Ultrasonic-microwave synergistic supramolecular solvent liquid-liquid microextraction of trace biogenic amines in fish and beer based on solidification of floating organic droplet.

It is important to detect the presence of biogenic amines (BAs) as indicators of food freshness. The purpose of this study was to develop a novel ultrasonic-microwave synergistic supramolecular solvent liquid-liquid microextraction based on solidification of floating organic droplet (UMS-SUPRAS-SFO-LLME) combined with high-performance liquid chromatography for the determination of BAs. The physical properties and microstructure of SUPRAS based on 1-dodecanol and tetrahydrofuran were studied, and the extraction conditions such as the SUPRAS volume, the UMS process, and the centrifugal conditions were optimized. The results for the extraction kinetics and thermodynamics showed that UMS-SUPRAS-SFO-LLME is a spontaneous, endothermic diffusion process. The linear ranges of this method are 0.1-2.0 × 105 ng·mL-1 (R2 > 0.994), the limits of detection are 4.0 × 10-3-6.0 × 10-2 ng·mL-1, and the recoveries were 96.28-103.15%. Compared with existing analysis methods, UMS-SUPRAS-SFO-LLME is a sensitive, green and economical sample pretreatment method for analyzing the enrichment of BAs in beer and fish.

Effects of Konjac Glucomannan/ε-Polylysine Hydrochloride/Ferulic Acid Composite Coating on the Freshness Preservation Performance and Flavor of Refrigerated Sea Bass Fillets.

Coating preservation has a remarkable effect on the preservation of aquatic products. This work prepared a composite coating using konjac glucomannan (KGM) as the film-forming matrix and ε-polylysine hydrochloride (ε-PL) and ferulic acid (FA) as the preservative. Three types of treated sea bass (KGM, KGM-ε-PL, and KGM-ε-PL-FA) and untreated sea bass were stored at 4 °C for 20 days to compare freshness changes under different treatment conditions. The results showed that the surface color and texture of sea bass in refrigerated storage changed dramatically and deteriorated as storage time increased. The composite coating treatment was significantly different from the control group. Using Gas-phase ion migration spectrometry (GC-IMS) technology, 32 volatile compounds, such as aldehydes, alcohols, and ketones, were found in fillets during flavor quality analysis. The composite coating can successfully inhibit the formation of odor compounds such as 2-nonenone, isoamyl alcohol monomer, ammonia, and trimethylamine, delaying the deterioration of fish and improving freshness. Among them, KGM-ε-PL-FA composite coating has the most remarkable preservation performance, which significantly inhibits the occurrence of rotten odor, and has a potential application prospect in the field of food preservation.

Significantly Different Lipid Profile Analysis of Litopenaeus vannamei under Low-Temperature Storage by UPLC-Q-Exactive Orbitrap/MS.

Low-temperature storage is one of the most important preservation methods for aquatic product storage. However, the effects of low-temperature storage on the lipid profiles of shrimp are unclear. Herein, UPLC-Q-Exactive Orbitrap/MS combined with LipidSearch software was applied to analyze the effect of three low storage temperatures (4 °C, -2 °C, and -18 °C) on the lipidomics of Litopenaeus vannamei. A total of 15 lipid classes were analyzed, and PC, PE, DG, and TG accounted for vast majority of peak areas. Furthermore, 531 individual lipid variables enriched in 12 metabolic pathways were identified via bioinformatics analysis methods. A total of 56 significantly different lipid molecular species (55 belonging to PC, PE, DG, and TG) were selected as potential biomarkers of lipid oxidation via correlational analysis between physical properties (texture and color) and individual lipid variables. The results indicated that the three low storage temperatures caused different effects on the lipidomics profile of L. vannamei, and PC, PE, DG, and TG could become potential focuses in further studies of lipid oxidation in L. vannamei.