NMR Metabolomics of Foods – Investigating the Influence of Origin on Sea Buckthorn Berries, Brassica Oilseeds and Honey

The origin of foods plays an important role in their metabolome (the set of compounds present as products of metabolic events). The compositions of food plants are inevitably determined by a number of inherent and external factors – most importantly by the genotype (species, subspecies, cultivar, variety) and the prevailing conditions and weather parameters at each growth environment. The declaration of food origin can be defined and protected by law. The constantly increasing consumer awareness towards food origin, authenticity and quality has set the need for efficient tools for their verification. Metabolomics based on nuclear magnetic resonance (NMR) spectroscopy is increasingly being applied in analysing food composition and quality and in detecting food frauds and adulterations. The aim of the current work was to determine the influence of origin-related variables in food composition and quality by using 1H NMR metabolomics. The model foods – sea buckthorn (Hippophaë rhamnoides) berries, oilseeds of Brassica spp. and varietal honey – represent different foods with special sensory, nutritional, bioactive, commercial and national significance. The sea buckthorn berry metabolites were investigated in respect to the genotype (subspecies, cultivar) and geographical origin, with special emphasis on the influence of northern latitudes and related conditions. In the oilseeds, the inter-species variation and the influence of environmental and developmental stage on the seed composition was investigated. NMR profiling was applied in characterising the marker compounds for different honey types for botanical authentication. Multivariate analysis methods such as principal component (PCA) and discriminant analyses (PLS-DA, OPLS-DA) were applied in every sub-study to determine the key metabolites and origin-related factors characterising the food samples. The sea buckthorn subspecies were mainly distinguished by the relatively high content of ethyl-β-D-glucopyranoside (ssp. rhamnoides) and malic acid and vitamin C (ssp. sinensis). The northern latitude and respective conditions (the length of growth season, temperature, radiation and precipitation) was shown to alter the chemical composition of berries of the same genetic origin. In subarctic latitudes, the berries formed more ascorbic acid while the levels of ethyl glucose remained relatively low. The berries of cultivar 'Tytti' contained more ethyl glucoside while the berries of 'Terhi' contained more quinic acid in comparison. Calculated from the start of the growing season until harvest, the effective temperature sum (degree days) and the radiation sum correlated positively with ethyl glucoside that accumulated up to six-fold in overripe berries in southern Finland. The sea buckthorn berries (ssp. sinensis) grown at over 2000 m altitude contained typically more ascorbic and malic acids. The seeds of turnip rape was characterised by a relatively higher sucrose and polyunsaturated fatty acid content over oilseed rape that had a higher content of sinapine and oil in general. Growth conditions with reduced temperature added to the level of unsaturation in the oilseed lipids and delayed the seed development. The varietal honeys were classified with the aid of NMR profiling, as the typical sugar composition and other botanical markers were characterised. Also, previously unreported markers were designated for dandelion honeys. The correlations between complex food metabolomes and the origin-related variables were easily accomplished with NMR metabolomics. Especially, the effect of northern conditions on the growth place-dependent compositional flexibility (phenotypic plasticity) of the plant foods was deemed considerable. The results of this thesis can be further used to determine food quality, origin and authenticity and as an aid in plant breeding operations.Alkuperällä on suuri vaikutus elintarvikkeen metabolomiin eli aineenvaihduntatuotteiden kokonaisuuteen. Erityisesti kasviperäisten elintarvikkeiden koostumukseen vaikuttavat lukuisat sisäiset ja ulkoiset alkuperään liittyvät tekijät, kuten perimä (laji, alalaji, lajike) ja kasvupaikalle tyypilliset ympäristö- ja sääolosuhteet. Elintarvikkeen alkuperä voidaan määritellä ja suojata lainsäädännöllisin perustein. Kuluttajien kasvanut kiinnostus ja tietämys elintarvikkeiden alkuperää, aitoutta ja laatua kohtaan on lisännyt tehokkaiden ja luotettavien laadunvarmistusmenetelmien tarvetta. Varsinkin ydinmagneettista resonanssispektroskopiaan (NMR) perustuvaa metabolomiikkatutkimusta hyödynnetään yhä useammin elintarvikkeiden koostumuksen, laadun ja aitouden analysoinnissa. Tämän tutkimuksen tarkoituksena oli selvittää alkuperän vaikutusta tyrnimarjojen (Hippophaë rhamnoides), rypsin- ja rapsinsiementen (Brassica spp.) sekä lajihunajan koostumukseen 1H-NMR-metabolomiikan avulla. Nämä elintarvikkeet ovat kansallisesti ja kaupallisesti arvokkaita ja mielenkiintoisia niille tyypillisten aistittavien, ravitsemuksellisten ja bioaktiivisten ominaisuuksien ansiosta. Tyrnimarjojen koostumusta vertailtiin eri alalajien (ssp. rhamnoides ja ssp. sinensis) ja lajikkeiden ('Terhi' ja 'Tytti') sekä kasvupaikkojen (Suomi, Kiina, Kanada) välillä. Tavoitteena oli erityisesti selvittää, miten erityisesti pohjoisille leveysasteille tyypilliset olosuhteet vaikuttavat marjojen aineenvaihduntatuotteisiin. Öljysiementen kohdalla tutkittiin myös miten lajikohtainen perimä sekä kasvupaikan/-olosuhteiden ja siemenen kehittymisvaihe vaikuttavat siementen kemialliseen koostumukseen ja laatuun. Hunajien tapauksessa NMR-metabolomiikkaa hyödynnettiin kasvialkuperäkohtaisten sormenjälkiyhdisteiden tunnistamiseen ja kotimaisten lajihunajien kasvialkuperän varmentamiseen. Kaikissa osatutkimuksissa sovellettiin pääkomponentti-(PCA) ja diskriminanttianalyysiin (PLS-DA, OPLS-DA) perustuvia monimuuttujamenetelmiä tärkeimpien näyteryhmiä erottavien ja määrittävien yhdisteiden ja taustatekijöiden selvittämiseksi. Tyrnin alalajit erottuivat pääasiassa suhteellisesti korkean etyyli-β-D-glukopyranosidin (ssp. rhamnoides) sekä omenahappo- ja C-vitamiini-pitoisuuden (ssp. sinensis) perusteella. Pohjoisen leveysasteen ja sille tyypillisten olosuhteiden (kasvukauden pituus, lämpötila, säteily, sademäärä) todettiin muokanneen samaa geneettistä alkuperää olevien marjojen kemiallista koostumusta. Subarktisilla leveyksillä tyrnimarjaan muodostui enemmän askorbiinihappoa ja etyyliglukosidin määrä oli alhainen. 'Tytti'-lajikkeen marjat sisälsivät enemmän etyyliglukosidia, kun taas 'Terhi' sisälsi vastaavasti enemmän kviinihappoa. Kasvukauden tehoisa lämpösumma ja säteilysumma korreloivat positiivisesti etyyliglukosidin kanssa, jota kertyi ylikypsiin marjoihin Etelä-Suomessa jopa kuusinkertainen määrä kypsiin verrattuna. Yli 2000 metrin korkeudessa kasvaneissa tyrnimarjoissa (ssp. sinensis) oli tyypillisesti korkeampi omena- ja askorbiinihappopitoisuus. Suhteellisesti korkeampi sakkaroosipitoisuus ja monityydyttymättömien rasvahappojen osuus oli tyypillisempää rypsille, kun taas rapsi erottui rypsistä korkeamman öljy- ja sinapiinipitoisuuden perusteella. Kylmempi kasvupaikka lisäsi monityydyttymättömien rasvahappojen osuutta öljysiemenissä ja hidasti siemenen kehittymistä. NMR-profiloinnin avulla lajihunajat pystyttiin luokittelemaan kullekin hunajalle ominaisen sokerikoostumuksen ja muiden kasvialkuperästä kertovien merkkiyhdisteiden perusteella. Voikukkahunajalle tunnistettiin myös aiemmin raportoimattomia merkkiyhdisteitä. NMR-metabolomiikan avulla pystyttiin helposti selvittämään monimutkaisten aineenvaihduntatuotteiden kokonaisuuksien ja elintarvikkeen alkuperään liittyvien muuttujien välisiä yhteyksiä. Varsinkin pohjoisten kasvuolosuhteiden vaikutus kasviperäisten elintarvikkeiden koostumukselliseen vaihteluun oli huomattava. Väitöskirjan tuloksia voidaan hyödyntää elintarvikkeiden laadun, alkuperän ja aitouden varmistamisessa sekä kasvinjalostuksen apuna.Siirretty Doriast

Determination of glucosinolates and isothiocyanates in glucosinolate-rich vegetables and oilseeds using infrared spectroscopy: A systematic review.

This is the final version. Available from Taylor & Francis via the DOI in this recordCruciferous vegetables and oilseeds are rich in glucosinolates that can transform into isothiocyanates upon enzymic hydrolysis during post-harvest handling, food preparation and/or digestion. Vegetables contain glucosinolates that have beneficial bioactivities, while glucosinolates in oilseeds might have anti-nutritional properties. It is therefore important to monitor and assess glucosinolates and isothiocyanates content through the food value chain as well as for optimized crop production. Vibrational spectroscopy methods, such as infrared (IR) spectroscopy, are used as a nondestructive, rapid and low-cost alternative to the current and common costly, destructive, and time-consuming techniques. This systematic review discusses and evaluates the recent literature available on the use of IR spectroscopy to determine glucosinolates and isothiocyanates in vegetables and oilseeds. NIR spectroscopy was used to predict glucosinolates in broccoli, kale, rocket, cabbage, Brussels sprouts, brown mustard, rapeseed, pennycress, and a combination of Brassicaceae family seeds. Only one study reported the use of NIR spectroscopy to predict broccoli isothiocyanates. The major limitations of these studies were the absence of the critical evaluation of errors associated with the reference method used to develop the calibration models and the lack of interpretation of loadings or regression coefficients used to predict glucosinolates.QUEX Institut

Evaluation of near infrared reflectance (NIR) spectroscopy to determine the nutrient composition of raw materials and compound ostrich feeds

The chemical analysis of feed samples can be time consuming and expensive. The use of near infrared reflectance (NIR) spectroscopy was evaluated in a range of studies as a rapid technique to predict the chemical constituents in feedstuffs and compound ostrich feeds. The prediction of accurate results by NIR spectroscopy relies heavily upon obtaining a calibration set which represents the variation in the main population, accurate laboratory analyses and the application of the best mathematical procedures. This research project was designed to meet five objectives: The first objective was to determine the feasibility of using near infrared reflectance (NIR) spectroscopy to predict dry matter, ash, crude protein, crude fibre, oil content, and fatty acids such as palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1) and linoleic acid (C18:2) in sunflower seed meal. The second objective was to develop calibration models to predict the dry matter, crude protein and oil content in milled canola seed, compared to whole canola seeds. The third objective was to investigate the feasibility of using NIR spectroscopy to predict the dry matter, ash, crude protein, crude fibre and oil content in milled lupin seeds, compared to whole lupin seeds. The fourth objective was to describe the development of near infrared reflectance (NIR) spectroscopy calibration equations for the prediction of chemical composition and amino acid content from different populations of alfalfa hay (Medicago sativa L.). The last objective was to determine the potential of NIR spectroscopy to predict the dry matter, ash, crude protein, crude fibre, ether extract, acid detergent fibre (ADF), neutral detergent fibre (NDF), calcium, phosphorus, in vitro organic matter digestibility (IVOMD) and amino acids such as lysine, methionine, threonine and arginine in compound ostrich feed samples. The results of this study indicate that NIR spectroscopy calibrations in sunflower seed meal are only applicable in sunflower breeding programmes for a fast screening as it was not suitable for prediction purposes. Screening of sunflower seeds by NIR spectroscopy represents a rapid, simple and cost effective alternative that is a great utility for users who need to analyse a large number of samples. Calibrations developed for crude protein and oil content in milled canola seeds proved to be better than calibrations for whole canola seeds. Although the results indicated that calibrations were better for milled canola seeds, it indicated values that were typical of equations suitable for screening purposes to select samples for more detailed chemical analysis. According to calibration statistics obtained for crude protein, crude fibre and oil content in whole lupin seeds, there is no need to grind the seeds to scan the meal as similarly accurate results were obtained by analysing whole seeds. Screening of whole lupin seeds by NIR spectroscopy represents a rapid, simple and cost effective alternative that may be of great utility for users who need to analyse a large number of samples with no sample preparation. The calibration and validation statistics obtained in the study to test the potential of NIR spectroscopy to predict the chemical composition and amino acid contents in alfalfa hay, showed the accuracy was too low for routine analysis, although NIR spectroscopy could be used as a screening tool. Further research needs to be done to improve the accuracy of the NIR spectroscopy analysis, including more samples from different cultivars and years. In the study to examine the possibility of using NIR spectroscopy to predict the chemical composition of compound ostrich feeds, the results indicated that NIR spectroscopy is a suitable tool for a rapid and reliable prediction of the crude protein, crude fibre, ether extract, IVOMD, ADF and NDF in compound ostrich feeds. Calibrations can be improved for amino acids if a larger sample pool is used to develop the calibrations. These studies indicated that NIR spectroscopy can be a rapid and successful tool for the prediction of the nutritive value up to certain amino acid contents of feedstuffs and compound ostrich feeds

Analysis of the Acid Detergent Fibre Content in Turnip Greens and Turnip Tops (Brassica rapa L. Subsp. rapa) by Means of Near-Infrared Reflectance

Standard wet chemistry analytical techniques currently used to determine plant fibre constituents are costly, time-consuming and destructive. In this paper the potential of near-infrared reflectance spectroscopy (NIRS) to analyse the contents of acid detergent fibre (ADF) in turnip greens and turnip tops has been assessed. Three calibration equations were developed: in the equation without mathematical treatment the coefficient of determination (R2) was 0.91, in the first-derivative treatment equation R2 = 0.95 and in the second-derivative treatment R2 = 0.96. The estimation accuracy was based on RPD (the ratio between the standard deviation and the standard error of validation) and RER (the ratio between the range of ADF of the validation as a whole and the standard error of prediction) of the external validation. RPD and RER values were of 2.75 and 9.00 for the treatment without derivative, 3.41 and 11.79 with first-derivative, and 3.10 and 11.03 with second-derivative. With the acid detergent residue spectrum the wavelengths were identified and associated with the ADF contained in the sample. The results showed a great potential of NIRS for predicting ADF content in turnip greens and turnip tops

Evaluation of near infrared reflectance (NIR) spectroscopy to determine the nutrient composition of raw materials and compound ostrich feeds

The chemical analysis of feed samples can be time consuming and expensive. The use of near infrared reflectance (NIR) spectroscopy was evaluated in a range of studies as a rapid technique to predict the chemical constituents in feedstuffs and compound ostrich feeds. The prediction of accurate results by NIR spectroscopy relies heavily upon obtaining a calibration set which represents the variation in the main population, accurate laboratory analyses and the application of the best mathematical procedures. This research project was designed to meet five objectives: The first objective was to determine the feasibility of using near infrared reflectance (NIR) spectroscopy to predict dry matter, ash, crude protein, crude fibre, oil content, and fatty acids such as palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1) and linoleic acid (C18:2) in sunflower seed meal. The second objective was to develop calibration models to predict the dry matter, crude protein and oil content in milled canola seed, compared to whole canola seeds. The third objective was to investigate the feasibility of using NIR spectroscopy to predict the dry matter, ash, crude protein, crude fibre and oil content in milled lupin seeds, compared to whole lupin seeds. The fourth objective was to describe the development of near infrared reflectance (NIR) spectroscopy calibration equations for the prediction of chemical composition and amino acid content from different populations of alfalfa hay (Medicago sativa L.). The last objective was to determine the potential of NIR spectroscopy to predict the dry matter, ash, crude protein, crude fibre, ether extract, acid detergent fibre (ADF), neutral detergent fibre (NDF), calcium, phosphorus, in vitro organic matter digestibility (IVOMD) and amino acids such as lysine, methionine, threonine and arginine in compound ostrich feed samples. The results of this study indicate that NIR spectroscopy calibrations in sunflower seed meal are only applicable in sunflower breeding programmes for a fast screening as it was not suitable for prediction purposes. Screening of sunflower seeds by NIR spectroscopy represents a rapid, simple and cost effective alternative that is a great utility for users who need to analyse a large number of samples. Calibrations developed for crude protein and oil content in milled canola seeds proved to be better than calibrations for whole canola seeds. Although the results indicated that calibrations were better for milled canola seeds, it indicated values that were typical of equations suitable for screening purposes to select samples for more detailed chemical analysis. According to calibration statistics obtained for crude protein, crude fibre and oil content in whole lupin seeds, there is no need to grind the seeds to scan the meal as similarly accurate results were obtained by analysing whole seeds. Screening of whole lupin seeds by NIR spectroscopy represents a rapid, simple and cost effective alternative that may be of great utility for users who need to analyse a large number of samples with no sample preparation. The calibration and validation statistics obtained in the study to test the potential of NIR spectroscopy to predict the chemical composition and amino acid contents in alfalfa hay, showed the accuracy was too low for routine analysis, although NIR spectroscopy could be used as a screening tool. Further research needs to be done to improve the accuracy of the NIR spectroscopy analysis, including more samples from different cultivars and years. In the study to examine the possibility of using NIR spectroscopy to predict the chemical composition of compound ostrich feeds, the results indicated that NIR spectroscopy is a suitable tool for a rapid and reliable prediction of the crude protein, crude fibre, ether extract, IVOMD, ADF and NDF in compound ostrich feeds. Calibrations can be improved for amino acids if a larger sample pool is used to develop the calibrations. These studies indicated that NIR spectroscopy can be a rapid and successful tool for the prediction of the nutritive value up to certain amino acid contents of feedstuffs and compound ostrich feeds

Target and Non-Target Approaches for Food Authenticity and Traceability

Over the last few years, the subject of food authenticity and food fraud has received increasing attention from consumers and other stakeholders, such as government agencies and policymakers, control labs, producers, industry, and the research community. Among the different approaches aiming to identify, tackle, and/or deter fraudulent practices in the agri-food sector, the development of new, fast, and accurate methodologies to evaluate food authenticity is of major importance. This book, entitled “Target and Non-Target Approaches for Food Authenticity and Traceability”, gathers original research and review papers focusing on the development and application of both targeted and non-targeted methodologies applied to verify food authenticity and traceability. The contributions regard different foods, among which some are frequently considered as the most prone to adulteration, such as olive oil, honey, meat, and fish. This book is intended for readers aiming to enrich their knowledge through reading contemporary and multidisciplinary papers on the topic of food authentication

Past and future of plant stress detection: an overview from remote sensing to Positron Emission Tomography

Plant stress detection is considered one of the most critical areas for the improvement of crop yield in the compelling worldwide scenario, dictated by both the climate change and the geopolitical consequences of the Covid-19 epidemics. A complicated interconnection of biotic and abiotic stressors affect plant growth, including water, salt, temperature, light exposure, nutrients availability, agrochemicals, air and soil pollutants, pests and diseases. In facing this extended panorama, the technology choice is manifold. On the one hand, quantitative methods, such as metabolomics, provide very sensitive indicators of most of the stressors, with the drawback of a disruptive approach, which prevents follow up and dynamical studies. On the other hand qualitative methods, such as fluorescence, thermography and VIS/NIR reflectance, provide a non-disruptive view of the action of the stressors in plants, even across large fields, with the drawback of a poor accuracy. When looking at the spatial scale, the effect of stress may imply modifications from DNA level (nanometers) up to cell (micrometers), full plant (millimeters to meters) and entire field (kilometers). While quantitative techniques are sensitive to the smallest scales, only qualitative approaches can be used for the larger ones. Emerging technologies from nuclear and medical physics, such as computed tomography, magnetic resonance imaging and positron emission tomography, are expected to bridge the gap of quantitative non disruptive morphologic and functional measurements at larger scale. In this review we analyze the landscape of the different technologies nowadays available, showing the benefits of each approach in plant stress detection, with a particular focus on the gaps, which will be filled in the nearby future by the emerging nuclear physics approaches to agriculture