Determination of multiple mycotoxins in chili powder using cold-induced liquid-liquid extraction and Fe3O4@MWCNTs-NH2 coupled with UPLC-Q-TOF/MS.

Food matrix interference is still a big challenge in analyzing multiclass mycotoxins. Herein, a novel cold-induced liquid-liquid extraction-magnetic solid phase extraction (CI-LLE-MSPE) coupled with ultra-high performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS) method was explored for the simultaneous determination of multiple mycotoxins in chili powders. Fe3O4@MWCNTs-NH2 nanomaterials were prepared and characterized, and the factors affecting the MSPE process were investigated. Based on this, the CI-LLE-MSPE-UPLC-Q-TOF/MS method was established for determining ten mycotoxins in chili powders. The proffered technique eliminated the matrix interference effectively and demonstrated strong linearity (0.5-500 µg/kg, R2 ≥ 0.999), high sensitivity (limit of quantification was 0.5-1.5 µg/kg), and the recovery was 70.6%-111.7%. The extraction process is simpler than conventional methods, as the adsorbent can be separated using magnets, and reusable adsorbents are beneficial in reducing costs. In addition, the method can provide a valuable reference for pretreatment procedures for other complex matrices.

In vitro bioaccessibility evaluation of pheophytins in gelatin/polysaccharides carrier.

The type of carrier agent could impact pheophytin stability and bioaccessibility. Hence, it is important to have an elaborate understanding on the extent and type of pheophytin transformation during in vitro digestion of microcapsules. Four kinds of protein/polysaccharides complex were used to fabricate pheophytin microcapsules and investigated for pigments bioaccessibility. With different carriers, pheophytin pigments showed new characteristics influencing particle size and zeta potential during in vitro digestion. Pheophytin b was widely transformed to pheophorbide b, confirming pheophorbidation of the b series in proper condition. No 151-hydroxy lactone chlorophyll or pheophytin derivatives were detected, indicating some protective effect of microencapsulation. Pheophytins loaded in gelatin-pectin complex exhibited a relatively higher recovery rate, micellarization rate, and bioaccessibility index. The result presented in this study shows that the type of carrier agent could initiate the removal of phytyl groups in pheophytins and also inhibit or mediate their bioaccessibility.

Utilization of different carrier agents for chlorophyll encapsulation: Characterization and kinetic stability study.

Chlorophyll-loaded nano/microparticles were fabricated using zein, casein, and whey protein isolate as carrier agents. Chlorophyll was adequately loaded in these wall materials with encapsulation efficiency, loading capacity, and particle size ranging from 83.6 to 96.3%, 0.8 to 5.5%, and 483 to 1020 nm respectively. As unveiled by differential scanning calorimetry (DSC), chlorophyll existed in a non-crystalline state inside the different wall materials. The encapsulation techniques and different carrier agents were effective in protecting chlorophyll from acid pH (pH 2 to 6, chlorophyll retention; 39.3 to 97.8%) and light (chlorophyll retention; 41.6 to 65.5%) conditions. Employing the first-order model to investigate the thermal degradation kinetics of the different chlorophyll loaded nano/microparticles showed activation energy, Gibbs free energy, enthalpy, and entropy change ranging from 49.6 to 70.1 kJ/mol, 93.4 to 100.0 kJ mol-1, 46.6 to 67.4 kJ mol-1, and -147.8 to -86.4 J mol-1 K-1, respectively.