The drying of sewage sludge by immersion frying

The objective of this work was to dry sewage sludge using a fry-drying process. The frying experiments were carried out in commercial fryers modified by adding thermocouples to the setup. During frying, typical drying curves were obtained and it was verified that, in relation to the parameters: oil temperature, oil type and shape of the sample, the shape factor the most effect on the drying rate, at least within the range chosen for the variables studied. Oil uptake and calorific value were also analyzed. The calorific value of the samples increased with frying time, reaching values around 24MJ/kg after 600s of frying (comparable to biocombustibles such as wood and sugarcane bagasse). The process of immersion frying showed great potential for drying materials, especially sewage sludge, obtaining a product with a high energy content, thereby increasing its value as a combustible

Proteomic Analysis of Grape Berry Cell Cultures Reveals that Developmentally Regulated Ripening Related Processes Can Be Studied Using Cultured Cells

The original publication is available at http:/www.plosone.orgBackground: This work describes a proteomics profiling method, optimized and applied to berry cell suspensions to evaluate organ-specific cultures as a platform to study grape berry ripening. Variations in berry ripening within a cluster(s) on a vine and in a vineyard are a major impediment towards complete understanding of the functional processes that control ripening, specifically when a characterized and homogenous sample is required. Berry cell suspensions could overcome some of these problems, but their suitability as a model system for berry development and ripening needs to be established first. Methodology/Principal Findings: In this study we report on the proteomic evaluation of the cytosolic proteins obtained from synchronized cell suspension cultures that were established from callus lines originating from green, véraison and ripe Vitis vinifera berry explants. The proteins were separated using liquid phase IEF in a Microrotofor cell and SDS PAGE. This method proved superior to gel-based 2DE. Principal component analysis confirmed that biological and technical repeats grouped tightly and importantly, showed that the proteomes of berry cultures originating from the different growth/ripening stages were distinct. A total of twenty six common bands were selected after band matching between different growth stages and twenty two of these bands were positively identified. Thirty two % of the identified proteins are currently annotated as hypothetical. The differential expression profile of the identified proteins, when compared with published literature on grape berry ripening, suggested common trends in terms of relative abundance in the different developmental stages between real berries and cell suspensions. Conclusions: The advantages of having suspension cultures that accurately mimic specific developmental stages are profound and could significantly contribute to the study of the intricate regulatory and signaling networks responsible for berry development and ripening. © 2011 Sharathchandra et al.Publishers' Versio

Sugar and abscisic acid signaling orthologs are activated at the onset of ripening in grape

The onset of ripening involves changes in sugar metabolism, softening, and color development. Most understanding of this process arises from work in climacteric fruits where the control of ripening is predominately by ethylene. However, many fruits such as grape are nonclimacteric, where the onset of ripening results from the integration of multiple hormone signals including sugars and abscisic acid (ABA). In this study, we identified ten orthologous gene families in Vitis vinifera containing components of sugar and ABA-signaling pathways elucidated in model systems, including PP2C protein phosphatases, and WRKY and homeobox transcription factors. Gene expression was characterized in control- and deficit-irrigated, field-grown Cabernet Sauvignon. Sixty-seven orthologous genes were identified, and 38 of these were expressed in berries. Of the genes expressed in berries, 68% were differentially expressed across development and/or in response to water deficit. Orthologs of several families were induced at the onset of ripening, and induced earlier and to higher levels in response to water deficit; patterns of expression that correlate with sugar and ABA accumulation during ripening. Similar to field-grown berries, ripening phenomena were induced in immature berries when cultured with sucrose and ABA, as evidenced by changes in color, softening, and gene expression. Finally, exogenous sucrose and ABA regulated key orthologs in culture, similar to their regulation in the field. This study identifies novel candidates in the control of nonclimacteric fruit ripening and demonstrates that grape orthologs of key sugar and ABA-signaling components are regulated by sugar and ABA in fleshy fruit

Modeling in food across the scales: towards a universal mass transfer simulator of small molecules in food

International audienceMultiscale modeling in food is the cutting-edge strategy to revisit food structure and food composition to meet specific targets such as bioavailability, oral perception, or to evaluate the contamination of food by chemicals. A special implementation of Langevin dynamics is proposed to describe mass transfer in structured food. The concepts of random walks over discrete times and physicochemical interactions are connected via an exact solution of the Fokker-Planck equation across interfaces. The methodology is illustrated on the calculation of effective diffusivities of small solutes in emulsions in relationship with their polydispersity, the volume fraction of dispersed phase d = [0.1, 0.4], the ratio of diffusion coefficients between the two phases, r D = [10 −2 , 10 2 ], and the partition coefficients between the continuous and disperse phases, K = [10 −2 , + ∞[. Simulated diffusion paths are detailed in 2D emulsions and the effective diffusivities compared with the core-shell model of Kalnin and Kotomin (J Phys A Math Gen 31(35):7227-7234, 1998). The same effects are finally tabulated for 3D emulsions covering the full range of food applications. The methodology is comprehensive enough to enable various extensions such as chemisorption, adsorption in the surfactant layer, local flows, flocculation/creaming

Effet du procédé de friture sur la répartition et l'état de l'eau mesurée par la RMN et IRM

The effects on frying on the water distribution and the starch granules of potatoes were studied using Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI). Potatoes slices, 5 cm diameter by 1.2 cm thickness were fried for 1, 3, 6 and 9 minutes at 170° C. The NMR relaxation results allowed to monitor the structural changes after frying. Into the sample core, the starch gelatinased and included changes on the water states and distribution. At the surface, the starch crystalline structure was confirmed and the water amount decrease and oil penetration were observed. The high sample heterogeneity induced by frying was confirmed by MRI measurements.Les effets du procédé de friture sur la répartition tissulaire de l'eau et dur les granules d'amidon sont étudiés par Résonance Magnétique Nucléaire (RMN) et Imagerie de Résonance Magnétique (IRM). Des tranches de pomme de terre de 5 cm de diamètre et 1,2 cm d'épaisseur sont frites pendant 1, 3, 6 et 9 minutes à 170° C. Les relaxations RMN permettent de caractériser les changements structuraux. A coeur, l'amidon gélatinise et modifie la relaxation des molécules d'eau et leur répartition. A la surface, la structure cristalline est confirmée, la teneur en eau diminue, tandis que la teneur en huile augmente. La forte hétérogénéité induite par le traitement est validée par les images IRM

Water mediated phenomena in some multi-functional food processes

Extrait de documentVarious food processes aim at controlling water in solid foodstuffs in order to increase their stability and shelf-life. In most cases, the main objective is to reduce water content and/or change the state and activity of water in the food matrix. This can be achieved throughout partial removing of water, addition of water activity lowering agents, or freezing . Processes to do so include air drying (conventional or super-heated steam), cooking, deep-fat frying, candying, salting, osmotic dehydration, air-blast or immersion freezing (1, 2, 3, 4). During such processes, water may migrate throughout the food matrix as well as at the interface between the solid food and the surrounding fluid (gaz, liquid). Water migration can be induced by different mechanisms, including diffusion, osmosis, or flowing in the matrix pores. Water may also undergo phase change (evaporation, freezing). Depending on the way water migrates or changes phase, the evolution in the multi-component and multiphase food are different, and can be classified into three types: i) evolution of inner concentration, pressure or structure fields ; ii) evolution of physical and physico-chemical state ; iii) evolution of microbiological, biochemical, thermal or enzymatic reaction kinetics. The objective of the present paper is to show how the further understanding of the "water mediated " phenomena makes it possible to improve process control and food quality. This is illustrated by various examples, such as: i) control of oil absorption related to the creation of pores and structural heterogeneity during frying, induced by water migration mechanisms and pressure fields; ii) control of thawing phenomena or solute concentration in the food outer layer in osmotic dehydration and immersion freezing, related to the evolution of inner concentration fields and /or crystallisation phenomena ; iii) control of cracker colour, related to solute entrainment by water during baking

Molecular dynamics simulations of the chain dynamics in monodisperse oligomer melts and of the oligomer tracer diffusion in an entangled polymer matrix

The apparent analogy between the self-diffusion of linear oligomers in monodisperse systems, 2 up to 32 monomers, and their tracer diffusion in an entangled polymer matrix of length 256 is investigated by molecular dynamics simulations at constant pressure. Oligomers and polymers are represented by the same coarse-grained (bead-spring) model. An analysis based on the Rouse model is presented. The scaling relationship of the self-diffusion coefficient D with the chain length N written as D proportional to N-alpha is analyzed for a wide range of temperatures down to the glass transition temperature T-g. Near T-g, the heterogeneous dynamics is explored by the self-part of the van Hove distribution function and various non-Gaussian parameters. For the self-diffusion in a monodisperse system a scaling exponent alpha(T)>1 depending on temperature is found, whereas for the tracer diffusion in an entangled matrix alpha=1 is obtained at all temperatures, regardless of the oligomer length. The different scaling behavior between both systems is explained by a different monomer mobility, which depends on chain length for monodisperse systems, but is constant for all tracers in the polymer matrix

Kinetics of moisture loss and fat absorption during frying for different varieties of plantain

This study compares the behaviour of four varieties of green plantain at their initial stage of maturity during the frying process. A variety traditionally used for the manufacture of thin plantain chips (Dominico Hartón commun) and three other varieties found in Latin America (Bouroukou, Bluggoe and FHIA 21) were used. The varieties were characterised by measuring initial moisture content, total sugar content, reducing sugar content, starch content and apparent density. Moisture loss and fat uptake kinetics during frying were assessed at different temperatures (145, 165 and 185°C). With all four varieties, the time required to produce a final moisture content of 40 g kg?1 (wb) was about 90 s at 165°C and 185°C. Use of a lower temperature (145°C) extended the processing time to 150 s. On the other hand, temperature had very little effect on fat content, which proved to be essentially determined by the variety of plantain. Fat content for final water content levels of 40 g kg?1 (wb) ranged from 300 g kg?1 (wb) for Bouroukou to 450 g kg?1 (wb) for Bluggoe regardless of the processing temperature