54 research outputs found

    Influence of drying process variables on fresh and osmotically pre-treated mushrooms.

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    The aim of this work was to study the drying of fresh and osmotically dehydrated mushrooms and evaluate their qualities. The osmotic treatment was carried out at 20 °C with a 10% w.w?1 salt solution, 80 rpm agitation and 60 min immersion time. The mushrooms were dried in a vertical bed dryer with forced air-flow. An experimental design was applied to evaluate the influence of the temperature and air velocity on the drying constant, obtained according to an exponential model and on the colour difference between the dried and fresh samples. Using Response Surface Methodology, a condition was chosen to obtain the largest drying constants and smallest colour differences. The optimum conditions for the drying process were 70 °C and 2.0 m/s, and 80 °C and 2.5 m/s for fresh and osmotically dehydrated mushrooms, respectively. The dried mushrooms aresented â-glucan content values of 6.14 ± 0.55 and 6.77 ± 0.47 g.100 g?1 d.b under the optimised drying conditions. Osmotically dehydrated samples showed a slower re-hydration rate and smaller water activity than samples without pre-treatment

    Effect of osmotic dehydration on the drying kinetics and quality of cashew apple,

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    The effect of different osmotic pretreatments on cashew apple drying kinetics and product quality were investigated

    Drying kinetic of fresh and osmotically dehydrated mushroom (Agaricus blazei).

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    The aim of this study was to model the drying kinetics of fresh and osmotically pretreated mushroom slices (Agaricus blazei). Besides the effects of drying air temperature and air velocity, the effect of osmotic pretreatment on drying kinetics and color of dried mushrooms was also determined. The osmotic treatment was carried out at 20C with a 10% (w/w) salt solution, 80 rpm agitation and 60 min immersion time. The fresh and osmosed mushrooms were dried in a vertical bed dryer with forced airflow at different temperatures (40, 60 and 80C) and air velocities (1.0, 1.75 and 2.5 m/s). Drying curves obtained from the experimental data were fitted to the different thin layer-drying models (Fick?s, Page?s and logarithmic models). Drying rates of osmosed mushroom decreased due to the presence of infused solids. Increasing the drying temperature and air velocity caused shorter drying times. Osmotically pretreated mushroom presented lower luminosity values (L*) when compared with fresh mushroom, indicating that the osmotic dehydration was not efficient to prevent color loss. Temperature strongly affected the color parameters luminosity L* (or lightness) and chroma C* (or color intensity)

    The physics of dynamical atomic charges: the case of ABO3 compounds

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    Based on recent first-principles computations in perovskite compounds, especially BaTiO3, we examine the significance of the Born effective charge concept and contrast it with other atomic charge definitions, either static (Mulliken, Bader...) or dynamical (Callen, Szigeti...). It is shown that static and dynamical charges are not driven by the same underlying parameters. A unified treatment of dynamical charges in periodic solids and large clusters is proposed. The origin of the difference between static and dynamical charges is discussed in terms of local polarizability and delocalized transfers of charge: local models succeed in reproducing anomalous effective charges thanks to large atomic polarizabilities but, in ABO3 compounds, ab initio calculations favor the physical picture based upon transfer of charges. Various results concerning barium and strontium titanates are presented. The origin of anomalous Born effective charges is discussed thanks to a band-by-band decomposition which allows to identify the displacement of the Wannier center of separated bands induced by an atomic displacement. The sensitivity of the Born effective charges to microscopic and macroscopic strains is examined. Finally, we estimate the spontaneous polarization in the four phases of barium titanate.Comment: 25 pages, 6 Figures, 10 Tables, LaTe

    Patterns and correlates of physical activity: a cross-sectional study in urban Chinese women

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    <p>Abstract</p> <p>Background</p> <p>Inactivity is a modifiable risk factor for many diseases. Rapid economic development in China has been associated with changes in lifestyle, including physical activity. The purpose of this study was to investigate the patterns and correlates of physical activity in middle-aged and elderly women from urban Shanghai.</p> <p>Methods</p> <p>Study population consisted of 74,942 Chinese women, 40–70 years of age, participating in the baseline survey of the Shanghai Women's Health Study (1997–2000), an ongoing population-based cohort study. A validated, interviewer-administered physical activity questionnaire was used to collect information about several physical activity domains (exercise/sports, walking and cycling for transportation, housework). Correlations between physical activity domains were evaluated by Spearman rank-correlation coefficients. Associations between physical activity and socio-demographic and lifestyle factors were evaluated by odds ratios derived from logistic regression.</p> <p>Results</p> <p>While more than a third of study participants engaged in regular exercise, this form of activity contributed only about 10% to daily non-occupational energy expenditure. About two-thirds of women met current recommendations for lifestyle activity. Age was positively associated with participation in exercise/sports and housework. Dietary energy intake was positively associated with all physical activity domains. High socioeconomic status, unemployment (including retirement), history of chronic disease, small household, non-smoking status, alcohol and tea consumption, and ginseng intake were all positively associated with exercise participation. High socioeconomic status and small household were inversely associated with non-exercise activities.</p> <p>Conclusion</p> <p>This study demonstrates that physical activity domains other than sports and exercise are important contributors to total energy expenditure in women. Correlates of physical activity are domain-specific. These findings provide important information for research on the health benefits of physical activity and have public health implications for designing interventions to promote participation in physical activity.</p

    Time trends in leisure time physical activity and physical fitness in elderly people: 20 year follow-up of the Spanish population national health survey (1987-2006)

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    <p>Abstract</p> <p>Background</p> <p>To estimate trends in leisure time physical activity and physical fitness between 1987-2006 in older Spanish people.</p> <p>Methods</p> <p>We analyzed data collected from the Spanish National Health Surveys conducted in 1987 (n = 29,647), 1993 (n = 20,707), 1995-1997 (n = 12,800), 2001 (n = 21,058), 2003 (n = 21,650), and 2006 (n = 29,478). The number of subjects aged ≥ 65 years included in the current study was 29,263 (1987: n = 4,958-16.7%; 1993: n = 3,751-17.8%; 1995-97: n = 2,229-17.4%; 2001: n = 4,356-20.7%; 2003: 6,134-28.3%; 2006: 7,835-26.5%). Main variables included leisure-time physical activity and physical fitness. We analyzed socio-demographic characteristics, self-rated health status, lifestyle habit and co-morbid conditions using multivariate logistic regression models.</p> <p>Results</p> <p>Women exhibited lower prevalence of leisure time physical activity and physical fitness compared to men (P < 0.05). The multivariate analysis for time trends found that practising leisure time physical activity increased from 1987 to 2006 (P < 0.001). Variables associated with a lower likelihood of practicing leisure time physical activity were: age ≥ 80 years old, ≥ 2 co-morbid chronic conditions, and obesity. Variables associated with lower physical fitness included: age ≥ 80 years, worse self rated health; ≥ 2 medications (only for walking), and obesity.</p> <p>Conclusions</p> <p>We found an increase in leisure time physical activity in the older Spanish population. Older age, married status, co-morbid conditions, obesity, and worse self-perceived health status were associated with lower activity. Identification of these factors can help to identify individuals at risk for physical inactivity.</p
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