Thesis (Ph. D.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 139-151). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

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Master of Science / Food Science Institute / David L. Wetzel / Grain processing and handling requires quality determinations to ensure wholesome products that meet or surpass legal standards and specifications required by the end consumer. Near infrared spectroscopy has proven to be a useful and versatile tool to enable grain processers to make adjustments as needed. Near infrared chemical imaging also provides spatial information within the image and relative composition of chemically distinct components within the product. The potential use of chemical imaging to determine extraneous material in bread baking quality flour was addressed. A specimen preparation technique was developed. Insect fragment spiked specimens were imaged to determine their imaging effectiveness for application near the allowable limit of insect fragment concentration. Imaging was achieved using indium antimonide array detection of diffusely reflected radiation. The detector array of 81,920 pixels collected radiation from an area of 30.72 mm by 38.4 mm with a pixel size of 120 µm². Spectra were collected simultaneously from each pixel without moving parts by scanning with a liquid crystal tunable filter. Partial least squares analysis of each pixel within the sample allowed a summation of the insect quantity. The chemical structural distinction of chitin in the high protein matrix of the insect residue was in contrast to the non-digested carbohydrate residue in the lesser protein matrix of the flour. The method developed provided a linear response for a concentration range from approximately half the allowable limit to twice the limit for two insects that commonly contaminate flour. For the two insects studied the slopes are comparable with a slight off-set over a practical working range, so that insect concentration can be determined independently of species recognition.

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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.

Mycotoxins which are associated with Fusarium spp. and disease caused by this genus, Fusarium Head Blight (FHB), on grains represents a global issue for food and feed security. In order to determinate if the BoMill IQ is capable to recognize the content of mycotoxin in grains of barley, we were testing three different varieties fromm five firms, in two repetitions. This technology uses Near Infrared Transmittance (NIT) to distinguish kernels containing mycotoxins form healthy based on individual kernel protein content. Correlations between content of proteins and tested mycotoxins (deoxynivalenol and nivalenol) were observed. We have found strong negative correlations between both mycotoxins and content of proteins, but there was a strong positive correlation between deoxynivalenol and nivalenol. Results showed that this technology can be used to determinate content of mycotoxins in individual kernels and to sort the grains in different fractions which differ in content of mycotoxins.

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A magnetic resonance imaging (MRI) compatible near infrared spectrometer (NIRS) system was developed and evaluated for continuous-wave diffuse optical spectroscopy (DOS) and concurrent functional MRI measurements of human muscle. Phantom and in-vivo experiments using the system’s fiber bundle suggested that an isolation distance greater than 8 mm needs to exist between adjacent illumination-detection channels. Using single and probe-pair arrangements (inter-fiber separations of 80 µm and 5 mm, respectively), in-vivo DOS point-measurements (total=20 images) were performed on 1) the antecubital vein and a reference tissue area and 2) the lower leg at the medial (MG) and lateral gastrocnemius (LG) under isokinetic exercise. Mean spectral morphological differences and relative mean intensity changes at Hemoglobin key wavelengths were found, namely reduced mean pixel intensity (~30%) for the vessel-area and a signal change of ~1-4% between the rest and the recovery condition at both muscle locations for the single-probe configuration. Subsequent work is necessary to evaluate the oxygenation assessment capabilities of this system. Lastly, experiments were performed in which two volunteers had concurrent measurement of optical and blood oxygen level dependent (BOLD) MRI, before and following exercise. The same probe arrangement was used for DOS measurements for this experiment. The BOLD signal was studied for manually-derived ROIs. BOLD recovery curves corresponding to the LG followed routine temporal progression where immediate post-exercise signal is hypointense, followed with a sigmoidal-shaped recovery. A decrease ranging between ~0.1-20% was found in the normalized mean spectral signal (20 images) for recovery with reference to the rest condition at both muscle locations for single-probe measurements and for one probe-pair measurement (for 800,808 and 850 nm). The specific trend of the measured decrease in the mean spectral curves during recovery was not consistent among these trials. Future steps include repeatable phantom experiments, increased optical power delivery, enhanced skin contact and improved reflectance measurements / Thesis / Master of Applied Science (MASc)

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