May unfortunately see can contains rejected mushroom starch component (11)

'rejected mushroom starch component' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'may unfortunately see can' is the wordplay.
'unfortunately' is an anagram indicator (a bad or unfortunate spelling).
'see' becomes 'lo' (archaic exclamation meaning 'look!').
'can' becomes 'pectin' (I can't justify this - if you can you should give a lot more credence to this answer).
'may' anagrammed gives 'amy'.
'amy'+'lo'+'pectin'='AMYLOPECTIN'

'contains' acts as a link.

Can you help me to learn more?