Protein hydrolysate is a complex mixture of peptides of different chain lengths and free amino acids that is produced through heating with acid or by addition of proteolytic enzymes amino acids (Manninen, 2009).

Whey concentrate, casein protein, whey isolates, hydrolysate protein, soy protein, milk protein isolate, and egg albumin are proteins used by bodybuilders.

Is is possible to determine how many amino acids are present in th hydrolysate if you forgot to mark the position of the solvent front when you tested the hydrolysate of aspartame

Yes

Hydrolysis is the decomposition of materials in water and usually involves strong acid or alkaline pH. In the case of gelatin (which is a protein) it is hydrolysed in alkaline solution with heat, so something like a few grams per litre of caustic soda will make a solution which decomposes gelatin when heated. The solution of decomposed gelatin is referred to as gelatin hydrolysate.