CAUSES OF RANCIDITY IN FEEDS AND FATS

Rancidity is a term that includes certain sensory changes that occur in some foods during storage, mainly in fats. When a raw material becomes rancid, volatile compounds are generated , with an unpleasant taste and smell, that is, therefore transferred to the feed that contains it . In fact , all foods containing lipids , even in extremely small quantities ( less than 1% ), may undergo oxidation, leading to rancidity (Wąsowicz et al, 2004).

There are many mechanisms involved in rancidity. T he best known is oxidative rancidity or autoxidation. During this process , hydroperoxides are produced, which after their degradation, are volatile and give off – flavours and bad taste to feed . In addition, simultaneous alternative pathways to autoxidation are produced, which generate dimers, epoxides and aldehydes from the oxidation initiation phase, parallel to the creation of hydroperoxides (Jacobsen, 2018).

Besides autoxidation, there are other processes that generate rancidity in fats. Hydrolytic ranci dity due to lipid hydrolysis, ketone rancidity in short – chain fatty acids, photooxidation, or reactions of oxidized lipids with other components present in foods , can be mentioned.

All these processes that lead to rancidity are irreversible, and o n ce the process starts it is very difficult to stop. Th is is the reason why it is much more effective to add antioxidants to feed and fats as early as possible.