RESUMEN
Cu-pyropheophytin a, the major Cu-pigment of Cu-chlorophyll, was determined in edible oil by high-resolution mass spectrometry with a high-performance liquid chromatography-quadrupole (HPLC-Q)-Orbitrap system and by HPLC coupled with a photodiode-array detector. Respective limit of detection and limit of quantification levels of 0.02 µg/g and 0.05 µg/g were obtained. Twenty-nine commercial oil products marked as olive oil, grapeseed oil and blended oil, all sourced directly from a food company that committed adulteration with Cu-chlorophyll, were investigated. In this company, four green dyes illegally used in oils were seized during factory investigation by the health authorities. The food additive Cu-pyropheophytin a was found in all confiscated samples in concentrations between 0.02 and 0.39 µg/g. Survey results of another 235 commercial oil samples manufactured from other companies, including olive pomace oil, extra virgin olive oil, olive oil, grapeseed oil and blended oil, indicated high positive incidences of 63%, 39%, 44%, 97% and 8%, respectively, with a concentration range between 0.02 and 0.54 µg/g. High Cu-chlorophyll concentrations are indications for fraudulent adulteration of oils.
Asunto(s)
Clorofilidas/análisis , Grasas Insaturadas en la Dieta/análisis , Colorantes de Alimentos/análisis , Contaminación de Alimentos , Inspección de Alimentos/métodos , Aceites de Plantas/química , Clorofila/análogos & derivados , Clorofila/análisis , Cromatografía Líquida de Alta Presión , Grasas Insaturadas en la Dieta/economía , Industria de Procesamiento de Alimentos/economía , Frutas/química , Guías como Asunto , Residuos Industriales/análisis , Residuos Industriales/economía , Límite de Detección , Aceite de Oliva/química , Aceite de Oliva/economía , Aceite de Oliva/normas , Feofitinas/análisis , Fotometría , Aceites de Plantas/normas , Semillas/química , Espectrofotometría Ultravioleta , Taiwán , Espectrometría de Masas en Tándem , Vitis/químicaRESUMEN
A high-performance liquid chromatography (HPLC) method was developed for the determination of maleic acid which was released from starch maleate (SM) through the alkaline hydrolysis reaction. The proper alkaline hydrolysis conditions and LC separation are reported in this study. The starch samples were treated with 50% methanol for 30 minutes, and then hydrolyzed by 0.5N KOH for 2 hours to release maleic acid. A C18 column and gradient mobile phase consisting of 0.1% phosphoric acid and methanol at a flow rate of 1.0 mL/minute were used for separation. The method showed a good linearity in the range of 0.01-1.0 ìg/mL, with a limit of quantification (LOQ) at 10 mg/kg in starch. The recoveries in corn starch, noodle, and fish balls were between 93.9% and 108.4%. The relative standard deviation (RSD) of precision was <4.9% (n = 3). This valid method was rapid, sensitive, precise, and suitable for routine monitoring of the illegal adulteration of SM in foods.