Metal–organic frameworks/titanium dioxide (UiO-66-NH₂/TiO₂) nanocomposites have been prepared by a simple hydrothermal reaction and they exhibit excellent electrocatalytic activity for chlorogenic acid oxidation due to the synergic effect of UiO-66-NH₂ and TiO₂. Under the optimal conditions, the sensor can be employed in the quantification of chlorogenic acid in the ranges of 0.01–1.0 μmol L⁻¹ and 1.0–15 μmol L⁻¹ with an ultralow detection limit of 7 nmol L⁻¹ (S/N = 3). Moreover, UiO-66-NH₂/TiO₂ nanocomposites demonstrate significant stability in acidic buffer solution and maintain their electrocatalytic activities at least up to 90 cycles. The potential utility was validated by the analysis of coffee and tea samples and good recoveries were obtained from different spiked values. The UiO-66-NH₂/TiO₂ based sensor with highly sensitive, selective and stable consecutive monitoring of chlorogenic acid is a promising candidate for the construction of highly active electrocatalyst in electrochemical biosensors.

Methyl-branched aldehydes, especially 3-methylbutanal, have been reported to be perceived either as a malty or as a nutty/chocolate-like aroma and were considered an important flavor contributor in fermented meat products. Decomposition of leucine (Leu) by branched-chain amino acid transaminase (BACT) is a crucial step in the metabolism of Leu to 3-methylbutanal. This study was conducted to explore the effects of mixed-starter culture (Lactobacillus fermentum YZU-06 and Staphylococcus saprophyticus CGMCC 3475) and addition of Leu (0, 1, and 3 mM) on the flavor and quality of fermented sausages. The pH, water activity, texture profile analysis, color, counts of lactic acid bacteria (LAB) and staphylococci, peptide, and flavor compounds were detected during fermentation. The results showed that the starter culture group increased hardness, elasticity, the counts of LAB and staphylococci, peptide content, volatile flavor compounds, as well as the sensorial scores of sausage, while decreasing pH, a_w, and L* and b* values compared with the non-inoculation group. The mixed starter of adding with 3 mM Leu enhanced the content of 3-methylbutanal and overall flavor of fermented sausages. It is applicable to directionally produce methyl-branched aldehydes and improve the overall quality of fermented sausage by the addition of Leu and using starter of L. fermentum YZU-06 and S. saprophyticus CGMCC 3475.

To investigate the role of sulfhydryl groups and disulfide bonds in different protein-stabilized emulsions, N-ethylmaleimide (NEM) was used as a sulfhydryl-blocking agent added in the emulsion. The addition of NEM to block the sulfhydryl groups resulted in a reduction in disulfide bond formation, which enabled the internal structure of the protein molecule to be destroyed, and then decreased the restriction of protein membrane on the oil droplets. Furthermore, with the NEM content increasing in the emulsion, a reduction in the protein emulsifying activity and emulsion stability also occurred. At the same time, the intermolecular interaction of the protein on the oil droplet interface membrane was destroyed, and the emulsion droplet size increased with the NEM content in the emulsion. Although NEM blocking sulfhydryl groups from forming disulfide bonds has similar effects on three types of protein emulsion, the degree of myofibrillar protein (MP), egg-white protein isolate (EPI), and soybean protein isolate (SPI) used as emulsifiers had a subtle difference.