Water activity (aw) of osmotically dehydrated and CaCl2 (OD-CaCl2) infused
purple sweet potatoes are shown in Figure 2. aw was decreased in the samples during
storage under room temperature and a low temperature (4˚C). The initial aw of
osmotically dehydrated and CaCl2 infused purple sweet potatoes was at 0.95 prior to
the storage. The minimum level of aw found at room temperature storage and it was
ranged 0.9343 at 10 days and whereas, potatoes stored at 4˚C was ranged lowest aw
(0.9400) on 5 days and then it fluctuated throughout the storage. aw of osmotically
dehydrated purple sweet potatoes during storage was significantly differed among the
different storage temperature. The samples stored at room temperature was losing aw
more quickly when compared with 4˚C. Water activity influences the reaction such as oxidation, browning in foods as the growth of microorganisms in food. The slightly
increased of a
w in samples that stored under a low temperature could absorb the
moisture in the storage environment. Ankita et al. (2014) reported OD treated papaya
found decreased of a
w. However, this study showed that OD-CaCl2 was not sufficient
enough to decrease aw, and as a consequence, the growth of microorganism found on
the stored samples (see figure 5).