25174
The greatest increase in non - protein nitrogen ( NPN ) content during ageing occurred in an inoculated sample , corresponding with the more pronounced decrease in pH .
 Chemical: nitrogen
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: nitrogen 
Answer:
 Chemical: nitrogen