processing... what a delightful word... and so hard to pin down

mechanical processing can mean cutting, drying or grinding... the food is still chemically unaltered.

chemical processing... it used to be adding salt or sugar to retard bacterail growth... but it can also be the start of the fermentation process. yum

or adding lye to corn to end up with hominey or boiling vegetables to remove things like oxalic acid.

heat can also change the chemistry... or using acid like vinegar or citrus.

Or you can process flour until it's little more than pure starch and then make a big deal out of adding back the missing vitamins.

Or substitute artificial flavors to a concoction of fats, carbohydrates and salt and get the ultimate junk food of your choice.

it ends up that you really need to understand what it is you are consuming and what steps are needed to ensure you are getting adequate nutrition. this was hard earned knowledge gained by our ancestors and passed on through the generations.. It is today in our modern world that we have become disconnected from our environment and that information.