Task: Classify the mental state of the tweeter based on the tweet, determining if it is 'neutral or no emotion' or characterized by any of the provided emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust).
Tweet: Did you know apples turn brown when a enzyme called polyphenol oxidase reacts with oxygen! Well I do #dull #applefacts 🤓🍏
This tweet contains emotions: 
joy, optimism