I would like to know definitively, whether or not, maltodextrin from corn and high fructose corn syrup are essentially the same ?

Not.: Both may be made from corn (MD is also made from wheat), but HFCS is first and foremost a sweetener whereas MD is often used for its texture or thickening rather than sweetening properties. HFCS is a physical mixture of fructose and glucose whereas MD is a polysaccharide of glucose - usually 3-17 units long. Both HFCS and MD contain a large number of calories.