褐変 is read as かっぺん (kappen) and means browning.
かっぺん
kappen
かっぺんはんのう
browning reaction
ひこうそてきかっぺん
non-enzymatic browning
こうそてきかっぺん
enzymatic browning
かっしょく
dark brown
かつをとく
to enter government service
かっしょくじんしゅ
brown race
あかげわしゅ
Japanese Brown (cattle breed)
かちいろ
dark indigo (almost black)
げきへん
sudden change
いへん
unusual event
かんこうへん
cirrhosis (of the liver)
りんきおうへん
adapting oneself to the requirements of the moment