Large deformation and crystallisation properties of process optimised cocoa butter emulsions

The objectives of the research presented in this thesis were: (1) optimise the processing conditions for the production of water-in-cocoa butter emulsions; (2) understand the role of water droplets on the large deformation behaviour and crystallisation properties of emulsified systems. Results showed that a scraped surface heat exchanger could be used to produce tempered emulsions with a small average droplet size (~3 µm). In all systems stability was provided by the emulsifier and fat crystals forming a network both in the bulk and at the interface of the water droplets. Characterisation of the large deformation properties of emulsions showed that the elastic behaviour remained constant at low aqueous phase percentages while the strength at fracture decreased. This result suggests that water droplets act as stress-concentrator elements, which is probably due to their partial sintering with the bulk network. Results of crystallisation experiments have shown that the effect of droplets on kinetics of crystallisation depends on the degree of supercooling: only at relatively high temperatures (15, 20 °C) the dispersed droplets increased the kinetics of crystallisation compared to bulk cocoa butter (CB). With respect to polymorphic evolution, emulsified systems evolved faster toward more stable forms than bulk CB at all temperatures

Material properties of cocoa butter emulsions: effect of dispersed phase droplet size and compression speed on mechanical response

Water-in-cocoa butter (CB) emulsions material properties were investigated using uniaxial compression test. Emulsions containing 20% (wt%) water and with a range of droplet size were manufactured to assess the role of defect size on emulsions mechanical properties. Although differences were not significant within the tested droplet size range, results showed a decreasing trend in the values of mechanical parameters at fracture with increasing structural defect size. The mechanical response of bulk CB and emulsions was also investigated at different compressive rates. Materials visco-elastic behaviour was confirmed by their strain-hardening behaviour at increasing test speed with bulk CB always displaying the highest mechanical strength. In the light of these results and microscopy evidences, it was hypothesised that droplets are only partially bonded to the CB network therefore playing a stress-concentration role by promoting fracture initiation. The addition of water droplets also resulted in a reduction of the overall network internal degree of connectivity: when large deformations are applied, droplet-matrix de-bonding occurs at the particle-fat network interface promoting fracture propagation and thus explaining the weakening structural effect of droplets

How much do needlestick injuries cost? a systematic review of the economic evaluations of needlestick and sharps injuries among healthcare personnel

objective. To provide an overview of the economic aspects of needlestick and sharps injury (NSI) management among healthcare personnel (HCP) within a Health Technology Assessment project to evaluate the impact of safety-engineered devices on health care methods. A systematic review of economic analyses related to NSIs was performed in accordance with the PRISMA statement and by searching PubMed and Scopus databases (January 1997–February 2015). Mean costs were stratified by study approach (modeling or data driven) and type of cost (direct or indirect). Costs were evaluated using the CDC operative definition and converted to 2015 International US dollars (Int$). results. A total of 14 studies were retrieved: 8 data-driven studies and 6 modeling studies. Among them, 11 studies provided direct and indirect costs and 3 studies provided only direct costs. The median of the means for aggregate (direct + indirect) costs was Int$747 (range, Int$199–Int$1,691). The medians of the means for disaggregated costs were Int$425 (range, Int$48–Int$1,516) for direct costs (9 studies) and Int$322 (range, Int$152–Int$413) for indirect costs (6 studies). When compared with data-driven studies, modeling studies had higher disaggregated and aggregated costs, but data-driven studies showed greater variability. Indirect costs were consistent between studies, mostly referring to lost productivity, while direct costs varied widely within and between studies according to source infectivity, HCP susceptibility, and post-exposure diagnostic and prophylactic protocols. Costs of treating infections were not included, and intangible costs could equal those associated with NSI medical evaluations. conclusions. NSIs generate significant direct, indirect, potential, and intangible costs, possibly increasing over time. Economic efforts directed at preventing occupational exposures and infections, including provision of safety-engineered devices, may be offset by the savings from a lower incidence of NSIs

Anandamide Uptake by Human Endothelial Cells and Its Regulation by Nitric Oxide

Anandamide (AEA) has vasodilator activity, which can be terminated by cellular re-uptake and degradation. Here we investigated the presence and regulation of the AEA transporter in human umbelical vein endothelial cells (HUVECs). HUVECs take up AEA by facilitated transport (apparent K(m) = 190 +/- 10 nm and V(max) = 45 +/- 3 pmol. min(-1).mg(-1) protein), which is inhibited by alpha-linolenoyl-vanillyl-amide and N-(4-hydroxyphenyl)-arachidonoylamide, and stimulated up to 2.2-fold by nitric oxide (NO) donors. The NO scavenger hydroxocobalamin abolishes the latter effect, which is instead enhanced by superoxide anions but inhibited by superoxide dismutase and N-acetylcysteine, a precursor of glutathione synthesis. Peroxynitrite (ONOO(-)) causes a 4-fold activation of AEA transport into cells. The HUVEC AEA transporter contributes to the termination of a typical type 1 cannabinoid receptor (CB(1)) -mediated action of AEA, i.e. the inhibition of forskolin-stimulated adenylyl cyclase, because NO/ONOO(-) donors and alpha-linolenoyl-vanillyl-amide/N-(4-hydroxyphenyl)-arachidonoylamide were found to attenuate and enhance, respectively, this effect of AEA. Consistently, activation of CB(1) cannabinoid receptors by either AEA or the cannabinoid HU-210 caused a stimulation of HUVEC inducible NO synthase activity and expression up to 2.9- and 2. 6-fold, respectively. Also these effects are regulated by the AEA transporter. HU-210 enhanced AEA uptake by HUVECs in a fashion sensitive to the NO synthase inhibitor Nomega-nitro-l-arginine methyl ester. These findings suggest a NO-mediated regulatory loop between CB(1) cannabinoid receptors and AEA transporter

The effect of monovalent (Na+, K+) and divalent (Ca2+, Mg2+) cations on rapeseed oleosome (oil body) extraction and stability at pH 7

Oleosomes are storage vehicles of TAGs in plant seeds. They are protected with a phospholipid-protein monolayer and extracted with alkaline aqueous media; however, pH adjustment intensifies the extraction process. Therefore the aim of this work was to investigate the extraction mechanism of rapeseed oleosomes at pH 7 and at the presence of monovalent and divalent cations (Na+, K+, Mg2+, and Ca+2). The oleosome yield at pH 9.5 was 64 wt%, while the yield at pH 7 with H2O was just 43 wt%. The presence of cations at pH 7, significantly enhanced the yield, with K+ giving the highest yield (64 wt%). The cations affected the oleosome interface and their interactions. The presence of monovalent cations resulted in aggregation and minor coalescence, while divalent cations resulted in extensive coalescence. These results help to understand the interactions of oleosomes in their native matrix and design simple extraction processes at neutral conditions

Machine learning and domain adaptation to monitor yoghurt fermentation using ultrasonic measurements

In manufacturing environments, real-time monitoring of yoghurt fermentation is required to maintain an optimal production schedule, ensure product quality, and prevent the growth of pathogenic bacteria. Ultrasonic sensors combined with machine learning models offer the potential for non-invasive process monitoring. However, methods are required to ensure the models are robust to changing ultrasonic measurement distributions as a result of changing process conditions. As it is unknown when these changes in distribution will occur, domain adaptation methods are needed that can be applied to newly acquired data in real-time. In this work, yoghurt fermentation processes are monitored using non-invasive ultrasonic sensors. Furthermore, a transmission based method is compared to an industrially-relevant non-transmission method which does not require the sound wave to travel through the fermenting yoghurt. Three machine learning algorithms were investigated including fully-connected neural networks, fully-connected neural networks with long short-term memory layers, and convolutional neural networks with long short-term memory layers. Three real-time domain adaptation strategies were also evaluated, namely; feature alignment, prediction alignment, and feature removal. The most accurate method (mean squared error of 0.008 to predict pH during fermentation) was non-transmission based and used convolutional neural networks with long short-term memory layers, and a combination of all three domain adaption methods

A mathematical model of a single seed oleosome

© 2020 The Authors In this work we report for the first time a mathematical approach to model the behaviour of a single oleosome (oil body) within a seed cellular environment. To describe the behaviour of the oleosome membrane, we adopted a dynamical continuum model based on the principle of the virtual work where the intrinsic energy of the lipid membrane is assumed to obey the Canham–Helfrich model with the rheology of the viscous interface governed by the Boussinesq–Scriven law. To show the suitability of this approach to study the mechanical behaviour of oleosomes, we present some numerical simulations of a single oleosome deformation occurring under in vivo and ex vivo conditions. This work aims to show how the mathematical and computational modelling allows studying the impact of otherwise hard-to-measure physical quantities in this field of biological applications

Assessment of rapeseed oil body (oleosome) lipolytic activity as an effective predictor of emulsion purity and stability

© 2020 Elsevier Ltd The lipolytic activity in oil body creams as affected by recovery and washing protocols was investigated. The effect of thermal treatment on the hydrolytic activity and physical stability of fresh and aged (up to 30 days) oil body emulsions was studied. The use of alkaline pH solutions (9.5) to soak and grind rapeseeds were more effective reducing the contamination of oil body material from seed proteins/enzymes, compared with neutral pHs. Soaking and grinding seeds with a NaHCO3 solution (0.1 M, pH 9.5) yielded oil bodies with a similar composition to those prepared in urea (9 M); however, the physical stability over storage was compromised due to the presence of hydrolytic enzymes. Heating a dispersion of oil bodies for 6 mins at 95 °C did not alter the physical properties of oil bodies and significantly reduced lipolytic activity (>90% enzyme inactivation), resulting in a stable emulsion

Food biotechnology

We investigate recent advances in the Chemical Engineering aspects of food structuring agents and macronutrients: carbohydrates, proteins and lipids, and also the fate of food upon ingestion. Prebiotic effects on host-microbe interactions enable improved immune response and pathogen control. Formulation Engineering is an emerging area in the field of Chemical Engineering and requires detailed knowledge of the materials used, and the processes by which they are transformed / functionalised into products. Understanding 'comb-like' polymers and their interactions provide new structuring opportunities. Sustainable sourcing of alternative protein sources, natural lipid organelles and structuring of liquid oils are framed in a waste valorisation approach, utilising biotechnological approaches for new functionalities. Controlling natural and fabricated microstructures enable controlled digestion profiles. Abstract We investigate recent advances in the major Chemical Engineering aspects of food structuring agents and macronutrients: carbohydrates, proteins and lipids, and also the fate of food upon ingestion. Prebiotic effects on host-microbe interactions enable improved immune response and pathogen control. Formulation Engineering is an emerging area in the field of Chemical Engineering and requires detailed knowledge of the materials used, and the processes by which they are transformed / functionalised into products. Understanding 'comb-like' polymers and their interactions provide new structuring opportunities. Sustainable sourcing of alternative protein sources, natural lipid organelles and structuring of liquid oils are framed in a waste valorisation approach, utilising biotechnological approaches for new functionalities. Controlling natural and fabricated microstructures enable controlled digestion profiles