Determination of toxic α-dicarbonyl compounds in sesame oils using dispersive liquid-liquid microextraction coupled with gas chromatography-mass spectrometry.

Glyoxal, methylglyoxal, and diacetyl are toxic α-dicarbonyl compounds found in heat-processed foods, including edible oils. Dispersive liquid-liquid microextraction was combined with gas chromatography mass spectrometry to determine the glyoxal, methylglyoxal, and diacetyl contents in sesame oil. Chloroform and methanol were selected as the optimal extraction and dispersive solvents, respectively. The maximum derivatization efficiency was obtained using 500 µg of the derivatization agent, o-phenylenediamine. The derivatization of glyoxal was completed in 1 h, whereas those of methylglyoxal and diacetyl were completed immediately. The optimized method was validated, and was found to exhibit a good linearity, recovery, intraday repeatability, and interday reproducibility. The α-dicarbonyl compound concentrations in the oils were dependent on the roasting temperature. The sesame oil concentrates contained 0-175.4, 0-990.5, and 0-220.9 ng g-1 of glyoxal, methylglyoxal, and diacetyl, respectively. For the perilla oils, the respective concentrations were 0-96.4, 0-410.8, and 0-197.5 ng g-1.

Novel QuEChERS-ultra-performance liquid chromatography-atmospheric-pressure chemical ionization tandem mass spectrometry method for the simultaneous determination of vitamin D and vitamin K in vitamin-fortified nanoemulsions.

Nanoemulsion is a new vehicle for food fortification. In this study, a simple and reliable method for the simultaneous analysis of vitamins D2, D3, K1, and K2 in vitamin-fortified nanoemulsions was developed using QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction and ultra-high performance liquid chromatography-atmospheric-pressure chemical ionization tandem mass spectrometry techniques. Response surface methodology was employed to optimize the extraction parameters. The method was validated for the vitamins in terms of LOD (0.03-0.25 µg/L), LOQ (0.10-0.77 µg/L), intra-day (≤4.50%), inter-day precisions (≤6.43%), and accuracy (98.5%-108.0%). The recoveries of the vitamin-fortified nanoemulsion and yogurt were in the ranges of 104.0%-109.2% and 73.3%-85.2%, respectively. The solvent consumption and analysis time were reduced by 5.6 and 3.3 folds, respectively, rendering it superior to the traditional extraction methods established by the Association of Official Analytical Chemists and the Ministry of Food and Drug Safety.

Impacts of fat types and myofibrillar protein on the rheological properties and thermal stability of meat emulsion systems.

Studies have shown the effects of fat or oil types and myofibrillar protein on meat emulsions. In this study, fat extracted from pork, beef, chicken, and duck, as well as corn oil, was used to emulsify the extracted porcine myofibrillar protein. We evaluated the thermal and rheological properties, emulsion stability, texture profiles, fatty acid compositions, and microstructures of these meat emulsions. Meat emulsions containing animal fat had lower emulsion stability and better thermal stability, rheological properties, and hardness than those containing oil. The ratio of polyunsaturated fatty acids in the meat emulsion containing corn oil was the highest, followed by duck, chicken, pork, and beef fat emulsions. Of the animal fat emulsions, chicken might be the best fat source when emulsifying porcine protein because of the high thermal and emulsion stability, rheological properties, and fatty acid composition of the emulsion and well-distributed fat particles in it.