Equipment
Food Ingredients Research Group Equipment
| LUMiSizer Accelerated Physical Stability Analyser |
| This instrument is an analytical centrifuge used for investigating the physical stability of solutions, dispersions, gels and foams under accelerated conditions. It is possible to analyse 12 samples simultaneously under accelerated conditions in the range 0-4000 rpm and 15-45oC. Typical applications include accelerated creaming and protein sedimentation testing of emulsions and protein beverages, respectively and also to facilitate a better understanding of the rehydration properties of high protein food powders. |
| High-Performance Liquid Chromatography (HPLC) |
| This Varian HPLC system consists of a tertiary solvent pump, auto-sampler, column oven and UV detector. The system is normally configured with reversed-phase chromatography columns used for separation, identification and quantification of proteins and peptides. |
| Membrane Filtration (polymeric) |
| This lab-scale membrane filtration plant is built around a Millipore Pellicon 2 filtration system that consists of a stainless steel holder which can accommodate up to 3 filter elements, each with 0.1 m2 surface area. The unit is used for ultrafiltration and microfiltration of a range of milk-, whey- and fruit-based feed materials for ingredient development projects. The unit facilitates complete monitoring and control of flow rates, pressure and temperature, which allows studies requiring process analytics (e.g., fouling analysis) to be conducted. |
| Auto-Titrator |
| This auto-titration unit from Metrohm consists of a computer-controlled, dual burette system with integrated magnetic and overhead stirrers for acid-base buffering studies of food matrices using standard pH electrodes. The system also has a conductivity probe and a calcium ion-selective electrode attached, in addition to a Karl Fischer apparatus for total moisture determination. The unit is also designed to operate in pH-stat mode for the preparation of protein hydrolysates. |
| Powder Flow Tester |
| This recently-developed instrument from Brookfield is based on shear cell technology, which is a standard approach for characterising the flow behavior of bulk solids. The flow tester is of particular relevance to researchers investigating powders for food and pharmaceutical applications. Example analyses include, but are not limited to, flowability, bulk density, compressibility and wall friction. The ProFlow software package facilitates the rapid estimation of hopper/silo dimensions which are optimal for a given powder based on data generated during flow testing. A low-volume cell can be used where sample quantitites are limited, such as studies involving materials which are finite or materials which are to be exposed to adverse environmental conditions (e.g., high temperature and/or relative humidity) prior to analysis. Example experiments include measuring the effect of the following factors on flow properties of a powder: particle size distribution, particle morphology, agglomeration-state, addition of flow improvers, moisture and fat content. |
| Viscometer |
| The HAAKE RotoVisco viscometer from Thermo Scientific is a controlled rate rotational viscometer which provides viscosity measurements with defined shear rates, flow curves with speed ramps in the range 0.15 to 1000 min⁻¹, and features fully automatic temperature programs in the range 0 to 100oC. This instrument consists of a series of measuring geometry cups and rotors and is typically used for measuring viscosity of samples of oils, creams, milk, whey and fruit based beverages. A method was also developed on this instrument some years ago for monitoring the hydration of rennet casein powders. |
| Mastersizer 3000 |
| This instrument from Malvern is a laser diffraction particle size analyser used for measurement of particle size distributions of both wet and dry dispersions. It does this by measuring the intensity of light scattered as a laser beam passes through a dispersed particulate sample. The system is composed of wet and dry dispersion units, an optical bench, and software that analyses the scattering data to calculate the particle size distribution of the dispersion. Typical applications include measurement of fat globule size distribution of food emulsions and particle size distribution of food powders. |
| KRÜSS Processor Tensiometer K12 |
| The K12 Tensiometer measures surface and interfacial tension (γ) of liquids based on the force acting on a probe located at the surface/interface. Two types of probes – a Wilhelmy plate or Du Noüy ring can be used to measure dynamics of surfactant adsorption at the surface/interface and their effectiveness in decreasing of the γ. A jacketed sample holder connected to a water bath allows measurements to be performed at controlled temperature. The tensiometer is a useful tool in assessment of emulsifier functionality for formulation development; it can be also used to study sedimentation of solutes, wettability of powders or critical micelle concentration of surfactants. |
| Zetasizer Nano-ZS-HT |
| The Zetasizer Nano-ZS uses dynamic light scattering to quickly characterize samples from less than a nanometer in particle size to several microns (0.3 nm -10 µm). It is particularly suitable for the characterization of proteins, protein aggregates and nanoparticles using non-invasive backscatter optics. The system can also measure zeta potential (surface charge) using electrophoretic light scattering. Zeta potential is a measure of the magnitude of the electrostatic or charge repulsion/attraction between particles, and is critical to stability of solutions. Its measurement brings detailed insight into the causes of dispersion, aggregation or flocculation, and can be applied to improve the formulation of dispersions, emulsions and suspensions. The system can be thermostatically controlled from 0-90oC and requires low sample volumes for measurement. The system is also equipped with a high temperature (HT) cell which allows measurements to be taken at up to 120oC and has an in-line auto-titrator which facilitates the study of pH and ionic conditions on size and charge of proteins. |
| Mini-Electrophoresis System |
| Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) separates proteins primarily by mass and several forms exist including native, non-reducing and reducing PAGE which can provide different types of information about the protein(s). Once separated by electrophoresis, proteins can be detected in a gel with various stains and/or excised and extracted for analysis by mass spectrometry. Mini-electrophoresis systems and their precast gels are more convenient, consistent, safer and faster to run compared to traditional poured gels. Mini gels require less time and reagents than their larger counterparts and are suited for rapid screening of samples. This system is commonly used to determine protein profile of a sample and to monitor protein denaturation/aggregation in response to different compositional (e.g., enzymatic activity) or processing conditions (e.g., thermal processing). |
| Rheometer |
| This AR-G2 rheometer is used to study the flow and deformation of a sample. The measuring system consists of a stator (peltier plate or peltier concentric cylinder) and a geometry (cone, plate, parallel plate or concentric cylinders). Rheological tests on simple and complex fluids like milk, yogurt, emulsions and semi-solid products like cheese and protein gels can be performed. Flow experiments can be performed to determine the viscosity data of fluid materials and to simulate a process shear rate. Oscillatory experiments can be used to have information on structure, time dependency, and temperature stability/dependency. Moreover, creep experiments can be run to have information on structure, long time processes, storage stability, and phase separation. The unit is also equipped with a starch pasting cell which is often used to generate real-time viscosity data during simulated high temperature-short time thermal processing of protein solutions. |