Shrinkage of dried durian chips
Table 2 shows the shrinkage percentage of durian chips under each drying condition. The HA method resulted in dried durian chips having a higher percentage of shrinkage than the MWVC and MWHA methods due to its long drying time. High microwave power and low vacuum pressure levels in the MWVC method helped create more porous structures as mentioned above and resulted in a low percentage of shrinkage. As the microwave power increased and vacuum levels decreased, the percentage of shrinkage also decreased. Similar results were also reported in Fiagiel (2010) and Maskan (2001). Without the effect of the low boiling point of water at low pressure, the dried durian chips from the MWHA method had more shrinkage than those from the MWVC method.