Flávia dos Santos Gomes

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.

Conservação de água de coco verde por filtração com membrana

The green coconut water is sterile inside the nut, but during its extraction and bottling microbiological contamination and biochemical alterations can occur, resulting in quality loss and decrease of its commercial value. The present work aimed at studying the conservation of the green coconut water by microfiltration and ultrafiltration. For microfiltration, a 0.1µm pore size membrane was tested and for the ultrafiltration 100, 50 and 20kDa molecular weight cut off membranes were evaluated. The process efficiency was evaluated by the permeate flux and microbiological, physical-chemical, biochemistry and sensory evaluations. It was not observed significant variation in the physical-chemical parameters. The permeate water presented higher luminosity and lower haze than the original coconut water. The protein content of the permeate coconut water, which is an indirect measure of enzyme concentration, was proportional to membrane porosity. The shelf-life evaluation revealed satisfactory results in relation to the microbiological quality. Among consumers who tasted the ultrafiltrated coconut water, 94% liked the product.

Avaliação dos efeitos da radiação gama na conservação da qualidade da polpa de amora-preta (Rubus spp. L.)

The blackberry is a fruit that has attracted the attention of producers and consumers due to its pleasant flavor, attractive color and composition present in high content of bioactive compounds. The major deterrent to consumption and marketing of the blackberry fruits is its high respiration rate, which reduces its lifetime. A viable alternative to the economic utilization of these fruits is its industrialization, can be frozen, canned, processed in pulp form, or in the form of juices and jellies. The objective of this study was to evaluate the effects of gamma radiation on the conservation of blackberry pulp. The irradiation was performed in the laboratory of gamma irradiation in the Development Center of Nuclear Technology (CDTN) in a cobalt 60 source, with the following radiation doses : 0.75 kGy ; 1.5 kGy and 3 kGy, under a dose rate of 3.24 kGy.h-1. The non-irradiated pulp was used as control. The irradiated blackberry pulps were stored at temperature of 4 oC and evaluated at 0, 7, 15, 30 and 60 days. To check the effects of gamma radiation on the pulp processing, it was realized physicochemical and chemical characterization through the analysis of acidity, pH , soluble solids, total solids, anthocyanins, antioxidant activity and color. Microbiological analysis according to Brazilian legislation was also done. The irradiation process increase the shelf life of the pulp within 60 days, and the treatment with a dose of 1.5 kGy was the one that provided better microbiological quality.

Effect of temperature on the degradation of bioactive compounds of Pinot Noir grape pomace during drying

The objective of this study was to evaluate the effect of temperature and drying time on the total phenolic content and antioxidant capacity of grape pomace. Experimental data of the drying kinetics were fitted to six mathematical models and the Page model was selected as the most suitable to represent the drying of grape pomace. The best preservation of the phenolic compounds and antioxidant capacity was observed at 60 °C, suggesting that the temperatures of 40 °C and 50 °C were not sufficient to inactivate the enzyme polyphenol oxidase, being responsible for the greater degradation of these compounds.

OTIMIZAÇÃO DO PROCESSO DE EXTRAÇÃO AQUOSA DE INULINA DE CHICÓRIA

Neste trabalho, o processo de extracao solido-liquido, usando a agua quente como solvente, foi otimizado para obtencao de um extrato concentrado de inulina a partir da raiz de chicoria desidratada. Na primeira parte deste trabalho, foram estudados os efeitos simultâneos da temperatura e razao agua/substrato (p/p) no rendimento do processo. Os dados experimentais foram gerados a partir de um planejamento composto central e analisados pela tecnica de superficie de resposta. O teor de inulina no extrato seco foi determinado por cromatografia liquida de alta eficiencia (CLAE). Pode-se concluir que o rendimento de extracao apresentou uma correlacao positiva com o aumento da razao solvente/substrato (p=0,002) mas nao foi influenciado pelo aumento da temperatura (p=0,3416) na faixa analisada (70 a 90o C). Nas diferentes condicoes do planejamento experimental, as analises indicaram um teor de solidos entre 5% e 10% no extrato aquoso e um teor de inulina maximo de 74 ± 5%, em base seca. De acordo com o estudo cinetico de transferencia de massa, a 70o C, nao se observou um aumento significativo no rendimento de extracao, apos 30 minutos de incubacao. Visando aumentar, simultaneamente, o teor de soluto na fase aquosa e o teor de inulina no extrato seco, foram realizados novos experimentos mantendo-se a temperatura de incubacao a 70o C e variando-se a concentracao de substrato na mistura entre 10 e 50% (p/p). Na condicao selecionada (25% p/p substrato/agua), obteve-se um extrato aquoso com cerca de 18% de soluto e um teor de inulina de 93 ± 1%, em base seca.