RESUMEN
Principal component analysis (PCA) is currently one of the most used multivariate data analysis techniques for evaluating information from food analysis. In this review, a brief introduction to the theoretical principles that underlie PCA will be given, in addition to presenting the most commonly used computer programs. An example from the literature was discussed to illustrate the use of this chemometric tool and interpretation of graphs and parameters obtained. A list of recently published articles will also be presented, in order to show the applicability and potential of the technique in the food analysis field.
RESUMEN
Concentrations of 11 elements (P, Cu, Ni, Co, Pb, Ca, Mn, Fe, Zn, Cr and Al) were measured in leachate samples collected monthly from the municipal landfill in Jequié, Bahia, Brazil. P (0.943-23.8 mg L(-1)), Ca (19.90-129 mg L(-1)) and Fe (0.115-2.87 mg L(-1)) were found in the highest levels, while Cu (Asunto(s)
Monitoreo del Ambiente/métodos
, Metales/análisis
, Fósforo/análisis
, Eliminación de Residuos/métodos
, Instalaciones de Eliminación de Residuos
, Contaminantes Químicos del Agua/análisis
, Brasil
, Análisis por Conglomerados
, Análisis Multivariante
, Análisis de Componente Principal
, Lluvia
, Reproducibilidad de los Resultados
, Estaciones del Año
RESUMEN
Caigua (in Brazil "maxixe do reino") is a fruit that is generally consumed either cooked or even raw as salad. This fruit has been used as a food and also in folk medicine. In this work, the mineral composition of Caigua was determined for the first time. Twenty-nine samples from five farms located in the southwestern region of Bahia, Brazil were acquired and analyzed using inductively coupled plasma optical emission spectrometry. The elements determined in this fruit included calcium, magnesium, sodium, potassium, phosphorus, manganese, iron, zinc, copper and vanadium. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied to evaluate the obtained results. The average concentrations of the determined elements (expressed as mg 100 g(-1)) were as follows: 0.91 for sodium, 152 for potassium, 19.4 for phosphorus, 11.9 for calcium, 8.4 for magnesium, 0.074 for manganese, 0.21 for iron, 0.013 for copper, 0.13 for zinc and 0.015 for vanadium.
Asunto(s)
Cucurbitaceae/química , Minerales/química , Brasil , Alimentos Orgánicos/análisis , Frutas/química , Análisis MultivarianteRESUMEN
The present paper describes the development of a microwave assisted digestion procedure for the determination of zinc, copper and nickel in tea samples employing flame atomic absorption spectrometry (FAAS). The optimization step was performed using a full factorial design (2(3)) involving the factors: composition of the acid mixture (CMA), microwave power (MP) and radiation time (RT). The experiments of this factorial were carried out using a certified reference material of tea GBW 07605 furnished by National Research Centre for Certified Reference Materials, China, being the metal recoveries considered as response. The relative standard deviations of the method were found below 8% for the three elements. The procedure proposed was used for the determination of copper, zinc and nickel in several samples of tea from Turkey. For 10 tea samples analyzed, the concentration achieved for copper, zinc and nickel varied at 6.4-13.1, 7.0-16.5 and 3.1-5.7 (microg g(-1)), respectively.