Abstract:
Sardines (Rastrineobola argentea), popularly known as “dagaa” is one of the leading
commercial fish species of Lake Victoria. The fatty fish species are attracting great attention
because they are good source of omega-3 polyunsaturated fatty acids which are vital for a wide
range of biological functions and are implicated in the prevention of numerous diseases. While
nutritionally valued omega-3 fatty acids are highly susceptible to oxidation during fish
processing due to their unsaturated nature. Oxidation reactions result in loss of omega-3 fatty
acids and production of undesired off-flavours which discourage consumption and limit
diversification of sardine products.Synthetic antioxidants may be used to prevent lipid oxidation
but have been claimed to be carcinogenic at higher levels. The replacement of synthetic
antioxidants with ones of natural origin is now in demand.
In this study, natural antioxidants rich extracts from clove buds were applied on sardines in a bid
to impede lipid oxidation during deep frying process. Lipid oxidation was assessed by peroxide
value (PV), volatile compounds and fatty acid profiles using Gas chromatograph (GC-MS and
GC-FID).The results showed that natural antioxidants from clove buds reduced peroxidation and
protected highly unsaturated omega-3 fatty acids from oxidation during deep frying process.
Total polyunsaturated fatty acids amounted 7.30 % in pre-treated deep fried sardines.Retention
of omega-3 fatty acids was 0.70 % more in pre-treated than untreated fish. Significantly lower
amounts of representative volatile compounds were produced in sardines pre-treated with clove
extracts. The study demonstrated feasibility to pre-treat sardines with natural antioxidants for
protecting omega-3 fatty acids against oxidation during deep frying.
