202,162 research outputs found
Estabilidade e propriedades sensoriais da bebida de farelo de arroz parbolizado orgânico e os efeitos de seu consumo em ratos
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Ciência dos Alimentos, Florianópolis, 2009O farelo de arroz estabilizado é um subproduto do beneficiamento dos grãos de arroz. O uso deste farelo vem crescendo no País devido ao seu valor nutricional e benefícios à saúde. Com o objetivo de oferecer alternativas para o consumo do farelo de arroz, foi elaborada uma bebida de extrato deste farelo em dois diferentes sabores. A bebida foi tratada termicamente e avaliada quanto à composição química, estabilidade e propriedades sensoriais, parâmetros de qualidade pertinentes ao novo produto. Os parâmetros para avaliar a vida de prateleira foram acidez titulável, pH e reologia. Foi realizado um ensaio biológico com ratos, para avaliar os efeitos do seu consumo no colesterol total e glicose e outro ensaio biológico para determinar o comportamento de ratos no nado forçado e no labirinto em cruz elevado com determinação de ACTH plasmático, além do efeito desta bebida na absorção de cálcio em ratos. A análise da composição nutricional mostrou um produto rico em ácidos graxos insaturados e minerais, especialmente, fósforo, potássio, manganês e magnésio. A reologia mostrou que a bebida obtida com este farelo estabilizado conservou-se por 20 dias sob refrigeração. A análise sensorial indicou que a bebida de farelo de arroz foi aceita dentro das formulações estabelecidas. Foi verificado que, em ratos, a bebida de farelo de arroz não apresentou efeito significativo (p>0,05) sobre o colesterol, mas apresentou efeito significativo (p0,05). Não houve efeito negativo na absorção de cálcio.The stabilized rice bran is a byproduct of processing grain of rice. Use of this meal is growing in the country because of its nutritional value and health benefits. Aiming to offer alternatives to the consumption of rice bran, was prepared for a drink of this bran extract in two different flavors. The drink was treated and evaluated as to the chemical composition, stability and sensory properties, the quality parameters relevant to the new product. The parameters to evaluate the shelf-life were acidity, pH and rheology. An assay was conducted with rats to evaluate the effects of its consumption in total cholesterol and glucose and other biological test to determine the behavior of rats in the forced swim and in the plus maze with determination of plasma ACTH, in addition to the effect of this drink in the absorption of calcium in rats. The analysis of the nutritional composition showed a product rich in unsaturated fatty acids and minerals, especially phosphorus, potassium, manganese and magnesium. The rheology showed that the drinks with the meal stabilized lasted 20 days under refrigeration. The sensory analysis indicated that the drink of rice bran was accepted into the formulations established. It was found that in rats, the drink of rice bran showed no significant effect (p> 0.05) on cholesterol, but significant effect (p 0.05). There was no negative effect on the absorption of calcium
A low-power 64-point FFT/IFFT architecture for wireless broadband communication
No full textA low power 64-point FFT/IFFT architecture is developed for the application in OFDM based wireless broadband communication system. The proposed architecture satisfies the specifications of IEEE 802.11a and ETSI Bran. The architecture requires 25% multiplication and 86% addition/subtraction operation compared to the conventional Cooley-Tukey approach. This leads to power and area saving as well. The architecture is capable to perform FFT and IFFT without changing the internal coefficients which makes it highly suitable for practical applications
Nutraceutical tortillas and tortilla chips prepared with bran from specialty sorghums
No full textThe effects of sorghum bran addition on table tortillas and tortilla chip
properties were evaluated. Texture, phenol content, antioxidant activity, and sensory
characteristics were evaluated. Texture was measured by objective and subjective
tests. Products were analyzed for phenols following the Folin-Ciocalteu procedure
and for antioxidant potential following the ABTS (2,2'-azinobis (3-
ethylbenzothiazoline-6-sulfonic acid) method. Sensory properties were evaluated
using a nine point hedonic scale.
Bran from two specialty sorghums: sumac (high tannin) and black (high
anthocyanins) was added at 0, 5, and 10% to table tortillas and tortilla chips. For
table tortillas the interaction of sorghum bran with an antistaling formula containing
guar gum, carboxymethylcellulose and maltogenic alpha-amylase was assessed.
Tortillas containing sorghum bran had a more friable structure than the
control. This detrimental effect was overcome by the antistaling formula. Additives
made fluffier tortillas with improved texture and appearance. Tortillas containing
sorghum bran and the antistaling formula were acceptable to panelists. At 5%
sorghum bran inclusion, there was no significant difference in sensory attributes
from the control aside from appearance. Tortillas containing sorghum bran had a
dark natural color comparable to that of blue corn tortillas.
Tortilla chip texture was not significantly affected by addition of bran to the
formula. As in table tortillas, addition of sorghum bran produced minor changes in
the texture and flavor of the product, but a significant change in appearance
acceptability. Tortilla chips had a dark color, comparable to the one of blue corn
tortilla chips. Sumac bran yielded larger amounts of phenols and antioxidant activity than
black bran. Levels of phenols and antioxidant potential increased with increased
bran. Although processing caused a measurable loss of sorghum bran antioxidants,
table tortilla and tortilla chips were still a significant source of phenols and
antioxidant activity.
The addition of sorghum bran produced tortillas and tortilla chips with
increased levels of dietary fiber and antioxidants, without adversely affecting other
sensory properties
A comparison of the HIPERLAN/2 and IEEE 802.11a wireless LAN standards
No full textAt present, WLANs supporting broadband multimedia communication are being developed and standardized around the world. Standards include HIPERLAN/2, defined by ETSI BRAN, 802.11a, defined by the IEEE, and HiSWANa defined by MMAC. These systems provide channel adaptive data rates up to 54 Mb/s (in a 20 MHz channel spacing) in the 5 GHz radio band. In this article an overview of the HIPERLAN/2 and 802.11a standards is presented together with software simulated physical layer performance results for each of the defined transmission modes. Furthermore, the differences between these two standards are highlighted (packet size, upper protocol layers etc.), and the effects of these differences on throughput are analyzed and discussed
Chemical, color, and sensory attributes of sorghum bran-enhanced beef patties in a high oxygen environment
No full textBottom rounds were shipped to the Rosenthal Meat Science and Technology Center, ground and enhanced with one of the following predetermined treatments: control; 0.4% sodium phosphates and 0.3% salt; 0.25% sorghum bran; 2.0% sorghum bran; 0.25% sorghum bran, 0.4% sodium phosphates and 0.3% salt; and 2.0% sorghum bran, 0.4% sodium phosphates, and 0.3% salt. The ground beef was formed into 226 g ground beef patties, packaged in an 80% O2 and 20% CO2 gaseous environment, and stored under retail display at 4 degrees for 0, 3, 6, or 9d. Measurements to determine rate and extent of oxidation, rate of discoloration, and sensory characteristics were taken to evaluate the effectiveness of sorghum bran.
Patties containing the highest amount of sorghum bran had the lowest TBARS values over 9 days of storage, lower a* values, greater amounts of discoloration, darker lean color, and less cook loss (P<0.05) than control patties. Patties enhanced with the highest level of sorghum bran had lower beefy/brothy and bloody flavor aromatics, higher sorghum flavor, more bitter and burnt aftertaste, and more sandy/gritty textures (P<0.05) when compared to control patties. Patties containing the low amount of sorghum had lower TBARS values (P<0.05), but similar amounts of cook loss as the control patties. Patties containing a low sorghum level, 0.4% sodium phosphates (SP) and 0.3% salt (S) had lower (P<0.05) amounts of cook loss when compared to control patties. Patties containing low amounts of sorghum were similar to control patties in terms of redness while the addition of low sorghum, SP, and S decreased (P<0.05) the degree of redness. Patties containing low amounts of sorghum bran had similar amounts of discoloration compared to control (CONT) patties. Also, these had less bloody flavor aromatics (P<0.05), but were similar in sorghum flavor aromatics and bitter taste when compared to control patties.
The addition of sorghum bran at low levels can retard oxidative rancidity in ground beef patties without causing detrimental color changes and negatively affecting sensory attributes, while patties enhanced with 2% sorghum bran have extensive discoloration and undesirable sensory attributes
How good are rodent models of carcinogenesis in predicting efficacy in humans? A systematic review and meta-analysis of colon chemoprevention in rats, mice and men
No full textTumours in rodent and human colon share many histological and genetic features. To know if rodent models of colon carcinogenesis are good predictors of chemopreventive efficacy in humans, we made a meta-analysis of aspirin, beta-carotene, calcium, and wheat bran studies. Controlled intervention studies of adenoma recurrence in human volunteers were compared with chemoprevention studies of carcinogen-induced tumours in rats, and of polyps in Min (Apc(+/-)) mice: 6714 volunteers, 3911 rats and 458 mice were included in the meta-analyses. Difference between models was small since most global relative risks were between 0.76 and 1.00. A closer look showed that carcinogen-induced rat studies matched human trials for aspirin, calcium, carotene, and were compatible for wheat bran. Min mice results were compatible with human results for aspirin, but discordant for calcium and wheat bran (no carotene study). These few results suggest that rodent models roughly predict effect in humans, but the prediction is not accurate for all agents. Based on three cases only, the carcinogen-induced rat model seems better than the Min mouse model. However, rodent studies are useful to screen potential chemopreventive agents, and to study mechanisms of carcinogenesis and chemoprevention
Lignocellulosic Enzymes Characterization and Scanning Electron Microscope Analysis on Rice Bran Surface Structure Changes
No full textRice bran was one of livestock food ingredients wit
h high crude fibers contents, including cellulose and
hemicelluloses. Lignocellulosic enzymes such as xylanase and cellulase functioned in degrading cellulose and hemicelluloses. The objectives of this study were to qualitatively screen Actinobacillus sp. (G6) and
Bacillus pumilus (G7) which produced xylanase and cellulase, determining molecular weight of xylanase and cellulase enz
ymes using SDS-PAGE and Zymogram, and analyzing structure changes on rice bran surface after Scanning Electron Microscope treatments using xylanase and cellulase
enzymes. The findings of this study indicated xylanolitic indexes for G6 and G7 were 2 and 1.7 respectively while cel
lulosic index for G6 and G7 were 1.6 and 2. Enzymesproduced
by Actinobacillus sp. (G6) had molecular weight 25-
35 kDa and above 100 kDa while enzymes produced by
Bacillus pumilus (G7) had molecular weight 25 kDa up to above 100 kDa. The result of rice bran SEM analysis indicated profile change of the samples before and after enzymes treatmen
Recuperação de y-orizanol a partir de resíduo da indústria de óleo de arroz utlizando extração supercrítica: avaliação de parâmetros de processo e caracterização dos extratos
No full textDissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-graduação em Engenharia de Alimentos, Florianópolis, 2010O óleo de arroz é naturalmente rico em antioxidantes, dentre os quais se destaca o ?-orizanol. Entretanto, no refino químico, o teor de ?-orizanol no óleo é reduzido expressivamente em consequência da etapa de neutralização, na qual quantidade significativa do ?-orizanol passa a fazer parte do resíduo (borra de neutralização) ao invés de permanecer no óleo neutro. A borra de neutralização pode ser utilizada como matéria-prima para a produção de ácidos graxos por meio de processo de destilação, sendo que o ?-orizanol fica concentrado no resíduo gerado neste processo. O objetivo principal do presente trabalho foi a recuperação do ?-orizanol pela técnica de extração supercrítica (ESC), utilizando como matéria-prima o resíduo da destilação da borra de neutralização do óleo de arroz (RDBN). O pré-tratamento da matéria-prima englobou as etapas de hidrólise alcalina, precipitação induzida por íons cálcio, filtração a vácuo, secagem e moagem. Análises de caracterização da matéria-prima, caracterização térmica do ?-orizanol e caracterização granulométrica da matriz das extrações foram efetuadas para melhor conhecimento dos materiais em estudo. A técnica de extração Soxhlet, utilizando diferentes solventes, foi realizada com o intuito de comparar resultados entre extração convencional e ESC em termos de rendimento e qualidade dos extratos. A influência dos parâmetros de processo (pressão e temperatura), sobre o rendimento e qualidade dos extratos supercríticos, foi avaliada por meio de experimentos realizados de acordo com um planejamento fatorial completo 32. A caracterização dos extratos obtidos por ESC e Soxhlet foi realizada em termos de rendimento global, teor de fenólicos totais, atividade antioxidante pelo método de DPPH, teor de ?-orizanol, taxa de recuperação do ?-orizanol e composição em ácidos graxos. A modelagem matemática da curva de ESC foi feita por meio da aplicação dos modelos de Esquível, Bernardo-Gil e King (1999), Crank (1975), Gaspar et al. (2003) e Martínez et al. (2003). Na ESC os extratos obtidos a 300 bar/30 ºC e 200 bar/30 ºC apresentaram os maiores rendimentos globais (39 ± 1% e 35 ± 4 %, m/m, respectivamente) maiores taxas de recuperação do ?-orizanol (31,3 % e 27,8 %, m/m, respectivamente) e teores de ?-orizanol relativamente altos (3,2 %, m/m, em ambas as condições). O modelo de Martínez et al. (2003) foi o que melhor se ajustou aos dados experimentais
Characterization of rice bran wax policosanol and its nanoemulsion formulation
No full textAminu Ishaka,1,2 Mustapha Umar Imam,1 Rozi Mahamud,3 Abu Bakar Zakaria Zuki,4 Ismail Maznah1 1Laboratory of Molecular Biomedicine, Institute of Bioscience, University Putra Malaysia, Serdang, Selangor, Malaysia; 2Department of Medical Biochemistry, College of Health Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria; 3Faculty of Medicine and Health Sciences, 4Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Selangor, Malaysia Abstract: Policosanol, a mixture of long-chain alcohols found in animal and plant waxes, has several biological effects; however, it has a bioavailability of less than 10%. Therefore, there is a need to improve its bioavailability, and one of the ways of doing this is by nanoemulsion formulation. Different droplet size distributions are usually achieved when emulsions are formed, which solely depends on the preparation method used. Mostly, emulsions are intended for better delivery with maintenance of the characteristics and properties of the leading components. In this study, policosanol was extracted from rice bran wax, its composition was determined by gas chromatography mass spectrophotometry, nanoemulsion was made, and the physical stability characteristics were determined. The results showed that policosanol nanoemulsion has a nanosize particle distribution below 100 nm (92.56–94.52 nm), with optimum charge distribution (-55.8 to -45.12 mV), pH (6.79–6.92) and refractive index (1.50); these were monitored and found to be stable for 8 weeks. The stability of policosanol nanoemulsion confers the potential to withstand long storage times. Keywords: rice bran wax, policosanol, nanoemulsion, characterizatio
Including buckwheat bran in wheat dough and bread: what happens?
No full textDevelopment of products rich in ingredients with high nutritional value –as dietary fiber– is currently one of the most important goals for food companies.
However, inclusion of high levels of fiber in cereal-based products is still technologically challenging, as for the texture and the sensory quality.
Buckwheat is a nutritionally-relevant pseudo-cereal and is traditionally used in Europe and Asia for pasta production, but rarely exploited in bakery applications.
In this study, we investigated the effects of enriching wheat flour with increasing levels of buckwheat bran (5, 10, 20%), before and after micronization.
DMTA and DSC allowed evaluating the effects of bran on the thermo-mechanical transition during processing while dough rheology at large deformations was assessed by the Kieffer test. Standard baking tests and TPA were performed on bread.
Regarding dough properties, both DMTA and DSC showed that bran enrichment resulted in increase in the temperature of starch gelatinization. The size of the effect depended on bran amount and particle size. DMTA also provided evidence as for changes in the viscoelastic behavior during heating. As for Kieffer test results, increasing bran inclusion led to a decrease of resistance to extension.
Concerning the baking quality, the decrease in loaf volume due to buckwheat enrichment clearly depended on the level of inclusion and on bran particle size. Moisture content of fresh bread reflected the behavior in dough hydration for both types of bran: gradual enrichment with buckwheat as such led to a more wet product, whereas the substitution level with micronized bran had no significant effect. Crumb firmness increased as the bran content increased and was positively correlated with crumb density. The Ahsby-Gibson theory for cellular solid was applied to correct for the effect of density. Bran as such increased the corrected hardness for addition level higher than 10%. On the contrary, micronized bran deeply altered crumb firmness already at 5% substitution level.
Overall, buckwheat bran greatly affected dough rheology and thermal transitions during baking, which resulted in considerable changes in bread quality. Such changes could be related not only to the enrichment degree but also to the size of the bran particles
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