The results of the application of HP pretreatments are reported in Fig. 3. HP applied with pressure cooker (HPC) at 143.27 kPa and 110
C resulted in significantly higher amounts of sugars from pineapple core than from peel samples especially for longer time periods (Fig. 3a). These results were already observed in a previous study by our group in which HPC was used to prepare pineapple waste for lignocellulosic hydrolysis (Roda et al., 2014). For the peel samples, the highest sugar yield was achieved with the shortest treatment time. These results were consistent with the Del Campo et al. (2006) study, in which HP pre-treatment at 110C for 5 min was optimal for enhancing sugar yield from tomato peels. In hydrothermal-