6730
In a second step , differently produced apple seed extracts and a phloridzin model solution were enzymatically treated by mushroom polyphenol oxidase to investigate the rate of pigment synthesis .
 phloridzin, polyphenol
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 phloridzin, polyphenol