This work used a central composite design to optimise a reverse phase high performance liquid chromatographic method for the simultaneous separation of gallic, syringic, 5-caffeoylquinic, caffeic, p-coumaric, ferulic, 3,4-dicaffeoylquinic, 3,5-dicaffeoylquinic, 4,5-dicaffeoylquinc acids, rutin in aqueous extracts of yerba mate (Ilex paraguariensis). The effect of the linear gradient time, the initial and the final methanol concentration in the mobile phase on the peak resolution and peak symmetry was evaluated. The 26 responses obtained were simultaneously optimised using the desirability method of Derringer and Suich. According to results, the increasing in the resolution and peak symmetry was achieved by using lesser levels of methanol in both initial and final gradient elution (-1.68, -1), as well as higher gradient times (+1, +1.68). The optimal condition (13.9-40% of methanol in 39.4 min) were successfully applied for analysis of chimarrão, tererê and mate tea aqueous extracts, which showed as excellent sources of chlorogenic acids.

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O objetivo do presente trabalho foi avaliar as modifi cações físico-químicas e sensoriais de mandioca pré-processada, durante armazenamento sob congelamento. As raízes de mandioca foram selecionadas, lavadas em água corrente, descascadas e cortadas manualmente, higienizadas, acondicionadas em sacos de polietileno e armazenadas sob congelamento a -18ºC durante 150 dias, sendo analisadas nos tempos 0, 7, 15, 30, 60, 90, 120 e 150 dias quanto ao pH, acidez titulável, umidade e análise de aceitação sensorial. O valor médio de umidade encontrado para as raízes de mandioca congeladas durante 150 dias foi de 60,65%. Para a variável pH das raízes de mandioca não foi verifi cada diferença signifi cativa durante todo o período. No entanto, observou-se acréscimo signifi cativo da acidez nas raízes a partir dos 90 dias de armazenamento. Com relação à análise sensorial, as médias obtidas para todos os atributos avaliados nos tempos zero e 150 dias mantiveram-se praticamente inalteradas e próximas do conceito "gostei muito". Os resultados sugerem que o congelamento de raízes de mandioca pré-processadas constitui método efi ciente para retardar o surgimento de modifi cações e deteriorações, sendo possível prolongar sua vida útil por até 150 dias. PALAVRAS-CHAVE: Manihot esculenta Crantz; MANDIOCA -PRÉ-PROCESSAMENTO; MANDIOCA -CONGELAMENTO; ANÁLISE SENSORIAL.

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The beverage obtained from the yerba mate tea, besides being the most consumed in Brazil, has high concentrations of chlorogenic acids. In this study, a central composite design was employed to establish the best infusion time, temperature and water volume to maximize the extraction of chlorogenic acids 5-caffeoylquinic (5CQ), 3.4-dicaffeoylquinic (3.4 DQ), 3.5-dicaffeoylquinic (3.5 DQ) and 4.5-dicaffeoylquinic (4.5 DQ), from the leaves and stems of yerba mate tea (beverage ready for consumption). Analyses were performed by high-performance liquid chromatography and the optimum conditions were obtained through the use of the desirability function of Derringer and Suich. The maximum chlorogenic acids content in the beverage was obtained when the infusion was prepared with 2 g of mate tea, in 300 mL of water at 95 °C, under infusion for 16 min. The optimal conditions were applied for the preparation of beverages from 15 commercial samples of yerba mate tea, and it was observed that the sum of the concentration of the four compounds showed variation of up to 79 times between the average of the samples, which can be attributed to climatic conditions of cultivation of the plant and/or of processing.

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A group of cassava landraces that occur naturally in Amazonia (Manihot esculenta Crantz) are known as mandiocaba or sugary cassava because they have high free sugar content, making them a possible feedstock for the production of syrup. The objective of the study was to evaluate the technological viability of obtaining sugary cassava syrup and to characterize the physical and physicochemical properties of the product. The yield of the syrup (80 °Brix) obtained from the manipueira (liquid obtained by crushing and filtering the cassava) concentration was 262.72 g per plant. The reducing sugars represented 77.26% of total sugars, the density was 1.4210 g cm–3 at 20°C, and the volumetric expansion coefficient was 38.6 m K–1. The Newtonian behavior and activation energy (≥69.65 kJ gmol–1) were similar to that of honey found in the literature.