Decoction and Subcritical Water Extraction of Date Palm Seed: Comparison of Bioactive Compound Analysis

Abstract

Date palm is one of the oldest cultivated plants and there are several thousand cultivars and varieties around the world. Date seed is a byproduct and a waste of date fruit. It is usually discarded and utilized as animal fodder. Studies have shown that date seeds are rich in dietary fibre, phenolic and antioxidant which can be extracted for industrial purpose. The purpose of this study was to conduct extraction of Safawy date palm seed using decoction and subcritical water extraction (SWE) followed by bioactive compound analysis. The reason for conducting this study is because there are only a few sources that reports the information for the bioactive compound analysis of this particular date palm variety. Extraction of date seed was conducted using decoction and SWE with extraction of 15 minutes and a ratio of sample to water of 1:20. Moreover, the bioactive compound analysis conducted was for the total phenolic and flavonoid content, and antioxidant activity using the Folin-Ciocalteu, aluminium colorimetric and DPPH method respectively and was measured using spectrophotometer. The findings have shown that Safawy date seed contains high phenolic and flavonoid content. SWE extract has shown the highest amount of phenolic and flavonoid content at 602.04  3.28 mg GAE/g and 81.75  2.84 mg QE/g respectively. Furthermore, date seed was reported to have at least 90 % antioxidant activity at 1000 ppm. However, extracts of decoction and SWE resulted in reduction of antioxidant activity at 87.29 and 86.50 % respectively. Overall, SWE offers a better extraction result than decoction with a slight reduction in antioxidant activity. In addition, the results showed that date seed potentially can be used for the production of functional foods and pharmaceuticals.