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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Healthy Processed Foods Research » Research » Publications at this Location » Publication #314522

Title: Beta-Carotene chemical stability in nanoemulsions was improved by stabilized with Beta-Lactoglobulin-Catechin conjugates through free radical method

item YI, JIANG - Jiangnan University
item Zhang, Yuzhu
item ZHONG, FANG - Jiangnan University
item LIANG, FANG - Jiangnan University
item MA, JIANGUO - Jiangnan University

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2014
Publication Date: 12/16/2014
Citation: Yi, J., Zhang, Y., Zhong, F., Liang, F., Ma, J. 2014. Beta-Carotene chemical stability in nanoemulsions was improved by stabilized with Beta-Lactoglobulin-Catechin conjugates through free radical method. Journal of Agricultural and Food Chemistry. 63:297-303. doi: 10.1021/jf5056024.

Interpretive Summary: High provitamin A activity and strong antioxidant activity make beta-carotene (BC) an important carotenoid for human nutrition. However, BC is highly susceptible to isomerization, oxidation, and degradation due to the polyunsaturated structure and its application in food systems was limited. An effective method for encapsulating BC and protect it from oxidation is desired. The whey protein beta-lactoglobulin (BLG) has protective activity when used to encapsulate bioactive compounds. This study reports the generation and characterization of BLG-catechin conjugates and its application as an improved encapsulation material for BC protection and delivery.

Technical Abstract: Beta-lactoglobulin (BLG)-catechin conjugates were prepared by a free radical method and investigated with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), electrospray ionization-mass spectrometry (ESI-MS), and far-UV circular dichroism (CD). Covalent binding between BLG and catechin were confirmed with SDS-PAGE and ESI-MS. About 93% of beta-lactoglobulin was conjugated with catechin or catecin fragments according to the gel intensity analysis software. Far-UV CD results showed that the content of ß-sheet decreased with a corresponding increase in unordered structures after grafting. Both nanoemulsions with mean particle size between 160 and 170 nm were prepared. Both the rate of particle growth and the total beta-carotene (BC) loss at 50 °C were significantly greater than at 4 and 25 °C. The retention rates of BC in nanoemulsions were 27.8% and 48.6% for BLG and BLG-catechin conjugates, respectively, after 30 days of storage at 50 °C. The BC retention encapsulated in nanoemulsion was significantly improved using BLG-catechin conjugates, compared with BLG alone. The increase of BC retention in nanoemulsions encapsulated with BLG-catechin conjugates was due to the significant improvement of antioxidative properties (reducing power, free radical scavenging activity, and hydroxyl radical scavenging activity) of BLG after covalent binding with catechin. The results indicated that the proteins modified with polyphenols can be widely used in a labile bioactive compounds encapsulation delivery system