We have now started watching The Botany of Desire. Today we watched the Introduction and the section on Sweetness (which focuses on the apple). Some of the clips are available at the following link:
http://www.pbs.org/thebotanyofdesire/lesson-plan-sweetness.php
The following is a line graph similar to the second one you created in our Sweetness Lab.
The following link is to an article on the science of how we detect sweetness
Diverse tastes: Genetics of sweet and bitter perception