Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Katie_MSThesis.pdf (2.58 MB)

ETD Abstract Container

Abstract Header

NMR Spectroscopy as a Robust Tool for the Analysis of Lipids in Fish Oil Supplements and Coffee

Williamson, Kathryn Maxine, Williamson
http://rave.ohiolink.edu/etdc/view?acc_num=osu1523978049728289

Abstract Details

2018, Master of Science, Ohio State University, Food Science and Technology.
Lipids have a variety of applications in pharmaceutical, cosmetic, and food industries. Fish oil provides a good source of n-3 fatty acids in the diet and its authentication and analysis is essential. Additionally, an Arabica coffee bean consists of about 15% lipids which can be important quality and shelf-life indicators for the coffee beverage. The objective of this work is to employ multinuclear and multidimensional NMR spectroscopy as a rapid and reliable method for the quantitative analysis and evaluation of fish oil supplements using high-resolution 1H and 13C NMR spectroscopy utilizing two different NMR instruments; a 500 MHz and an 850 MHz instrument, as well as for evaluating the non-polar, including unsaponifiable, fraction of Coffea Arabica. Quantification was achieved by integration of the appropriate diagnostic signals in the NMR spectra using 2,6-Di-tert-butyl-4-methylphenol (BHT) as an internal standard (IS), as well as the PULCON method, which offers several advantages compared to IS. Bland-Altman analysis showed that PULCON and IS approaches are in a good agreement. Our results suggest that NMR can be a valuable tool for the determination of many compounds in fish oil and coffee oil, and can be used for quantifying the impact of the coffee roasting process. Green and roasted coffee beans, as well as brewed coffee and spent coffee grounds, were analyzed for their lipid components. 1H NMR offers a more rapid analysis compared to 13C NMR, as the spectrum can be recorded in less than 1 min, in contrast to 13C NMR analysis, which lasts from 10 min to one hour. The 13C NMR spectrum, however, is much more informative. It can provide quantitative data for a greater number of individual fatty acids and can be used for determining the positional distribution of fatty acids on the glycerol backbone. Overall, it was found that the major fatty acids in coffee oil are linoleic, oleic, linolenic and saturated fatty acids. Targeted analysis showed that, with the exception of linolenic acid, only minor changes occur in the fatty acid profile during roasting. A statistically significant increase occurs in the secondary oxidation product 2,4-hepta-dienal and free fatty acids after roasting. Additionally, 1,3-diacylglycerides significantly decrease with roasting due to their instability to hydrolysis. Untargeted analyses, namely PCA and OPLS-DA, revealed differences between green and roasted samples. MRI indicated significant morphological changes in coffee beans due to roasting, which may be responsible for these compositional variations. Finally, lipids extracted from spent coffee grounds can be successfully epoxidized and are therefore promising precursors for the production of bioplastics.
Emmanuel Hatzakis, Dr. (Advisor)
Yael Vodovotz, Dr. (Committee Member)
Luis Rodriguez-Saona, Dr. (Committee Member)
141 p.
Chemistry; Food Science
NMR spectroscopy; coffee; fish oil supplements; coffee oil; MRI

Recommended Citations

Citations

  • Williamson, Williamson, K. M. (2018). NMR Spectroscopy as a Robust Tool for the Analysis of Lipids in Fish Oil Supplements and Coffee [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523978049728289

    APA Style (7th edition)

  • Williamson, Williamson, Kathryn. NMR Spectroscopy as a Robust Tool for the Analysis of Lipids in Fish Oil Supplements and Coffee. 2018. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1523978049728289.

    MLA Style (8th edition)

  • Williamson, Williamson, Kathryn. "NMR Spectroscopy as a Robust Tool for the Analysis of Lipids in Fish Oil Supplements and Coffee." Master's thesis, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523978049728289

    Chicago Manual of Style (17th edition)

osu1523978049728289
1,437
© 2018, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.