Ultrasound-assisted extraction of phenolic compounds and soluble sugars from the stem portion of peach palm

The aim of this work was to investigate the ultrasound-assisted extraction (UAE) of total phenolic compounds (TPC) and soluble sugars (SS) from the by-product of peach palm (stem portion). The effect of the processing variables temperature (30-60 degrees C), time (15-45 min), and power density (8.47-25.42 mW cm(-3)) were evaluated. The maximum contents (dry basis) of TPC (345.81 +/- 2.82 mg gallic acid equivalent 100 g(-1)) and SS (16.68 +/- 0.24 g 100 g(-1)) were obtained, respectively, at 60 degrees C, 30 min and 8.47 mW cm(-3)(condition 1) and 60 degrees C, 45 min and 25.42 mW cm(-3); in these conditions, the extracts had higher sucrose content than glucose and fructose. The highest content of phenolic acids (gallic, coumaric, vanillic, ferulic, trans-cinnamic) and highest antioxidant activity were obtained in the condition 1. UAE can be considered an effective method for the extraction of TPC and SS from peach palm stem. Practical applications The ultrasound-assisted extraction (UAE) was applied in the by-product of heart-of-palm (stem portion) to the removal of phenolic compounds and soluble sugars. To realize this process with time and energy economy, the maximized condition of extraction observed at 60 degrees C, 30 min, and 8.47 mW cm(-3)was the most interesting. This extract showed the highest content of phenolic compounds and highest antioxidant potential, which can allow its application to preserve the shelf life of food products or to produce food supplements. The soluble sugars extracted can also be used, as example, in fermentative process. Therefore, the results indicate the viability of UAE to offer alternatives to utilization of stem portion of peach palm.