Desenvolvimento e avaliação dos perfis sensorial e emocional de infusões premium e otimização da valorização de características extrínsecas.

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Increasing phenolic and aromatic compounds extraction and maximizing liking of lemon verbena (Aloysia triphylla) infusions through the optimization of steeping temperature and time

Publication . Rocha, C.; Coelho, M.; Lima, R. C.; Campos, F. M.; Pintado, M.; Cunha, L. M.

Herbal infusions are a new emerging trend among consumers, appearing in the market in many different forms. Due to intense competition, the commercial success of herbal infusions largely depends on flavour. The identification of the best combinations of steeping time and water temperature for the preparation of Aloysia triphylla infusions using a central composite design and response surface methodology was performed. The procedure aimed to maximize its antioxidant activity, phenolic and aromatic compounds, and consumers’ liking of the infusions. The antioxidant activity and phenolic content were evaluated using the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid radical cation) method and the Folin–Ciocalteu procedure. The analysis of aromatic compounds was performed based on the method of terpenic compounds. Sensory evaluation encompassed overall liking using a 9-point hedonic scale. Antioxidant activity and extraction of most phenolic compounds was higher for longer steeping times and higher temperatures, with some presenting a contrasting effect due to degradation at higher temperatures for longer steeping times. Results for terpenic compounds showed similar contrasting patterns. Based on the quadratic response surface, it was possible to predict the maximum overall liking for lemon verbena infusions prepared by brewing for 6 min at 96 ℃. Under such conditions, extraction of bioactive compounds was kept at a high level, close to the maximum attainable, while reducing the extraction of bitter compounds. These results are considered of great importance for the development of premium infusions from organic lemon verbena leaves.

2019Journal article

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Influence of harvesting factors on sensory attributes and phenolic and aroma compounds composition of Cymbopogon citratus leaves infusions

Publication . Coelho, Marta; Rocha, C.; Cunha, L.M.; Cardoso, L.; Alves, L.; Lima, R.C.; Pereira, M. J.; Campos, Francisco M.; Pintado, M. E.

Herbal infusions are receiving increasing attention for the number of physiological benefits that can bring to human health. Cymbopogon citratus is one the most used plants in traditionalmedicine besides its characteristics and unique aroma appreciated by the consumers; however, little is known about the effects of harvesting on functional and sensory properties of this plant. The present work aimed to assess the lemongrass infusions, which were harvested following a factorial plan according to the type of cut (manual and mechanical) and part of the plant (tips and 2nd half leaves). Total phenolic content, antioxidant capacity, aroma compounds composition (terpenoids) and sensory profiles and consumer perception of different samples were assessed. The quantitative descriptive analysis (QDA) and Check-All-That-Apply (CATA) methods were used to describe the lemongrass infusion, complemented with the overall liking evaluation, using a 9-point scale. Results showed that there were significant differences between type of cut and part of the plant concerning phenolic compounds: samples obtained by mechanical cut showed in general higher content of individual phenolic compounds (in particular for chlorogenic acid) and tips showed in general the highest contents for both types of cut. Consumers panel did not found significant differences between samples. Generally, consumers indicate a bitter taste in all infusions when the content of the phenolic compounds was higher, in particular for p-coumaric acid. Concerning the aroma compounds no significant differences were observed between type of cut and part of the plant, and citral was the terpenoid present in higher quantity. Regarding the sensory profile methods, it was found that QDA and CATA were both good methods to describe this infusion. Considering the role of consumers' evaluation throughout the value chain, the infusion preparedwith plant tips of lemongrass was selected as the premium herbal tea.

2016Journal article

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