U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Healthy Processed Foods Research: Albany, CA
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Pacific West Area Albany, California Western Regional Research Center Healthy Processed Foods Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications
- Rebecca Milczarek *(Scopus)*
- Yuzhu Zhang *(PubMed)*

Title:   Author  item
                                            ZHU, SONG - Jiangnan Universityitem
                                            LI, YUE - Jiangnan Universityitem
                                            LI, ZHE - Jiangnan Universityitem
                                            MA, CHAOYANG - Jiangnan Universityitem
                                            LOU, ZAIXIANG - Jiangnan Universityitem
                                            Yokoyama, Wallace

                                                         - *Wally*item
                                            WANG, HONGXIN - Jiangnan University
  Submitted to: Food Research International
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 10/17/2013
                                    Publication  Date: 2/17/2014
                                    Citation: Zhu, S., Li, Y., Li, Z., Ma, C., Lou, Z., Yokoyama, W.H., Wang, H. 2014. Lipase-catalyzed synthesis of acetylated EGCG and antioxidant properties of the acetylated derivatives. Food Research International. 56:279-286.Interpretive Summary: Unsaturated and polyunsaturated fats become rancid due to oxidation.  Synthetic antioxidants are soluble in fat and efficiently prevent oxidation.  Epigallocatechin-3-O-gallate is a natural, water soluble antioxidant found in green tea.  This study shows that acetylation can increase its oil solubility and delay the oxidation of fat.
                                Technical Abstract: (-)-Epigallocatechin-3-O-gallate (EGCG) acetylated derivatives were prepared by lipase catalyzed acylation of EGCG with vinyl acetate to improve its lipophilicity and expand its application in lipophilic media. The immobilized lipase, Lipozyme RM IM, was found to be the optimum catalyst. The optimized conditions were as follows, 1:1 of the molar ratio of EGCG to vinyl acetate, 2.0 % (w/w of both substrates) of enzyme amountt, and 84.5 % conversion was obtained after 8 h reaction at 40 °C in acetonitrile. The presence of mono-, di- and tri-acetylated derivatives in acetylated
EGCG were confirmed by LC-MS-MS and the tri-acetylated EGCG was identified as 5’, 3’’, 5’’-3-O-acetyl-EGCG by NMR. Their enhanced lipophilicity was confirmed by octanol-water partition coefficient. The antioxidant activity of the acetylated EGCG derivatives were superior to butylated hydroxytoluene (BHT), tert-butyl hydroquinone (TBHQ) and EGCG as determined by peroxide values (POV) in sunflower oil as well as by the p-anisidine method. Acetylated EGCG exhibited the highest 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (IC50 of
0.09 mg/mL) compared to EGCG, BHT and TBHQ. Acetylated EGCG might be used as a potent antioxidant for controlling oxidation of sunflower oil.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov