Comparing extraction methods for the determination of tocopherols and tocotrienols in seeds and germinating seeds of soybean transformed with OsHGGT

• Published in: Journal of food composition and analysis 2012-08, Vol.27 (1), p.70-80
• Main Authors: Lee, Yu Young, Park, Hyang Mi, Lee, Choon Ki, Kim, Sun Lim, Hwang, Tae-Young, Choi, Man Soo, Kwon, Young-Up, Kim, Wook Han, Kim, Si Ju, Lee, Sang Chul, Kim, Yul Ho
• Format: Article
• Language: English
• Subjects: Antioxidant activity; Biological and medical sciences; Cereal and baking product industries; Direct extraction; Extraction; Food analysis; Food composition; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; Methods of analysis, processing and quality control, regulation, standards; Rice homogentisate geranylgeranyl transferase (OsHGGT); Saponification; Soxhlet extraction; Soybean; Tocopherols; Tocotrienols
• ISSN: 0889-1575; 1096-0481
• DOI: 10.1016/j.jfca.2012.03.010

► Transgenic soybeans producing tocotrienols, not found in soybean, were developed. ► We applied different extraction methods for analyzing of tocopherol and tocotrienol. ► In transgenic seeds, rapid Soxhlet extraction yielded the highest analytical values. ► Direct extraction in germinating seeds provide fast, simple, reproducible procedures. ► A direct correlation was observed between the activity and the content of vitamin E. Previously, transgenic soybeans were generated and reported to produce tocotrienols (α-, γ- and δ-tocotrienols), compounds not normally found in soybean. Three procedures were evaluated to optimize the extraction method for transgenic soybean seeds and germinating seeds. Significant differences were observed among the extraction methods in seeds and germinating seeds. In seeds, the highest analytical values (tocopherols, 37.11mg100g−1; and tocotrienols, 1.54mg100g−1) were observed by using rapid Soxhlet extraction. In germinating seeds, the content of transgenic soybean (B20 and C5) total vitamin E (tocopherols, 18.04, 20.73mg100g−1; and tocotrienols, 0.82 and 0.84mg100g−1) by direct extraction was approximately 16% and 9% greater than the amount obtained by saponification. In addition, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) tests demonstrated a direct correlation between the radical-scavenging capacity and the total content of natural tocopherols and tocotrienols. Therefore, these results suggest that an optimal extraction method will provide a fast, simple, reproducible procedure for analyzing tocotrienols and tocopherols. Furthermore, this method may be used to determine novel minor functional compounds such as tocotrienols for the evaluation of biological activity.