Starch is not included in the bag because it is used as a thickening agent in the soup and would not have the same texture or flavor profile if it was included in the bag before cooking.
The starch solution diffuses out of the bag during osmosis.
The IKI Is small so the pores of in the bag allow it to go throuch but the starch is to big. So based on the size of the molecules, the glucose and IKI would move out of the bag, the water in, and the starch left in the beaker.
Solutions tend to move from areas of high concentration to areas of low concentration. So if a bag is permeable to starch, the starch will rush into the bag.
You can determine if iodine entered the dialysis bag containing starch by performing a simple iodine test. Add a few drops of iodine solution to the bag. If the iodine turns blue or purple, it means that iodine has entered the bag and reacted with the starch inside.
corn starch
The starch indicator solution will turn dark blue/black since it will react with the starch in the solution. Glucose will not react with the starch indicator, so it will remain the same color. This can be used to detect the presence of starch in the solution.
Iodine is permeable to a plastic bag because the starch's molecules are too large to pass through the bag (starch is a complex sugar made of a large chain of monosaccharides), while the Iodine can pass through since iodine is usually only two Iodine atoms (I2).
I am not quite sure what happens when corn starch and iodine are mixed but when corn starch, iodine and water are mixed, it creates a purple solution. The darkness of the colour mostly depends on the iodine. Without the starch with iodine and water, it is deep yellow or brown.
Flour and corn starch are measured the same, but the results aren't always the same.
In the dialysis tubing bag experiment, if glucose and I2KI are present inside the bag, the color of the I2KI solution will turn blue-black due to the reaction of iodine with starch present in the glucose solution. This color change indicates the presence of glucose inside the bag.
After 20 minutes, the glucose molecules will diffuse out of the bag through the partially permeable membrane because they are smaller in size than the starch molecules. The starch molecules, being too large to pass through the membrane, will remain inside the bag.