ResumoEste trabalho teve por objetivo avaliar o efeito de diferentes agentes carreadores (Maltodextrina 5DE, Maltodextrina 10DE, Goma arábica e Capsul ® ) nas características físico-químicas (umidade, densidade, solubilidade, teor de antocianinas e atividade antioxidante) da polpa de morango desidratada por atomização e armazenada à temperatura ambiente por 90 dias. A utilização dos diferentes agentes carreadores resultou em pós com valores de densidade aparente entre 0,40 e 0,52 g/cm 3 e umidade menor do que 2,5%. Todas as amostras foram altamente solúveis, mas os pós obtidos com a Maltodextrina 5DE e com a Goma arábica apresentaram menor higroscopicidade. As isotermas de sorção obtidas foram do tipo III e o modelo de GAB foi o que melhor se ajustou aos dados experimentais. A amostra produzida com goma arábica apresentou a maior concentração de antocianinas e, consequentemente, maior valor de atividade antioxidante, tanto imediatamente após a secagem como ao longo de 90 dias de armazenamento. Os resultados obtidos indicaram que a goma arábica foi o agente carreador mais adequado para a produção de polpa de morango em pó. Palavras-chave: Isotermas de sorção; atividade antioxidante; antocianinas. SummaryThis study aimed to evaluate the effect of different carrier agents (5DE Maltodextrin, 10DE Maltodextrin, gum Arabic and Capsul ® ) on the physicochemical characteristics (moisture content, density, solubility, total anthocyanins and antioxidant activity) of strawberry pulp processed by spray drying and stored at room temperature for 90 days. The use of different carrier agents resulted in powders with bulk densities ranging from 0.40 to 0.52 g/cm 3 and moisture contents below 2.5%. All the samples were highly soluble, but the powders obtained with 5DE Maltodextrin and gum Arabic were less hygroscopic. The sorption isotherms were of type III and the GAB model was the model that best fitted the experimental data. The powder produced with gum Arabic had the highest anthocyanin content and consequently the greatest antioxidant activity value, both immediately after the drying process and during the storage period. The results obtained showed that gum Arabic was the most suitable carrier agent for the production of strawberry pulp powder. Campinas, v. 16, n. 4, out

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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.

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.

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.