Aflatoxin M₁ (AFM₁), one of the most toxic mycotoxins, is a feed and food contaminant of global concern. In this study, we developed a fast and simple method for detection of AFM₁ based on a structure-switching signaling aptamer. This aptasensor is based on the change in fluorescence signal due to formation of an AFM₁/aptamer complex. To generate the aptasensor, the specific aptamer was modified with FAM (carboxyfluorescein), and their complementary DNAs (cDNA) were modified with a carboxytetramethylrhodamine (TAMRA) quenching group. In the absence of AFM₁, the aptamers were hybridized with cDNA, resulting in quenching of the aptamer fluorescence due to the proximity of the aptamer’s fluorophore to the quenching group on the cDNA. On the other hand, in the presence of AFM₁, a structural switch in the aptamer was induced by formation of an AFM₁/aptamer complex. Changes in the structure of the aptamer led to the release of the cDNA, causing the generation of a fluorescence signal. Thus, AFM₁ concentrations could be quantitatively monitored based on the changes in fluorescences. Under optimized conditions, this assay exhibited a linear response to AFM₁ in the range of 1–100 ng/mL and a limit of detection of 0.5 ng/mL was calculated. This proposed aptasensor was applied to milk samples spiked with a dilution series of AFM₁, yielding satisfactory recoveries from 93.4 to 101.3%. These results demonstrated that this detection technique could be useful for high-throughput and quantitative determination of mycotoxin levels in milk and dairy products.

Bioactive peptides (BPs) are fragments of 2–15 amino acid residues with biological properties. Dietary BPs derived from milk, egg, fish, soybean, corn, rice, quinoa, wheat, oat, potato, common bean, spirulina, and mussel are reported to possess beneficial effects on redox balance and metabolic disorders (obesity, diabetes, hypertension, and inflammatory bowel diseases (IBD)). Peptide length, sequence, and composition significantly affected the bioactive properties of dietary BPs. Numerous studies have demonstrated that various dietary protein‐derived BPs exhibited biological activities through the modulation of various molecular mechanisms and signaling pathways, including Kelch‐like ECH‐associated protein 1/nuclear factor erythroid 2‐related factor 2/antioxidant response element in oxidative stress; peroxisome proliferator‐activated‐γ, CCAAT/enhancer‐binding protein‐α, and sterol regulatory element binding protein 1 in obesity; insulin receptor substrate‐1/phosphatidylinositol 3‐kinase/protein kinase B and AMP‐activated protein kinase in diabetes; angiotensin‐converting enzyme inhibition in hypertension; and mitogen‐activated protein kinase and nuclear factor‐kappa B in IBD. This review focuses on the action of molecular mechanisms of dietary BPs and provides novel insights in the maintenance of redox balance and metabolic diseases of human.

Remarkable advancements have been achieved in the development of rapid analytic techniques toward fumonisin B₁ (FB₁) monitoring and even trace levels for food safety in recent years. However, the point-of-care testing for quantitative and accurate FB₁ determination is still challenging. Herein, an innovative aptasensor was established to monitor FB₁ by utilizing graphene oxide (GO) and nuclease-triggered signal enhancement. GO can be utilized as a fluorescence quenching agent toward a fluorophore-modified aptamer, and even as a protectant of the aptamer from nuclease cleavage for subsequent target cycling and signal amplification detection. This proposed sensing strategy exhibited a good linearity for FB₁ determination in the dynamic range from 0.5 to 20 ng mL⁻¹ with a good correlation of R² = 0.995. Its limit of detection was established at 0.15 ng mL⁻¹ (S/N = 3), which was significantly lower than the legal requirements by three orders of magnitude. The interferent study demonstrated that the introduced aptasensor possessed high selectivity for FB₁. Moreover, the aptasensor was successfully applied to the detection of wheat flour samples, and the results were consistent with the classical ELISA method. The rapid response, sensitive and selective analysis, and reliable results of this sensing platform offer a promising opportunity for food mycotoxin control in point-of-care testing.