Get keyword that used for sentiment analysis

[louiswe989]

Hello, I would like to get the keyword that used for sentiment analysis after the categories and score is printed.
Something like:

String: This cake looks amazing
Dominant: positive, scores: Array
(
[positive] => 0.5 //keyword: amazing
[neutral] => 0.251
[negative] => 0.25
)

is there a way to do that?