Estudo de métodos analíticos alternativos para quantificação do teor de cálcio, ferro e vitamina C em pré-misturas enriquecidas em micronutrientes

  • Catarina Pereira de Melo Vila Real (Student)

Student thesis: Master's Thesis


Nowadays, the quality of food products has become of increasing demand in international markets. In the food industry, it is current practice to use minerals and vitamins fortification in infant nutrition products in order to achieve the infants’ and young children’s nutritional needs. For this reason it is imperious to ensure the quality of these products. This quality control can be made on-line using alternative analytical methods, enabling, on the one hand, the permanent control of essential production parameters and on the other a decreased release time of the product and of the amount of product to rework. The main objective of this work was to study X-Ray Fluorescence Spectroscopy and Fourier Transform Near Infrared Spectroscopy as two alternative analytical methods to Atomic Absorption Spectrophotometry in calcium and iron quantification and Potentiometric Titration, in vitamin C quantification, respectively, in infant nutrition products. To develop robust mathematical models, were used samples from the product line and samples prepared in laboratory, covering a wide range of concentrations. The total number of used samples for each calibration curve was approximately thirty-three. Twenty-two calibration models were developed and there was no possibility to develop five models, two for calcium and three for iron, since all the conditions of applicability of the linear regression were not ensure. In approximately 86% of all cases, the correlation coefficient was bigger than 0.90, showing that the predicted results were very similar to the reference results. With these results it was possible to conclude that the two alternative analytical methods have a good correlation with the reference analytical methods, for calcium, iron and vitamin C in infant nutrition products. In order to conclude if these methods are, indeed, a valid alternative for the reference analytical methods, there’s necessary to perform the validation of the current models.
Date of Award8 Jul 2014
Original languagePortuguese
Awarding Institution
  • Universidade Católica Portuguesa
SupervisorHugo Ricardo Viegas Gomes da Costa (Supervisor) & Ana Maria Gomes (Co-Supervisor)


  • Quality control
  • X-Ray fluorescence spectroscopy and Fourier transform near infrared spectroscopy
  • Alternative analytical methods
  • Calibration
  • Quantification
  • Enriched premixes
  • Micronutrients


  • Mestrado em Engenharia Alimentar

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