Engineering of bioaerogels as key ingredients in the development of functional foods to deliver health through diet

This Ph.D. research project aims at exploiting the peculiar characteristics of innovative porous food-grade materials, called bioaerogels, in the development of foods with tailored health-related functionalities. In particular, bioaerogels will be used to develop: (i) delivery systems able to protect bioactives through the gastrointestinal tract; (ii) fat replacers rich in unsaturated fatty acids, able to mimic the technological functions of traditional saturated hard fats; (iii) lighting ingredients, able to incorporate air in food formulations, thus leading to caloric density reduction

Engineering of bioaerogels as key ingredients in the development of functional foods to deliver health through diet

Aerogels are solid nanostructured materials characterized by low density, high porosity and a high internal surface area. When obtained from biopolymers (polysaccharides and/or proteins), they are called bioaerogels. Bioaerogels are typically obtained by a multi-step process, involving the gelation of a biopolymer water solution followed by water-to-ethanol solvent exchange and subsequent ethanol removal by supercritical-CO2-drying [1]. Bioaerogels have gained increasing research attention as innovative food ingredients, thanks to their biocompatibility and food-grade nature, associated with unique porosity-driven functionalities. In particular, whey protein-based bioaerogel particles have been used to structure liquid oil into semi-solid materials (i.e., oleogels) presenting rheological properties analogous to those of traditional saturated fats, associated with an improved nutritional profile, rich in unsaturated fatty acids [2]. In the current context of the plant protein transition, food industries and consumers are increasingly seeking for plant-based alternatives to animal proteins, in view of the lower environmental impact and health benefits. The development of bioaerogels based on plant proteins rather than animal ones is thus particularly interesting. Moreover, recent studies have demonstrated that oil structuring can alter lipid digestibility, but no knowledge is available on the digestibility of aerogel-templated oleogels

Experiment-based computational method for proper annotation of the molecular function of enzymes

The rate of protein functional elucidation lags far behind the rate of gene and protein sequence discovery, leading to an accumulation of proteins with no known function. Millions of protein database entries are not assigned reliable functions, preventing the full understanding of chemical diver­sity in living organisms. Pfam contains over 16,712 families, among which more than 3,919 families are of unknown function (DUF families). An additional difficulty, often underestimated, is that only a tiny fraction of enzymes have experimentally established functions and in most cases, function is extrapolated from a small number of characterized proteins to all members of a family leading to over-annotation1,2. Here, two examples of an integrated strategy for the discovery of various enzymatic activities catalyzed within protein families will be presented. This approach relies with a high-throughput enzymatic screening on representatives, structural and modeling investigations, analysis of genomic and metabolic context. The structural analysis is in both cases based on the Active Site Clustering Method3 developed at Genoscope. We investigated the protein family with no known function, DUF849 Pfam family, and unearthed 14 potential new enzymatic activities, leading to the designation of these proteins as -keto acid cleavage enzymes4. In addition, we propose an in vivo role for four enzymatic activities and suggest key residues for guiding further functional annotation. The second study will illustrate that proteins with high sequence similarity might not have the same function. We determined the enzymatic activities of 100 O-acyl-L-homoserine transferases representative of the biodiversity of the two unrelated families, MetX and MetA, involved in the first step of the methionine biosynthesis and assumed to always use acetyl-CoA and succinyl-CoA, respectively. We interpreted the results by structural classification of active sites based on protein structure modeling. We identified the specific determining positions responsible for acyl-CoA specificity in the active sites of MetX and MetA enzymes, actually iso-functional for both activities. We then predict that \u3e60% of the 10,000 sequences from these families currently in databases are incorrectly annotated. Finally, we uncovered a divergent subgroup of MetX enzymes in fungi that participate only in L-cysteine biosynthesis as O-succinyl-L-serine transferases5. Our results show that the functional diversity within a family may be largely underestimated. The extension of this strategy to other families will improve our knowledge of the enzymatic landscape and the chemical capabilities of biodiversity. References: 1 de Crecy-Lagard, V. Quality Annotations, a Key Frontier in the Microbial Sciences. Microbe 11, 303-310 (2016). 2 Schnoes, A. M., Brown, S. D., Dodevski, I. & Babbitt, P. C. Annotation error in public databases: misannotation of molecular function in enzyme superfamilies. PLoS Comput Biol 5, e1000605 (2009). 3 de Melo-Minardi, R. C., Bastard, K. & Artiguenave, F. Identification of subfamily-specific sites based on active sites modeling and clustering. Bioinformatics 26, 3075-3082, doi:10.1093/bioinformatics/btq595 (2010). 4 Bastard, K. et al. Revealing the hidden functional diversity of an enzyme family. Nature chemical biology 10, 42-49, doi:10.1038/nchembio.1387 (2014). 5 Bastard, K. et al. Parallel evolution of non-homologous isofunctional enzymes in methionine biosynthesis. Nature chemical biology june (2017)

Performance Analyses of the D'aDif Pavilion☆

Abstract All over the world, during the past as well as today, different kinds of buildings in different climate zones use the envelope, and in particular way the cover, to operate on the inner thermal and visual comfort. Vernacular tradition shows that textile skins allow creating adaptive envelopes that integrate principles of active control. This paper presents the results of the optimization design process of an adaptive umbrella configured in a double covering system for a small temporal pavilion. The pavilion is characterized by a small inner space with changeable dimensions and an adaptive enclosure. Materials like coated fabrics as well as lightweight structures like aluminum frames are combined together and used in an innovative architectural solution. Due to the transient nature of the analyzed building, the great challenge is to guarantee an adequate level of inner thermal comfort all over the year and in different climate zones and conditions. The research starts from the assumption that membranes combined with lightweight structures provide some special properties to temporal small buildings, like easy transportability and installation. The umbrella, used in a double roof consisting of three different textile layers, define an active responsive covering directly controlled by users in order to obtain shading and air flow permeability depending on the seasons and the environmental conditions. The computerized analysis has been carried out by means of the software package Energy Plus which allowed the simulation of a wide range of alternatives for the external envelope (cover, materials, layers, air gaps etc.) and the comparison of the performance in several climatic conditions to respond to user's requirements

PV Integration in Minor Historical Centers: Proposal of Guide-criteria in Post-earthquake Reconstruction Planning☆

Abstract One of the main challenges in next years will be the retrofit of existing built heritage. Even the most ancient settlements, to avoid the absolute neglect, will have to consider a "contemporary" and environmentally aware vision of refurbishment. In Italian territories hit by earthquake, this challenge is already today a potential for their life return: BIPV, or in general PV implementation, is one of the possible ways to be faced for ensuring a renewable contribution in the perspective of "Nearly-Zero Energy Settlements". The presented study, after synthesizing some main key-strategies for PV introduction at landscape, urban and building scale, focuses on the definition of reference requirements and practical findings useful in the proposal of guide-criteria for urban re-planning of minor historical centers. The outcomes could also be used in the ongoing reconstruction process, for defining innovative and sustainable strategies for PV implementation in minor (nearly-zero energy) historical centers

Open spaces and environmental design

The urban fabric of any human settlement can be analyzed at two levels: the built fabric and the system of empty spaces. Graphically, the two levels are contrary to each other. The first is the structure generated by the aggregation of the elementary unit that represents its governing and invariable element. It is a component that can be managed and its spatial, functional and structural entity can be controlled due to its “box like” structure. The empty system consists of public and private open spaces that form a network of relational, representative and social spaces but also an interconnecting system. So, the identification of the methods to analyze the environmental characteristics of these empty spaces and, therefore, the criteria to improve the comfort conditions of the users, is the aim of this research. The survey follows the branch of research that studies the methods of intervention in historical centers. The need to carry out project interventions in historic urban fabrics pushes the researchers to find the methods to introduce the comfort levels required by contemporary users and, at the same time, to respect the values to pass down to posterity The choice of a strategy involving a certain degree of invasiveness and reversibility depends on the designer's knowledge of the particular context of intervention For this reason, the project carried out in a context having important values, as it is a minor center, requires a detailed cognitive analysis of the site under study that, inevitably, will limit the designer's freedom. The study area is located in the Abruzzi Region, full of minor historical centers rich in deep cultural values

energy simulation and optimization of a double ventilation chimney in a historical building in l aquila italy

Abstract The paper presents the operation mode of a ventilation chimney placed in a historical building through the use of Design Builder, a modeling and dynamical simulation software. The aim is to verify the improvement of the comfort level and energy efficiency of the simulated environments through the usage of the duct as a passive ventilation system. The method adopted to intervene in a complex system, such as that represented by historic buildings, is to enhance the preexisting architectural values through their conversion into devices able to improve the performance of the building in terms of CO 2 and energy consumption reduction. The case study is Palazzo Bruni-Riga, a valuable building located in the historic center of L'Aquila. The building has a double ventilation duct, probably also used as a light-pipe, in correspondence of two windowless rooms of similar dimensions. The dynamical simulations presented concern the analysis of the passive ventilation duct and its effects on the thermo-hygrometric well-being of the modeled rooms. The goal of this paper and this research in general, is that the wise use of such devices installed in times when there were no air conditioning systems, allows you to better use the ventilation chimneys, and have the maximum thermal indoor comfort, with the minimum effort and use of mechanical systems. Through the simulations it was possible to verify that through the use of the ventilation chimney, it is possible to have the indoor comfort conditions, by checking the Fanger indices for the data obtained from the simulations carried out

Controlling aerogel surface porosity to enhance functionality in foods

Aerogels based on biopolymers, such as proteins, are food-grade materials characterized by distinctive physical properties, which make them intriguing candidates for the development of new ingredients with unique functionalities. The aerogel typical aerated structure can be exploited to deliver health-protecting bioactives or reduce food calories by increasing air content. However, aerogel porosity is easily lost upon contact with liquid food ingredients (water and oil). This issue might be overcome by closing the pores at the aerogel surface. In this work, processing and formulation strategies were applied to increase the structural stability of whey protein aerogels obtained by traditional ethanol exchange and supercritical-CO2-drying. Aerogels characterized by different levels of surface collapse were obtained by subjecting alcolgels to a controlled ethanol evaporation procedure prior to supercritical-CO2-drying. Alternatively, aerogels were coated with hydrophilic (alginate, agar) or hydrophobic (ethylcellulose) polymers. Aerogel microstructure was studied by SEM. Water and oil absorption kinetics were then measured. Ethanol evaporation time, polymer concentration and gelation rate were identified as key parameters affecting aerogel surface structure, allowing to significantly decrease water and oil absorption kinetics in the aerogels. This study suggests that aerogel structure-driven functionalities could be maintained in complex food formulations by controlling aerogel surface porosity