Regina Isabel Nogueira

Ultrasound Effects on the Mass Transfer Processes during Drying Kinetic of Olive Leaves (Olea Europea, var. Serrana)

The large amount of materials derived from olive trees pruning may constitute a source of compounds with antioxidant activity. The air drying of raw matter is a previous stage before extraction preserving the raw matter and avoiding the interference of water on the process but it constitutes a slow and high energy demanding process. In this sense, the application of high intensity ultrasound could affect the mass transfer rate. In order to address the influence of ultrasound on the drying process of olive leaves, air drying experiments were carried out (40°C and1 m/s) without (0 W) and with ultrasound application (8, 16, 25 and 33 kW/m3). The different drying conditions were tested by triplicate. To model the experimental data, diffusional models considering or not the external resistance to mass transfer were used. The model without considering external resistance did not fit well to the experimental data. However, the model including external resistance achieved percentages of explained variance above 99.7%. The influence of ultrasound on diffusivity was not significant but a significant dependence was found for the mass transfer coefficient, proportional to the power density applied.

Partition of Free Fatty Acids in Deacidification of Macaúba Pulp Oil by Liquid-Liquid Extraction Using Ethanol/Water as Solvent

Free fatty acids (FFA) is one of the most frequently determined quality indices in fats and oils industry because it has the economic impacts on production [1]. The FFA in macaúba pulp oil is usually very high (10 to 40%) due to enzymatic activity in the raw material [2]. In this case, alkali neutralization is not economically recommended due to neutral oil loss by occlusion in soapstock. The differential solubility of fatty acids and triacylglycerides (TAG) in various organic solvents has formed the basis of several processes for deacidification of crude oils by liquid–liquid extraction [3]. The aim of the present work was to evaluate the influence of raw oil acidity, ethanol/water ratio, water content in ethanol and temperature extraction on partition coefficients of FFA during macaúba oil deacidification. The macaúba crude oil presented high acid index, about 86  1.2 mg KOH/g. The extraction data for the system macaúba oil + free fatty acids + ethanol + water was determined for oil:solvent mass ratios 1:1. Alcoholic solutions containing 2 to 10 % (w/w) of water were used to FFA extraction and the partition coefficients were determined after 24 hours at room temperature (293 K). The phase’s separation was observed for water content in the mixture above 4%. After solvent evaporation, the FFA in oil phase was evaluated by AOCS standard method. Regarding the high acid oil, the single stage liquid-liquid extraction reduced the FFA in macaúba pulp oil in about 23 % while the three batch stages reduced up to 60%. At the selected parameters (ethanol 94oGL, solvent/substrate ratio = 2), the partition coefficients in the firs stage to FFA (KFFA) were 30.45, 12.00 and 1.95, respectively to high acid, acid and low acid macaúba oils and the partition coefficients to TAG (KTAG) were 7.07, 0.04 and 0.02, respectively to high acid, acid and low acid macaúba oils. These results show the potential of ethanol to vegetable oil deacidification. Besides reduced generation of environmental pollutants, this new approach could also lead to reduction in oil losses, especially for low acid oil.

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.

Influence on Olive Leaves (Olea Europaea, var. Serrana) Antioxidant Extraction Kinetics of Ultrasound Assisted Drying

The olive crop has a great importance in the economy of Spain. Every year during the pruning of the olive trees a significant quantity of leaves are cut and discarded. It is known that these leaves constitute a source of antioxidant compounds and its processing would provide an added value to this raw material. Antioxidant compounds may be damaged when drying, the previous process to extraction. Thus, the goal of this work was to study the influence of the high intensity ultrasound applied during the drying of olive leaves on the kinetic of extraction of antioxidants compounds. From the parameters identified from Naik model, it can be concluded that the application of high intensity ultrasound during drying reduced the antioxidant activity of extracts at the equilibrium but increased the initial extraction kinetic compared to conventional hot air drying. This last aspect could have high interest to the antioxidant extraction from an industrial scale point of view.

Blending of pressed vegetable oils from pomegranate seeds and soybean to increase functional lipids consume

Nowadays, the byproduct of fruit industrialization has been recommended as a raw material to obtain new functional ingredients that contribute to sustainability in agribusiness. Pomegranate fruit processing discards up to 50% of the raw-fruit, of which 14% are seeds.1 Pomegranate seed oil (PSO) contains over 70% of a rare punicic acid (PA) in its fatty acid composition. PA, a conjugated linolenic acid (CLnA), presents anti-inflammatory properties, and has been commercialized despite its very high sensibility to oxidation and its high price. Due to its availability, and competitive price, soybean oil (SO) is the most consumed vegetable oil in Brazil, and the Brazilian soybean production is the second largest in the world.2 Thus, the PSO blend with a more stable and accessible oil, such as so, will contribute to the manufacture of a more stable product, extending its useful life. The blending of vegetable oils with different fatty acid profiles is a common practice to improve physical-chemical characteristics and achieve new industrial applications.3

Powdered yoghurt produced by spray drying and freeze drying: a review

Yoghurt is one of the dairy products most consumed worldwide but dehydrated yoghurt is still uncommon. Considered a nutritious food, yoghurt powder could be used as an ingredient or supplement in juices, cookies, ice cream and dairy beverages. Spray drying and freeze drying are the methods most widely used to dehydrate dairy products, and the process conditions are directly associated with the production costs and value of the final product. Due to osmotic and thermal stress during dehydration, it is often necessary to incorporate agents such as carriers, thermal protectants, cryo-protectants and stabilizers in order to improve the process yield, preserve nutrients and even facilitate rehydration of the product. Thus the present review presents the technologies available to obtain yoghurt powder, including the processes, drying agents, drying rates, rehydration conditions and survival of the lactic acid bacteria.

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.