Tahani Alidee ^{(1) *} and Maytham Jales⁽¹⁾

(1). Department of Food Technology-General Commission of Scientific Agricultural Research (GCSAR), Damascus, Syria.

(*Corresponding author: Dr. Tahani Alidee. E-Mail: tahane.alidee@yahoo.com).

Received: 14/01/2024                 Accepted: 24/09/2024

Abstract: 

This study aimed to optimize the extraction conditions of phenolic compounds and antioxidant activity from Al-Shami mulberry leaves (Morus nigra) grown in Syria using Response Surface Methodology (RSM) and the Minitab17 program for use in food and pharmaceutical industries later. The fresh leaves were collected from Khan Arnabah, Al Qunaitra Governorate, Syria, in 2022, shade-dried, and kept in a dry place until they were analyzed. The phenolic compounds were extracted using ultra-pure deionized water (extraction solvent) related to solvent:solid ratio and the mixture was put in a water bath at three temperatures (30, 40, and 50 C) for 15, 30, and 45 minutes, and the design included 30 experiments. The total phenolic content (TPC) of the extracts was analyzed using the Folin-Ciocalteu colorimetric method, whereas the antioxidant activity was measured using the DPPH method. The TPC ranged from 11.47 to 43.97 mg of gallic acid equivalent per 100 g, and the antioxidant activity ranged from 31.98 to 79.78%. The statistical results showed that the linear effects of temperature, the ratio of water, and the quadratic effect of temperature on TPC were significant. Whereas the linear effect of the temperature on antioxidant activity was significant (P≤0.05). The optimum results showed that the maximum TPC value (420.91 mg/100 g) with the highest antioxidant activity (71.56%) was observed at an extraction time of 45 min, a temperature of 50 °C, and a solvent-solid ratio of 30:1 by using water as an extraction solvent.

Keywords: Al-Shami mulberry, Morus nigra, Syria, phenolic compounds, DPPH, RSM.          

Full Paper in Arabic: pdf