of Salmonella (2.5 × 10³ to 1.95 × 10⁸ cfu mL⁻¹) were observed with this proposed method. The total assay time for Salmonella was 30 min, and no cross-reaction to other microbial strains, such as Staphylococcus aureus, Escherichia coli (E. coli) and Escherichia coli O157:H7 (E. coli O157:H7), were found using this detection system. All our results showed that the simple homogeneous immunoassay could be applied in Salmonella screening without time-consuming extra-enrichment of bacteria.