The three formulations, prevented water loss by producing high
relative humidity at the surface of sliced apples, thus reducing the gradient
to the exterior. The best coating to prevent water loss was 2%AA+
0.5%CaCl2 +1%chitosan (pb0.05), which allowed a 14.3% loss compared
to 19% for control apples at day 2 (pb0.05). No performance differences
were found between 1% chitosan and 2%AA+0.5%CaCl2,which allowed
about 15% less weight loss than the control apple slices (pb0.05) at day
10, although it is well known that hydrocolloids do not perform very well
as water vapor barriers in high water activity foods due to their high
hydroscopic nature. However, in this case , 2%AA+0.5%CaCl2 +1%
Chitosan and 2%AA+0.5%CaCl2 performed relatively well in limiting
water loss. This is probably due to the ability of calcium to cross-link
chitosan, making the coating insoluble, bearing in mind that the capacity
of hydrocolloid-based films to function as water vapor barriers increases
as their solubility in water decreases (Kester & Fennema, 1986).