Emulsifying properties of hemp proteins: Effect of isolation technique

peer-reviewedHemp protein was isolated from hemp seed meal using two different isolation procedures: alkali extraction/isoelectric precipitation (HPI) and micellization (HMI). The ability of these proteins to form and stabilize 10% (w/w) sunflower oil-in-water emulsions (at pH = 3.0) was studied at three different concentrations, 0.25, 0.75 and 1.5% (w/w), by monitoring emulsion droplet size distribution, microstructural and morphological properties, rheological behaviour and stability against flocculation, coalescence and creaming. In addition, hemp proteins were analysed for water solubility, denaturation degree and surface/interfacial activity. HMI protein, which was found to be less denatured after isolation, exhibited higher solubility and slightly higher surface/interfacial activity than HPI protein. HMI emulsions possessed a smaller volume mean droplet diameter (d4,3 = 1.92–3.42 μm in 2% SDS) than HPI emulsions (d4,3 = 2.25–15.77 μm in 2% SDS). While HMI stabilized emulsions were characterized with individual droplets covered by protein film, both confocal laser scanning microscopy and flocculation indices indicated occurrence of bridging flocculation in HPI stabilized emulsions. Protein aggregation, which induced flocculation of the droplets, contributed to higher apparent viscosity of HPI stabilized emulsions compared to HMI stabilized emulsions. Interestingly, emulsions stabilized with 1.5% (w/w) HPI exhibited much better creaming and coalescence stability than other emulsions due to the formation of a weak transient network of floccules and higher continuous phase viscosity which both suppressed the movement of the droplets

Calcium Montmorillonite for the Mitigation of Aflatoxicosis and Gastrointestinal Inflammation

Clays have been used for centuries as ‘ancient medicine’ for their therapeutic benefits. One particular clay, calcium montmorillonite, has historically been used as an anti-caking agent in animal feeds, but has also demonstrated the ability to bind toxins and alleviate infectious diarrhea. The full breadth of therapeutic applications and molecular mechanisms of montmorillonite is still unknown. Therefore, the purpose of this research was to explore novel therapeutic applications for NovaSil (NS), a calcium montmorillonite clay to reduce the risk of aflatoxicosis in farm-raised fish and alleviate gastrointestinal inflammation and dysbiosis in a mouse model of Crohn’s disease (CD). Aflatoxin B_(1) (AFB_(1)) is a fungal mycotoxin that commonly contaminates corn and peanut crops. It is produced by the fungi Aspergillus flavus and A. parasiticus during times of drought or due to improper post-harvest storage. Aflatoxin B_(1) is known to cause hepatocellular carcinoma, immunosuppression and growth stunting in several species. Recently, incorporation of plant-based alternatives into feed for farm-raised fish has become a trend, thereby increasing the risk for mycotoxin contamination. Inexpensive strategies to reduce AFB_(1) exposure are needed. Calcium montmorillonite clay, which is both inexpensive and abundant, has a dioctahedral structure that is known to sequester AFB_(1) in its negatively-charged interlayer, thereby reducing systemic bioavailability. There is also some evidence to suggest that calcium montmorillonite clays may possess gastrointestinal anti-inflammatory properties. NovaSil was used as a strategy to reduce the effects of AFB_(1) in Nile tilapia (Oreochromis niloticus) and red drum (Scieanops ocellatus). Juvenile tilapia and red drum were dosed with AFB_(1) and NS over the course of 10 and 7 weeks, respectively. Additionally, proinflammatory cytokine-clay binding was characterized using isothermal analysis, X-ray diffraction (XRD) and transmission electron microscopy (TEM). Furthermore, a TNBS (2,4,6-Trinitrobenzenesulfonic acid)-colitis gastrointestinal mouse model was employed to study the anti-inflammatory properties of NS and its ability to protect the gut microbiome. Results suggest that NS can prevent aflatoxicosis in red drum at a 2% inclusion level over the course of 7 weeks. NovaSil also prevented some toxicity in Nile tilapia; however, these results were not significant. In vitro results also indicate that NS sorbs proinflammatory cytokines such as TNFα and IL-1β in its interlayers. Additionally, NS was found to reduce serum pro-inflammatory cytokine levels in TNBS-induced mice and reduce gut dysbiosis. These results could positively impact both human and animal populations with AFB_(1) exposure and/or chronic gastrointestinal inflammation

Software design for the control system for Small-Size Telescopes with single-mirror of the Cherenkov Telescope Array

The Small-Size Telescope with single-mirror (SST-1M) is a 4 m Davies-Cotton telescope and is among the proposed telescope designs for the Cherenkov Telescope Array (CTA). It is conceived to provide the high-energy ($>$ few TeV) coverage. The SST-1M contains proven technology for the telescope structure and innovative electronics and photosensors for the camera. Its design is meant to be simple, low-budget and easy-to-build industrially. Each device subsystem of an SST-1M telescope is made visible to CTA through a dedicated industrial standard server. The software is being developed in collaboration with the CTA Medium-Size Telescopes to ensure compatibility and uniformity of the array control. Early operations of the SST-1M prototype will be performed with a subset of the CTA central array control system based on the Alma Common Software (ACS). The triggered event data are time stamped, formatted and finally transmitted to the CTA data acquisition. The software system developed to control the devices of an SST-1M telescope is described, as well as the interface between the telescope abstraction to the CTA central control and the data acquisition system.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

Effect of phytosterol enrichment on the crystallisation, physiochemical, and interfacial behaviour of bulk and emulsified milk fat triacylglycerol matrices

Phytosterols possess the ability to significantly lower levels of low-density lipoprotein (LDL) cholesterol in the blood, but their bioaccessibility is dependent upon the solubility of the phytosterol in the consumable food or pharmaceutical product. Phytosterols are one of the most commonly used groups of bioactive compounds in the functional food industry. However, very little research has examined how phytosterols crystallise within food systems or how the physiochemical properties of the food system change upon phytosterol addition. The studies in this thesis investigated phytosterol addition in bulk and emulsified milk fat matrices, as dairy products are a common matrix for phytosterol enrichment. The main objectives of the thesis were to: (i) characterise the collective crystalline behaviour of both milk fat and phytosterols; (ii) quantify how phytosterol enrichment influences the physiochemical properties of the food system; (iii) investigate how an oil-in-water (o/w) interface influences phytosterol and milk fat crystalline behaviour; and (iv) develop and assess the means by which phytosterol solubility could be improved in milk fat matrices. In both the emulsion and bulk milk systems employed, the level of phytosterol-enrichment in milk fat was either 0 (the control), 3, or 6%. In phytosterol-enriched emulsions, whey protein (1%) was employed as the emulsifier in emulsions with 10% oil and 89% water. During cooling, phytosterols addition altered the nucleation temperature of emulsions, but no such effect was identified in bulk milk fat. During the crystallisation process, emulsified milk fat triacylglycerols (TAG) packing expanded upon phytosterol enrichment, which was observed as an increase in the triple-chain length (3L). In bulk milk fat, both doublechain length (2L) and 3L TAG packing was seen during cooling; the 3L spacing also increased with phytosterol enrichment, but no differences were seen in the 2L packing. These results suggest that phytosterols can insert themselves into the milk fat TAG network during cooling; however, the overall polymorphic form did not change. After storage, the milk fat TAG network developed into more structured polymorphic forms, and phytosterols were no longer found within the TAG packing. Phytosterols were also found to be able to decrease the average size of droplets in an emulsion and participate in a synergistic interaction with whey protein at the emulsion interface. In addition, phytosterol enrichment was found to have no negative effect on the creaming behaviour of the emulsions. Phytosterol crystallisation was altered by the addition of low molecular weight surfactants, lecithin and monoacylglycerol (MAG), and by changing the average droplet size from 1.0 to 0.2 µm. Lecithin and MAG addition significantly decreased phytosterol crystallisation in the bulk form, but changes in phytosterol crystallisation behaviour in the emulsified form were mainly driven by the decrease in droplet size. The lecithin-containing emulsions with the smaller droplets, however, showed the greatest potential for improved phytosterol solubility; in addition, they possessed better emulsion stability, as compared to the control and MAG-enriched emulsions. As the crystallisation properties of an emulsion are greatly affected by the o/w interface, two purified milk fat TAG lipids without surfactants or emulsifiers were studied in a grazing incidence synchrotron system. Differences between the lipid droplets were distinguishable, but further work is needed on the droplet deposition. In conclusion, the studies conducted in this thesis provide important insight on the behaviour of phytosterols in a model TAG-based system and can be utilised by the functional food or pharmaceutical industries to improve the bioaccessibility of phytosterols and possibility other lipophilic bioactives

The SST-1M camera for the Cherenkov Telescope Array

The prototype camera of the single-mirror Small Size Telescopes (SST-1M) proposed for the Cherenkov Telescope Array (CTA) project has been designed to be very compact and to deliver high performance over thirty years of operation. The camera is composed of an hexagonal photo-detection plane made of custom designed large area hexagonal silicon photomultipliers and a high throughput, highly configurable, fully digital readout and trigger system (DigiCam). The camera will be installed on the telescope structure at the H. Niewodnicza{\'n}ski institute of Nuclear Physics in Krakow in fall 2015. In this contribution, we review the steps that led to the development of the innovative photo-detection plane and readout electronics, and we describe the test and calibration strategy adopted.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.05894; Full consortium author list at http://cta-observatory.or

Physical and interfacial characterization of phytosterols in oil-in-water triacylglycerol-based emulsions

peer-reviewedPhytosterols possess the ability to significantly lower low-density lipoprotein (LDL) cholesterol levels in the blood, but their bioaccessibility is highly dependent upon the solubility of the phytosterol within the carrier matrix. Currently, there is a limited amount of knowledge on how phytosterols interact at oil-water interfaces, despite research indicating that these interfaces could promote the crystallization of phytosterols and thus decrease bioaccessibility. In order to fill this knowledge gap, this work expands upon a previously studied emulsion system for encapsulating phytosterols and addresses whether phytosterols can crystalize at an oil-in-water emulsion interface. Images from multiple microscopic techniques suggest interfacial phytosterol crystallization in 0.6% phytosterol-enriched emulsions, while interfacial tension results and calculated models showed that whey protein and phytosterols had a synergistic effect on interfacial tension. A deeper understanding of the interfacial behavior of phytosterols in emulsions can provide the functional food and pharmaceutical industry with the knowledge needed to design more bioaccessible phytosterol-enriched products

Evidence of human Bourbon virus infections, North Carolina, USA

Bourbon virus is a tickborne virus that can cause human disease. Cases have been reported in Kansas, Oklahoma, and Missouri, USA. We identified Bourbon virus-specific neutralizing antibodies in patients from North Carolina. Bourbon virus infections are likely more common than previously thought, highlighting the need for improved diagnostics and surveillance