Answer to Question 1
The acidic environment prevented oxidizing and browning of the avocado.
Answer to Question 2
Apples cooked in water alone will have different characteristics than those cooked in sugar solutions. Heating destroys the membrane's ability to prevent the loss or uptake of solutes through the cell wall. Heating in water compromises and softens the texture. Placing the apples in a low-concentrated sugar solution allows for water to diffuse out of the cells and the sugar to diffuse in which helps fruit retain its shape and firmness. Excess sugar added during cooking will result in a mushy product. The apples prepared in Splenda had a distinctly sweeter flavor, different from granulated sugar. These apples also retained more rigidity in their texture.