Lourdes Maria Corrêa Cabral

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.

Cold sterilization and clarification of pineapple juice by tangential microfiltration

Abstract Pineapple is a very appreciated tropical fruit due to its unique aroma and flavour. Pineapple juice was cold sterilised and clarified by crossflow microfiltration associated with an enzymatic treatment. A tubular polyethersulfone 0.3 μm pore size membrane with effective filtration area of 0.05 m2 was used in the pilot system. Ten experiments were carried out under the same operational conditions, 25°C and 100 kPa, in order to evaluate the cold sterilisation and clarification of pineapple juice by microfiltration. It was observed that the permeate flux did not change significantly after fifteen minutes of processing time. It was stabilised around 100 L/hm2. The clarification process was considered very efficient due to the great reduction of haze and viscosity, and by showing no significant changes in pH, acidity, sugar and soluble solid content of the juice. The permeate of the process was collected in sterile bottles inside a laminar flow station and kept under refrigeration (8°C) for a period of 28 d. The samples were submitted to microbiological evaluations in intervals of seven days. The microbiological analysis of the microfiltered pineapple juice showed that it was in agreement with the requirements by the Brazilian Legislation for juices and drinks.

Cashew apple juice stabilization by microfiltration

Abstract Cashew apple is a tropical fruit that presents high vitamin C content, rich flavour and aroma. Brazilian market of cashew apple juice is about 40,000 ton/y and it presents a low consumption at the international market. This work had the objective of studying the shelf-life stability of cashew apple juice clarified by microfiltration associated with enzymes, supposedly to present a lower astringency and a better physical stability. Cashew apple pulp was used as raw material. It was first hydrolysed and then microfiltered in a 0.3-μm pore size tubular membrane. Permeate juice was collected in a sterilised closed system and stored at room (30°C) and refrigeration (4°C) temperatures for 2 months. Ascorbic acid and tannin contents, haze, pH, acidity, soluble solids of the juice as well as microbiological counting were determined each 15 d. Juice storage at the lower temperature was appropriate for consumption after a 2-month shelf life, still as a vitamin C source and without any haze.

Oligosaccharide distribution in Brazilian soya bean cultivars

Abstract The composition of digestible sugars (ds) and non-digestible sugars (nds) was determined in 20 soya bean cultivars grown in Brazil. In addition, a comparison of three different extraction procedures for sugar analysis by HPLC is presented. Total α-galactosides in the samples were in the range 3.9–5.3 g% while fructose + sucrose varied from 4.0 to 6.1 g% dry basis. Based on the analysis of protein and oil data together with total galactosides, stachyose and ds nds ratios, one variety (IAS-4) appears to be more appropriate for selection.

Production of grape juice powder obtained by freeze-drying after concentration by reverse osmosis

This study aimed to evaluate the freeze-drying proc ess for obtaining grape juice powder by reverse osm osis using 50% grape juice pre-concentrated (28.5 °Brix) and 5 0% hydrocolloids (37.5% maltodextrin and 12.5% arab ic gum). The morphology of the glassy food showed the absence of crystalline structure, which was the amo rphous wall that protected the contents of the powder. The samples were stored in clear and dark containers a t room temperature, evaluated for their physical (X-ray di ffraction) for 65 days and chemical (polyphenol con tent) stability for 120 days. During the storage time in plastic ve ssels, samples remained physically stable (amorphou s) and the phenolic concentration was constant, indicating the potentiality of this technique to obtain a stable product with a high concentration of phenolic compounds. Therefore , the freeze-drying process promoted the encapsulat ion of concentrated grape juice increasing its stability a nd shelf life, as well as proving to be an applicab le process to food industry.

Suco de maracujá orgânico processado por microfiltração

The objective of this work was to evaluate the use of microfiltration to obtain clarified organic passion fruit juice and analyse its sensory acceptability. Passion fruit was cultivated under organic system in Rio de Janeiro State. The juice was submitted to an enzymatic treatment before microfiltration, in order to decrease its viscosity and pulp content, and to improve permeate flux. Microfiltration had been accomplished with a tubular 0.3 µm pore size membrane with 0.05 m2 of filtration area. The process promoted complete removal of the suspended pulp in permeated juice, which resulted in a limpid and clarified juice. Concerning the sensorial analysis, passion fruit refreshment obtained from clarified juice was approved by 75% of the consumers. The microfiltered passion fruit juice was conserved in plastic package for 28 days under refrigeration temperature (7oC). Results confirm the efficiency of microfiltration as an alternative method for conservation of passion fruit juice, and point out the importance of this technology for the processing of organic juices.

Microfiltered acerola juice: evaluation of shelf life

This work had as objective to study the physical, chemical and microbiological stability of clarified acerola juice, obtained by membrane process. Microfiltered juice was collected in a sterilized closed system and transferred to glass or PET bottles, also previously sterilized, in a laminar cabinet. Products were maintained under refrigeration (4oC) and room (30oC) temperatures during 90 days. Shelf-life evaluation of acerola juice showed that refrigeration storage preserves juice properties and that there was no difference between the two types of packing material.

Estabilidade da polpa de morango atomizada utilizando diferentes agentes carreadores

Este trabalho teve por objetivo avaliar o efeito de diferentes agentes carreadores (Maltodextrina 5DE, Maltodextrina 10DE, Goma arabica e Capsul®) nas caracteristicas fisico-quimicas (umidade, densidade, solubilidade, teor de antocianinas e atividade antioxidante) da polpa de morango desidratada por atomizacao e armazenada a temperatura ambiente por 90 dias. A utilizacao dos diferentes agentes carreadores resultou em pos com valores de densidade aparente entre 0,40 e 0,52 g/cm3 e umidade menor do que 2,5%. Todas as amostras foram altamente soluveis, mas os pos obtidos com a Maltodextrina 5DE e com a Goma arabica apresentaram menor higroscopicidade. As isotermas de sorcao obtidas foram do tipo III e o modelo de GAB foi o que melhor se ajustou aos dados experimentais. A amostra produzida com goma arabica apresentou a maior concentracao de antocianinas e, consequentemente, maior valor de atividade antioxidante, tanto imediatamente apos a secagem como ao longo de 90 dias de armazenamento. Os resultados obtidos indicaram que a goma arabica foi o agente carreador mais adequado para a producao de polpa de morango em po.

Caracterização física e tecnológica de seis cultivares de soja plantadas no Brasil

In the present work, six soybean cultivars commonly grown in Brazil (IAS-5, IGUACU, DAVIS, BR-16, IAS-4 and EMBRAPA-4) were physically and technologically evaluated, viith the aim of identifying the most adequate one for human consumption. The following determinations were carried out: grain apparent density and volume, weight of one hundred seeds, percentage of hull, cotyledon and germ, seed coat and hilum colour, soaking time, water absorption and finally, cooking time. The apparent density varied from 1.1592 to 1.1992 g/cm3 and the grain volume from 0.1262 to 0.1711 cm3, the weight of one hundred seeds from 15.31 to 19.76 ghull, germ and cotyledon percentages from 6.94 to 8.40%,2.29 to 3.05% and 88.77 to 90.77%, respectively. For the conditions used, it was observed that the seed coat and the hilum colours were very similar for all six cultivars. The minimum soaking time varied from 6 to 9 hours and the maximum soaking time varied from 12 to 15 hours. The water absorption at the minimum soaking time varied from 108.05 to 124.60 g H2O/100 g and the water absorption at the maximum soaking time varied from 125.67 to 132.54 g H2O/100 g. The cooking time varied from 155 to 219 minutes.

Recuperação e concentração de componentes do aroma de caju (Anacardium occidentale L.) por pervaporação

Pervaporation is a membrane separation process in which components from liquid mixtures are fractionated due to their partial vaporisation through a dense selective membrane. This process can be used to recover aroma compounds. The objective of this work was to evaluate the pervaporation to obtain a natural aroma extract from cashew apple fruit, which can be used as an additive in the food industry. Cashew pulp was used as raw material. Pervaporation was carried out at 25 and 35 °C using polymethylsiloxane membranes. Samples of the cashew juice in the beginning and at the end of the pervaporation and from the permeate were picked to characterise the aromatic profile by GC-MS. The pervaporation of the cashew juice presented a high permeate flux, 0.11 kgh-1m-2 and 0.17 kg.hm-2, at 25 and 35 °C, respectively. The chromatograms showed an increase in the number of compounds in the permeate samples when compared to the chromatograms of the cashew juice. By comparing the peak areas, it could be observed that almost 50% of the identified components in the permeate samples presented an increase in the peak area, showing the potentiality of this process to the concentration of the aroma of cashew apple juice.