Elisângela Elena Nunes

Obtaining a protocol for extraction of phenolics from açaí fruit pulp through Plackett–Burman design and response surface methodology

This work aimed to obtain a simplified extraction protocol for simultaneous achievement of total anthocyanin and total phenolic in açaí pulp using a 3-step optimization approach. First, a Plackett-Burman 20 was applied in 16 independent variables selected in literature. Secondly, seven factors pre-selected in the first screening were reassessed using a Plackett-Burman 12. Then, four selected factors; solid/solvent ratio (g:mL), acetone concentration (%), time of extraction in acidified ethanolic solution (min) and ethanol concentration (%) were optimized using a central composite design with response surface methodology. In addition, the optimized protocol were compared with two standardized extraction procedures assessing açaí and grape pulps. The optimized method is effective for the simultaneous extraction of total phenolics and total anthocyanins, allowing representative measurements of free radical-scavenging capacity (DPPH) and trolox equivalent capacity (TEAC) of grape and açaí pulps, with savings of time and reagents, moreover, avoiding the use of methanol.

Qualidade de mandioquinha-salsa minimamente processada e armazenada sob atmosfera modificada

The aim of this research was to verify the effect of the passive and active modified atmosphere on the conservation of fresh-cut peruvian carrot, cv. Amarela de Senador Amaral, purchased from a commercial crop of Lavras, MG, Brazil. The roots were screened, washed with neutral detergent and rinsed in running water. Afterwards, they were immersed into a solution of 300mg L-1 sodium hypochlorite for 15 minutes and dried at room temperature. The roots were peeled and cut in slices of about 1cm of thickness and immersed into a solution of 50mg L-1 sodium hypochlorite for 10 minutes, drained in plastic sieves and packed. The trays containing the slices of Peruvian carrot were stored in a cold room (5±1°C and 98% RH) for 15 days. The following analyses were performed every 3 days: : pH, titrable acidity, total soluble solids, firmness, L* and b* values, starch and sensorial evaluation (appearance and color). The experimental design was completely randomized (CRD) in a 3 x 6 factorial scheme, with 3 sorts of atmospheres (passive; active with initial injection of the mixtures: 2% O2 + 10% CO2 e 5% O2 + 5% CO2) and 6 times of storage (0, 3, 6, 9, 12 and 15 days) with 3 replicates. The average values of pH, titrable acidity, soluble solids and firmness found in this work were 6.79, 0.13% of malic acid, 4.04°Brix and 5.17 N, respectively. The active modified atmosphere (5% de O2 + 5% CO2) determined higher L* value to the fresh cut Peruvian carrots at the sixth and twelfth day of storage as compared with the active (2% of O2 + 10% CO2). The active modified atmosphere with 5% O2 + 5% CO2 determined higher b* values and starch contents to the slices of Peruvian carrots as compared with the other atmospheres. It can be concluded that the passive modified atmosphere associated with refrigeration and good practices of manufacture is enough to extend the shelf life of fresh cut Peruvian carrots, keeping their quality attributes. In accord to the sensorial evaluation, both appearance and color of the slices of Peruvian carrots are kept acceptable for consumption until the end of the storage period.

Avaliação de diferentes sanificantes na qualidade microbiológica de mandioquinha-salsa minimamente processada

Objetivou-se, neste trabalho, avaliar a eficiencia dos sanificantes hipoclorito de sodio, peroxido de hidrogenio e dicloro isocianurato de sodio aplicados antes e apos o processamento minimo de mandioquinha-salsa. Foram utilizadas raizes de mandioquinhasalsa da cultivar Amarela de Senador Amaral adquiridas no comercio local. Para limpeza superficial das raizes foram utilizados detergente e agua. Apos, as raizes foram divididas em dois grupos: controle (nao sanificado) e sanificado, por imersao em dicloro isocianurato de sodio 100 mg.L-1, por 15 minutos. Em seguida foram descascadas, fatiadas em rodelas e imersas nos seguintes sanificantes: hipoclorito de sodio (25, 50 e 100 mg.L-1, por 10 minutos), peroxido de hidrogenio (3 e 6%, por 5 minutos) e dicloro isocianurato de sodio (50, 100 e 200 mg.L-1, por 10 minutos); embaladas e armazenadas em câmara fria ( 5 ± 1oC e 98% UR), durante 15 dias. As analises realizadas a cada 3 dias foram pH, acidez titulavel, solidos soluveis, colimetria e pesquisa de Salmonella sp.. As variaveis pH, AT e SS nao foram influenciadas pelos tratamentos utilizados. A presenca de coliformes 45 oC e Salmonella sp. nao foi detectada, durante o armazenamento de mandioquinha-salsa minimamente processada, controle ou sanificada e foram observadas contagens baixas para coliformes 35 oC. A sanificacao do produto antes do processamento com dicloro isocianurato de sodio 100 mg.L-1 e condicoes higienico-sanitarias adequadas, durante o processamento, possibilita a obtencao de um produto com padrao microbiologico de acordo com a legislacao de alimentos, ate o 15o dia de armazenamento.

Armazenamento de morango sob atmosfera modificada e refrigeração

The goal of this work was to draw out the shelf-life of strawberries, submitted to the active modified atmosphere (2% O2 + 10% CO2 and 5% O2 + 5% CO2) and stored under refrigeration (9 ± 1oC and 99% UR) by 10 days. The experiment was carried through in the DCA/Ufla, in Lavras, MG. With the results gotten in this work, it may be concluded that the strawberries did not suffer any influence of the modified atmosphere in relation to the controlled fruits, according to the evaluated parameters.