
Russell FrewUniversity of Otago and Oritain · Chemistry
Russell Frew
Doctor of Philosophy
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188
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Introduction
Skills and Expertise
Publications
Publications (188)
Over the past decade, there has been overwhelming interest in rapid and routine origin tracing and authentication methods, such as near infrared (NIR) spectroscopy. In a systematic and comprehensive approach, this study coupled NIR with advanced machine learning models to explore the origin classification of coffee at various scales (continental to...
Vibrational spectroscopy is a green, rapid, and affordable analytical tool for analysing the quality, safety, and origin of biological materials in agri-food sectors. Pre-processing spectral data is crucial to removing instrumental interferences and physical artifacts when developing a classification model. However, there has yet to be a consensus...
This study aimed to establish a rapid and practical method for monitoring and predicting volatile compounds during coffee roasting using near-infrared (NIR) spectroscopy coupled with chemometrics. Washed Arabica coffee beans from Ethiopia and Congo were roasted to industry-validated light, medium, and dark degrees. Concurrent analysis of the sample...
Stable isotope ratios and trace elements are well-established tools that act as signatures of the product's environmental conditions and agricultural processes; but they involve time, money, and environmentally destructive chemicals. In this study, we tested for the first time the potential of near-infrared reflectance spectroscopy (NIR) to estimat...
BACKGROUND
This study investigated the geographical origin classification of green coffee beans from continental to country and regional levels. An innovative approach combined stable isotope and trace element analyses with non‐linear machine learning data analysis to improve coffee origin classification and marker selection. Specialty green coffee...
Soybean has developed a reputation as a superfood due to its nutrient profile, health benefits, and versatility. Since 1960, its demand has increased dramatically, going from a mere 17 MMT to almost 358 MMT in the production year 2021/22. These extremely high production rates have led to lower-than-expected product quality, adulteration, illegal tr...
This research aimed to authenticate the geographical origin of imported fresh apples using isotopic techniques. The results show that the correlation between δ2H and δ18O of water from the US and Australian apples imported to Vietnam followed the respective linear evaporation line models. The apple water isotopic compositions of the two countries w...
Marine primary production is sensitive to multiple environmental stressors from land-based and maritime anthropogenic activities. Stressors may alter the distribution, abundance and composition of primary producers and thereby directly influence the fluxes of organic matter into marine food webs. To investigate these effects, we measured the relati...
We appreciate Dr Horacek’s interest in our paper and his feedback [...]
Information on the geographic origin of milk is important in determining quality attributes and for economic gain through building brand value associated with origin. Stable isotope signatures and trace element concentrations have been increasingly used in authentication of milk, though information on the power of such technology in verifying agroc...
This work presents the first use of Sr isotope ratios for determining the provenance of bovine milk from different regions of Slovenia. The analytical protocol for the determination of 87Sr/86Sr isotope ratio was optimised and applied to authentic milk samples. Considerable variability of 87Sr/86Sr ratios found in Slovenian milk reflects the substa...
Milk is a favorable for humans due to its nutritional composition. Metabolites in milk relevant to human health have received increased attention. Proton nuclear magnetic resonance (¹H-NMR) is commonly used for water-soluble metabolites due to rapid data acquisition and excellent precision. Extraction to separate fats and proteins from the metaboli...
Fresh milk is an important source of essential mineral supplement for humans. However, the levels of trace elements in milk are an important component of its safety and quality. Trace elements also act as a bio-indicator of agricultural pollution. Samples of raw cow milk (n = 68), animal feed [forage (n = 36) and concentrates (n = 14)], and water (...
Background
Milk is one of the most important food sources for human nutrition. The chemical composition of milk varies depending on many factors and may influence its nutritional value and safety. Metabolomics has recently become one of the major approaches applied to understand the chemical profiles and dynamic changes in milk products.
Scope and...
Characterizing the spatial distribution of δ18O in seawater and δ15N and δ13C in marine particulate organic matter pools can be useful in identifying isotopic discriminators of major water masses and serve as a baseline for food web and other ecological studies. Nevertheless, we do not know how isoscapes of δ18O, δ15N and δ13C are distributed and i...
Liquid chromatography (LC)–nuclear magnetic resonance (NMR) combines the advantage of the outstanding separation power of liquid chromatography (LC) and the superior structural elucidating capability of nuclear magnetic resonance (NMR). NMR has proved that it is a standout detector for LC by providing maximum structural information about plant orig...
Characterizing the spatial distribution of δ 18 O in seawater and δ 15 N and δ 13 C in marine particulate organic matter pools can be useful in identifying isotopic discriminators of major water masses and serve as a baseline for food web and other ecological studies. Nevertheless, we do not know how isoscapes of δ 18 O, δ 15 N and δ 13 C are distr...
This study is the first to provide a comprehensive characterization of the liquid and volatile fractions of whole goat milk powder (GMP). Robust nuclear magnetic resonance (NMR)- and gas chromatography-mass spectrometry (GC-MS)-based chemical fingerprinting methods were optimized and implemented. The untargeted ¹H-NMR analysis resolved 44 metabolit...
Dairy products occupy a special place among foods in contributing to a major part of our nutritional requirements, while also being prone to fraud. Hence, the verification of the authenticity of dairy products is of prime importance. Multiple stable isotopic studies have been undertaken that demonstrate the efficacy of this approach for the authent...
The abundances of low-molecular-weight metabolites in milk have been known to change during the lactation stage, and this is of relevance to the milk nutritional or processing properties. Metabolomics was used to investigate changes in 46 milk samples from 19 Jersey cows. Metabolites were measured using both nuclear magnetic resonance and mass spec...
Isotopic ecology has been widely used to understand spatial connectivity and trophic interactions in marine systems. However, its potential for monitoring an ecosystem's health and function has been hampered by the lack of consistent sample storage and long‐term studies. Preserved specimens from museum collections are a valuable source of tissue fo...
This study is the first to investigate the evolution of cow milk metabolites throughout the vat pasteurization process and storage using untargeted metabolomics based on a multiplatform approach. Nuclear magnetic resonance and ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry were used for fingerprinting water-solub...
BACKGROUND
Post‐border detection of a single brown marmorated stink bug (BMSB) in New Zealand warranted a biosecurity response, the nature of which would be influenced by its status as part of an established population or as a new arrival. Stable isotope analysis has the potential to determine natal origins, but is difficult to achieve for samples...
In this investigation, two previously reported precipitation δ²H isoscapes for New Zealand were used to develop a δ²H isoscape for blackberry (Rubus sp.) leaf. These isoscapes were calibrated using the measured δ²H values of 120 authentic blackberry leaf samples collected from across the country. A regression model based on environmental variables...
Hydrogen and oxygen isotope ratios are of use to determine the origin of matter. Thermolysis is used to convert matter to H2 and CO gases which are the respective substrates for measurement of these two isotope ratios using isotope ratio mass spec-trometry (IRMS). It is of advantage to decrease the limit of measurement for isotope ratiometry of hyd...
Fraud is endemic throughout the food industry and a major concern to producers and consumers. Adulteration or substitution with inferior product may cause economic or health problems, thus, it is important to establish a method to authenticate food. The aim of this work is to develop a an effective toolbox to discriminate raw milk samples from New...
Infant formula (IF), regarded as the optimal substitute for human breast milk (HBM), is very important for infant growth and development. Phospholipids (PLs) are ubiquitous components of infant formula as they have good emulsifier properties in addition to their nutritional and biological functions. In this study, the PL contents in four different...
• The relative availability of alternative organic matter sources directly influences trophic interactions within ecological communities. As differences in trophic ecology can alter the productivity of communities, understanding spatial variability in trophic structure, and the drivers of variability, is vital for implementing effective ecosystem‐b...
Rationale
Stable isotope ratios can provide a ‘fingerprint' to enable differentiation of sources of monofluoroacetate (MFA) hence providing a means to eliminate potential sources of MFA in a blackmail case involving the contamination of milk.
Methods
The stable isotopic composition (δ²H, δ¹³C and δ¹⁸O values) of a library of 43 samples of MFA was...
The global distribution of dissolved cadmium (Cd) in the world’s oceans is generally well understood. However, information on seasonal variability of this and other trace metals in the open ocean is difficult to obtain and, therefore, our understanding is limited. Here, we present a 3-year time series of field measurements of dissolved and particul...
Isotopic ecology has been widely used to understand spatial connectivity and trophic interactions in marine systems, but comparisons over long time periods are rare. Preserved specimens from museum collections are a potentially valuable source of tissue for isotope analyses, but isotopic signatures are known to be affected by fixatives. Isotopic va...
Sewage, waste organic matter from domestic and municipal wastewater, causes increased secondary productivity, eutrophication and trace metal contamination, reduced oxygen levels, and biodiversity which can lead to ecological disturbances in the natural aquatic ecosystem. The impact of sewage-derived organic matter (SDOM) on the nearshore marine eco...
The Subtropical and Subantarctic Fronts, which separate Subtropical, Subantarctic, and Antarctic Intermediate Waters, are diverted to the south of New Zealand by the submerged continental landmass of Zealandia. In the upper ocean of this region, large volumes of dissolved or suspended material are intermittently transported across the Subtropical F...
Sewage, waste organic matter from domestic and municipal wastewater causes increased secondary productivity, eutrophication and trace metal contamination, reduced oxygen levels and biodiversity which can lead to ecological disturbances in the natural aquatic ecosystem. Inadequately treated sewage effluent discharged into the marine area, poses envi...
Dissolved free amino acids (DFAA) in seawater are a form of nitrogen (N) available for marine microbes. In oligotrophic environments where N-containing nutrients are the limiting factor for microbial growth, N nutrition from DFAA could be crucial, but as yet it is poorly resolved. Measurements of individual DFAA are challenging as concentrations ar...
Food forensics is a multi-disciplinary science involving advanced analytical techniques, plant and animal metabolism, and sophisticated data interpretation tools. This book explains how plants, and in turn animals eating those plants, assimilate stable isotopes and trace elements from their environments. It provides extensive reviews of the use of...
Lipids are very important for human health and milk is a rich dietary source of lipids. In this study, the lipid content in three types of milk (goat, soy and bovine) were determined by using UPLC-Q-Exactive Orbitrap Mass Spectrometry. A total of 13 classes of lipids (including Cer, SM, LPC, PC, PE, DG, TG, PA, PG, PI, PS, LPE, FA) were measured. M...
Availability of iron limits productivity in the Southern Ocean where vast regions of high-nitrogen low-chlorophyll conditions are punctuated by hotspots of production surrounding the subAntarctic islands. Here, we compare patterns in accumulation of iron, as indicated by [Fe] and Fe?:?C (from Wing et al. 2014), with proxies for uptake of iron withi...
Food fraud is a concern for the producers of high-quality food products as it causes brand damage and loss of profit. Tea (Camellia sinensis L.) is one of the major agricultural products of Sri Lanka and accounts for more than 300 million of kilograms per year, roughly 2% of the national GDP. Trace metals and stable isotope ratios in tea samples or...
Background:
Milk is an important food component in human diet and is a target for fraud, including many unsafe practices. For example, the unscrupulous adulteration of soymilk into bovine and goat milk, or bovine milk into goat milk in order to gain profit without declaration is a health risk as the adulterants source and sanitary history in unkno...
Non-protein nitrogen compounds may be added to milk by unscrupulous producers to boost the apparent protein concentration. These compounds are nephrotoxic and may cause urinary disease. Nuclear magnetic resonance (NMR) was employed for the simultaneous determination of urea, melamine, guanidine, biuret, and diaminoguanidine in milk. The nitrogen-co...
Predictive understanding of precipitation δ2H and δ18O in New Zealand faces unique challenges, including high spatial variability in precipitation amounts, alternation between subtropical and sub-Antarctic precipitation sources, and a compressed latitudinal range of 34 to 47 °S. To map the precipitation isotope ratios across New Zealand, three year...
Predictive understanding of precipitation δ2H and δ18O in New Zealand faces unique challenges, including high spatial variability in precipitation amounts, alternation between subtropical and sub-Antarctic precipitation sources, and a compressed latitudinal range of 34 to 47 °S. To map the precipitation isotope ratios across New Zealand, three year...
Carbon and nitrogen stable isotope ratios of amino acids (δ13CAA and δ15NAA) have been recently used to unravel trophic relationships in aquatic and terrestrial environments. However, none have studied the specific case of a symbiotic relationship. Here we use the stable isotope ratios of amino acids (AAs) to investigate the link between a scarab l...
Nitrous oxide (N2O) is a biogenic trace gas in the atmosphere having significant role in global climate change and stratospheric chemistry. Its concentration in the ambient air has increased to the current value of 325 ppbv from 275ppbv in last hundred years. Oceans account for 25-30 % of global N2O emissions. Tropical and coastal regions contribut...
An untargeted metabolomics approach was applied for the discrimination of honey of various floral and geographical origins using ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-QToF MS). Evaluation of data by multivariate data analysis allowed the discrimination of New Zealand and Australian honeys from hon...
A report on the results from a 3 year project sampling and analysing rainfall from across NZ for the stable isotope rations of H and O.
Understanding the influence of spatial scale on ecological processes that occur with exotic plant invasion can help us identify underlying mechanisms of successful invasion. Here we studied spatial associations between Thymus vulgaris invasion and plant community species richness, composition and abundance at multiple spatial scales. These scales i...
Alterations to ecosystem nitrogen (N) cycling by introduced plant species may increase the invasibility of habitat providing a positive feedback for the introduced species to become invasive. Spatial patterns of foliar and soil δ15N ratios reflect variation in rates and process of N-cycling across invaded landscapes and provide insight into N-sourc...
Carbohydrate metabolism has been observed to be altered in males exercising in the cold. Whether metabolism is affected in females in the cold is unknown, therefore, the present study was conducted. Female cyclists (n=11) conducted two trials of 75 min cycling (74±4% VO 2max) each followed by a 4-km time-trial, at 5 ºC (Cold) and 15 ºC (Temperate),...
Traceability of dairy products is an important issue for the dairy industry. Empirical studies have demonstrated the utility of stable isotope measurements on milk for verification of origin. However, various drivers influence the isotopic composition of a food stuff, such as rainfall levels or food supplements. Relationships between the isotopic c...
Compound-specific isotope analysis (CSIA) offers great potential as a tool to provide chemical evidence in a forensic investigation. Many attempts to trace environmental oil spills were successful where isotopic values were particularly distinct. However, difficulties arise when a large data set is analyzed and the isotopic differences between samp...
Arhopalus ferus (Mulsant) (Coleoptera: Cerambycidae) is a forest pest that does not occur in Australia. In February 2010, the container ship Tatiana Schulte, en route from New Zealand, was refused permission to enter Australia following the discovery of numerous A. ferus aboard. The place where the infestation occurred was unknown, representing an...
Identifying the mechanisms underlying invasion success is important for our understanding of why some exotic plants negatively impact the biodiversity and functioning of only certain ecosystems. Allelopathy is one potential mechanism of invasion in which invasive plants produce secondary compounds (allelochemicals) that inhibit the growth of nearby...
Biological vectors are important for
redistribution of nutrients in many ecological systems.
While availability of iron (Fe) to phyto -
plankton limits pelagic productivity in the Southern
Ocean, biomagnification within marine food webs
can lead to high concentrations of Fe in the diet of
seabirds and marine mammals. We investigated
patterns in con...
The aim of this research was to increase understanding of how exotic plant invasion can alter abiotic and biotic soil properties across multiple sites encompassing the geographic distribution of the study species, between aspects at each site, and across the edge of invasion. Our research questions were: do soil physicochemical properties and soil...
Compound-specific isotope analysis offers potential for fingerprinting of diesel fuels, however, possible confounding effects of isotopic fractionation due to evaporation need to be assessed. This study measured the fractionation of the stable carbon and hydrogen isotopes in n-alkane compounds in neat diesel fuel during evaporation. Isotope ratios...
Protecting a nation's primary production sector and natural estate is heavily dependent on the ability to determine the risk presented by incursions of exotic insect species. Identifying the geographic origin of such biosecurity breaches can be crucial in determining this risk and directing the appropriate operational responses and eradication camp...