Structural and photoactive properties of self-assembled peptide-based nanostructures and their optical bioapplication in food analysis.

BACKGROUND: Food processing plays an important role in the modern industry because food quality and security directly affect human health, life safety, and social and economic development. Accurate, efficient, and sensitive detection technology is the basis for ensuring food quality and security. Optosensor-based technology with the advantage of fast and visual real-time detection can be used to detect pesticides, metal ions, antibiotics, and nutrients in food. As excellent optical centres, self-assembled peptide-based nanostructures possess attractive advantages, such as simple preparation methods, controllable morphology, tunable functionality, and inherent biocompatibility. AIM OF REVIEW: Self-assembled peptide nanostructures with good fabrication yield, stability, dispersity in a complex sample matrix, biocompatibility, and environmental friendliness are ideal development goals in the future. Owing to its flexible and unique optical properties, some short peptide self-assemblies can possibly be used to achieve the purpose of rapid and sensitive detection of composition in food, agriculture, and the environment, expanding the understanding and application of peptide-based optics in analytical chemistry. KEY SCIENTIFIC CONCEPT OF REVIEW: The self-assembly process of peptides is driven by noncovalent interactions, including hydrogen bonding, electrostatic interactions, hydrophobic interactions, and π-π stacking, which are the key factors for obtaining stable self-assembled peptide nanostructures with peptides serving as assembly units. Controllable morphology of self-assembled peptide nanostructures can be achieved through adjustment in the type, concentration, and pH of organic solvents and peptides. The highly ordered nanostructures formed by the self-assembly of peptides have been proven to be novel biological structures and can be used for the construction of optosensing platforms in biological or other systems. Optosensing platforms make use of signal changes, including optical signals and electrical signals caused by specific reactions between analytes and active substances, to determine the content or concentration of an analyte.

Aroma Compounds in Chicken Broths of Beijing Youji and Commercial Broilers.

The unique flavor of Beijing Youji (BJY) chicken broth compared with that of commercial broilers (CB) was investigated by solvent-assisted flavor evaporation combined with AEDA/GC-O (aroma extract dilution analysis of gas chromatography-olfactometry), quantitation, and aroma recombination. A total of 71 odorants with almost the same major odorants (≥10 ng/g broth) were found by GC-O in both BJY and CB broths. However, BJY broth had thirty-two more extra odorants than CB broth, indicating the rich fragrance of the former. Aroma recombination and omission experiments demonstrated that 21 versus 17 odorants (with OAV ≥ 1) contributed significantly to BJY and CB broth aromas, respectively. Those key odorants mainly included sulfur-containing compounds and aliphatic aldehydes, such as 2-methyl-3-furanthiol, 3-(methylthio)propanal, ( E, E)-2,4-decadienal, etc. Furthermore, composition analysis of the meat suggested that the better flavor, with rather more odorants, of BJY broth is probably due to higher contents of polyunsaturated fatty acids and water-soluble flavor precursor, including ribose, cysteine, thiamine, etc., present in the BJY meat.

Health risk assessment of cadmium via dietary intake by adults in China.

BACKGROUND: Cadmium in the human diet constitutes a potential chronic hazard to health. The objective of this study was to make a health risk assessment of dietary cadmium intake by adults in the 31 provinces (excluding Hong Kong, Taiwan and Macau) of China. RESULTS: The cadmium levels in a total of 2629 individual food samples ranged from not detected (below the limit of detection) to 17.32 mg kg⁻¹, with the highest concentration being found in an offal sample. The food group 'meat' showed the highest mean level of 0.129 mg kg⁻¹, while the lowest concentration of 8.0×10⁻4 mg kg⁻¹ was measured in the food group 'fruit'. The mean cadmium intakes, hazard quotients and annual excess lifetime cancer risks for national, northern and southern adult populations in China were 3.67 µg kg⁻¹ body weight (BW) week⁻¹, 0.52 and 4.56×10⁻5 a⁻¹, 2.63 µg kg⁻¹ BW week⁻¹, 0.38 and 3.27×10⁻5 a⁻¹ and 4.56 µg kg⁻¹ BW week⁻¹, 0.65 and 5.67×10⁻5 a⁻¹ respectively. CONCLUSION: The results of risk characterization for the national adult population were lower than safety risk levels of hazard quotient and annual excess lifetime cancer risk (5×10⁻5 a⁻¹). The mean annual excess lifetime cancer risk for the southern adult population was higher than the safety risk level. Therefore the carcinogenic risk for the southern population is of concern.