Extraction conditions and antioxidant activities of the extract of pineapple peel by ultrasonic

In the present work, a ultrasonic-assistant method was used for the extraction of antioxidants (total phenol and total flavonid) in pineapple peel. The experimental parameters, including extraction time, the ratio of solution to peel and the concentration of solvent on the contents of total phenol and total flavonid were investigated. Orthogonal designs were also used to test the results of single experiments. Based on the contents of total phenol and total flavonid, the optimal ultrasonic conditions for extraction were taken as follows: extracting 65 min with 75% ethanol solution by ultrasonic, and the solution to peel ratio was 10:1. The antioxidant activities of the extract were also investigated. The research here indicated that pineapple was rich in natural antioxidants and possessed excellent antioxidant activities. It also provided application for the waste produced in pineapple processing.