Authentication of Geographical Origin and Crop System of Grape Juices by Phenolic Compounds and Antioxidant Activity Using Chemometrics
Granato, D. ; Koot, A.H. ; Schnitzler, E. ; Ruth, S.M. van - \ 2015
Journal of Food Science 80 (2015)3. - ISSN 0022-1147 - p. C584 - C593.
in-vitro - red wines - oxidative stress - fruit juices - rats - capacity - vivo - mechanism - profile
The main goal of this work was to propose an authentication model based on the phenolic composition and antioxidant and metal chelating capacities of purple grape juices produced in Brazil and Europe in order to assess their typicality. For this purpose, organic, conventional, and biodynamic grape juices produced in Brazil (n = 65) and in Europe (n = 31) were analyzed and different multivariate class-modeling and classification statistical techniques were employed to differentiate juices based on the geographical origin and crop system. Overall, Brazilian juices, regardless of the crop system adopted, presented higher contents of total phenolic compounds and flavonoids, total monomeric anthocyanins, proanthocyanidins, flavonols, flavanols, cyanidin-3-glucoside, delphinidin-3-glucoside, and malvidin-3,5-glucoside. No differences were observed for trans-resveratrol, malvidin-3-glucoside, and pelargonidin-3-glucoside between countries and among crop systems. A total of 91% of Brazilian and 97% of European juices were adroitly classified using partial least squares discriminant analysis when the producing region was considered (92% efficiency), in which the free-radical scavenging activity toward 2,2-diphenyl-1-picrylhydrazyl, content of total phenolic compounds, gallic acid, and malvidin-3-glucoside were the variables responsible for the classification. Intraregional models based on soft independent modeling of class analogy were able to differentiate organic from conventional Brazilian juices as well as conventional and organic/biodynamic European juices.
Temporal dominance of emotions: Measuring dynamics of food-related emotions during consumption
Jager, G. ; Schlich, P. ; Tijssen, I.O.J.M. ; Yao, Y.J. ; Visalli, M. ; Graaf, C. de; Stieger, M.A. - \ 2014
Food Quality and Preference 37 (2014). - ISSN 0950-3293 - p. 87 - 99.
time-intensity - mood - experience - perception - chocolate - profile - liking - memory
Mapping food-evoked emotions in addition to sensory profiling is topical. In sensory profiling, the Temporal Dominance of Sensation (TDS) method focuses on the assessment of the temporal evolution of dominant sensory attributes over time. We hypothesize that food-evoked emotions also show temporal dynamics that can be related to dynamic sensory perception. This study assessed temporal dynamics of sensory and emotional attributes during chocolate tasting. We used TDS to determine dynamic sensory properties of dark chocolates providing a list of 10 sensory attributes. Comparably, Temporal Dominance of Emotions (TDE) was assessed by replacing the sensory attributes with 10 emotional attributes. Sixty-two participants assessed TDS and TDE of five commercially available dark chocolates (plain and flavoured). Multivariate comparisons (Hotelling test) showed significant differences between products based on the dominance duration of sensory (p <0.05) and emotional attributes (p <0.05). TDS difference curves revealed products to differ based on their dominant sensory attributes, with different attributes peaking at different time moments. TDE difference curves showed that products also differed in the temporal distribution of dominant emotional attributes. Comparing the average dominance rates between plain dark and flavoured dark chocolates revealed that for flavoured dark chocolates mainly flavour attributes and positive/active emotions were perceived as salient whereas for plain dark chocolates textural as well as taste attributes were dominant accompanied by more negative/non-energetic emotions. A joint CVA plot on the duration of dominance for sensory and emotional attributes per product revealed that temporal evolution of sensory – and emotional attributes was related. This suggests a mutual reciprocity between those two entities (sensory and emotional attributes) resulting in more complex, richer product characterization. In conclusion, these findings show TDE to be a promising new venue in characterising food-evoked emotions in relation to sensory profiling.
Concentrations of n-3 and n-6 fatty acids in Dutch bovine milk fat and their contribution to human dietary intake
Valenberg, H.J.F. van; Hettinga, K.A. ; Dijkstra, J. ; Bovenhuis, H. ; Feskens, E.J.M. - \ 2013
Journal of Dairy Science 96 (2013)7. - ISSN 0022-0302 - p. 4173 - 4181.
conjugated linoleic-acid - lactating dairy-cows - fed fish-oil - extruded soybeans - calcium salts - food sources - rumen biohydrogenation - maize silage - supplementation - profile
Weekly samples representative of Dutch milk were analyzed for concentrations of n-3 and n-6 fatty acids (FA). Concentrations of the n-3 FA a-linolenic acid (ALA), eicosatetraenoic acid, eicosapentaenoic acid, and docosapentaenoic acid were 0.495 ± 0.027, 0.041 ± 0.004, 0.067 ± 0.005, and 0.086 ± 0.008 g per 100 g of fat, respectively, whereas docosahexaenoic acid was absent or present in concentrations lower than 0.020 g per 100 g of fat. Concentrations of the n-6 FA linoleic acid (LeA), ¿-linoleic acid, dihomo-¿-linoleic acid, and arachidonic acid were 1.428 ± 0.068, 0.070 ± 0.007, 0.066 ± 0.004, and 0.089 ± 0.004 g per 100 g of fat, respectively; adrenic acid was present in concentrations lower than 0.020 g per 100 g of fat, whereas docosapentaenoic acid was absent in all samples. The concentrations of ALA and LeA were significantly higher in spring and summer, compared with autumn and winter. The concentrations of all other ALA- and LeAderived n-3 and n-6 FA were not significantly different between seasons. The contribution of milk fat to the daily intake of eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid was calculated for human consumption levels in different countries. Milk fat contributed between 10.7 and 14.1% to the daily intake of eicosapentaenoic acid and between 23.5 and 34.2% to the intake of docosapentaenoic acid; whereas docosahexaenoic acid contribution was marginal. Arachidonic acid from milk fat contributed between 10.5 and 18.8% to the human intake of n-6 FA.
Improving Stable Boundary-Layer Height Estimation Using a Stability-Dependent Critical Bulk Richardson Number
Richardson, H. ; Basu, S. ; Holtslag, A.A.M. - \ 2013
Boundary-Layer Meteorology 148 (2013)1. - ISSN 0006-8314 - p. 93 - 109.
large-eddy simulation - turbulence structure - resistance laws - climate model - surface - depth - formulations - evolution - profile - range
For many decades, attempts have been made to find the universal value of the critical bulk Richardson number (Ri Bc ; defined over the entire stable boundary layer). By analyzing an extensive large-eddy simulation database and various published wind-tunnel data, we show that Ri Bc is not a constant, rather it strongly depends on bulk atmospheric stability. A (qualitatively) similar dependency, based on the well-known resistance laws, was reported by Melgarejo and Deardorff (J Atmos Sci 31:1324–1333, 1974) about forty years ago. To the best of our knowledge, this result has largely been ignored. Based on data analysis, we find that the stability-dependent Ri Bc estimates boundary-layer height more accurately than the conventional constant Ri Bc approach. Furthermore, our results indicate that the common practice of setting Ri Bc as a constant in numerical modelling studies implicitly constrains the bulk stability of the simulated boundary layer. The proposed stability-dependent Ri Bc does not suffer from such an inappropriate constraint.
Association between High Fat-low Carbohydrate Diet Score and Newly Diagnosed Type 2 Diabetes in Chinese Population
Na, Y. ; Feskens, E.J.M. ; Li, Y.P. ; Zhang, J. ; Fu, P. ; Ma, G.S. ; Yang, X.G. - \ 2012
Biomedical and environmental sciences 25 (2012)4. - ISSN 0895-3988 - p. 373 - 382.
coronary-heart-disease - insulin sensitivity - risk - women - metaanalysis - profile - index - men
Objective To study the association between high fat-low carbohydrate diet score and newly diagnosed type 2 diabetes in Chinese population. Methods Data about 20 717 subjects aged 45-59 years from the cross-sectional 2002 China National Nutrition and Health Survey were analyzed. High fat-low carbohydrate diet was scored according to the energy of carbohydrate, fat, and protein. Results Of the 20 717 subjects, 1 332 were diagnosed with hyperglycemia and 662 were newly diagnosed with type 2 diabetes. Multivariate adjusted analysis showed that the highest score of type 2 diabetes patients was 2.75 (95% CI: 2.09-3.61). The score of type 2 diabetes patients was 1.87 (95% CI: 1.35-2.58) after further adjustment for their socioeconomic status and physical activity. No significant difference was found in the odds ratio after further adjustment for BMI, blood pressure, lipid level, and energy intake. No evidence was observed for the relation between high fat-low carbohydrate-diet score in type 2 diabetes patients due to high family income, less education, physical activity, overweight, hypertension, high TG, or low HDL level. Conclusion High fat-low carbohydrate diets, far different from traditional Chinese diets, are associated with the high incidence of type 2 diabetes in Chinese population.
Typicality and Geographical Origin Markers of Protected Origin Cheese from The Netherlands Revealed by PTR-MS
Galle, S.A. ; Koot, A.H. ; Soukoulis, C. ; Cappellin, L. ; Biasioli, F. ; Alewijn, M. ; Ruth, S.M. van - \ 2011
Journal of Agricultural and Food Chemistry 59 (2011)6. - ISSN 0021-8561 - p. 2554 - 2563.
reaction-mass-spectrometry - volatile organic-compounds - flavor compounds - fragmentation patterns - profile - fraction - water - taste
Volatile fingerprints of 30 cumin cheese samples of artisanal farmers' cheese of Leiden with EU Protected Designation of Origin (PDO) and 29 cumin cheese samples of varying commercial Dutch brands without PDO protection were used to develop authentication models. The headspace concentrations of the volatiles, as measured with high sensitivity proton-transfer mass spectrometry, were subsequently subjected to partial least-squares discriminant analysis (PLS-DA). Farmers' cheese of Leiden showed a distinct volatile profile with 27 and 9 out of the 60 predominant ions showing respectively significantly higher and lower concentrations in the headspace of the cheese in comparison to the other cumin cheeses. The PLS-DA prediction models developed classified in cross-validation 96% of the samples of PDO protected, artisanal farmers' cheese of Leiden correctly, against 100% of commercial cumin cheese samples. The characteristic volatile compounds were tentatively identified by PTR-time-of-flight-MS. A consumer test indicated differences in appreciation, overall flavor intensity, creaminess, and firmness between the two cheese groups. The consumers' appreciation of the cumin cheese tested was not influenced by the presence of a name label or PDO trademark.
Three-dimensional mapping of soil organic matter content using soil type-specific depth functions
Kempen, B. ; Brus, D.J. ; Stoorvogel, J.J. - \ 2011
Geoderma 162 (2011)1-2. - ISSN 0016-7061 - p. 107 - 123.
carbon storage - map - information - variability - prediction - profile - trend - reml
This paper proposes a method for mapping depth functions of soil organic matter (SOM) that combines general pedological knowledge with geostatistical modeling. A pedometric soil map that represents soil type at any location with a probability distribution formed the starting-point. For each of the ten soil types depicted on this map a depth function structure was defined that describes the variation of SOM over depth based on pedological knowledge about soil profile morphology. To this end five depth function building blocks were defined, referred to as ‘model horizons’. For each soil type the depth function structure was obtained by stacking a subset of model horizons. The parameters of the ten soil type–specific depth functions were calibrated with data from soil profile descriptions and spatially interpolated using environmental covariates as predictors. The predicted parameters and the soil-type specific depth function structures then allowed us to construct the depth function of SOM for each soil type at each prediction site. By combining the soil type–specific depth functions with the probability distributions of the soil types, a probability distribution of depth functions was obtained at each location in the study area. The soil type–specific depth functions and their associated probabilities were used to map the SOM stock for depth intervals 0–30 cm, 30–60 cm, 60–90 cm, and 0–90 cm. The mapped SOM stocks were validated with an independent probability sample. R2-values ranged between 0.09 and 0.75, with 0.46 for the 0–90 cm layer. The RSME was largest for the 30–60 cm layer (13.4 kg/m2). This is typically the layer with the largest within-soil type and between-soil type variation of SOM and is therefore the most challenging to predict. Similar to other studies better predictions were found for the top layer than for subsurface layers, which illustrates a general challenge of capturing subsurface variation of soil properties by our pedometric models. The pedometric approach to three-dimensional mapping of SOM presented in this paper is closely related to the conventional approach that represents depth distribution of soil properties with representative profile descriptions that are associated to the map units of a soil type map. A comparison of our pedometric approach with the conventional approach showed that there was little difference in performance. However, our modeled depth functions might give a more realistic representation of the vertical variation than the discrete (stepped) functions based on representative soil profile descriptions and thus might provide better predictions of the SOM content at small depth intervals
Changes in fatty acid content and composition in silage maize during grain filling
Khan, N.A. ; Cone, J.W. ; Pellikaan, W.F. ; Khan, M.A. ; Struik, P.C. ; Hendriks, W.H. - \ 2011
Journal of the Science of Food and Agriculture 91 (2011)6. - ISSN 0022-5142 - p. 1041 - 1049.
whole-plant digestibility - total mixed ration - dairy-cows - lipid-metabolism - leaf senescence - stem characteristics - milk - forages - profile - corn
Background: The stage of maturity at harvest has a major effect on the fatty acid (FA) content and composition of forage plants consumed by dairy cows. The present study investigated the dynamics of FA content and composition in stover (leaves and stem) and ears (cob, shank and husks) of two maize genotypes (G2 and G6) grown on sandy and clay soils and harvested at 14, 42, 56, 70 and 84 days after flowering (DAF). In addition, the FA content and composition of six maize genotypes (G1-G6) grown on the two soil types were compared at the normal harvest time of early genotypes in the Netherlands (70 DAF). Results: The contents of total FAs and major individual FAs in both stover and ears changed significantly (P <0.001) during the grain-filling period (14-84 DAF). In stover the contents of C16:0, C18:2, C18:3 and total FAs declined (P <0.001) while those of C18:0 and C18:1 increased (P <0.001) with progressive grain filling. The rate of decline in C18:3 and total FA contents was slower during 14-56 DAF as compared with 56-84 DAF. In ears, the contents of C16:0, C18:1, C18:2 and total FAs increased up to 56 DAF and then remained more or less constant until 84 DAF. At 70 DAF the content of polyunsaturated fatty acids (PUFAs) in both stover and ears did not differ among the six genotypes. However, the average contents of C16:0, C18:3 and total FAs in stover were higher (P <0.05) on clay soil, whereas those of C18:0 and C18:1 were higher on sandy soil. Conclusion: The results demonstrate that the maximum PUFA content in silage maize is harvested around 56 DAF, in the present study at a T(sum) of 927 °C.d or at an ear dry matter content of 440 g kg(-1) , which is before the onset of rapid senescence. Any further delay in harvesting will cause a rapid decline in C18:3 content in maize silages.
A high intake of conjugated linoleic acid does not affect liver and kidney function tests in healthy human subjects
Wanders, A.J. ; Leder, L. ; Banga, J.R. ; Katan, M.B. ; Brouwer, I.A. - \ 2010
Food and Chemical Toxicology 48 (2010)2. - ISSN 0278-6915 - p. 587 - 590.
body-fat mass - overweight humans - obese humans - cla - mice - supplementation - metabolism - glucose - isomers - profile
Conjugated linoleic acid (CIA) is consumed widely as a supplement. It Causes hepatomegaly in animals, but toxicological data in humans are limited We therefore studied the effect of a high daily intake of CIA on liver and kidney function in healthy subjects. Twenty Subjects received 14 6 g cis-9,trans-11 CIA and 4.7 g trans-10,cis-12 CIA isomers a day for 3 weeks. Liver and kidney function was measured at 0, 3, 7, 10, 16, and 21 days. Mean values of all tests remained within normal limits Lactate dehydrogenase (mean +/- SD) increased from 290 9 +/- 43.6 to 322.5 +/- 60.7 U/L (p = 0.04) on day 21. One subject exceeded the tipper limit of normal of 450 U/L on day 21. to 472 U/L and another showed an isolated elevation to 555 U/L on day 7. gamma-Glutamyltranspeptidase increased from 12 1 +/- 5 9 to 13 5 +/- 6.2 U/L (p = 0.002) No one exceeded the upper limit of 50 U/L for men and 40 U/L for women A daily intake of 19.3 g CIA for 3 weeks does not produce clinically relevant effects on markers of liver and kidney function in healthy volunteers. (C) 2009 Elsevier Ltd. All rights reserved.
MetAlign: Interface-Driven, Versatile Metabolomics Tool for Hyphenated Full-Scan Mass Spectrometry Data Preprocessing
Lommen, A. - \ 2009
Analytical Chemistry 81 (2009)8. - ISSN 0003-2700 - p. 3079 - 3086.
liquid-chromatography - differential analysis - plant metabolomics - lc-ms - alignment - identification - extraction - profile - lc/ms
Hyphenated full-scan MS technology creates large amounts of data. A versatile easy to handle automation tool aiding in the data analysis is very important in handling such a data stream. MetAlign software-as described in this manuscript-handles a broad range of accurate mass and nominal mass GC/MS and LC/MS data. It is capable of automatic format conversions, accurate mass calculations, baseline corrections, peak-picking, saturation and mass-peak artifact filtering, as well as alignment of up to 1000 data sets. A 100 to 1000-fold data reduction is achieved. MetAlign software output is compatible with most multivariate statistics programs.
The effect of soil texture and organic amendment on the hydrological behaviour of coarse-textured soils
Wesseling, J.G. ; Stoof, C.R. ; Ritsema, C.J. ; Oostindie, K. ; Dekker, L.W. - \ 2009
Soil Use and Management 25 (2009)3. - ISSN 0266-0032 - p. 274 - 283.
water - nitrogen - systems - profile
To gain more insight into the hydrological behaviour of coarse-textured soils, the physical properties of artificially created soil mixtures with different texture were determined. The mixtures were prepared according to the specifications of the United States Golf Association (USGA) for constructing putting greens. In addition, the effect of 10 vol.% organic matter addition was studied. The soil moisture retention and hydraulic conductivity relationships of the different mixtures were determined and their hydrological behaviour was studied using the numerical model SoWaM. Both texture and organic matter addition substantially affected the hydraulic properties. Hydraulic conductivity significantly increased with increasing coarseness while moisture retention decreased. On the other hand, organic matter addition reduced saturated hydraulic conductivity by a factor of 10 to 100 and distinctly increased moisture retention capacity. The amounts of total available water were increased by the addition of organic matter between 144% (slightly coarse texture) and 434% (very coarse texture). Results indicate that the mixtures can contain only 2–16% plant available water and therefore need frequent irrigation to maintain plant growth. Addition of organic matter seems a good solution to reduce the irrigation water requirements but it increases the risk of ponding or runoff because of large reductions in the saturated hydraulic conductivity sometimes to below the rate of 3.6 m/day recommended by the USGA
The effect of rice kernel microstructure on cooking behaviour: A combined µ-CT and MRI study
Mohoric, A. ; Vergeldt, F.J. ; Gerkema, E. ; Dalen, G. van; Doel, L.R. van den; Vliet, L.J. van; As, H. van; Duynhoven, J.P.M. van - \ 2009
Food Chemistry 115 (2009)4. - ISSN 0308-8146 - p. 1491 - 1499.
magnetic-resonance - water migration - puffed rice - nmr - grain - gelatinization - starch - profile - flour - model
In order to establish the underlying structure-dependent principles of instant cooking rice, a detailed investigation was carried out on rice kernels that were processed in eight different manners. Milling, parboiling, wet-processing and extrusion were applied, with and without a subsequent puffing treatment. The mesostructure of the rice kernels was examined by DSC and XRD, and the microstructure by µ-CT. Hydration behaviour during cooking was studied by MRI in a real-time manner. Based on simple descriptive models, three different classes of cooking behaviour can be discerned. The water ingress profiles during cooking of these three classes matched well with simulations from a model that was based on water demand of the starch mass and the porous microstructure of the kernels. Thus a clear correlation between meso/microstructure of a rice kernel and the cooking behaviour has been established
Sand transport dynamics after a foredune breach: a case study from Schoorl, the Netherlands
Meerkerk, A. ; Arens, B. ; Lammeren, R.J.A. van; Stuiver, H.J. - \ 2007
Geomorphology 86 (2007)1-2. - ISSN 0169-555X - p. 52 - 60.
sediment transport - aeolian processes - transverse dunes - natural tracers - profile - models - desert - island - inlet - wind
Near Schoorl in The Netherlands a gap was created in the foredunes during a nature development project in 1997. This resulted in considerable aeolian sand transport and allowed the sea to enter the swale valley behind the foredunes during storm events. From 1997 to 2002 a monitoring program was carried out and various data sets were collected. This study used a part of those data to investigate the effects of a foredune breach on sand transport dynamics. The main focus was on the aeolian transport of sediment through the gap in the dunes. After the breach calcareous beach sand was transported into the swale valley where exclusively decalcified sand was present. This enabled a study of the spatial aspects of transport based on six data sets of carbonate content that were collected during the 1997¿2002 period. Grids of carbonate content were interpolated and analysed together with data on geomorphology, topography and wind characteristics. The results provided insight on the displacement speed of the deposition front of calcareous sand, the influence of transport barriers and the correlation of transport directions with wind data. In addition, the study led to the observation that the trend of increase of available digital data during the last two decades is significant in facilitating the study of sand transport at the landscape scale. This is encouraging given the fact that the practical use of existing sand transport models in this context remains limited.
Characterization of amaranth seed oils
Gamel, T.H. ; Mesallam, A.S. ; Damir, A.A. ; Shekib, L.A. ; Linssen, J.P.H. - \ 2007
Journal of Food Lipids 14 (2007)3. - ISSN 1065-7258 - p. 323 - 334.
fatty-acid - chemical-composition - germination - profile - flour
The oil fractions of Amaranthus caudatus L. and Amaranthus cruentus L. seeds were studied after different treatments of the seeds. The oil contents were 7.1 and 8.5% for raw A. caudatus L. and A. cruentus L. seeds, and consisted of 80.3¿82.3% of triacylglycerols (TAGs). Phospholipids represented 9.1¿10.2% of the oil. The squalene content was 4.8¿4.9% in both types of oil. Air classification increased the lipid content and decreased the content of squalene, while heating (popping and cooking) increased the squalene content. After germination, the lipid fraction was decreased in their TAGs and increased in their phospholipids. The main fatty acid composition (palmitic, linoleic and oleic) was not affected by thermal treatments or by germination of the seeds. The hydroperoxide stability test showed that the stability of amaranth oil was more than that of sunflower oil. PRACTICAL APPLICATIONS This research provides some information about the effect of different treatments ¿ including heat treatments, germination and air classification ¿ on the oil characteristics of two species of amaranth seeds. Fatty acids and triacylglycerol profiles, lipid fractions and squalene content were the main characteristics studied during this research. The stability of the oil against oxidation is also presented as compared with sunflower oil. The results of this research provide a clearer picture for the potential use of amaranth oil on an industrial scale and its characteristic stability under different process conditions
The impact of bioturbation by small mammals on heavy metal redistribution in an embanked floodplain of the River Rhine
Wijnhoven, S. ; Thonon, I. ; Velde, G.D. ; Leuven, R. ; Zorn, M. ; Eijsackers, H.J.P. ; Smits, T. - \ 2006
Water Air and Soil Pollution 177 (2006)1-4. - ISSN 0049-6979 - p. 183 - 210.
ecological risk-assessment - spatial variability - soil - sedimentation - earthworms - grassland - profile
Floodplains along large European rivers are diffusely polluted with heavy metals due to emissions in the past. Because of low mobility of heavy metals in floodplain soils and improvements of water quality, these pollutants will remain in place, and can gradually become covered with less contaminated sediments. Bioturbators, especially earthworms, can play an important role in the mixing and surfacing of contaminated substrate. Surfaced substrate can be redistributed by recurrent flooding events, even to areas outside the floodplain. The question remained to what extent bioturbation by small mammals contributes to the redistribution of heavy metals from river sediments in floodplains. Extensive fieldwork on bioturbators such as voles, moles and earthworms and their distribution patterns, as well as on sediment deposition and bioturbation, was conducted at the `Afferdensche en Deestsche Waarden¿ floodplain over the years 2001¿2003. Field data were combined with data of experiments in field enclosures and substrate columns to calculate the amounts of sediment and heavy metals (Zn, Cu, Pb and Cd) redistributed during the floods as well as on an annual basis. Moles and voles surfaced considerable amounts of substrate and heavy metals, but not as much as earthworms which contribute a substantial proportion of the total deposition and redistribution during floods. Although the impact of moles and voles on the redistribution during floods was only locally important, on an annual basis the bioturbation activity of especially moles in floodplains cannot be neglected. The annual amounts of substrate and heavy metals surfaced by all investigated bioturbators were even larger than the total amounts of substrate and heavy metals deposited during floods
Polarimetric weather radar retrieval of raindrop size distribution by means of a regularized artificial neural network
Vulpiani, G. ; Marzano, F.S. ; Chandrasekar, V. ; Berne, A.D. ; Uijlenhoet, R. - \ 2006
IEEE Transactions on Geoscience and Remote Sensing 44 (2006)11. - ISSN 0196-2892 - p. 3262 - 3275.
rainfall estimation - differential phase - parameters - attenuation - hydrology - wsr-88d - profile - model
The raindrop size distribution (RSD) is a critical factor in estimating rain intensity using advanced dual-polarized weather radars. A new neural-network algorithm to estimate the RSD from S-band dual-polarized radar measurements is presented. The corresponding rain rates are then computed assuming a commonly used raindrop diameter speed relationship. Numerical simulations are used to investigate the efficiency and accuracy of this method. A stochastic model based on disdrometer measurements is used to generate realistic range profiles of the RSD parameters, while a T-matrix solution technique is adopted to compute the corresponding polarimetric variables. The error analysis, which is performed in order to evaluate the expected errors of this method, shows an improvement with respect to other methodologies described in the literature. A further sensitivity evaluation shows that the proposed technique performs fairly well even for low specific differential phase-shift values
In vivo monitoring of strawberry flavour release from model custards: effect of texture and oral processing
Aprea, E. ; Biasioli, F. ; Gasperi, F. ; Tilmann, M.D. ; Ruth, S.M. van - \ 2006
Flavour and Fragrance Journal 21 (2006)1. - ISSN 0882-5734 - p. 53 - 58.
reaction-mass-spectrometry - ptr-ms - medical applications - breath analysis - perception - aroma - food - gels - headspace - profile
The interaction of oral processing protocols and food texture on in vivo flavour release was evaluated by nose-space analysis. Nose-space analysis was carried out by proton transfer reaction mass spectrometry, and strawberry-flavoured custards were prepared with 0.1% (w/w) and 1.0% (w/w) carboxymethyl cellulose to modify the texture. Two oral processing protocols were adopted during the study; a free-chewing protocol and an imposed protocol. Twenty-one subjects participated in the study. Significant effects on in-nose flavour release were observed for the type of compound, the custard's texture, the oral processing protocol and the subjects. When people were allowed to eat as they normally do, individuals could be divided into three groups on the basis of swallowing time: first group, swallowing time 6 s; intermediate group, t(swallow) varying (4-6 s). Within each group, different effects of the texture of the custards on in-nose flavour concentrations were observed, indicating that individual behaviour plays a considerable role in determining texture effects on flavour perception
Rainfall rate retrieval in presence of path attenuation using C-band polarimetric weather radars
Vulpiani, G. ; Marzano, F.S. ; Chandrasekar, V. ; Berne, A.D. ; Uijlenhoet, R. - \ 2006
Natural Hazards and Earth System Sciences 6 (2006). - ISSN 1561-8633 - p. 439 - 450.
drop size distributions - differential phase - reflectivity - algorithm - frequencies - validation - airborne - profile
Weather radar systems are very suitable tools for the monitoring of extreme rainfall events providing measurements with high spatial and temporal resolution over a wide geographical area. Nevertheless, radar rainfall retrieval at C-band is prone to several error sources, such as rain path attenuation which affects the accuracy of inversion algorithms. In this paper, the so-called rain profiling techniques (namely the surface reference method FV and the polarimetric method ZPHI) are applied to correct rain path attenuation and a new neural network algorithm is proposed to estimate the rain rate from the corrected measurements of reflectivity and differential reflectivity. A stochastic model, based on disdrometer measurements, is used to generate realistic range profiles of raindrop size distribution parameters while a T-matrix solution technique is adopted to compute the corresponding polarimetric variables. A sensitivity analysis is performed in order to evaluate the expected errors of these methods. It has been found that the ZPHI method is more reliable than FV, being less sensitive to calibration errors. Moreover, the proposed neural network algorithm has shown more accurate rain rate estimates than the corresponding parametric algorithm, especially in presence of calibration errors