Recovery of glucose and acetic acid from Piper betle Linn leaves by subcritical water hydrolysis

Piper betle Linn (PBL) leaves contain high carbohydrate, which can be hydrolysed into glucose and acetic acid by hydrolysis method. Subcritical water hydrolysis (SWH) is an environmentally friendly method that uses water as a solvent and is suitable for the hydrolysis process. Thus, the aim of this study is to evaluate the glucose and acetic acid recovered from PBLleaves using SWH. SWH was performed under different process conditions (temperature range from 100 to 275°C and time range from 5 to 30 min) using a factorial design. Glucose and acetic acid were determined using high performance liquid chromatography (HPLC) with a refractive index (RI) detector. The ANOVA results show that temperature, time, and the interaction of temperature and time have a significant impact on the yield of glucose and the acetic acid concentration. The yield of glucose and acetic acid show opposite trend, with glucose degrading to acetic acid. The highest glucose concentration was obtained at two different conditions of SWH at 175°C for 30 min (6.237 mg/g extract) and 200°C for 5 min (6.143 mg/g extract), while the highest acetic acid concentration was obtained at 275°C for 15 min (2.536 mg/g extract).