| Date | May 2012 | Marks available | 3 | Reference code | 12M.3.sl.TZ1.F2 |
| Level | SL | Paper | 3 | Time zone | TZ1 |
| Command term | State | Question number | F2 | Adapted from | N/A |
Question
Rancidity limits the shelf life of foods containing oils and fats.
Rancidity can occur as a result of two separate processes. State these processes and explain the difference between them.
Markscheme
hydrolytic rancidity and oxidative rancidity;
hydrolytic rancidity involves (reaction with water) breaking ester bond / formation of a fatty acid and glycerol / OWTTE;
oxidative rancidity involves reaction of carbon-carbon double bond/C=C with oxygen / addition reaction with oxygen;
Examiners report
The majority of candidates struggled in part (a) where the difference between hydrolytic and oxidative rancidity was seldom written correctly.
Syllabus sections
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