930 resultados para food processing
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Objective: To assess time trends in the contribution of processed foods to food purchases made by Brazilian households and to explore the potential impact on the overall quality of the diet. Design: Application of a new classification of foodstuffs based on extent and purpose of food processing to data collected by comparable probabilistic household budget surveys. The classification assigns foodstuffs to the following groups: unprocessed/minimally processed foods (Group 1); processed culinary ingredients (Group 2); or ultra-processed ready-to-eat or ready-to-heat food products (Group 3). Setting: Eleven metropolitan areas of Brazil. Subjects: Households; n 13 611 in 1987-8, n 16 014 in 1995-5 and n 13 848 in 2002-3. Results: Over the last three decades, the household consumption of Group 1 and Group 2 foods has been steadily replaced by consumption of Group 3 ultra-processed food products, both overall and in lower- and upper-income groups. In the 2002-3 survey, Group 3 items represented more than one-quarter of total energy (more than one-third for higher-income households). The overall nutrient profile of Group 3 items, compared with that of Group 1 and Group 2 items, revealed more added sugar, more saturated fat, more sodium, less fibre and much higher energy density. Conclusions: The high energy density and the unfavourable nutrition profiling of Group 3 food products, and also their potential harmful effects on eating and drinking behaviours, indicate that governments and health authorities should use all possible methods, including legislation and statutory regulation, to halt and reverse the replacement of minimally processed foods and processed culinary ingredients by ultra-processed food products.
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In this work, the effect of glycerol on the physical properties of edible films were identified by X-ray diffraction (XRD), differential scanning calorimetry (DSC), infrared (FTIR) and microwave spectroscopy. According to XRD diffractograms, films with 0 and 15% glycerol displayed an amorphous character, and a tendency to semicrystallization, for films with 30% and 45% glycerol. From DSC thermograms, the glass transition (Tg) of the films decreased with glycerol content. However, two Tgs were observed for samples with 30% and 45% glycerol, due to a phase separation. The intensity and positions of the peaks in FTIR fingerprint region presented slight variations due to new interactions arising between glycerol and biopolymer. Microwave measurements were sensitive to moisture content in the films, due to hydrophilic nature of the glycerol. The effect of plasticizer plays, then, an important rule on the physical and functional properties of these films, for applications in food technology.
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The xylanolytic system of Aspergillus versicolor is controlled by induction and carbon catabolite repression. Carboxymethylcellulose and wheat bran were the best inducers of xylanolytic activity. When the fungus was grown for 5 days on VOGEL's liquid medium with wheat bran, the optimal pH and temperature for xylanase production were 6.5 and 30 degrees C, respectively. Optimal conditions for the xylanolytic activity assay were at pH 6.0 and 55 degrees C. The half-life at 60 degrees C of the crude enzyme was 6.5 and 21 minutes, in the absence or presence of substrate, respectively.Xylan is the main hemicellulosic component of plant biomass being present in appreciable quantities in agricultural and several agroindustrial wastes. From the products of xylan enzymatic hydrolysis it is possible to obtain cell protein, fuels and other chemicals. Xylanases combined with cellulase could have applications in food processing. Cellulase-free xylanases can be also utilized for preparation of cellulose pulps and liberation of textile fibres (WOODWARD 1984; BIELY 1985, WONG et al. 1988). In view of the potential applications of xylanases, a study of these enzymes from various sources and their multiplicity is desirable.Among xylanolytic microorganisms, filamentous fungi have been more extensively studied and the genus Aspergillus has been shown to be an efficient producer of xylanases. Preliminary observations from our laboratory have demonstrated that a strain of Aspergillus versicolor, isolated from Brazilian soil, produced high xylanase and low cellulase levels, which is an interesting characteristic for some industrial applications. In this report we describe the production and some properties of xylanase obtained from this fungus.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Water sorption isotherms for vacuum-dried persimmon pulp (PP) powder were determined in the temperature range of 20-50C, and the effects of maltodextrin (MD) or gum arabic (GA) addition on the water sorption behavior of the dried powders were analyzed. Several models were evaluated to fit the experimental data and the Guggenheim-Anderson-de Boer model was selected as the most adequate to describe the observed behavior. Addition of encapsulants affected the isotherms: at the same water activity, PP powder with added GA (PP + GA) or MD (PP + MD) presented lower equilibrium water content than pure PP and were less affected by temperature variations. Samples of PP + MD presented lower equilibrium moisture content than those of PP + GA. The isosteric heats of sorption of pulp powders with encapsulants were higher (less negative) than those of PP, suggesting that there are more active polar sites in PP than in pulp powder containing encapsulants.PRACTICAL APPLICATIONSThe choice of persimmon to carry out this work was due to the large persimmon production available in Brazil; moreover, persimmon pulp is rich in vitamin C, vitamin A and iron, as well as in phenolic compounds. Drying of fruit pulps with high sugar content presents technical difficulties because the hygroscopicity and thermoplasticity of the resulting powders when exposed to high temperature and relative humidity. For this reason, addition of high-molar-mass biopolymers, such as maltodextrin or gum arabic, is a strategy to aid drying and to improve storage stability. Knowledge of water sorption isotherms and net isosteric heats of sorption is important to various food processing operations, including drying, storage and packaging. They are useful in calculating time and energy consumptions during drying, modeling moisture changes during storage and predicting shelf life of food products.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Racional A retirada total ou parcial do estômago resulta em conseqüências nutricionais, agudas ou crônicas, perfeitamente prognosticáveis, mas nem sempre ponderadas na terapia pós-operatória. Objetivo - Rever as participações mecânicas e químicas do estômago no aproveitamento do nutriente dietético, e as conseqüências nutricionais da gastrectomia. Resultados - A deficiência energética, com conseqüente perda de peso, acompanha inversamente o volume gástrico remanescente e o tempo pós-operatório; tem a anorexia e diarréia (má absorção) como principais causas, sendo a primeira decorrente de fatores emocionais ou de mediadores químicos de ação hipotalâmica. A diarréia pode ser decorrente da maior motilidade ou do supercrescimento bacteriano intestinais, com o agravante da insuficiência pancreática exócrina e maior esvaziamento da vesícula biliar. A má absorção traz conseqüências não apenas energética-protéica com a perda fecal de gordura e nitrogênio, como também vitamínico-mineral pelo menor aproveitamento da vitamina D e cálcio dietéticos. A anemia verificada no gastrectomizado é conseqüente à diminuição da produção de HCl (e menor solubilização do ferro) e do fator intrínseco (com menor absorção da vitamina B12). Conclusão - Perda de peso e anemia são os sinais de desnutrição mais comumente observados nestes pacientes, em intensidade e duração variáveis dependentes do tipo de cirurgia e do tempo e tratamento nutricional pós-operatório, sendo recomendável o tratamento dietético supervisionado.
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The accurate determination of thermophysical properties of milk is very important for design, simulation, optimization, and control of food processing such as evaporation, heat exchanging, spray drying, and so forth. Generally, polynomial methods are used for prediction of these properties based on empirical correlation to experimental data. Artificial neural networks are better Suited for processing noisy and extensive knowledge indexing. This article proposed the application of neural networks for prediction of specific heat, thermal conductivity, and density of milk with temperature ranged from 2.0 to 71.0degreesC, 72.0 to 92.0% of water content (w/w), and 1.350 to 7.822% of fat content (w/w). Artificial neural networks presented a better prediction capability of specific heat, thermal conductivity, and density of milk than polynomial modeling. It showed a reasonable alternative to empirical modeling for thermophysical properties of foods.
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The optimum conditions for the production of low methoxyl pectin using pectinmethylesterase (PME) from acerola (Malpighia glabra L.), immobilized in gelatin, have been established by factorial design and response surface methodology. In the case of the free enzymes the optimum conditions for activity, within ranges adequate for food processing, are low NaCl concentrations (0.10 M), relatively high temperatures (55 degreesC) and slightly basic pH values (pH = 9). The temperature and pH seem to have strong influence on the observed activity. In the immobilized enzyme, optimum NaCl concentration was 0.15 M, while the optimum pH remained at 9.0. (C) 2003 Elsevier Ltd. All fights reserved.
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Carinated teeth are common in Mesoeucrocodylia, and the occurrence of denticles over the carinae is related to high predacious species, often referred as ziphodont. This characteristic is broadly recognized as homoplastic. Carinae morphology is cryptic, difficult to be studied under common techniques, and Scanning Electronic Microscopy (SEM) allows the access to detailed information, offering a higher degree of confidence. Previous SEM study allowed the recognition of true/false ziphodont patterns, according to the morphology of the denticles, but such studies on gondwanan mesoeucrocodyles are uncommon. Mariliasuchus amarali is an Upper Cretaceous notosuchian mesoeucrocodyle from South America (Bauru Group, Brazil), with carinated teeth and specialized dentition. Its geological and biochronological distribution are reappraised. SEM study of two teeth shows carinae composed of isolated tuberous anisomorphic true denticles, supporting previous study. Enamel ornamentation does not develop over the carinae, and fabric becomes anastomosed in middle and posterior teeth. Carinae only occur in posterior molariform teeth, related to food processing. Morphological variability of Mariliasuchus is commented, focusing on dentition. Overall characteristics, molariform morphology and wear planes support a non-predacious habit for Matiliasuchus. Matiliasuchus pattern could not be related to true/false ziphodont patterns, either by morphology or function, and is defined as ziphomorph. Ziphomorph pattern is evaluated within the range of mesoeucrocodyles. The detailed study of homoplastic characteristics, such as dental carinae, may provide useful apomorphic information for cladistic analysis.
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Incluye Bibliografía
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The carbohydrates provide 50 to 80% of the dry matter of grain and roughage and can be divided into structural (cellulose, hemicellulose) and non-structural (starch, pectin and sugars). The non-structural carbohydrates are primarily digested in the rumen and its dynamic process is a sequence for the supply of nutrients to the intestine. The quality and quantity of products resulting from ruminal fermentation are dependent on the type and activity of microorganisms in the rumen influenced by the type of food processing and that are subject of cereal grains that make up the diet. The NSC escape of rumen fermentation to be digested into glucose in the small intestine by pancreatic enzymes of origin (α-amylase) and intestinal mucosa (maltase and isomaltase). Starch is the most important energy supplier of cereals, which are important components of diets for intensive production of milk and meat.
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Includes bibliography
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This study examined the antioxidant activity of lyophilized rosemary extract added to soybean oil, subjected to thermoxidation conditions and also its synergistic effect with the synthetic antioxidant tertiary butylhydroquinone (TBHQ). Soybean oil samples with no antioxidant added (SO), 3,000mg/kg rosemary extract (RE), 50mg/kg TBHQ (TBHQ), and a mixture of those two antioxidants (RE+TBHQ) were heated to 180C for 20h. After 0, 10 and 20h, the oxidative stability, total polar compounds, tocopherol content and fatty acid profile were determined. The addition of rosemary extract increased oxidative stability and resulted in a lower formation of total polar compounds and a higher retention of tocopherols. The RE treatment showed the highest amount of polyunsaturated fatty acids after 20h. There was not any synergy between TBHQ and rosemary extract in preventing oxidation of soybean oil. Rosemary extract showed a higher antioxidant potential when compared with TBHQ. PRACTICAL APPLICATIONS: Antioxidants are important ingredients in food processing because they have the capacity to protect foods, containing oils and fats, from damage caused by free radicals and reactive oxygen species. Synthetic antioxidants are widely used in the food industry; however, their utilization has been questioned because of toxicity. Therefore, there is a growing interest in the use of natural antioxidants to reduce or replace the synthetic antioxidants. Several species are used in cooking, medicine and by the pharmaceutical industry, standing out the rosemary. Being rich in compounds with high antioxidant activity, the rosemary extract can be used to replace synthetic antioxidants used in vegetable oils. © 2012 Wiley Periodicals, Inc.
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The antioxidant activity from basil ethanol extract, the effect on oxidative stability, total polar compounds, tocopherols levels and fatty acid profile in soybean oil under thermoxidation were evaluated. The basil leaves were dried in lyophilizer, ground and subjected to extraction with ethanol. The soybean oil (SO), soybean oil with 50mg/kg of tert-butylhydroquinone (TBHQ), soybean oil with 3,000mg/kg of extract (BE) and soybean oil with 3,000mg/kg of extract and 50mg/kg of TBHQ (mixture) treatments were subjected to 180±5C for 20h. Oil samples were taken at 0, 10 and 20h and subjected to analysis. The addition of the basil extract increased oxidative stability and resulted in lower formation of total polar compounds. Although the content of tocopherols and polyunsaturated fatty acids decreased over the course of heating, their values remained higher than the SO treatments. Synergistic effect was not observed in the mixture treatment. © 2012 Wiley Periodicals, Inc.