Optimization of Instrument Design for In-Line Monitoring of Dry Matter Content in Single Potatoes by NIR Interaction Spectroscopy

Dry matter (DM) content is one of the most important quality features of potatoes. It defines the physical properties of the potatoes and determines what kind of product the potatoes can be used for. This paper presents the results obtained by a novel prototype NIR (near-infrared) instrument designed to measure DM content in single potatoes in process. The instrument is based on interaction measurements to measure deeper into the potatoes. It measures rapidly, up to 50 measurements per second, allowing several moving potatoes to be measured per second. The instrument also enables several interactance distances to be recorded for each measurement. The instrument was calibrated based on three different potato varieties and the calibration measurements were done in a process plant, making the calibration model suitable for in-line use. A good calibration for DM was obtained by partial least squares regression (RMSECV = 0.78% DM, R2 = 0.91). The instrument was tested in-line in the process plant and several batches of potatoes were monitored for the estimation of the DM distribution per batch. Accuracy of DM determination as function of measurement position on the potato was studied, and results indicate that NIR scans along the center part of the potatoes give slightly better results compared to scans taken on either side of the center. Small differences in optical measurement geometry influence the accuracy of the calibration models, underlining the importance of optimizing instrument design for successful measurementspublishedVersio

In-line Raman spectroscopy for characterization of an industrial poultry raw material stream

publishedVersio

In-line and non-destructive monitoring of core temperature in sausages during industrial heat treatment by NIR interaction spectroscopy

During industrial heat treatment of food products, the core temperature is a critical control parameter with respect to food quality and in particular food safety. This paper presents a novel prototype system based on near infrared spectroscopy (NIRS) that enables continuous in-line and non-contact monitoring of core temperature in sausages during heat treatment in an industrial oven. NIRS interaction measurements in the 761–1081 nm region were used to probe the interior of the sausages. NIRS calibrations for the estimation of core temperature were developed for three different sausage types in the temperature range 60–90 �C. The best accuracy obtained for core temperature with NIRS was about �1.0 �C. Results indicate that calibrations for core temperature can be transferred between different sausage types, which will ease implementation of such a method. The method was successfully tested in a modern sausage production plant.publishedVersio

Inter seasonal validation of non-contact NIR spectroscopy for measurement of total soluble solids in high tunnel strawberries

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Prediction of chemical and sensory properties in strawberries using Raman spectroscopy

publishedVersio

Raman spectroscopy and NIR hyperspectral imaging for in-line estimation of fatty acid features in salmon fillets

Raman spectroscopy was compared with near infrared (NIR) hyperspectral imaging for determination of fat composition (%EPA + DHA) in salmon fillets at short exposure times. Fillets were measured in movement for both methods. Salmon were acquired from several different farming locations in Norway with different feeding regimes, representing a realistic variation of salmon in the market. For Raman, we investigated three manual scanning strategies; i) line scan of loin, ii) line scan of belly and iii) sinusoidal scan of belly at exposure times of 2s and 4s. NIR images were acquired while the fillets moved on a conveyor belt at 40 cm/s, which corresponds to an acquisition time of 1s for a 40 cm long fillet. For NIR images, three different regions of interest (ROI) were investigated including the i) whole fillet, ii) belly segment, and iii) loin segment. For both Raman and NIR measurements, we investigated an untrimmed and trimmed version of the fillets, both relevant for industrial in-line evaluation. For the trimmed fillets, a fat rich deposition layer in the belly was removed. The %EPA + DHA models were validated by cross validation (N = 51) and using an independent test set (N = 20) which was acquired in a different season. Both Raman and NIR showed promising results and high performances in the cross validation, with R2CV = 0.96 for Raman at 2s exposure and R2CV = 0.97 for NIR. High performances were obtained also for the test set, but while Raman had low and stable biases for the test set, the biases were high and varied for the NIR measurements. Analysis of variance on the squared test set residuals showed that performance for Raman measurements were significantly higher than NIR at 1% significance level (p = 0.000013) when slope-and-bias errors were not corrected, but not significant when residuals were slope-and-bias corrected (p = 0.28). This indicated that NIR was more sensitive to matrix effects. For Raman, signal-to-noise ratio was the main limitation and there were indications that Raman was close to a critical sample exposure time at the 2s signal accumulation.publishedVersio

Raman and near Infrared Spectroscopy for Quantification of Fatty Acids in Muscle Tissue—A Salmon Case Study

The aim of the present study was to critically evaluate the potential of using NIR and Raman spectroscopy for prediction of fatty acid features and single fatty acids in salmon muscle. The study was based on 618 homogenized salmon muscle samples acquired from Atlantic salmon representing a one year-class nucleus, fed the same high fish oil feed. NIR and Raman spectra were used to make regression models for fatty acid features and single fatty acids measured by gas chromatography. The predictive performance of both NIR and Raman was good for most fatty acids, with R2 above 0.6. Overall, Raman performed marginally better than NIR, and since the Raman models generally required fewer components than respective NIR models to reach high and optimal performance, Raman is likely more robust for measuring fatty acids compared to NIR. The fatty acids of the salmon samples co-varied to a large extent, a feature that was exacerbated by the overlapping peaks in NIR and Raman spectra. Thus, the fatty acid related variation of the spectroscopic data of the present study can be explained by only a few independent principal components. For the Raman spectra, this variation was dominated by functional groups originating from long-chain polyunsaturated FAs like EPA and DHA. By exploring the independent EPA and DHA Raman models, spectral signatures similar to the respective pure fatty acids could be seen. This proves the potential of Raman spectroscopy for single fatty acid prediction in muscle tissue.Raman and near Infrared Spectroscopy for Quantification of Fatty Acids in Muscle Tissue—A Salmon Case StudypublishedVersio

Hurtige spektroskopiske målemetoder for prediksjon av vannbindingsevne i kjøtt

Water-holding capacity (WHC) is one of the most important quality traits in meat, and the main aim of this thesis was to examine the potential for rapid spectroscopic techniques to predict WHC in meat. A secondary aim was to examine the potential for spectroscopic techniques to analyze pH and proteolysis; mechanisms known to affect WHC of meat. A model system consisting of isolated myofibrils from pork was used to investigate if spectroscopic techniques have potential to identify changes in samples with different pH or degree of protein degradation. Raman, Fourier transform-infrared (FT-IR), near-infrared (NIR) and fluorescence spectroscopy were used for analyses. Raman and FT-IR spectroscopy performed very well in the pH- and proteolysis experiment. Changes in protein secondary structure and protonation of carboxylic acid side chains of amino acids were affected by changes in pH. Degree of protein degradation affected spectral regions related to breakage of peptide bonds, such as CN-vibrations and carboxylic acid vibration caused by C-terminal formation, as well as changes in protein secondary structure. NIR performed poorly in the pH experiment, but performed reasonably well for dried samples in the proteolysis experiment, attributing this to an increased ability to form protein gels at low degrees of protein degradation. Fluorescence spectroscopy performed worse in the proteolysis experiment than in the pH experiment, attributing the performance in the pH experiment to a pH-related shift caused by changes in the microenvironment of tryptophan. A study analyzing 122 samples from longissimus lumborum of Norwegian landrace boars was conducted to investigate if spectroscopic techniques have the potential to predict WHC and estimate ultimate pH in pork. WHC was measured as EZ-DripLoss and drip loss formed during eightdays of vacuum storage. Assessment of results from partial least squares regression (PLSR) analyses from spectroscopy and reference measurements showed that Raman spectroscopy performed the best, followed by NIR and at last, fluorescence. PLSR models from Raman spectroscopy gave coefficient of correlation from cross validation (Rcv2) of 0.51, 0.41 and 0.49 and root mean square error of cross validation (RMSECV) of 1.2, 0.82 and 0.06 for EZ-DripLoss, vacuum drip loss and pH, respectively. In comparison, NIR yielded PLSR models with Rcv2 of 0.27, 0.16 and 0.29 and RMSECV of 1.5, 0.97 and 0.07 for EZ-DripLoss, vacuum drip loss and pH, respectively. Regarding pH in meat, changes in Raman spectra related to protein secondary structure were similar in the model system and in meat. Changes in carboxylic acid protonation were not detected in meat, but signals from molecules related to metabolism were identified. In conclusion, this highly encourages more research using Raman spectroscopy for analysis of meat quality.Vannbindingsevne (VBE) er en av de viktigste kvalitetsegenskapene i kjøtt, og hovedmålet med denne avhandlingen var å undersøke potensialet for bruk av hurtige spektroskopiske metoder til prediksjon av VBE i kjøtt. Et sekundært mål var å undersøke potensialet for spektroskopiske metoder til analyse av pH og proteinnedbryting (proteolyse); mekanismer som er kjent å kunne påvirke VBE. Et modellsystem bestående av isolerte myofibriller fra svinekjøtt ble brukt til å undersøke om spektroskopiske teknikker kan identifisere endringer i prøver som følge av pH-forandringer eller ulik grad av proteinnedbrytning. Raman-, Fourier transform-infrarød- (FT-IR), nær-infrarød- (NIR) og fluorescensspektroskopi ble brukt i analysene. Raman- og FT-IR-spektroskopi viste gode evner til å analysere prøvene fra pH- og proteolyseforsøkene. Endringer i proteinenes sekundærstruktur og protonering av karboksylsyregruppen i sidekjedene til aminosyrer ble påvirket av endring i pH. Grad av proteinnedbrytning påvirket områder i spektrene knyttet til brudd av peptidbånd, som CNvibrasjoner og karboksylsyrevibrasjoner forårsaket av dannelsen av nye C-terminaler, i tillegg til endringer i proteinenes sekundærstruktur. NIR viste begrenset evne til å identifisere endringer som følge av pH-forandring, men viste rimelig god evne til å identifisere tørkede prøver med ulik grad av proteinnedbrytning, som ble tilskrevet spektrale områder relatert til proteinenes evne til å danne gel. Fluorescens viste bedre evne til å beskrive prøver fra pH-forsøket enn fra proteolyseforsøket, hvor dette ble tilskrevet et skift i spektrene forårsaket av endring i mikromiljøet rundt aminosyren tryptofan. For å undersøke potensialet spektroskopiske metoder har for prediksjon av VBE og estimering av slutt-pH, ble en studie gjennomført hvor 122 prøver fra longissimus lumborum fra Norske landsvin råner analysert. VBE ble målt som EZ-DripLoss og som væskeslipp i vakuumposer etter åtte dagers lagring. Vurdering av resultater fra partial least squares regression (PLSR) av spektroskopi og referanseanalyser viste at Raman ga best resultat, etterfulgt av NIR, med fluorescens til slutt. PLSRmodellen fra Raman ga en korrelasjonskoeffisient fra kryssvalidering (Rcv2) på 0.51, 0.41 og 0.49 og root mean square error of cross validation (RMSECV) på 1.2, 0.82 og 0.06 for henholdsvis EZDripLoss, vakuumdrypptap og pH. Til sammenligning ga NIR PLSR-modeller med Rcv2 på 0.27, 0.16 og 0.29, og RMSECV på 1.5, 0.97 og 0.07 for henholdsvis EZ-DripLoss, vakuumdrypptap and pH. Endringer i Ramanspektrene som følge av forskjeller i pH var like for protein sekundærstruktur i modellsystemet og i kjøtt. Spektroskopiske endringer i karboksylsyreprotonering ble ikke oppdaget i kjøtt, men endringer knyttet til metabolske molekyler ble avdekket. Resultatene fra denne avhandlingen viser at videre forskning knyttet til bruken av Ramanspektroskopi for analyse av kjøttkvalitet bør prioriteres.Foundation for Research Levy on Agricultural products ; Agricultural Agreement Research Fund of Norwa

Rapid spectroscopic methods for predicting water-holding capacity in meat

Water-holding capacity (WHC) is one of the most important quality traits in meat, and the main aim of this thesis was to examine the potential for rapid spectroscopic techniques to predict WHC in meat. A secondary aim was to examine the potential for spectroscopic techniques to analyze pH and proteolysis; mechanisms known to affect WHC of meat. A model system consisting of isolated myofibrils from pork was used to investigate if spectroscopic techniques have potential to identify changes in samples with different pH or degree of protein degradation. Raman, Fourier transform-infrared (FT-IR), near-infrared (NIR) and fluorescence spectroscopy were used for analyses. Raman and FT-IR spectroscopy performed very well in the pH- and proteolysis experiment. Changes in protein secondary structure and protonation of carboxylic acid side chains of amino acids were affected by changes in pH. Degree of protein degradation affected spectral regions related to breakage of peptide bonds, such as CN-vibrations and carboxylic acid vibration caused by C-terminal formation, as well as changes in protein secondary structure. NIR performed poorly in the pH experiment, but performed reasonably well for dried samples in the proteolysis experiment, attributing this to an increased ability to form protein gels at low degrees of protein degradation. Fluorescence spectroscopy performed worse in the proteolysis experiment than in the pH experiment, attributing the performance in the pH experiment to a pH-related shift caused by changes in the microenvironment of tryptophan. A study analyzing 122 samples from longissimus lumborum of Norwegian landrace boars was conducted to investigate if spectroscopic techniques have the potential to predict WHC and estimate ultimate pH in pork. WHC was measured as EZ-DripLoss and drip loss formed during eightdays of vacuum storage. Assessment of results from partial least squares regression (PLSR) analyses from spectroscopy and reference measurements showed that Raman spectroscopy performed the best, followed by NIR and at last, fluorescence. PLSR models from Raman spectroscopy gave coefficient of correlation from cross validation (Rcv2) of 0.51, 0.41 and 0.49 and root mean square error of cross validation (RMSECV) of 1.2, 0.82 and 0.06 for EZ-DripLoss, vacuum drip loss and pH, respectively. In comparison, NIR yielded PLSR models with Rcv2 of 0.27, 0.16 and 0.29 and RMSECV of 1.5, 0.97 and 0.07 for EZ-DripLoss, vacuum drip loss and pH, respectively. Regarding pH in meat, changes in Raman spectra related to protein secondary structure were similar in the model system and in meat. Changes in carboxylic acid protonation were not detected in meat, but signals from molecules related to metabolism were identified. In conclusion, this highly encourages more research using Raman spectroscopy for analysis of meat quality

Apoptosis is induced in bovine satellite muscle cells after removal of available oxygen

Abstract Post-mortem tenderisation of meat is a complex process, of which all the details are far from understood. Cell death by apoptosis is recently proposed as a novel mechanism in this process. The main aim of this study was to investigate if bovine satellite muscle cells, cultivated in vitro, would induce apoptosis when oxygen was removed from the incubation medium. Satellite muscle cells was seeded out in Entactin-Collagen IV-Laminin (ECL) coated culture wells and allowed to differentiate before oxygen was removed by adding EC-Oxyrase® to the differentiation medium (DM). Muscle cells were incubated without oxygen for 2h, 4h, 6h and 22h. Samples were analysed by immunofluorescence microscopy, quantitative real-time PCR, western blot, caspase 3/7 assay, caspase 9 assay and viability assay. Evident signs of actin filament depolymerisation and actin degradation following oxygen removal were observed. Tubulin filaments depolymerised soon after oxygen removal, while the tubulin monomers was unchanged. The mRNA expression of the pro-apoptotic protein Bim increased significantly at all times investigated, as did the mRNA of caspase-independent apoptosis inducing factor (Aif). Mitochondrial membrane potential decreased significantly at 6h after oxygen removal. Concentration of protective Hsp-70 and PARK7 protein seemed to increase transiently, with maximum concentrations at 2h and 4h respectively. Concentration of caspase 9 decreased significantly at all times investigated, with a minimum concentration at 22h. Concentration of caspase 3/7 decreased significantly at 2h and 4h, before increasing gradually from 4h to 22h, ending with a concentration above the control sample. Viability of muscle cells increased at 2h, before decreasing gradually afterwards, ending in a significant decrease at 22h. In conclusion, the results strongly indicated that satellite muscle cells induced apoptosis when oxygen was removed from the incubation medium, and that the mitochondrion was an important element in the apoptotic event. Sammendrag Mørning av kjøtt post-mortem er en kompleks prosess, og det er mange faktorer som påvirker den endelige mørheten i kjøtt. Celledød ved apoptose er nylig foreslått som en av mekanismene som kan påvirke mørningsprosessen. Hovedmålet i denne studien var å undersøke om satellittmuskelceller, dyrket in vitro, ville indusere apoptose når oksygen ble fjernet fra vekstmediet. Satellittceller fra muskler av storfe ble sådd ut på Entactin-Collagen IV-Laminin (ECL)-belagte dyrkningsbrønner, hvor muskelcellene differensierte før oksygen ble fjernet ved å tilsette EC-Oxyrase® til differensieringsmediet. Muskelcellene ble satt til inkubasjon uten oksygen i 2t, 4t, 6t og 22t. Prøver ble analysert ved immunfluorescens mikroskopi, kvantitativ real-time PCR, western blot, caspase 3/7 assay, caspase 9 assay og viability assay. Fjerning av oksygen ga tegn på en depolymerisering av actinfilamentene, og at actinmonomerer ble destruert. Tubulinfilamentene ble tydelig depolymerisert etter fjerning av oksygen, men tubulinmonomerene viste ingen tegn på destruksjon. mRNA uttrykk av det pro-apoptotiske proteinet Bim økte signifikant ved alle undersøkte tidspunkter, det samme gjorde mRNA uttrykket til caspaseuavhengig apoptose induserende faktor (Aif). Membranpotensialet til mitokondrier avtok signifikant 6t etter fjerning av oksygen. Konsentrasjonen av de beskyttende proteinene Hsp70 og PARK7 nådde en topp etter henholdsvis 2t og 4t etter fjerning av oksygen, før konsentrasjonen avtok igjen ved lengre inkubasjonstider. Konsentrasjonen av caspase 9 minket signifikant på alle undersøkte tidspunkter, med et minimum etter 22t. Konsentrasjonen av caspase 3/7 minket signifikant etter 2t og 4t, men økte igjen fra 4t til 22t, hvor konsentrasjonen etter 22t var høyere enn i kontrollprøven. Levedyktigheten til muskelcellene økte etter 2t, før den gradvis minket, og til slutt nådde en levedyktighet signifikant lavere enn kontrollen ved 22t. Resultatene indikerte at satellittmuskelceller induserte apoptose når oksygen ble fjernet fra vekstmediet, og at mitokondriene spilte en viktig rolle i denne prosessen