Effect of pre-treatments on the saccharification of pineapple waste as a potential source for vinegar production

Properly saccharified pineapple waste can be considered the chief raw material for further fermentation into vinegar, which has wider applications as a food dressing or preservative both in industry and rural communities in developing countries. Previous investigations into the use of pineapple waste as a potential source for vinegar production highlighted the optimal conditions for the enzymatic hydrolysis step and outlined the need to facilitate enzyme access for saccharification. The effects of four physical pre-treatments were investigated to reduce biomass recalcitrance. Microwave heating (MW), boiling (B), cooking at high pressure with a pressure cooker (HPC) and with an autoclave (HPA) were carried out on peel and core samples for different lengths of time. When HPA preceded the enzymatic hydrolysis, the sugar yield was 70.2 g/kgfw and 72.8 g/kgfw from pineapple peel and core, respectively. When pineapple waste was subjected to HPC, B, or MW, the sugar yield obtained was lower than 60 g/kgfw. This study outlines the most effective pre-treatment method for obtaining a satisfactory sugar yield while maintaining practical feasibility when implementing the process prior to fermentation.