Although both near infrared (NIR) spectroscopy and mid infrared (MIR) spectroscopy combined with multivariate data analysis (MVA) have been extensively used to measure chemical composition (e.g. ...protein, moisture, oil) in a wide number of grains few reports can be found on the use of this methods for varietal discrimination and traceability of cereals. In this overview applications of NIR spectroscopy and MIR spectroscopy combined with multivariate data methods such as principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), linear discriminant analysis (LDA) to aid on the authentication and traceability of cereals are discussed.
•Near and mid infrared are used to authenticate and trace several cereals.•Few reports were found to determine the geographical origin of grains.•Both NIR and MIR have a great potential to authenticate the origin of grains.
The testing and rapid detection of pathogenic organisms is a crucial protocol in the prevention and identification of crises related to health, safety and wellbeing. Pathogen detection has become one ...of the most challenging aspects in the food and water industries, because of the rapid spread of waterborne and foodborne diseases in the community and at significant costs. With the prospect of inevitable population growth, and an influx of tourism to certain water bodies testing will become a requirement to control and prevent possible outbreaks of potentially fatal illnesses. The legislation is already particularly rigorous in the food industry, where failure to detect pathogenic materials represents a catastrophic event, particularly for the elderly, very young or immune-compromised population types. In spite of the need and requirement for rapid analytical testing, conventional and standard bacterial detection assays may take up to seven days to yield a result. Given the advent of new technologies, biosensors, chemical knowledge and miniaturisation of instrumentation this timescale is not acceptable. This review presents an opportunity to fill a knowledge gap for an extremely important research area; discussing the main techniques, biology, chemistry, miniaturisation, sensing and the emerging state-of-the-art research and developments for detection of pathogens in food, water, blood and faecal samples.
Verification of the authenticity of natural and agricultural foods has become a potential application of spectroscopic methods such as ultraviolet (UV), visible (VIS), near infrared (NIR), and ...mid-infrared (MIR). Adulteration can take many forms, including the addition of sugars, acids, volatile oils, overdilution of concentrate, addition of juices of other fruits, use of concentrate in a fresh product, and use of low-quality product recovered from what are normally waste products of manufacture. Food adulteration has been practiced since ancient times but has become more sophisticated in the recent past. Foods or ingredients most likely to be targets for adulteration include those that are of high value or subject to the vagaries of weather during their growth or harvest. The practice of adulteration commonly arises for two main reasons: firstly, it can be profitable, and secondly, adulterants can be easily mixed and are subsequently difficult to detect. To counter this problem, manufacturers subject their raw material and by-products to a series of quality controls, including high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC), enzymatic tests, and physical tests. This mini-review highlights recent applications on the use of NIR and MIR spectroscopy to trace and authenticate natural and agricultural products.
One of the main challenges that face the modern wine sciences is how to optimise grape and wine production in order to have a minimum environmental footprint, lower production costs, as well as how ...to improve or maintain the quality of the wine produced. It has been generally accepted that a single analytical technique will not provide sufficient information about the wine metabolome and therefore a holistic-omics approach is suggested for a more comprehensive analysis. Metabolomics is an emerging field in grape and wine research enabling chemical and biochemical profiling of samples (e.g. grapes, wine) in order to obtain insight into its biological characteristics and properties. By means of a literature review of the most recent published reports on the use of the metabolomics approach, the aim of this paper is to provide with an overview on the use of this approach in grape and wine research. Most of the studies presented in this review have highlighted the importance of metabolomics in wine science, as well as emphasised on the need of a multidisciplinary team approach where the participation of scientists from different disciplines such as biology, biochemistry, chemistry and chemometrics (mathematics and statistics) being equally important to deliver successful and reliable data, in order to improve our knowledge about wine. The combination of different techniques provides both the research and industry with powerful and complementary tools that differ from the conventional routine methods currently in use by the grape and wine industry.
•Elimination of distortion through the application of rolling after deposition.•Reduced residual stresses – particularly adjacent to the baseplate.•Grain refinement when the rolled material was ...reheated by the subsequent deposition pass.•A simple analytical model for predicting the residual stress and distortion in AM parts.
Parts manufactured by Wire and Arc Additive Manufacture (WAAM) can have significant residual stress and distortion, as well as large grain sizes. To overcome these problems, each layer on a linearly deposited steel WAAM part was rolled with either a ‘profiled’ roller, which had a similar shape to the deposited layer, or a ‘slotted’ roller, in which a groove prevented lateral deformation. Both rollers reduced the distortion and surface roughness, but the slotted roller proved more effective – eliminating the distortion. The residual stresses in the rolled WAAM parts were measured and were lower than those in the unrolled control specimen – particularly adjacent to the baseplate. Rolling also induced additional grain refinement when the rolled material was reheated during the subsequent deposition pass. The application of rolling may be a key technology for enabling implementation of WAAM on large-scale structures.
Principal component analysis (PCA) is one of the most widely used data mining techniques in sciences and applied to a wide type of datasets (e.g. sensory, instrumental methods, chemical data). ...However, several questions and doubts on how to interpret and report the results are still asked every day from students and researchers. This brief communication is inspired in relation to those questions asked by colleagues and students. Please note that this article is a focus on the practical aspects, use and interpretation of the PCA to analyse multiple or varied data sets. In summary, the application of the PCA provides with two main elements, namely the scores and loadings. The scores provide with a location of the sample where the loadings indicate which variables are the most important to explain the trends in the grouping of samples.
During the last 30 years, food scientists and technologists all over the world are dealing with massive amounts of data derived from the use of different measuring devices (e.g. instrumental and ...sensory data), the integration of different analytical techniques and processes during the analysis and production of foods. Therefore, complementary disciplines and tools to the traditional ones used in food science such as statistics, experimental design and chemometrics have become essential in modern sciences and are an integral component in the day-to-day analysis of foods and derived products. The aim of this paper is to introduce as well as provide with an overview of different concepts, methods, techniques and general steps used in the quantitative analysis of foods when chemometrics or multivariate analytical methods are applied.
Soil is critical to the world, supplying virtually all of the food and fiber that sustain the human population and providing the space for the ecosystems that support life. The characterization of ...soil properties through laboratory analysis is an essential part of the diagnosis of the potential use of lands and their fertility. However, conventional soil chemical analyses are expensive and time consuming, hampering the adoption of soil management practices. In recent years, farmers are also increasingly demanding rapid, cost-effective, and nondestructive methods for monitoring changes as well as measuring the physical-chemical properties in soils. This article reviews applications of near infrared (NIR) spectroscopy to assess, monitor, and classify soils in South America.
The mechanisms of post-weld rolling and how it reduces and eliminates residual stress and distortion are poorly understood. Finite element analysis was applied to two different methods of rolling: ...rolling the weld bead directly with a single roller and rolling beside the weld bead with a dual flat roller. The models showed that both rolling techniques were able to induce compressive stress into the weld region, which increased with rolling load. The distribution of stress was sensitive to the coefficients of friction between the workpiece and the roller and the backing bar. High friction coefficients concentrated the plastic deformation and compressive stress within the centre of the weld bead. Distortion can be eliminated by rolling; however, the experiments indicated that this was only achieved when applied to the weld bead directly.
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