Phenolic acids, flavanols, flavonols, flavones and dihydrochalcones are found in apples. An extraction procedure with minimal pre-treatment and an ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/ MS) method have been validated to determine polyphenols in flesh and peel of several varieties of apples (Golden, Granny, Pink Lady, Red, Royal, Ambrosia and Fuji). The varieties with the highest concentration of phenolic compounds in flesh were Granny and Fuji (793.8 and 793.1 mg/kg dry weight (DW), respectively), whereas the highest concentration in peel was obtained in Pink Lady (4,106.7 mg/kg DW), showing significant differences in relation to the other varieties. The peel of apple showed higher polyphenolic content than flesh because of the high levels of flavonols glycosides, epicatechin and phloridzin. The phenolic content in fresh-cut apple (Royal variety) was also evaluated, observing a higher concentration of phenolic compounds in fresh apple (562.8 and 3,339.5 mg/kg DW in flesh and peel, respectively) than in fresh-cut apple (375.8 and 2,475.3 mg/kg DW in flesh and peel, respectively).
A new method has been developed and validated for the simultaneous determination of four biogenic (putrescine, cadaverine, histamine, and tyramine) and three volatile amines (trimethylamine, triethylamine, and tripropylamine) in anchovy. Separation and determination of the selected compounds were carried out by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS), using an electrospray ionization source (ESI) in positive ion mode. Chromatographic separation was carried out using an aqueous solution of formic acid (0.1%) and methanol as mobile phase in gradient mode. The method was validated, and mean recoveries were evaluated at three concentration levels (75, 150, and 250 μg/kg), ranging from 70 to 110% at the three levels assayed. Intra- and interday precision, expressed as relative standard deviation (RSD), were lower than 15% and 20%, respectively. Limits of quantitation (LOQs) were 25 μg/kg for all cases, except for that of TMA, which was set at 60 μg/kg. The developed procedure was applied to determine the target compounds in anchovy samples stored during 7 days at 4 °C, observing the increasing in the concentration of these compounds at longer storage time.
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