Received: 08-08-2016 / Accepted: 12-04-2017
Cacao tree (Theobroma cacao L.) is widely grown in the Central Highlands of Vietnam. During the harvest period, the leaves are not used for any purpose. The present study was conducted to determine the suitable extraction conditions to obtain a rich polyphenol and antioxidative extract from the cacao leaf. The dried cacao leaf extract was applied to prevent lipid peroxidation in the cobia muscles. The suibtale extraction conditions were determined as follows: the extraction solvent was 50% ethanol, the extraction temperature was 75°C, the extraction time was 90 min and the extraction method was ultrasound-assisted extraction. The extract obtained under the suitable conditions had the total polyphenol level, DPPH radical scavenging activity (EC50) and total reducing power (EC50) of 21.33 mg GAE/g dry matter, 0.05 mg/ml and 0.39 mg/ml, respectively. The dried cacao leaf extract was effective in retarding lipid oxidation of minced cobia muscles during cold storage of 9 days. Thus, the cacao leaf extract had a potential to be used as a natural antioxidant to control lipid oxidation during the cold storage of aquatic products.