ANSWER
Rancidity is the process of which a substance becomes ‘bad’ with unpleasant smell or taste. It is the hydrolysis or autoxidation of fats which denotes to objectionable in taste and odor in oil. (Henry, 2015). Rancidity of an oil may impact the nutritional value of the oil or its intended application (Chong, 2012).
The Free Fatty Acids (FFA) content is expressed as a percentage of palmitic acid, the major fatty acid in palm oil. FFA content is the most used criterion for determining the quality of palm oil, as it must not exceed 5% (expressed as palmitic acid) according to Normes alimentaires pour huiles et graisses (CODEX-STAN 210). The presence of free fatty acids moieties in palm oi is an indication of the impairment of oil quality (Frank et al., 2011).
Peroxide value is another important parameter used to assess the quality of palm oil which is an indicator of the lipid peroxidation or oxidative degradation levels. It is used to assess the stability or rancidity of fats by measuring the amount of lipid peroxides and hydroperoxides formed during the initial stages of oxidation. Thus, it could be used to estimate to which extend spoilage of a dietary oil (level of rancidity). The Codex Alimentarius/FAO/WHO recommends a maximum peroxide value of 10 meqO2/kg1 palm oil (Frank et al., 2011).
Remark
1meqO2/kg: milliequivalents of active oxygen/kg oil
References
Henry, L. N. (2015). Effect of Light and Air on the Quality and Stability of Selected Vegetable Oils. International Journal of Innovative Research in Science, Engineering and Technology, 5(5), 1-7.
Ogan, I., Marie-Josee, D. & Michael, N. (2015). Palm oil: Processing, characterization and utilization in the food industry – A review. Food Bioscience, 10, 26-41. https://doi.org/10.1016/j.fbio.2015.01.003
Chong, C. L. (2012). Measurement and Maintenance of Palm Oil Quality (pp. 431-470). Urbana, Illinois: AOCS Press.
Frank, N. E. G., Albert, M. M. E., Laverdure, D. E. E. & Paul, K. (2011). Assessment of the quality of crude palm oil from smallholders in Cameroon. Journal of Stored Products and Postharvest Research, 2(3), 52-8.
Codex Alimentarius Commission. (2005). Normes alimentaires pour huiles et graisses (CODEX-STAN 210).
