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Chutima Ponchurdchai. Deriving a NMR method for use in assessing the stability of cold-pressed rice bran oil. Master's Degree(Chemistry). Thammasat University. Thammasat University Library. : Thammasat University, 2015.
Deriving a NMR method for use in assessing the stability of cold-pressed rice bran oil
Name: Chutima Ponchurdchai
keyword:
Rice bran oils
;
Rice oil
;
Quality
;
1H NMR
;
13C NMR
Abstract:
Oil obtained from the rice bran (Oryza sativa L.) has attracted much interest due to its rich source of γ-oryzanol, tocopherols and tocotrienols. Those compounds are considered to have an important role in preservation of the quality of oils, due to their antioxidant activity. Oil quality is evaluated by classical methods such as acid value, peroxide value, and iodine value and by chromatographic methods such as gas chromatography-mass spectrometry (GC-MS). In addition, a recently developed rapid and simple alternative method using nuclear magnetic resonance (NMR) spectroscopy allows for the determination of the proportions of the different acyl groups and minor components in oil. In this research, the stability of cold-pressed RBO samples from 2 different regions (Lopburi province, L-RBO and Yasothorn province, Y-RBO) were evaluated over a year through monitoring their stability. 1H NMR assignments of oils are applied to study the degradation of RBOs, normally caused by hydrolysis and oxidation over period of times. The integration of signals in the 1H NMR spectra allows for the monitoring of the fatty acid compositions throughout the RBO aging process. GC-MS was also used to determine the fatty acid composition, and compared with results from 1H NMR. Both 1H NMR and 13C NMR spectra were used to identify the formation of monoglyceride, diglyceride, and free fatty acids and to observe oxidative changes for quality assessment. This study is the first example where RBOs are assessed using the rapid and convenient NMR method to monitor stability, and these results could be applied to the assessment of the freshness and quality of organic or non-organic, refined or cold-pressed RBOs. The aim of this work is to achieve a practical methodology for rapid quality assessment of cold-pressed RBOs used in food, cosmetic and pharmaceutical applications. The results confirm that cold-pressed can maintain their quality over one year storage under no air and light exposure. One year shelf-life of cold-pressed RBO with quality assessment has been reported in molecular level and revealed low degree of hydrolytic degradation with no primary or secondary oxidative intermediates
Thammasat University. Thammasat University Library
Address:
BANGKOK
Email:
preserv@tu.ac.th
Name: Jirada Singkhonrat
Role:
advisor
Name: Smith, Christopher
Role:
co-advisor
Created:
2015
Modified:
2021-09-29
Issued:
2021-09-29
วิทยานิพนธ์/Thesis
application/pdf
eng
DegreeName: Master of Science
Level: Master's Degree
Descipline: Chemistry
Grantor: Thammasat University
©copyrights Thammasat University
RightsAccess:
ใช้เวลา
0.033775 วินาที
Chutima Ponchurdchai
| Title | Contributor | Type |
|---|---|---|
| Deriving a NMR method for use in assessing the stability of cold-pressed rice bran oil
มหาวิทยาลัยธรรมศาสตร์ Chutima Ponchurdchai | Jirada Singkhonrat Smith, Christopher | วิทยานิพนธ์/Thesis |
Jirada Singkhonrat
Smith, Christopher
| Title | Creator | Type and Date Create |
|---|---|---|
| Deriving a NMR method for use in assessing the stability of cold-pressed rice bran oil
มหาวิทยาลัยธรรมศาสตร์ Jirada Singkhonrat;Smith, Christopher | Chutima Ponchurdchai | วิทยานิพนธ์/Thesis |