RESUMO
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.
Assuntos
Clorofilídeos/análise , Gorduras Insaturadas na Dieta/análise , Corantes de Alimentos/análise , Contaminação de Alimentos , Inspeção de Alimentos/métodos , Óleos de Plantas/química , Clorofila/análogos & derivados , Clorofila/análise , Cromatografia Líquida de Alta Pressão , Gorduras Insaturadas na Dieta/economia , Indústria de Processamento de Alimentos/economia , Frutas/química , Guias como Assunto , Resíduos Industriais/análise , Resíduos Industriais/economia , Limite de Detecção , Azeite de Oliva/química , Azeite de Oliva/economia , Azeite de Oliva/normas , Feofitinas/análise , Fotometria , Óleos de Plantas/normas , Sementes/química , Espectrofotometria Ultravioleta , Taiwan , Espectrometria de Massas em Tandem , Vitis/químicaRESUMO
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.
