Rafaella de Andrade Mattietto

Chemical characterization and evaluation of antioxidant properties of Açaí fruits (Euterpe oleraceae Mart.) during ripening

Consumption of açaí fruits has been linked to positive health effects due to its phenolic content and nutritive value. The objective of this study was to characterize açaí fruits chemically and to determine the antioxidant capacity at three different maturity stages. With the exception of fat, amounts of macronutrients, minerals and titratable acids decreased during the ripening process. The same trend was observed for most of the phenolic constituents identified by HPLC-ESI-MS/MS. A consistent decline was shown for flavones and hydroxycinnamic acids. The concentration of the anthocyanins increased in the course of ripening. In accordance with the total amount of the identified phenolic compounds, the antioxidant capacity, measured by TEAC and TOSC, also decreased. However, the contribution of the main phenolic compounds to the overall antioxidant capacity evaluated by TOSC was estimated to be low.

Chemical composition and antioxidant capacity of açaí (Euterpe oleracea) genotypes and commercial pulps.

BACKGROUND Açaí has been reported to contain many bioactive compounds, including phenolic compounds such as anthocyanins. This study aimed to determine the chemical composition and antioxidant potential of pulps of three different açaí genotypes from the Active Germplasm Bank of Embrapa Eastern Amazon and three commercial açaí pulps from Belém, state of Pará, Brazil. RESULTS Anthocyanin 3-rutinoside was the major anthocyanin present in freeze-dried açaí pulp samples. The commercial sample C showed the greatest amounts of cyanidin 3-glucoside and cyanidin 3-rutinoside (18 942 and 34 397 µg g-1 respectively). The content of phenolic compounds varied significantly among the commercial and genotype samples, and vanillic acid was found in the highest concentration in the samples studied. All açaí samples showed high DPPH, ORAC and TEAC values, confirming the exceptionally high radical-scavenging capacity of açaí pulp previously reported by other researchers. CONCLUSION The commercial samples showed higher antioxidant capacity and higher levels of anthocyanins and non-anthocyanic compounds than those of the genotype samples. Among the genotypes studied, L4P16 stood out for its higher contents of fibre and bioactive compounds and higher antioxidant capacity, indicating that this genotype has great potential for use in plant breeding programs that should be further explored.

Ideal sweetness of mixed juices from Amazon fruits

Ready-to-drink fruit juices represent a large share of the market and are an important target for product development. The mixture of fruits can bring about improvements to nutritional and sensory aspects of these beverages while making used of the wide variety of exotic fruits from the Amazon region. Therefore, it is necessary to select mixed fruits and determine their ideal sweetness according to consumer acceptance. Consumers in the city of Belem (Brazil) evaluated five different concentrations of sugar using the just-about-right scale in two blends selected by preference ranking. For the cupuassu-acerola-acai blend, the optimum concentration of sugar was 9.5 g/100 mL, and for the soursop-camucamu-yellow mombin blend, it was 10.7 g/100 mL.

Bioactive compounds and antioxidant activity of pepper (Capsicum sp.) genotypes

Eight pepper genotypes (Capsicum sp., Capsicum annun L., C. chinense Jacq, and C. baccatum L. var. umbilicatum) were assayed for total phenolics, anthocyanins, carotenoids, vitamin C, and total antioxidant activity in order to determine their bioactive compound profile and to establish the correlations between these compounds and their antioxidant activity. The genotype IAN 186311 (C. chinense Jacq.) showed the highest total antioxidant activity and the highest concentrations of phenolic compounds. As for the content of carotenoids, the genotype with the highest concentration was IAN 186324 (Capsicum sp.), and the genotype IAN 186305 (C. baccatum L. var. umbilicatum) showed the highest content of vitamin C and anthocyanins. Terefore, it can be concluded that the Capsicum sp. genotypes analyzed demonstrated a rather high diversity of bioactive compounds that should be further explored given the benefits they can provide to consumer health.

Rheological behavior of Brazilian Cherry (Eugenia uniflora L.) pulp at pasteurization temperatures

Neste trabalho, foi estudado o comportamento reologico da polpa de pitanga na faixa de temperatura de pasteurizacao de 83 a 97 °C. Os resultados indicaram que a polpa apresentou comportamento pseudoplastico e o modelo de Herschel-Bulkley foi considerado o mais adequado para representar o comportamento reologico do produto nas temperaturas estudadas. Os indices de comportamento de fluido (n) variaram na faixa de 0,448 a 0,627. O efeito da temperatura sobre a viscosidade aparente pode ser descrito pela equacao analoga a de Arrenhius, observando-se a diminuicao da viscosidade aparente da polpa de pitanga com o aumento da temperatura.

Comportamento reológico de suco misto elaborado com frutas tropicais

Neste trabalho, foi determinado o comportamento reologico do suco misto obtido a partir de uma mistura de frutas tropicais, mediante um viscosimetro de cilindros concentricos, no intervalo de temperatura de 10 oC a 60 oC. Os modelos Lei da Potencia e Mizrahi-Berk foram ajustados aos dados experimentais. Os modelos mostraram-se adequados para descrever o comportamento reologico do suco misto, de acordo com os parâmetros estatisticos de ajuste. O produto apresentou indice de comportamento menor do que 1 (um), caracterizando a pseudoplasticidade do suco. Os indices de comportamento de consistencia decresceram com o aumento da temperatura. O efeito da temperatura no comportamento reologico do suco foi descrito por uma equacao analoga a de Arrhenius e discutida em termos de energia de ativacao (Ea). Os valores de Ea variaram de 4,27 a 4, 66 kcal.gmol-1, com o aumento da taxa de deformacao.

Características físicas e físico-química da casca de mangostão em três períodos da safra

In this work, it was evaluated the physical characteristics of fruit and physiochemical of the mangosteen peel, harvested in different periods (beginning, middle and end). The physical characteristics of fruits range significantly (p<0.05) from the beginning to the end, and it was observed that the fruits average weight, ranged from 91.33 to 50.82 g and the peel consists of an average from 72.12 to 76.86% of the total fruit weight. The physiochemical characterization shows that the peel possesses high moisture content (64.5 to 66%), total fibers (24.9 to 29.1%), high water activity (0.96 - 0.98), low energy value (24.8 to 34.7 Kcal/ 100g) and expressive content of total anthocyanins (25.9 to 63.9 mg/100g), mainly in the intermediate harvest period.

Phenolic compounds are highly correlated to the antioxidant capacity of genotypes of Oenocarpus distichus Mart. fruits

This research aimed to evaluate 32 genotypes of Oenocarpus distichus fruits regarding the contents of total phenolic compounds, flavonoids, flavanols, monomeric anthocyanins, antioxidant capacity (ABTS and DPPH assays), and the phenolic compound profiles of the five genotypes that presented the highest yields of bioactive compounds. The genotypes were harvested in three different locations in Pará State, Northern Brazil, (Belém, São João do Araguaia and Marabá). Among the 32 genotypes, the highest bioactive compound contents and antioxidant capacity were found for three genotypes harvested in Belém (B-3, B-7 and B-8) and two harvested in São João do Araguaia (SJ-1 and SJ-4), and the total phenolic compounds varied from 131.97 to 363.01 mg gallic acid equivalent/100 g, total flavonoids from 24.23 to 38.19 mg quercetin equivalent/100 g, total flavanols from 72.29 to 259.18 mg catechin equivalent/100 g, and monomeric anthocyanins from 21.31 to 67.76 mg cyanidin 3-rutinoside/100 g. The main phenolic compounds tentatively identified in the five selected genotypes were cyanidin 3-O-rutinoside (48.47 to 196.51 μg/g), which could be identified and quantified as the major phenolic compound in Oenocarpus distichus fruits, for the first time, followed by chlorogenic acid (0.71 to 64.56 μg/g) and rutin (13.98 to 56.76 μg/g).

Otimização dos parâmetros tecnológicos para produção de estruturado a partir de polpa de açaí.

Este trabalho teve por objetivo investigar os parâmetros relevantes para a estruturacao de polpa de acai, avaliando-se o efeito da combinacao de diferentes hidrocoloides nas caracteristicas do gel de fruta. Foi realizado planejamento experimental 23, em que as concentracoes de alginato (X1), pectina (X2) e gelatina (X3) foram testadas, tendo como respostas atividade de agua (Y1), firmeza (Y2), solidos soluveis (Y3) e pH (Y4). A polpa de acai e a formulacao de estruturado selecionada a partir da analise do planejamento experimental foram caracterizadas em relacao aos compostos funcionais, avaliando-se o teor de taninos e antocianinas, alem das analises de composicao centesimal, pH, acidez titulavel, solidos soluveis, atividade de agua, fracao Nifext e valor energetico total. Os resultados obtidos por meio do planejamento experimental indicam que, a medida que se aumenta a concentracao dos hidrocoloides, independentemente da combinacao entre eles, aumenta-se tambem a firmeza dos estruturados. A variacao dos hidrocoloides nao afetou de forma significativa os solidos soluveis e a atividade de agua final dos produtos; porem, observou-se que a presenca de alginato afeta a acidez do produto, reduzindo-a. Sensorialmente, o produto selecionado apresentou medias de aceitacao elevadas, indicando potencial de consumo na forma em que se apresenta, alem da possibilidade de utilizacao na formulacao de produtos de confeitaria ou alimentos congelados.

Estudo da estabilidade de polpas de frutas tropicais mistas congeladas utilizadas na formulação de bebidas.

O objetivo deste trabalho foi avaliar a estabilidade de duas polpas de frutas tropicais mistas, armazenadas sob congelamento (?18 °C), durante 365 dias, a partir de sucos tropicais mistos: F1 - suco tropical misto de acerola (10%), abacaxi (20%), acai (5%), caju (5%), caja (5%), camu-camu (5%), agua (43,1%) e acucar (6,9%) e F2 - suco tropical misto de acerola (10%), abacaxi (20%), acai (10%), caja (10%), agua (43,4%) e acucar (6,6%). Analises fisicas, quimicas e de capacidade antioxidante foram realizadas a cada 45 dias. Os sucos tropicais mistos mostraram-se adequados em termos da legislacao vigente no que se refere a acidez e aos solidos soluveis. Quanto a presenca de constituintes bioativos, o suco tropical misto com maior concentracao de acai e caja apresentou os maiores teores de antocianinas totais e carotenoides totais. Depois de 365 dias de armazenamento congelado, as perdas observadas para o teor de carotenoides foram 2,80% para a formulacao F1 e 10,07% para a formulacao F2. Ja para antocianinas totais, as perdas foram maiores, 44,35% e 73,48%, para as formulacoes F1 e F2, respectivamente. De maneira geral, observou-se que o armazenamento sob congelamento foi eficaz na manutencao das caracteristicas quimicas e de atividade antioxidante das polpas de frutas mistas estudadas, resultando, apos o descongelamento e adicao de agua e sacarose, em sucos tropicais mistos com boa qualidade nutricional e funcional.