Alternative Extraction Method of Bioactive Compounds from Mulberry (Morus nigra L.) Pulp Using Pressurized-Liquid Extraction

Black mulberry (Morus nigra L.) is one of the most important species of the genus Morus as its fruit contains substantial levels of anthocyanins and phenolic compounds which show a potentially positive effect on the human health. Nowadays, PLE is becoming a promising extraction technology. Therefore, the development of fast extraction methods of anthocyanins and phenolic compounds from mulberry pulp using pressurized-liquid extraction (PLE) has been studied in this paper. The operating conditions (solvent, temperature, pressure, purge time, pH, and flushing) were investigated by a Box-Behnken design. Analysis of the model clearly showed that the most influential factors were temperature and solvent composition. The optimum extraction conditions for anthocyanins were 47.2% methanol in water, a temperature of 75.5 A degrees C, pressure of 200 atm, a purge time of 90 s, pH 3.01, and 50.2% for flushing. The best conditions for the extraction of phenolics were 74.6% methanol, 99.4 A degrees C, 100 atm, 90 s purge, pH 7, and 100% flushing. The optimum extraction time was 10 min. The precision values of the methods were also evaluated and excellent results (RSD < 5%) were obtained. The developed methods were successfully applied to several mulberry marmalade samples. The results using PLE were compared to those achieved by UAE methods. Similar extraction yields were obtained for anthocyanins by PLE and UAE under optimized conditions; however, PLE required less methanol consumption. Besides, PLE showed higher extraction efficiency for total phenolic compounds. From the results, it can be concluded that pressurized-liquid extraction can be considered as an efficient alternative and powerful tool for the extraction of bioactive compounds from mulberries.