Bentonite is a clearing(fining) agent and pectic enzyme is an agent to break down the cellular structure of fruit nad help extract more juices and color from a fruit and reduces the hazes caused by excess pectin so it is also a clarifier.
Bentonite is a form of clay that is used to clear the wine of particles in suspension that cause a haze. It is used mostly in white wines.
When making wine from pure juice (like grocery bought juice) you can add some bentonite to the juice. The bentonite will then act as a vessel for the yeast to lift on in their yourney through the must.
It helps fermentation by spreading the yeast better throughout the whole must.
But besides that it is just an aid in clearing a wine.
Pectic enzymes are a natural product that break down the pectics in a juice. Now pectic is what makes a jam or jelly thick. We do not want that. We want a juice. So the enzyme will break down the pectic and fruit cells. That way more juice is freed, just what we need for winemaking.
I did some tests with pectic enzymes on my web-log describing with photos exactly what it does and when it does it.
You can find these tutorials here: