Canada is a major global producer of pulse products including pulse starch, which notably contributes to a healthy diet. Strategically, Canada is taking steps to research methods of adding greater value to these crop products, and functional foods like resistant starch are particularly interesting. The primary objectives of this study were to develop an effective reactive extrusion process to produce gelatinized lipid complexed pea starches with enhanced enzyme resistance and examine the effects of bulk lipid complexing conditions on physicochemical and functional properties of extruded pea starches. One type of commercially available pea starch, Nutri-Pea, was chosen as the research subject in this study. A number of methods including; Englyst digestion method, differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), contact angle, titrations, residence time distribution (RTD) and rapid visco analysis (RVA) were used to characterize the properties of extruded pea starches. The effects of feed formulation and extrusion conditions on lipid complexing and Englyst digestion profiles were systematically examined on two mixing devices. An extensive kinetics study was conducted on a lab scale twin-screw compounder, DSM-Xplore. The process was then scaled up to produce bulk lipid complexed pea starch on a Leistritz twin-screw extruder. The results showed that lipid complexing and digestion profiles were highly dependent on feed moisture and induced screw shear. Reactive extrusion of pea starches under optimized conditions achieved a significant but moderate increase in either resistant starch (RS) content (from 13.3% to 20.2%) or slowly digestible starch (SDS) content (from 7.85% to 23.3%) compared to their native counterparts. However, RS and SDS content could not be improved simultaneously based on the pea starch and extrusion process in this study. Increased degree of substitution (DS) was found for myristic acid complexed pea starches (nominal DS= ~0.8) when compared to palmitic acid complexed pea starch (nominal DS= ~0.5). Contact angle measurements, FTIR and DSC thermograms confirmed the presence of lipids. Lipid complexed starch films showed increasing hydrophobicity with increasing lipid content. As an alternative product compared to functional foods, the modified starch was considered as a biodegradable film for industrial applications. The material was produced at the highest moisture content for extruded native starch and two concentrations of lipid complexed starch using an intensive screw design. Preliminary results show that increasing lipid content and adding 1% glycerol to samples decreases the force per film thickness required to puncture films. However further investigation is required to determine effect of heat and moisture deformation. / Thesis / Master of Applied Science (MASc) / Incorporation of pulses into food products has been a major area of Canadian research for its potential to create new avenues of enzyme resistant food starches. Extrusion cooking is commonly used in industry for producing various food products such as snacks and cereals but little research has been reported on using an extruder to rapidly produce resistant pulse starches as a functional ingredient on a large scale; resistant starch is a functional food beneficial to humans in the same manner as insoluble fiber but exhibits improved textural properties. This study aimed to develop an effective reactive extrusion process to produce lipid complexed pea starches with enhanced enzyme resistance (i.e. increased slowly digestible starch (SDS) and resistant starch (RS) content) by an examination of the effects of reaction conditions on the properties of extrusion products. The lipid complexed pea starches under optimized conditions achieved a significant but moderate increase in either RS content or SDS content depending on the sample formulation compared to their native counterparts. However, RS and SDS content could not simultaneously be improved in this study.

No / Polymer extrusion is an energy intensive process, which is often run at less than optimal conditions. The extrusion process consists of gradual melting of solid polymer by thermal conduction and viscous shearing between a rotating screw and a barrel; as such it is highly dependent upon the frictional, thermal and rheological properties of the polymer. Extruder screw geometry and extrusion variables should ideally be tailored to suit the properties of individual polymers, but in practice this is rarely achieved due to the lack of understanding of the process. Here, in-process monitoring techniques have been used to characterise the thermal dynamics of the extrusion process. Novel thermocouple grid sensors have been used to measure melt temperature fields within flowing polymer melts at the entrance to an extruder die in conjunction with infra-red thermometers and real-time quantification of energy consumption. A commercial grade of polyethylene has been examined using three extruder screw geometries at different extrusion operating conditions to understand the process efficiency. Extruder screw geometry, screw rotation speed and set temperature were found to have a significant effect on the thermal homogeneity of the melt and process energy consumed. (C) 2012 Elsevier Ltd. All rights reserved.

No / The development and validation of a sensor for extrusion melt temperature field measurement is described. A grid of opposing thermocouple wires was constructed and held in position by a supporting frame. Wires were joined together at crossing points to form thermocouple junctions, which were computer monitored. The mesh was used to monitor melt temperature fields during single screw extrusion at the die entrance. Design and construction of the mesh is described in addition to experimental optimization of wire diameter and junction forming. Calibration of the sensor and potential measurement errors including shear heating effects are discussed. Initial results from single screw extrusion are presented for a commercial grade of low density polyethylene using five- and seven-junction thermocouple meshes. The dependence of melt temperature profile on screw speed is illustrated. At low screw speeds melt temperature profiles were flat in shape and higher than set wall temperatures. At higher screw speeds the profiles became more pointed in shape. Use of higher resolution sensors exposed more complex temperature profiles with shoulder regions.

<p dir="ltr">Extrusion is a complex process that is difficult to model due to the complex geometry. In addition, modeling the flow of a shear and thermal sensitive material such as waxy corn starch further complicates the problem. Starch undergoes three main transformations during processing: 1. Gelatinization, 2. Melting, and 3. Fragmentation. The first two can be combined into starch conversion and have been studied in detail, along with their effect on viscosity.</p><p dir="ltr">This work extruded waxy corn starch using the “NASA” autogenous single screw extruder with and without steam locks at moisture contents of 30% w.b. and 35% w.b. as well as screw speeds of 300 rpm and 600 rpm. A Brabender single screw was used at 100 rpm, 35% w.b., and 140°C to obtain starch at another molecular weight. Molecular weight was measured using HPSEC-MALLS-RI, and viscosity was measured using a capillary rheometer. Starch conversion was checked by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC).</p><p dir="ltr">The work extended upon previous rheological models by separating the lumped SME (specific mechanical energy) parameter into degree of starch conversion and molecular weight reduction. The new viscosity model can be combined with kinetics to predict rheology in computational fluid dynamics models that model the extrusion process. The approach can aid in designing the extrusion process and other unit operations by predicting extrusion characteristics without having to build the new design using a trial-and-error approach.</p><p dir="ltr">Additionally, a method was investigated to decouple SME into an average shear rate and mean residence time by setting SME equal to SEC (specific energy consumption). Shear history was found from the decoupled average shear rate and mean residence time. Shear history was a worse predictor for molecular weight reduction than SME alone because it was derived from SME with approximated average values from the extrusion trials.</p><p dir="ltr">Finally, the effect of steam locks in the “NASA” extruder was investigated and found to marginally reduce molecular weight, reduce the mass flow rate and increase the mean residence time for every condition except at a screw speed of 600 rpm and moisture content of 30% w.b. The work as a whole demonstrates the importance of understanding how materials change during processing.</p>

No description available.

There is interest in increasing the content of omega-3 (n-3; e.g., linolenic acid [C18:3n3]) fatty acids and conjugated linoleic acid (CLA) in bovine milk, primarily because of their beneficial effects on human health. One strategy to alter bovine milk fatty acid composition is the dietary inclusion of flaxseed, which is a rich source of C18:3 n-3. The aim of this study was to evaluate the effects of extrusion processing of flaxseed and the inclusion of condensed tannins (CT) in a flaxseed supplement on omasal flow of nutrients, ruminal fermentation characteristics, animal performance, and milk fatty acid profiles in dairy cattle. Eight multiparous Holstein cows (712.7 ± 92.3 kg body weight; 116.5 ± 17.5 days-in-milk at the beginning of the study) were assigned to four dietary treatments in a replicated 4 x 4 Latin square design consisting of 28-d periods with 20 d of dietary adaptation. Four cows in one Latin square were ruminally-cannulated to allow ruminal and omasal sampling. Cows were fed either a control diet (CTL) or one of 3 treatment diets that consisted of the daily substitution of 3 kg (DM basis) of the CTL concentrate pellet with 3 kg (DM basis) of either a non-extruded flaxseed and pea product (55% flax¬seed, 36% peas, 8% alfalfa, 1% antioxidant; designated RAW), a extruded flaxseed and pea product (55% flaxseed, 36% peas, 8% alfalfa, 1% anti¬oxidant; designated LPR), or a extruded flaxseed and high-tannin fava bean product (55% flaxseed, 36% high-tannin faba beans, 8% alfalfa, 1% antioxidant; designated LPF). Diets were fed twice daily as total mixed rations. Omasal flow of nutrients was estimated using the omasal sampling technique using iNDF as the single indigestible marker. Dry matter intake was lower (P = 0.01) in cows fed the flaxseed diets (24.0 kg/d) compared to those fed CTL (25.9 kg/d). Milk yield was higher (P = 0.02) in cows fed the LPR diet ( 44.4 kg/d) compared to those fed the RAW diet ( 42.3 kg/d); and tended to be higher (P = 0.07) in cows fed the flaxseed diets compared to those fed the CTL diet. Milk fat yield was unaffected by dietary treatment (P = 0.94), whereas milk protein yield tended (P = 0.10) to increase in cows fed the flaxseed diets compared to those fed the CTL diet. No detrimental effects of dietary treatments on ruminal fermentation and omasal flow of microbial protein were observed. The omasal flow of C18:3 n-3 was higher in cows fed the flaxseed diets compared to those fed the CTL diet (P = 0.04), with the RAW diet (56.9 g/d) having the highest flow of C18: 3n-3 compared to the other diets (LPR = 14.0 g/d; LPF = 14.8 g/d). The omasal flow of total CLA isomers were higher (P = 0.03) in cows fed the LPF diet (6.06 g/d) compared to those fed the LPR diet (3.70 g/d). The C18:3 n-3 content in milk fat (% of fatty acid methyl esters) was higher in cows fed the LPR diet (0.950%) compared to those fed the RAW diet (0.745%). The level of total CLA isomers in milk was also higher in cows fed the LPR diet (0.845%) compared to those fed the RAW diet (0.308%). These results demonstrated that feeding extruded flaxseed products is more effective than feeding whole flaxseed at improving the fatty acid composition of milk fat without negatively impacting animal performance and ruminal fermentation; however, the inclusion of CT in the extruded flaxseed product had no additional benefit.

Doctor of Philosophy / Department of Grain Science and Industry / Sajid Alavi / Sorghum grain (Sorghum bicolor) is safe for consumption by individuals afflicted with celiac disease, and its proteins can be used as a supplement in gluten-free foods. However, utilization of sorghum in human foods is limited by the poor digestibility and lack of functionality of its proteins, which result from their entrapment in protein bodies, tight association with starch, and high degree of cross-linking induced by cooking. The first part of this study presents an extensive review of current methods for concentration and isolation of sorghum proteins, which are laboratory-scale techniques used for protein characterization and have no potential for commercial scale-up. Furthermore, these methods typically use non-food grade reagents and do not improve protein digestibility and functionality. In the second part, a novel extrusion-enzyme liquefaction (EEL) process was used to produce sorghum protein concentrates to overcome the aforementioned limitations. EEL involves extrusion pre-treatment of sorghum flour and starch liquefaction with a thermostable α-amylase, followed by enzyme inactivation, protein separation and drying. To demonstrate the concept, a laboratory-scale EEL process was used to produce concentrates with higher protein content (PC; 80% db) and digestibility (D; 74%) than those made by batch liquefaction. The optimum conditions for producing concentrates with both high PC and D were 32% wb in-barrel moisture content and 2.5% α-amylase added after extrusion. Using these conditions, EEL was scaled-up to a pilot-scale process to produce sorghum protein concentrates with 72-80% db PC and 62-74% D, while the batch liquefied control had only 70% db PC and 57% D. Dynamic oscillatory measurements of dough (55% moisture) and batter (65% moisture) containing sorghum protein concentrates (5 and 10%) and potato starch were performed to evaluate protein functionality. At lower moisture, pure potato starch and dough containing 10% sorghum protein concentrate had similar elastic and viscous moduli. At higher moisture, potato starch was more stable and exhibited significantly higher moduli than the batters with protein concentrates. Sorghum protein concentrates can improve the quality of some gluten-free foods. EEL shows promise for commercial production of sorghum protein concentrates because of its high throughput and potential for delivering high protein content and digestibility.

published_or_final_version / Electrical Engineering / Master / Master of Philosophy

With the advance of combinational chemistry and high throughput screening, an increasing number of pharmacologically active compounds have been discovered and developed. A significant proportion of those drug candidates are poorly water-soluble, thereby exhibiting limited absorption profiles after oral administration. Therefore, advanced formulation and processing technologies are demanded in order to overcome the biopharmaceutical limits of poorly water-soluble drugs. A number of pharmaceutical technologies have been investigated to address the solubility issue, such as particle size reduction, salt formation, lipid-based formulation, and solubilization. Within the scope of this dissertation, two of the pharmaceutical technologies were investigated names thin film freezing and hot-melt extrusion. The overall goal of the research was to improve the oral bioavailability of poorly water-soluble drugs by producing amorphous solid dispersion systems with enhanced wetting, dissolution, and supersaturation properties. In Chapter 1, the pharmaceutical applications of hot-melt extrusion technology was reviewed. The formulation and process development of hot-melt extrusion was discussed. In Chapter 2, we investigated the use of thin film freezing technology combined with template emulsion system to improve the dissolution and wetting properties of itraconazole (ITZ). The effects of formulation variables (i.e., the selection of polymeric excipients and surfactants) and process variables (i.e., template emulsion system versus cosolvent system) were studied. The physic-chemical properties and dissolution properties of thin film freezing compositions were characterized extensively. In Chapter 3 and Chapter 4, we investigated hot-melt extrusion technology for producing amorphous solid dispersion systems and improving the dissolution and absorption of ITZ. Formulation variables (i.e., the selection of hydrophilic additives, the selection of polymeric carriers) and process variables (i.e., the screw configuration of hot-melt extrusion systems) were investigated in order to optimize the performance of ITZ amorphous solid dispersions. The effects of formulation and process variables on the properties of hot-melt extrusion compositions were investigated. In vivo studies revealed that the oral administration of advanced ITZ amorphous solid dispersion formulations rendered enhanced oral bioavailability of the drug in the rat model. Results indicated that novel formulation and processing technologies are viable approaches for enhancing the oral absorption of poorly water-soluble drugs. / text

La compréhension et la modélisation des phénomènes physiques qui sont mis en jeu au cours du procédé d'extrusion monovis de mélange d'élastomère constituent l'objectif du travail de recherche. Après formulation d'un mélange clair, celui-ci a fait l'objet de plusieurs campagnes d'essais rhéologiques. Le même mélange a été rendu plus glissant par l'ajout de stéarate de zinc. Nous avons pu montrer que la rhéologie de volume restait proche de celle du mélange précédent et proposer différentes lois de glissement, dépendantes de la géométrie, par l'intermédiaire des dépouillements classiques de la littérature. Une étude expérimentale systématique a été entreprise, tout d'abord, sur une extrudeuse industrielle (5 vis différentes représentatives des vis utilisées en production), puis sur une extrudeuse de laboratoire (profils simples et modulaires). Des informations ont été obtenues par le relevé de paramètres tels que la pression, la température, le débit, le taux de remplissage (démontage)... Ainsi, à partir des résultats expérimentaux et de leurs interprétations, nous avons pu comparer les performances des différentes géométries et mélanges, et extrapoler les résultats d'une machine à l'autre. L'approche de modélisation 1D a mis en évidence la grande importance des effets de bord, liée au caractère très pseudoplastique du produit utilisé. En conséquence, le modèle 1D est inutilisable. On s'est alors dirigé vers un calcul en deux dimensions par éléments finis. Il intègre différents couplages qui ont été réalisés et validés au fur et à mesure. La comparaison à l'expérience montre un certain nombre de désaccords. La comparaison entre un vrai calcul 3D et le calcul à deux dimensions couplé montre un écart grandissant lorsque le coefficient de pseudoplasticité diminue. Comme pour l'approche 1D, le couplage longitudinal/transversal est pris en défaut pour des caoutchoucs à cause d'un indice de pseudoplasticité très faible. L'avenir semble donc passer par un vrai calcul tridimensionnel. Nous en avons montré la faisabilité en simulant l'écoulement dans de petits tronçons de vis. L'accord avec l'expérience est satisfaisant.