Microwave modification of sugar cane to enhance juice extraction during milling

Abstract

Sugar extraction from cane requires shredding and crushing, both of which are energy intensive activities. Cane shredders account for almost 30% of the total power requirements for the juice extraction train in a sugar mill with four mills. Shredder hammers also wear quickly during the crushing season and need to be regularly maintained or replaced. Microwave pre-treatment of other plant based materials has resulted in significant reductions in total processing energy. This paper briefly reviews the underlying structure of sugar cane and how microwave pre-treatment may interact with sugar cane. Microwave treatment reduced the strength of sugar cane samples to 20 % of its untreated value. This strength reduction makes it easier to crush the cane and leads to a 320 % increase in juice yield compared with untreated cane when cane samples were crushed in a press. There was also a 68 % increase in Brix %, a 58 % increase in total dissolved solids, a 58 % reduction in diffusion time, a 39 % increase in Pol %, and a 7 % increase in juice purity compared with the control samples after 60 minutes of diffusion in distilled water.