Food testing is the correct option.
Test for starch with iodine soln. The soln will change to blue-black if starch present and retain the color of iodine if not present.
Test for reducing and non-reducing sugars by Copper (II) sulphate, Hcl and naoh.
The Lipids can be tested by Sudan (III). The mixture will form a layer of brick-red ppts.
And to onserve the color change.