I found the decrease in FFA (%oleic acid) content of fish mince after a certain period of days during frozen storage. What may be the probable reason? In paper, FFA increased with the increased in storage. Is there any paper that given about the decrease in FFA? Thank you
Your finding appears to be dubious. Under frozen conditions, the likelihood of rancidity drastically reduces and hence, the levels of free fatty acids either stabilizes or slightly increase during analysis (freeze-thaw cycle).
Check with the protocol and try with AOAC method.
Did you conducted peroxide value (PV) test? Or TBARS test. It is may be due to the peroxidation.
DearJag Pal,
During frozen storage study so many reactions taking place in fish meat which includes rancidity, protein break down and microbial spoilage etc. FFA is an indicator of hydrolytic activity due to lipolytic enzymes. Usually this will increase during storage. when the basic amines are formed by proteolytic action these components along with water in fish meat react with free fatty acids and a reduction in acidity occurs. this may be a possible reason for your observation.
Thank you for kind information. I have found two papers regarding the decrease in FFA in later stages of storage. In 1st paper, reason could be the interaction with protein. 2nd paper- might be related to the increased lipid oxidation. It could be attributable to the growth of some microorganisms that can use the FFA as an energy source. Is there any paper about how FFA interaction with protein leads to decrease in FFA ?
We have found that when we use an antimicrobial (lactates, buffered vinegar) the secondary oxidation products continue to increase possibly indicating enzymatic (raw only) and autoxidation (as measured by hexanal levels by GCFID) proceeds during storage. We generally assume the hexanal levels are indicative of fatty acid oxidation (analytical methods to measure decrease in fatty acid levels seems to be less sensitive). Some studies related to animal fats indicate that free fatty acids oxidize at a faster rate than fatty acids bound by glycosidic linkages to glycerol.
- Badges
- Science topic
- Similar topics
- Biological Science
- Zoology
- Ichthyology
- Vertebrates
- Fish