Rheological and microstructural evolution of the most common gluten-free flours and starches during bread fermentation and baking

Mechanistic relations between the evolution of the starch/flour structure, dough rheology and bread quality were investigated using the most common flours and starches in gluten-free bread-making. Micrographs showed that the small wheat starch granules filled the spaces of the big granules, forming a uniform starch-hydrocolloid matrix. This granular advantage decreased the consistency and increased the uniformity of wheat-starch based doughs throughout fermentation, as shown by micrographs and the higher critical strain. The viscoelastic properties of the different doughs strongly influenced the bread volume and the crumb texture. Thus, starch-based breads showed higher specific volume and lower hardness, especially those made with wheat starch, whose lower pasting temperature also reinforced the continuous phase of the crumb. On the other hand, the large potato starch granules did not form a continuous starch-hydrocolloid matrix, resulting in breads with the lowest specific volume, elasticity, cohesiveness and resilience, and the highest hardness

Fruit and vegetable by-products as novel ingredients to improve the nutritional quality of baking foods

The industrial manufacturing of fruits and vegetables generates approximately 50% by-product waste, causing a negative environmental impact and significant expenses. Nevertheless, fruit and vegetable by-products (FVB) are rich nutrients and extranutritional compounds that contribute to bowel health, weight management, lower blood cholesterol levels and improved control of glycemic and insulin responses. Due to the positive influence of FVB fibers and bioactive compounds during the digestion of glycemic carbohydrates, such as starch, baked goods are ideal food systems to accommodate FVB, since most of them have a high glycemic index. Therefore, this is an area of recent interest with critical environmental, economic and health implications worldwide. However, the utilization of FVB in baked goods leads to the loss of acceptability, in many cases caused by a lack of understanding of the physical structure and composition of FVB and their effects on food quality. The objective of this review is to provide a mechanistic understanding of the impact of the physical structure and composition of FVB on common baked goods and their influence on the nutritional and physical quality of the resulting product. This review will support the use of FVB as ideal ingredients while improving the added value of waste streams.Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2) and the European Regional Development Fund (FEDER

Methodology to quantify clogging coefficients for grated inlets: application to SANT MARTI catchment (Barcelona)

This is the accepted version of the following article: Gómez, M, Parés, J, Russo, B, Martínez‐Gomariz, E. Methodology to quantify clogging coefficients for grated inlets. Application to SANT MARTI catchment (Barcelona). J Flood Risk Management. 2019; 12:e12479. https://doi.org/10.1111/jfr3.12479, which has been published in final form at https://onlinelibrary.wiley.com/doi/10.1111/jfr3.12479.Within the drainage system of a city, the set of inlets is in charge of taking the runoff produced by local storms to the stormwater/sewer. In the drainage system design the selection of appropriate inlet models and their location is one of the fundamental aspects. The hydraulics of these inlets has received great attention within the last years; however, few inlet makers provide the hydraulic capacity of their products. In addition, these data usually consider clean water, while in reality, numerous inlets can be either totally or partially clogged. This aspect should be kept in mind within the design process. In this paper, a methodology to consider the hydraulic effects of clogging phenomena is presented. The work started from a visual inspection of the grated inlets throughout the urban catchment of Sant Martí, Barcelona, as a means of identifying clogging patterns, their repetitive forms and their associated frequency. After that, clogged patterns were reproduced in laboratory testing of typical inlets types, thereby obtaining the real quantity of water that could be captured by each of them. It was shown that the same expression employed to describe the efficiency of clean inlets can be used to assess the efficiency of those clogged. A reduction factor in terms of hydraulic capacity and related to each clogging pattern has been defined for use in hydraulic studies of runoff along streets. Finally, the paper compares the obtained results in terms of clogging coefficient with another experimental campaign carried out in other catchment of the city.Peer ReviewedPostprint (author's final draft

Assessment of inlet efficiency through a 3D simulation: numerical and experimental comparison

Inlet efficiency is a requirement for characterizing the flow transfers between surface and sewer flow during rain events. The dual drainage approach is based on the joint analysis of both upper and lower drainage levels, and the flow transfer is one of the relevant elements to define properly this joint behaviour. This paper presents the results of an experimental and numerical investigation about the inlet efficiency definition. A full scale (1:1) test platform located in the Technical University of Catalonia (UPC) reproduces both the runoff process in streets and the water entering the inlet. Data from tests performed on this platform allow the inlet efficiency to be estimated as a function of significant hydraulic and geometrical parameters. A reproduction of these tests through a numerical three-dimensional code (Flow-3D) has been carried out simulating this type of flow by solving the RANS equations. The aim of the work was to reproduce the hydraulic performance of a previously tested grated inlet under several flow and geometric conditions using Flow-3D as a virtual laboratory. This will allow inlet efficiencies to be obtained without previous experimental tests. Moreover, the 3D model allows a better understanding of the hydraulics of the flow interception and the flow patterns approaching the inlet.Preprin

A new experiments-based methodology to define the stability threshold for any vehicle exposed to flooding

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Urban water journal on 2017, available online at: http://www.tandfonline.com/doi/full/10.1080/1573062X.2017.1301501A vehicle exposed to flooding, after losing stability, becomes buoyant and may be washed away with potential injuries and fatalities. Such vehicles cause additional disruption to traffic that is already affected by flooding, which may lead to substantial indirect economic impact, especially in urban areas. Therefore, the analysis of the stability of vehicles exposed to flooding is important in order to make decisions to reduce damages and hazards. In this research, based on an experimental campaign that included a range of twelve car models, a new methodology to obtain the stability threshold for any real vehicle exposed to flooding is developed. A stability coefficient (SCmod) is derived with which the vehicles can be sorted by stability against water flows and their stability functions may be determined. The experiments were conducted with three different model scales (1:14, 1:18 and 1:24) and involved analysis of both friction and buoyancy effects, which made this the most comprehensive research study to date. This methodology enables the definition of a stable area in the flow depth-velocity domain for any real vehicle. A tool is provided that decision-makers in the field of urban flood risk management can employ and after defining a design vehicle they can obtain its corresponding stability threshold.Peer ReviewedPostprint (author's final draft

Texture development in gluten-free breads: Effect of different enzymes and extruded flour

Producción CientíficaOne of the main problems with gluten-free breads is their texture and their rapid staling. In this work the influence of different enzymes (one protease, one lipase and two amylases) and of extruded rice flour on rice-bread texture and texture development was studied. For this purpose, the development of firmness, cohesiveness, resilience, springiness and chewiness was modelled and the parameters that define the initial values and the development of these characteristics were measured. The addition of lipase and extruded flour increased bread volume and reduced the initial firmness and hardening of breads. There was an early fall in cohesiveness and resilience, with minimum values reached a few days after elaboration. There were 99.9% significant correlations between bread density and firmness, springiness and chewiness development. PRACTICAL APPLICATIONS This methodology simplifies the study of gluten free breads textural parameters during storage and the result interpretation. Moreover, the correlation analysis has demonstrated that the number of textural parameters of gluten free breads to study can be reduced. Finally, the results obtained show that use of enzymes and extruded flours decreases bread staling

Gasification effects in the heterogeneous ignition of a condensed fuel by a hot gas

An analysis is presented to describe the heterogeneous ignition of a condensed fuel suddenly exposed to a hot oxidizing atmosphere. The exothermic heterogeneous reaction, generating gaseous products, is considered to be of the Arrhenius type with a large activation energy compared with the initial thermal energy of the fuel. Instantaneously after contact with the gases, the surface temperature rises to a jump value which is calculated allowing for variable transport properties of fuel and gas. The effect of the chemical heat release and the cooling effect due to the gasification flow are taken into account in obtaining an integral equation which is solved to describe the evolution of surface temperature with time

Ignition of a reactive solid by an inert hot spot

A theoretical analysis is presented for the description of the ignition of a reactive media by inert hot bodies of finite size, when the activation energy of the reaction is large. The analysis leads to closed-form relations for the minimum "critical" size of the hot spot resulting in ignition and for the ignition time by hot spots of supercritical size. The analysis is carried out, first, for inert spots with heat conductivities and diff usivities of the order of those of the reactive media, and, second, for inert bodies of large conductivity

Effect of different extrusion treatments and particle size distribution on the physico-chemical properties of rice flour

Producción CientíficaRice flour is an interesting alternative for developing gluten free products, but its features do not meet the process requirements. The objective of this study was to modify the functional properties of rice flour by combining extrusion and size fractionation. Different extrusion conditions were applied to vary the severity of the treatment on the flour constituents. Extrusion and mechanical fractionation of the rice flours modified their behavior affecting hydration, thermal and pasting features, besides their susceptibility to enzymatic hydrolysis. Thermal properties (temperature and enthalpy) increased with the intensity of the extrusion and that effect was intensified with the greatest particle size of the flours. Fine flours with stronger extrusion showed the highest susceptibility to enzymatic hydrolysis and extrusion process increased that effect. Overall the combination of both physical treatment maybe an attractive alternative for obtaining clean label rice flours with modified features