Detecting management gaps for biodiversity conservation: An integrated assessment.

The latest report on the state of nature in Europe (2013-2018) shows that biodiversity is declining at an alarming rate, with most protected species and habitats in poor condition. Despite an increasing volume of collected biodiversity information, urgent action is needed to integrate biodiversity data and knowledge to improve conservation efforts. We conducted a study in Catalonia (NE Spain), where we collected management measures implemented between 2013 and 2018, including allocation, budget, pressures aimed, and habitats/species potentially benefiting. We integrated information on pressures and habitats/species with the measures to identify non-spatial management gaps. Then, we integrated the spatially explicit information to determine the spatial management gap, identifying geographical areas where species/habitats are under pressure without registered measures. We demonstrated the importance of integrating existing information. Our findings revealed that resources were often not distributed adequately across species/habitats, with biases towards certain taxa being a common issue. The non-spatial management gap analysis identified taxonomic groups, especially plants and mollusks with the wider management gaps. We also identified threatened areas, especially in the northeast of the region with the larger spatial management gaps. These results could guide priority objectives to optimize conservation efforts. Integrating different information sources provided a broader view of the challenges that conservation science is facing nowadays. Our study offers a path toward bending the curve of biodiversity loss by providing an integrative framework that could optimize the use of the available information and help narrow the knowing-doing gap. In the context of the EU, this example demonstrates how information can be used to promote some environmental policy instruments, such as the Prioritized Action Frameworks (PAFs). Additionally, our findings highlight the importance of supporting decision-making with systematic assessments to identify deficiencies in the conservation process, reduce the loss of critical ecosystems and species, and avoid biases among taxa.

Dynamic digestion of a high protein beverage based on amaranth: Structural changes and antihypertensive activity.

An amaranth beverage (AB) was subjected to a simulated process of dynamic gastrointestinal digestion DIDGI®, a simple two-compartment in vitro dynamic gastrointestinal digestion system. The structural changes caused to the proteins during digestion and the digesta inhibitory capacity of the angiotensin converting enzyme (ACE) were investigated. In gastric compartment the degree of hydrolysis (DH) was 14.7 ± 1.5 % and in the intestinal compartment, proteins were digests in a greater extent (DH = 60.6 ± 8.4 %). Protein aggregation was detected during the gastric phase. The final digesta obtained both at the gastric and intestinal level, showed ACE inhibitory capacity (IC50 80 ± 10 and 140 ± 20 µg/mL, respectively). Purified fractions from these digesta showed even greater inhibitory capacity, being eluted 2 (E2) the most active fraction (IC50 60 ± 10 µg/mL). Twenty-six peptide sequences were identified. Six of them, with potential antihypertensive capacity, belong to A. hypochondriacus, 3 agglutinins and 3 encrypted sequences in the 11S globulin. Results obtained provide new and useful information on peptides released from the digestion of an amaranth based beverage and its ACE bioactivity.

In vitro protein digestibility of RuBisCO-enriched wheat dough: a comparative study with pea and gluten proteins.

Growing demand for sustainable, plant-based protein sources has stimulated interest in new ingredients for food enrichment. This study investigates the nutritional and digestive implications of enriching wheat dough with RuBisCO, in comparison to pea protein-enriched and gluten-enriched doughs. The protein quality and digestibility of these enriched doughs were analysed through dough characterization, in vitro digestion experiments and biochemical analysis of digesta. Our findings indicate that an enrichment at 10% of RuBisCO or pea proteins improves the chemical score and the in vitro PDCAAS (IV-PDCAAS) score of wheat dough as compared to the control dough. Digestibility assays suggest that RuBisCO introduction modifies the protein hydrolysis kinetics: the nitrogen release is lower during gastric digestion but larger during intestinal digestion than other samples. The analysis of the protein composition of the soluble and insoluble parts of digesta, using size-exclusion chromatography, reveals that the protein network in RuBisCO-enriched dough is more resistant to gastric hydrolysis than the ones of other doughs. Indeed, non-covalently bound peptides and disulfide-bound protein aggregates partly composed of RuBisCO subunits remain insoluble at the end of the gastric phase. The digestion of these protein structures is then mostly performed during the intestinal phase. These results are also discussed in relation to the digestive enzymatic cleavage sites, the presence of potential enzyme inhibitors, the protein aggregation state and the secondary structures of the protein network in each dough type.

Egg yolk: structures, functionalities and processes.

Hen egg yolk is an ideal example of natural supramolecular assemblies of lipids and proteins with different organization levels. These assemblies are mainly due to interactions between proteins and phospholipids, and these interactions are essential in understanding and controlling the production of food made with yolk, and particularly emulsions. Furthermore, these assemblies can be modulated by external constraints among which thermo-mechanical and high-pressure treatments. This review focuses on multi-scale structures present in egg yolk, and their modulation by processes, in relation with their emulsifying properties. Egg yolk is mainly composed of two fractions-plasma and granules-which are natural nano- and micro-assemblies. These two fractions possess different composition, structures and functionalities and exhibit specific behaviour under treatments such as high pressure and temperature. Plasma contains a large quantity of lipids structured as lipoproteins (low-density lipoproteins), whereas granules are mainly composed of proteins aggregated in micrometric assemblies. If plasma is responsible for the important emulsifying properties of yolk, granules bring interesting emulsifying properties when assemblies are in the form of micelles in presence of salts. High-pressure or thermal treatments, applied before or after emulsion fabrication, alter their functionalities and could be used to commercially exploit these fractions.

Walnut (Juglans regia L.) kernel oil bodies recovered by aqueous extraction for utilization as ingredient in food emulsions: Exploration of their microstructure, composition and the effects of homogenization, pH, and salt ions on their physical stability.

Natural oil-in-water emulsions containing plant oil bodies (OBs), also called oleosomes, rich in health-promoting omega-3 polyunsaturated fatty acids (ω3 PUFA) are of increasing interest for food applications. In this study, we focused on walnut kernel OBs (WK-OBs) and explored their microstructure, composition and physical stability in ionic environments as well as the impact of homogenization. A green process involving aqueous extraction by grinding of WK allowed the co-extraction of OBs and proteins, and centrifugation was used to recover the WK-OBs. Confocal laser scanning microscopy images showed the spherical shape of WK-OBs with an oil core envelopped by a layer of phospholipids (0.16 % of lipids) and embedded proteins. Their mean diameter was 5.1 ± 0.3 µm. The WK-OBs contained 70.1 % PUFA with 57.8 % ω6 linoleic acid and 12.3 % ω3 α-linolenic acid representing 68 % and 11.6 % of the total fatty acids in the sn-2 position of the triacylglycerols (TAG), respectively. Trilinolein was the main TAG (23.1 %). The WK-OBs also contained sterols (1223 ± 33 mg/kg lipids; 86 % ß-sitosterol), carotenoids (0.62 ± 0.01 mg/kg lipids; 49.2 % ß-carotene), and tocopherols (322.7 ± 7.7 mg/kg lipids; 89 % γ-tocopherol), confirming their interest as health-promoting ingredients. The decrease in the size of WK-OBs under high-pressure homogenization avoided phase separation upon storage. The anionic WK-OB surface at neutral pH was affected by stressful ionic environments (pH, NaCl, CaCl2), that induced aggregation of WK-OBs and decreased the physical stability of the emulsions. Emulsions containing WK-OBs are promising to diversify the market of the ω3-rich plant-based food products and beverages.

Oil Bodies from Chia (Salvia hispanica L.) and Camelina (Camelina sativa L.) Seeds for Innovative Food Applications: Microstructure, Composition and Physical Stability.

Exploring and deciphering the biodiversity of oil bodies (OBs) recovered from oilseeds are of growing interest in the preparation of sustainable, natural and healthy plant-based food products. This study focused on chia (Salvia hispanica L.) and camelina (Camelina sativa L.) seed OBs. A green refinery process including ultrasound to remove mucilage, aqueous extraction by grinding and centrifugation to recover OBs from the seeds was used. The microstructure, composition and physical stability of the OBs were examined. Confocal laser scanning microscopy images showed that chia and camelina seed OBs are spherical assemblies coated by a layer of phospholipids and proteins, which have been identified by gel electrophoresis. The mean diameters determined by laser light scattering measurements were 2.3 and 1.6 µm for chia and camelina seed OBs, respectively. The chia and camelina seed OBs were rich in lipids and other bioactive components with, respectively, 64% and 30% α-linolenic acid representing 70% and 53% of the total fatty acids in the sn-2 position of the triacylglycerols, 0.23% and 0.26% phospholipids, 3069 and 2674 mg/kg oil of ß-sitosterol, and lipophilic antioxidants: 400 and 670 mg/kg oil of γ-tocopherol. Phenolic compounds were recovered from the aqueous extracts, such as rutin from camelina and caffeic acid from chia. Zeta-potential measurements showed changes from about -40 mV (pH 9) to values that were positive below the isoelectric points of pH 5.1 and 3.6 for chia and camelina seed OBs, respectively. Below pH 6.5, physical instability of the natural oil-in-water emulsions with aggregation and phase separation was found. This study will contribute to the development of innovative and sustainable food products based on natural oil-in-water emulsions containing chia and camelina seed OBs for their nutritional and health benefits.

A pilot study for the intrinsic labeling of egg proteins with 15N and 13C.

The aim of this study was to produce intrinsically and uniformly doubly (15)N-(13)C-labeled proteins. These proteins can be used as intrinsic tracers of dietary amino acids, both α-amino groups and carbon skeletons, during postprandial metabolic utilization. Two (Rhodes) laying hens were fed for 16 days with a standard poultry diet supplemented with 0, 0.2% or 0.4% of a mixture of 20 doubly (15)N-(13)C-labeled AAs. A third hen was given a non-enriched diet, as the control. The eggs laid were collected over 24 days, from 3 days before to 4 days after supplementation. The (15)N and (13)C enrichments in proteins from white and yolk were measured by EA-IRMS and GC-C-IRMS for enrichment in individual amino acids. After 10 days of supplementation, the (15)N enrichment reached an isotopic plateau at 1500 to 3000 ‰, depending on the supplementation level, in both white and yolk while the (13)C enrichment was 220 to 650 ‰ in white and was 100 to 250 ‰ in yolk. The (15)N enrichment was similar among the amino acids, except for the aromatic ones in which the enrichment was lower. The δ(13)C values were variable among amino acids in both white and yolk, ranging from 77 ‰ for tyrosine to 555 ‰ for proline with the 0.2 % supplementation level. In conclusion, the incorporation of 0.2 % labeled amino acids in the hen diet allowed us to achieve sufficient enrichment for metabolic studies. However, due to the non-homogeneity of the (13)C labeling, adequate (13)C enrichment of individual amino acids must be considered depending on the investigated metabolic pathway.

Biochemical and physical-chemical characterisation of leaf proteins extracted from Cichorium endivia leaves.

This study provides a detailed characterisation of a leaf protein concentrate (LPC) extracted from Cichorium endivia leaves using a pilot scale process. This concentrate contains 74.1% protein and is mainly composed of Ribulose-1,5-BISphosphate Carboxylase/Oxygenase (RuBisCO). We show that the experimentally determined extinction coefficient (around 5.0 cm-1 g-1 L depending on the pH) and refractive index increment (between 0.27 and 0.39 mL g-1) are higher than the predicted ones (about 1.6 cm-1 g-1 L and 0.19 mL g-1, respectively). In addition, the UV-visible absorption spectra show a maximum at 258 nm. These data suggest the presence of non-protein UV-absorbing species. Chromatographic separation of the concentrate components in denaturing conditions suggests that RuBisCO SC may be covalently bounded to few phenolic compounds. Besides, the solubility of LPC proteins is higher than 90% above pH 6. Such high solubility could make LPC a good candidate as a functional food ingredient.

Deciphering the properties of hemp seed oil bodies for food applications: Lipid composition, microstructure, surface properties and physical stability.

Hemp seed oil bodies (HSOBs) are of growing interest in response to the demand of consumers for healthy and natural plant-based food formulations. In this study, we used minimal processing including aqueous extraction by grinding and centrifugation to obtain HSOBs. We determined the lipid composition of HSBOs, their microstructure, and the impact of the homogenization pressure, pH and minerals on their surface properties and the physical stability of the emulsions. HSOBs contain high levels of well-balanced PUFA with LA/ALA = 2.9, γ-tocopherol, lutein and phytosterols. The mean diameter of HSOBs was 2.3 ± 0.1 µm with an isoelectric point in the range of pH 4.4 to 4.6. Homogenization of hemp seed extracts induced a decrease in the size of HSOBs but did not eliminate the sedimentation of the protein bodies composed of the globulin edestin. By changing the surface properties of HSOBs, pH values below 6 and NaCl induced the aggregation of HSOBs, while CaCl2 induced both aggregation and membrane-fusion mediated coalescence of HSOBs by involving probably the anionic phospholipids together with membrane proteins. This study will contribute to extend the range of novel food products and designed emulsions containing hemp seed proteins and oil bodies.

Long-term and large-scale multispecies dataset tracking population changes of common European breeding birds.

Around fifteen thousand fieldworkers annually count breeding birds using standardized protocols in 28 European countries. The observations are collected by using country-specific and standardized protocols, validated, summarized and finally used for the production of continent-wide annual and long-term indices of population size changes of 170 species. Here, we present the database and provide a detailed summary of the methodology used for fieldwork and calculation of the relative population size change estimates. We also provide a brief overview of how the data are used in research, conservation and policy. We believe this unique database, based on decades of bird monitoring alongside the comprehensive summary of its methodology, will facilitate and encourage further use of the Pan-European Common Bird Monitoring Scheme results.

Impact of sodium caseinate concentration and location on magnesium release from multiple W/O/W emulsions.

Water-in-oil-in-water (W/O/W) double emulsions were prepared and the rate of release of magnesium ions from the internal to the external aqueous phase was followed. Sodium caseinate was used not only as a hydrophilic surface-active species but also as a chelating agent able to bind magnesium ions. The release occurred without film rupturing (no coalescence). The kinetics of the release process depended on the location (in only one or in both aqueous compartments) and on the concentration of sodium caseinate. The rate of release increased with the concentration of sodium caseinate in the external phase and decreased when sodium caseinate was present in the inner droplets. The experiments were interpreted within the frame of a mean-field model based on diffusion, integrating the effect of ion binding. The data could be adequately fitted by considering a time-dependent permeation coefficient of the magnesium ions across the oil phase. Our results suggested that ion permeability was influenced by the state of the protein interfacial layers which itself depended on the extent of magnesium binding.

Loading of lutein in egg-sphingomyelin vesicles as lipid carriers: Thermotropic phase behaviour, structure of sphingosome membranes and lutein crystals.

Lutein is a xanthophyll carotenoid provided exclusively by the diet, that has protective functions and beneficial effects on human health. Supplementation in lutein is necessary to reach the recommended daily dietary intake. However, the introduction of lutein into foods and beverages is a real challenge since this lipophilic nutrient has a poor aqueous solubility and a low bioavailability. In this study, we investigated the capacity of egg-sphingomyelin (ESM) vesicles called sphingosomes to solubilise lutein into the bilayers. The thermal and structural properties of ESM bilayers were examined in presence of various amounts of lutein by differential scanning calorimetry (DSC) and temperature-controlled X-ray diffraction (XRD), the structures of sphingosomes and lutein crystals were observed by microscopic techniques. ESM bilayers were in the fluid Lα phase above the phase transition temperature Tm = 39.6 °C and in the lamellar ripple Pß' phase below Tm where ESM sphingosomes exhibited ondulations and were facetted. Lutein molecules were successfully incorporated into the ESM bilayers where they induced a structural disorganisation. For ESM/lutein 90/10 %mol (91.8/8.2 %wt; 89 mg lutein / g ESM), lutein partitioning occured with the formation of lutein crystals in the aqueous phase together with lutein-loaded ESM vesicles. This study highlighted the capacity of new lipid carriers such as egg-sphingosomes to solubilise lutein and opens perspectives for the formulation of effective lutein-fortified functionnal foods and beverages providing health benefits.

Studying the real-time interplay between triglyceride digestion and lipophilic micronutrient bioaccessibility using droplet microfluidics. 1 lab on a chip method.

This article is the first part of a series reporting on real-time digestion kinetics of triglyceride droplets containing different lipophilic micronutrients. This part focuses on the design, fabrication, and operation of a polydimethylsiloxane microfluidic device which enables the generation and digestion of oil droplets. The micro-channels were made hydrophilic to obtain oil droplets in an aqueous continuous phase. Optimized chip design and outlet control were implemented to provide efficient oil droplet generation, manipulation, and immobilization on a single chip. Highly monodisperse oil droplets were generated, immobilized in an array of traps and monitored in real time by fluorescence using a confocal microscopy method. The device was used to study the kinetics of beta-carotene release during tricaprylin digestion (intestinal lipolysis and micellar solubilization). The effect of the gastric phase on beta-carotene degradation was also investigated using the same method.

Studying the real-time interplay between triglyceride digestion and lipophilic micronutrient bioaccessibility using droplet microfluidics. 2 application to various oils and (pro)vitamins.

The kinetics of micellar solubilization of lipophilic micronutrients (bioaccessibility) in relation with triglyceride digestion remains poorly known. To study this interplay in real-time, a droplet microfluidic method was designed and used as reported in the first part of this article series. In this second part, the interplay between the micellar solubilization of (pro)vitamins (beta-carotene or retinyl palmitate) and the digestion of triglyceride oils (tricaprylin TC, or high-oleic sunflower seed oil HOSO, or fish oil FO) during simulated gastrointestinal digestion was investigated. The relation between the release of both micronutrients and of triglyceride lipolytic products was found to be non-linear. The kinetics of beta-carotene was found to follow the kinetics of lipolytic products, depending on the oil type (TC > HOSO > FO). The effect of the gastric phase on the intestinal phase was also found to follow this order, mostly due to partial lipolysis during the gastric phase.

Contrasting impacts of precipitation on Mediterranean birds and butterflies.

The climatic preferences of the species determine to a large extent their response to climate change. Temperature preferences have been shown to play a key role in driving trends in animal populations. However, the relative importance of temperature and precipitation preferences is still poorly understood, particularly in systems where ecological processes are strongly constrained by the amount and timing of rainfall. In this study, we estimated the role played by temperature and precipitation preferences in determining population trends for birds and butterflies in a Mediterranean area. Trends were derived from long-term biodiversity monitoring data and temperature and precipitation preferences were estimated from species distribution data at three different geographical scales. We show that population trends were first and foremost related to precipitation preferences both in birds and in butterflies. Temperature preferences had a weaker effect on population trends, and were significant only in birds. The effect of precipitation on population trends operated in opposite directions in the two groups of species: butterfly species from arid environments and bird species from humid habitats are decreasing most. Our results indicate that, although commonly neglected, water availability is likely an important driver of animal population change in the Mediterranean region, with highly contrasting impacts among taxonomical groups.

Phosvitin-calcium aggregation and organization at the air-water interface.

Phosvitin, an egg yolk protein constituted by 50% of phosphorylated serines, presents good emulsifying properties whereas its interfacial properties are not yet clearly elucidated and remain object of discussion. Phosvitin has a high charge density and naturally forms aggregates through phosphocalcic bridges in egg yolk. This high charge density, doubled by this capacity to aggregate, limits the adsorption of the protein at the air-water interface. In this work, we investigated the aggregation impact by calcium ions on the organization of the phosvitin interfacial film using the atomic force microscopy. Phosvitin interfacial films without calcium ions are compared to phosvitin interfacial films formed in the presence of calcium ions in the subphase. We demonstrated that phosvitin is able to anchor at air-water interfaces in spite of its numerous negative charges. In the compression isotherm a transition was observed just before 28 mN/m signifying a possible modification of the interfacial film structure or organization. Calcium ions induce a reorganization towards a greater compaction of the phosvitin interfacial film even at low surface pressure. In conclusion we suggest that, in diluted regime, phosvitin molecules could adsorb by their two hydrophobic extremities exhibiting loops in the aqueous phase, whereas in concentred regime (high interfacial concentration) it would be adsorbed at the interface by only one extremity (brush model).

Structuring and functionalization of dispersions containing egg yolk, plasma and granules induced by mechanical treatments.

In this study, the impact of mechanical treatments on the physicochemical and emulsifying properties of hen egg yolk and its fractions plasma and granules has been assessed. Yolk, plasma, and granule dispersions at pH 4.0 and 0.75 M NaCl were subjected to rotor-stator and high-pressure pretreatments at different dynamic pressure levels: 30, 100, and 200 bar at 20 degrees C. Physicochemical characteristics (protein solubility, rheological behavior, and micro- and ultra-structures) and emulsifying properties (oil/water 60:40 emulsions: droplet size and flocculation, protein adsorption) of control dispersions and dispersions subjected to mechanical pretreatments (rotor-stator or high pressure) were compared. Homogenization at high pressures (100 and 200 bar) led to a decreased protein solubility and to an increase in apparent viscosity of yolk and plasma dispersions. These pressures certainly disrupted low-density lipoproteins (LDL) particles and generated aggregates of proteins liberated from LDL and livetins in the plasma fraction, and led to a moderated reorganization of the microstructure of granules. Despite the modifications observed in the pretreated plasma and granules dispersions, the oil droplet diameter and the bridging flocculation obtained in emulsions made with these dispersions were similar to that obtained with untreated dispersions. Results concerning interfacial protein adsorption suggested that preformed or natural aggregates at least partially persist at the oil-water interface.

Structures and rheological properties of hen egg yolk low density lipoprotein layers spread at the air-water interface at pH 3 and 7.

Low density lipoproteins (LDL) from egg yolk have a classical structure of lipoprotein with a core of neutral lipids surrounded by a monolayer of apoproteins and phospholipids. This structure collapses during adsorption and all constituents spread at the interface. To understand better the nature of the interactions between apoproteins and lipids at the interface, we have deposited LDL at an air-water interface and analysed the isotherms during their compression on a Langmuir trough. Then, these LDL films were studied by atomic force microscopy (AFM) imaging. To identify the protein and lipid structures, we imaged films before and after lipid solubilisation by butanol. To study the interactions in the LDL films, we have varied the pH, ionic strength and used simplified model systems. We also studied the correlation between observed structures and interfacial rheology of the film. The isotherms of interfacial LDL films were similar for pH 3 and 7, but their structures observed in AFM were different. At surface pressures below the transition corresponding to the demixion of apoprotein-neutral lipid complexes, the LDL film structure was not governed by electrostatic interactions. However, above this surface pressure transition (45mN/m), there was an effect of charge on this structure. Around the transition zone, the rheological properties of LDL films at pH 3 were different as a function of pH (viscous at pH 3 and visco-elastic at pH 7). So, the rheological properties of LDL films could be linked to the structures formed by apoproteins and observed in AFM.

Structure modification in hen egg yolk low density lipoproteins layers between 30 and 45 mN/m observed by AFM.

We have studied the structure of films made by low density lipoproteins (LDL) from hen egg yolk, which are composed of apoproteins, neutral lipids and phospholipids. These LDL have been deposited on air-water interface to form a monolayer which has been compressed to measure an isotherm using Langmuir balance. This isotherm presented three transitions (neutral lipid (surface pressure, pi=19 mN/m), apoprotein-lipid (pi=41 mN/m) and phospholipid (pi=51 mN/m) transitions). We have studied only the apoprotein-lipid transition. In order to observe the LDL film structure before (pi=30 mN/m) and after (pi=45 mN/m) the apoprotein-lipid transition, the formed films were transferred and visualised by atomic force microscopy (AFM). Our results have shown that the structures observed in the LDL film were different depending on the surface pressure. The apoproteins and neutral lipids appeared to be miscible up to the apoprotein-lipid transition, when demixing occurred. The structures observed after the apoprotein-lipid transition should be due to the demixing between apoproteins and neutral lipids. On the other hand, apoproteins and phospholipids seemed miscible whatever the surface pressure. Hence, the first transition (pi=19 mN/m) should be attributed to the free neutral lipid collapse; the second transition (pi=41 mN/m) should be attributed to the demixing of apoprotein-neutral lipid complexes; and the last transition (pi=51 mN/m) should be attributed to phospholipid collapse or to demixing of apoprotein-phospholipid complexes.

Collagen type I from bovine bone. Effect of animal age, bone anatomy and drying methodology on extraction yield, self-assembly, thermal behaviour and electrokinetic potential.

Natural collagen is easily available from animal tissues such as bones. Main limitations reported in the use of natural collagen are heterogeneity and loss of integrity during recovery. However, its natural complexity, functionality and bioactivity still remain to be achieved through synthetic and recombinant ways. Variability of physicochemical properties of collagen extracted from bovine bone by acetic acid was then investigated taking into account endogenous and exogenous factors. Endogenous: bovine's bones age (4 and 7 years) and anatomy (femur and tibia); exogenous: thermal treatments (spray-drying and lyophilisation). Scanning electron microscopy, spectroscopy (EDS, FTIR, UV/Vis and CD), differential scanning calorimetry (DSC), centesimal composition, mass spectrometry, amino acids and zeta-potential analysis were used for the purpose. Age correlated negatively with yield of recovery and positively with minerals and proteoglycans content. Comparing the anatomy, higher yields were found for tibias, and higher stability of tibias collagen in solution was noticed. Whatever the age and the anatomy, collagens were able to renature and to self-assemble into tri-dimensional structures. Nonetheless thermal stability and kinetics of renaturation were different. Variability of natural collagen with bone age and anatomy, and drying methodology, may be a crucial advantage to conceive tailor-made applications in either the biological or technical sector.