Production and Characterization of Astaxanthin Nanoparticles

There is increasing interest on behalf of consumers and the food industry for the enrichment of common food with health-promoting bioactive molecules. Clinical studies have demonstrated that tangible health benefits may derive from the intake of bioactive compounds, in the prevention of dietary related pathologies such as diabetes, cancer, obesity and cardiovascular diseases. The beneficial effect is usually given by the presence in food of peculiar molecules such us carotenoids, polyphenols, polyunsaturated fatty acids and bioactive peptides, to cite a few. Unfortunately, these compounds display high susceptibility to environmental conditions such as light, extreme pH and temperature, and to standard food manufacturing processes. They can also account for undesirable flavors, colors or affect final product stability and appearance, thus rendering their presence in the product an issue rather than a useful addition. The addition of nutrients in small quantities into a food system may not significantly affect its proprieties, but the high amounts, often required to meet certain health claims and benefits, might bring to a product with a poorly acceptable sensory profile and a scarce stability. In particular, lipophilic bioactive ingredients display a major challenge. Besides their limited solubility in most of the foods and beverages, they are characterized by high susceptibility to oxidation and by a lower adsorption through the gastrointestinal tract in comparison to more hydrophilic substances, meaning a scanty bioavailability. Hence, there is a pressing need for the production of edible delivery systems or carriers that could efficiently encapsulate, protect and improve the handling of lipophilic molecules. The objective of this thesis was to develop a system suitable for the encapsulation of lipophilic molecules, capable of: a) protecting the ingredient from the surrounding environment (extreme pH, heat, UV light, oxygen); b) preserving its functionality (e.g. antioxidant activity); c) reducing the impact on the organoleptic level; d) improving the bioavailability of the encapsulated molecules. This last point in particular could be achieved by using sub-cellular delivery systems referred to as nanoparticles or nanocarriers, which may potentially enhance the transport across the intestinal wall. To this purpose, astaxanthin was chosen as a model bioactive compound. Astaxanthin is a keto-carotenoid that displays several biological activities, such as high antioxidant capacity, that may contribute to the prevention of degenerative pathologies like diabetes, cancer, cardiovascular diseases and chronic bowel disease. However, like all carotenoids it is characterized by a strong lipophilic character that makes its inclusion in many types of aqueous-based foods and beverages rather a challenge. This aspect is the main cause of its poor absorption through the human intestinal mucosae. Moreover, astaxanthin is labile to common processing conditions such as the presence of light and oxygen, extreme pH and high temperatures. For these reasons a lot of efforts have been put in these past years to find suitable solutions for its protection and manipulation. In order to develop the suitable encapsulate, in chapter 2 an emulsification and solvent-evaporation technique was used as encapsulation approach; whey proteins were selected as the matrix to envelope the core constituted by an astaxanthin-enriched oleoresin derived from Haematococcus pluvialis, a microalgae representing the main natural source of the carotenoid. The process was optimized by varying crucial parameters and the stability of the nanoparticles was tested in different conditions. This analysis highlighted a better performance of the encapsulated molecule in comparison to the starting oleoresin. Good release properties during in-vitro simulated digestion and the increase of the solubility in water were observed. In chapter 3, the study was focused on the research for plant alternative proteins as encapsulating matrices in order to satisfy the increasing interest of the consumers for substitutes of animal-deriving ingredients. This allowed to identify pea protein isolate as a valid candidate for the development of a vegetarian/vegan-allergen free nanocarrier. Finally, Chapter 4 dealt in depth with the antioxidant properties displayed by the astaxanthin nanoparticles through in vitro colorimetric assay and by the development of a cell-based assay. The encapsulates showed higher antioxidant capacity in comparison to the oleoresin. The uptake of the nanoparticles was studied in cell model systems through confocal laser microscopy and flow cytometry that indicated a probable energy-dependent mechanism

Allergens from Edible Insects: Cross-reactivity and Effects of Processing

Purpose of Review The recent introduction of edible insects in Western countries has raised concerns about their safety in terms of allergenic reactions. The characterization of insect allergens, the sensitization and cross-reactivity mechanisms, and the effects of food processing represent crucial information for risk assessment. Recent Findings Allergic reactions to different insects and cross-reactivity with crustacean and inhalant allergens have been described, with the identification of new IgE-binding proteins besides well-known pan-allergens. Depending on the route of sensitization, different potential allergens seem to be involved. Food processing may affect the solubility and the immunoreactivity of insect allergens, with results depending on species and type of proteins. Chemical/enzymatic hydrolysis, in some cases, abolishes immunoreactivity. Summary More studies based on subjects with a confirmed insect allergy are necessary to identify major and minor allergens and the role of the route of sensitization. The effects of processing need to be further investigated to assess the risk associated with the ingestion of insect-containing food products

A framework for the analysis of the influence of rainfall spatial organization and basin morphology on flood response

This work describes the derivation of a set of statistics, termed spatial moments of catchment rainfall, that quantify the dependence between rainfall spatial organization, basin morphology and runoff response. These statistics describe the spatial rainfall organisation in terms of concentration and dispersion along the flow distance coordinate. These statistics were derived starting from an analytical framework, and related with the statistical moments of the flood hydrograph. From spatial moments we also created an index quantifying catchment scale storm velocity. This index measures the overall movement of the rainfall system over the catchment, reflecting the filtering effect of its morphology. We also extended spatial moments to the hillslope system, developing a framework to evaluate the relevance of hillslope and channel propagation in the flood response to spatially variable rainfall fields. Data from six flash floods occurred in Europe between 2002 and 2007 are used to evaluate the information provided by the framework. High resolution radar rainfall fields and a distributed hydrologic model are employed to examine how effective are these statistics in describing the degree of spatial rainfall organisation, which is important for runoff modelling. The size of the study catchments ranges between 36 to 2586 km2. The analysis reported here shows that spatial moments of catchment rainfall can be effectively employed to isolate and describe the features of rainfall spatial organization which have significant impact on runoff simulation. Rainfall distribution was observed to play an important role in catchments as small as 50 km2. The description timing error was further improved by the inclusion in the framework of hillslope propagation. This development allows to compare scenarios of hillslope conditions, to evaluate the sensitivity of single basins or the effect of catchment scale. The analysis of catchment scale storm velocity showed a nonlinear dependence with basin scale. The values of velocity observed were however rather moderate, in spite of the strong kinematic characteristics of individual storm elements, and did not play a relevant effect on the flood analyzed

TOPMELT 1.0: a topography-based distribution function approach to snowmelt simulation for hydrological modelling at basin scale

Abstract. Enhanced temperature-index distributed models for snowpack simulation, incorporating air temperature and a term for clear sky potential solar radiation, are increasingly used to simulate the spatial variability of the snow water equivalent. This paper presents a new snowpack model (termed TOPMELT) which integrates an enhanced temperature-index model into the ICHYMOD semi-distributed basin-scale hydrological model by exploiting a statistical representation of the distribution of clear sky potential solar radiation. This is obtained by discretizing the full spatial distribution of clear sky potential solar radiation into a number of radiation classes. The computation required to generate a spatially distributed water equivalent reduces to a single calculation for each radiation class. This turns into a potentially significant advantage when parameter sensitivity and uncertainty estimation procedures are carried out. The radiation index may be also averaged in time over given time periods. Thus, the model resembles a classical temperature-index model when only one radiation class for each elevation band and a temporal aggregation of 1 year is used, whereas it approximates a fully distributed model by increasing the number of the radiation classes and decreasing the temporal aggregation. TOPMELT is integrated within the semi-distributed ICHYMOD model and is applied at an hourly time step over the Aurino Basin (also known as the Ahr River) at San Giorgio (San Giorgio Aurino), a 614 km2 catchment in the Upper Adige River basin (eastern Alps, Italy) to examine the sensitivity of the snowpack and runoff model results to the spatial and temporal aggregation of the radiation fluxes. It is shown that the spatial simulation of the snow water equivalent is strongly affected by the aggregation scales. However, limited degradation of the snow simulations is achieved when using 10 radiation classes and 4 weeks as spatial and temporal aggregation scales respectively. Results highlight that the effects of space–time aggregation of the solar radiation patterns on the runoff response are scale dependent. They are minimal at the scale of the whole Aurino Basin, while considerable impact is seen at a basin scale of 5 km2

Constraining co-creation? An ethnographic study of Healthwatch organizations in England

While the potential benefits of co-production and co-creation are widely vaunted, the degree to which they precipitate innovative change in systems varies, and influences on their impact demand greater attention. We present an ethnographic study of organizations intended to foster co-creation in English health and social care. Comparing five cases, we find demonstrable activity and some tangible impacts. At the same time, the positioning of these organizations as collaborative insiders in local governance systems constrained the publics and issues that were prioritized in co-creative activities. Our findings highlight the significance of discursive forms of meta-governance in delimiting co-creation’s scope

Spatial moments of catchment rainfall: rainfall spatial organisation, basin morphology, and flood response

Abstract. This paper describes a set of spatial rainfall statistics (termed "spatial moments of catchment rainfall") quantifying the dependence existing between spatial rainfall organisation, basin morphology and runoff response. These statistics describe the spatial rainfall organisation in terms of concentration and dispersion statistics as a function of the distance measured along the flow routing coordinate. The introduction of these statistics permits derivation of a simple relationship for the quantification of catchment-scale storm velocity. The concept of the catchment-scale storm velocity takes into account the role of relative catchment orientation and morphology with respect to storm motion and kinematics. The paper illustrates the derivation of the statistics from an analytical framework recently proposed in literature and explains the conceptual meaning of the statistics by applying them to five extreme flash floods occurred in various European regions in the period 2002–2007. High resolution radar rainfall fields and a distributed hydrologic model are employed to examine how effective are these statistics in describing the degree of spatial rainfall organisation which is important for runoff modelling. This is obtained by quantifying the effects of neglecting the spatial rainfall variability on flood modelling, with a focus on runoff timing. The size of the study catchments ranges between 36 to 982 km2. The analysis reported here shows that the spatial moments of catchment rainfall can be effectively employed to isolate and describe the features of rainfall spatial organization which have significant impact on runoff simulation. These statistics provide useful information on what space-time scales rainfall has to be monitored, given certain catchment and flood characteristics, and what are the effects of space-time aggregation on flood response modeling

Corrigendum to "Spatial moments of catchment rainfall: rainfall spatial organisation, basin morphology, and flood response" published in Hydrol. Earth Syst. Sci., 15, 3767–3783, 2011

No abstract available

Phagocytosis of Astaxanthin-Loaded Microparticles Modulates TGFβ Production and Intracellular ROS Levels in J774A.1 Macrophages

Radiation-induced fibrosis is a serious long-lasting side effect of radiation therapy. Central to this condition is the role of macrophages that, activated by radiation-induced reactive oxygen species and tissue cell damage, produce pro-inflammatory cytokines, such as transforming growth factor beta (TGFb). This, in turn, recruits fibroblasts at the site of the lesion that initiates fibrosis. We investigated whether astaxanthin, an antioxidant molecule extracted from marine and freshwater organisms, could help control macrophage activation. To this purpose, we encapsulated food-grade astaxanthin from Haematococcus pluvialis into micrometer-sized whey protein particles to specifically target macrophages that can uptake material within this size range by phagocytosis. The data show that astaxanthin-loaded microparticles are resistant to radiation, are well-tolerated by J774A.1 macrophages, induce in these cells a significant reduction of intracellular reactive oxygen species and inhibit the release of active TGFb as evaluated in a bioassay with transformed MFB-F11 fibroblasts. Micro-encapsulation of bioactive molecules is a promising strategy to specifically target phagocytic cells and modulate their own functions

Effects of Combination Treatments with Astaxanthin-Loaded Microparticles and Pentoxifylline on Intracellular ROS and Radiosensitivity of J774A.1 Macrophages

Radiation-induced fibrosis (RIF) is a serious, yet incurable, complication of external beam radiation therapy for the treatment of cancer. Macrophages are key cellular actors in RIF because of their ability to produce reactive oxidants, such as reactive oxygen species (ROS) and inflammatory cytokines that, in turn, are the drivers of pro-fibrotic pathways. In a previous work, we showed that phagocytosis could be exploited to deliver the potent natural antioxidant astaxanthin specifically to macrophages. For this purpose, astaxanthin encapsulated into \u3bcm-sized protein particles could spe- cifically target macrophages that can uptake the particles by phagocytosis. In these cells, astaxanthin microparticles significantly reduced intracellular ROS levels and the secretion of bioactive TGF\u3b2 and increased cell survival after radiation treatments. Here we show that pentoxifylline, a drug currently used for the treatment of muscle pain resulting from peripheral artery disease, amplifies the effects of astaxanthin microparticles on J774A.1 macrophages. Combination treatments with pentoxifylline and encapsulated astaxanthin might reduce the risk of RIF in cancer patients