Desenvolvimento de um concentrado de infusão de erva-príncipe

  • Raquel Pereira Duarte (Student)

Student thesis: Master's Thesis

Abstract

Currently there is a need to respond to the new demands of consumer by developing new products. The objective of this work is to develop a concentrated infusion of Lemongrass to be diluted in water, both hot and cold, responding to the needs of the company Cantinho das Aromáticas, which hopes to build up a new product line. We used the reverse osmosis technique to concentrate the infusion, followed by microfiltration to ensure the safety of the microbiological product for an acceptable period of time. However, after two weeks of storage and both chemical and microbiological studies we could observe microbial grow. We studied the stability of the product with the addition of preservatives, including citric, sorbic and benzoic acid. Due to the delicate balance of flavors that the infusion should have we took into account the preservative to choose and the amount added. Three concentrations were tested, 150, 300 and 600 mg/L along five weeks, and all assured absence of microbiological growth. Meanwhile, the antioxidant capacity and the total phenolics compounds content were analyzed by the method of radical cation ABTS reagent and Folin-Ciocalteu reagent, respectively. In the end the sorbic acid was chosen to add to the concentrate. The infusion with 150 mg/L of preservative had, in terms of antioxidant activity 0,53 ± 0,06 g/L of equivalent to ascorbic acid with a slight decrease of 0,43 ± 0,01 g/L after 5 weeks. In terms of content of phenolic compounds, in the beginning it presented the value of 0,26 ± 0,02 g/L of equivalent to gallic acid, with an increase to 0,3 ± 0,01 g/L in the end of the fifth week. The other concentrations showed different values within the same ranges and with similar trends. To perform sensory tests of the diluted concentrate with both hot and cold water, the sorbic acid was chosen as a preservative to add to our product, while testing only two concentrations, 150 and 300 mg/L. All the samples were well accepted in general, specially the one containing the minor amount of a preservative and the one that has been diluted in hot water which was the most appreciated by the consumers. In this drink the most abundant phenolic compounds were α-terpinol and eucalyptol. The most representative aromatic compounds were protocatechuich and p-coumaric acid.
Date of Award1 Feb 2017
Original languagePortuguese
Awarding Institution
  • Universidade Católica Portuguesa
SupervisorConceição Hogg (Supervisor)

Keywords

  • Infusion
  • Lemongrass
  • Concentrated
  • Reverse osmosis
  • Benzoic acid
  • Sorbic acid

Designation

  • Mestrado em Engenharia Alimentar

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