Formulation of infant formula with different casein fractions and their effects on physical property and digestion character

This study investigated whether casein (CN) fractions exhibit better physical propertiess and digestibility than native casein micelle presently used in the production of infant formula. Structural performance of native casein...

Detection of Inorganic and Metal Nanoparticles using qNano – IZON Science’s Nanoparticle Analysis System

<p>This thesis investigates the potential and capability of the qNano instrument, a nanoparticle analysis research instrument developed by IZON Science Ltd. The qNano operates on the basis of the Scanning Ion Occlusion Spectroscopy (SIOS) technology which is similar to the Coulter technique also known as resistive pulse sensing. This coupled with an adjustable nanopore and IZON’s recently developed Variable Pressure Module (VPM) makes qNano a versatile nanoparticle analysis apparatus. In this study the potential of the instrument to detect inorganic and metal nanoparticles is explored. Polystyrene, silica, gold, silver, and magnetic nanoparticles have been used in this research to better understand the system and its components and to discover the capacity of the instrument to detect these particles. Using polystyrene nanoparticles, it was found that the adjustable nanopore exhibit membrane softening and follows the Mullins effect. Each of the apertures also possesses a characteristic window of operation, which refers to a range of stretch setting for accurate particle detection. The adjustable nanopore also allows for sizing particles with different diameters. The effect of surface functionality in the signal output was also investigated. Gold nanoparticles were synthesized via the citrate reduction method and the study of gold nanoparticles suspended in IZON’s standard buffer solution was looked into in depth. It was found that the gold nanoparticles aggregate in the buffer solution due to the presence of potassium chloride (KCl) salt which screens the electrostatic stabilization provided by the citrate ions. Silver nanoparticles show similar aggregation. With the concentration of gold and KCl remaining constant, resistive pulses caused by gold aggregates were detected after a period of three hours. Varying the concentration of gold nanoparticles shows that larger aggregates are formed as opposed to small aggregates with higher population. Identification of different types of particles present in a solution is yet to be achieved at this stage. Silica and magnetic nanoparticles were studied briefly. Successful measurements of magnetic particles were achieved with the aid of the pressure module. However, aggregates of magnetic particles were also formed and can be seen with the naked eye after solution was left standing overnight. Casein stabilized silica particles shows erratic current readings as the ethanol used in fabricating the silica particles collapse the casein micelle structure thus making the stabilization by casein void. Overall, this thesis has shown the qNano instrument’s ability in detecting nanoparticles other than biological molecules. This thesis also shows the potential of qNano as a versatile research instrument. The prospect of further research using this instrument is tremendous especially in characterising in greater detail inorganic and metal nanoparticles.</p>

Detection of Inorganic and Metal Nanoparticles using qNano – IZON Science’s Nanoparticle Analysis System

<p>This thesis investigates the potential and capability of the qNano instrument, a nanoparticle analysis research instrument developed by IZON Science Ltd. The qNano operates on the basis of the Scanning Ion Occlusion Spectroscopy (SIOS) technology which is similar to the Coulter technique also known as resistive pulse sensing. This coupled with an adjustable nanopore and IZON’s recently developed Variable Pressure Module (VPM) makes qNano a versatile nanoparticle analysis apparatus. In this study the potential of the instrument to detect inorganic and metal nanoparticles is explored. Polystyrene, silica, gold, silver, and magnetic nanoparticles have been used in this research to better understand the system and its components and to discover the capacity of the instrument to detect these particles. Using polystyrene nanoparticles, it was found that the adjustable nanopore exhibit membrane softening and follows the Mullins effect. Each of the apertures also possesses a characteristic window of operation, which refers to a range of stretch setting for accurate particle detection. The adjustable nanopore also allows for sizing particles with different diameters. The effect of surface functionality in the signal output was also investigated. Gold nanoparticles were synthesized via the citrate reduction method and the study of gold nanoparticles suspended in IZON’s standard buffer solution was looked into in depth. It was found that the gold nanoparticles aggregate in the buffer solution due to the presence of potassium chloride (KCl) salt which screens the electrostatic stabilization provided by the citrate ions. Silver nanoparticles show similar aggregation. With the concentration of gold and KCl remaining constant, resistive pulses caused by gold aggregates were detected after a period of three hours. Varying the concentration of gold nanoparticles shows that larger aggregates are formed as opposed to small aggregates with higher population. Identification of different types of particles present in a solution is yet to be achieved at this stage. Silica and magnetic nanoparticles were studied briefly. Successful measurements of magnetic particles were achieved with the aid of the pressure module. However, aggregates of magnetic particles were also formed and can be seen with the naked eye after solution was left standing overnight. Casein stabilized silica particles shows erratic current readings as the ethanol used in fabricating the silica particles collapse the casein micelle structure thus making the stabilization by casein void. Overall, this thesis has shown the qNano instrument’s ability in detecting nanoparticles other than biological molecules. This thesis also shows the potential of qNano as a versatile research instrument. The prospect of further research using this instrument is tremendous especially in characterising in greater detail inorganic and metal nanoparticles.</p>

Vitamin D Fortification of Consumption Cow’s Milk: Health, Nutritional and Technological Aspects. A Multidisciplinary Lecture of the Recent Scientific Evidence

Vitamin D is essential in assuring bone health at all stages of life, but its non-skeletal effects are also essential: This vitamin impacts the physiology of the immune system, skeletal muscles and adipose tissue, glucose metabolism, skin, cardiovascular and reproductive systems, neuro-cognitive functions and cell division. The incidence of vitamin D deficiency is widespread worldwide, at any age, in young and healthy subjects, as well as in pregnant women and the elderly population, due to several factors, including inadequate sunlight exposure, skin pigmentation and coverage, adiposity, lifestyle and low dietary intakes. To overcome this problem, the fortification of foods that are consumed on a daily basis, such as milk, is strongly advisable. This opinion paper aims to discuss, in a multidisciplinary way, the current evidence supporting the importance of vitamin D in health and disease and the role of milk as an optimal carrier of this vitamin, to promote adequate intakes, highlighting its unique physico-chemical characteristics linked to both fat globule membrane and casein micelle structure. Moreover, it addresses the impact of industrial processing and storage of consumption milk on the stability of these structures, thus in determining vitamin D bioavailability and the achievement of adequate intakes.

Variation in Dairy Milk Composition and Properties Has Little Impact on Cheese Ripening: Insights from a Traditional Swedish Long-Ripening Cheese

The monthly variation in raw dairy silo milk was investigated and related to the ripening time of the resulting cheese during an industrial cheese-making trial. Milk composition varied with month, fat and protein content being lowest in August (4.19 and 3.44 g/100 g, respectively). Casein micelle size was largest (192–200 nm) in December–February and smallest (80 nm) in August. In addition, SCC, total bacteria count, proteolytic activities, gel strength, and milk fatty acid composition were significantly varied with month. Overall sensory and texture scores of resulting cheese were mainly influenced by plasmin and plasminogen activity, indicating the importance of native proteolytic systems. Recently, concepts based on the differentiated use of milk in dairy products have been suggested. For the investigated cheese type, there might be little to gain from such an approach. The variation in the investigated quality characteristics of the dairy milk used for cheese making had little effect on cheese ripening in our study. In contrast to our hypothesis, we conclude that as long as the quality of the milk meets certain minimum criteria, there are only weak associations between cheese milk characteristics and the time required for the development of aroma and texture in the cheese. To find answers behind the observed variation in cheese ripening time, studies on the effects of process parameters are needed.

Structure and Vitamin D₃-Binding Affinity of Milk Proteins

Two projects formed the basis of this thesis related to protein-vitamin D₃ (VD₃) binding mechanisms and efficacy. First, a method to characterize the binding of VD₃ to food-related macromolecules that may be used for enrichment of milk was devised. Results suggested that sodium caseinate and hydroxylpropyl-β-cyclodextrin could effectively bind VD₃ and may be used as carriers. Secondly, molecular dynamics simulations were used to determine the conformation ensemble of the β-casein phosphopeptide (β-CPP). Radius of gyration, H-bonding, Ramachandran plot, and secondary structure were ascertained, and showed good agreement with simulations of other disordered pepitides as well as experimental data of β-CPP. Overall, this new binding assay now affords the ability to study interactions between macromolecules and vitamin D₃. As well, by performing simulations of a single casein peptide, important data needed to understand the intramolecular interactions and structure of β-casein (as well as the casein micelle) have be elucidated.