Changes in fatty acids during storage of artisanal-processed freshwater sardines (Rastrineobola argentea)
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Date
2023
Journal Title
Journal ISSN
Volume Title
Publisher
WILEY
Abstract
For ages, indigenous small fish species have been important in food and nutritional
security of poor communities in low income countries. Freshwater fish, in particu-
lar fatty fish species are attracting a great attention because they are good sources
of health promoting long chain omega-3 fatty acids. Docosahexaenoic acid (DHA,
C22:6n-3), Docosapentaenoic acid (DPA, C22:5n-3) and eicosapentaenoic acid (EPA,
C20:5n-3) are the main omega-3 PUFAs known to confer health benefits in humans if
consumed in required amounts. While nutritionally valued, omega-3 PUFAs in fish are
susceptible to oxidative damage during processing, transportation and subsequent
storage. Lake Victoria sardines (Rastrineobola argentea), are rich source of chemically
unstable omega-3 fatty acids DHA, DPA and EPA. Traditionally, sardines are pre-
served by sun drying, deep frying and smoking. Sardine products are transported,
stored and marketed at ambient temperatures. Generally, uncontrolled and higher
temperatures are known to increase vulnerability of polyunsaturated fatty acids to
oxidation which in turn results into loss of nutritional and sensory qualities. This study
investigated changes of fat acids in sun dried, deep fried and smoked sardines during
storage. Lipolysis and the progressive hydroperoxides formation were monitored by
free fatty acids (FFAs) and peroxide value (PV) respectively. None volatile secondary
products of lipid oxidation were measured by thiobabituric acid reactive substances
(TBARS). Fatty acids were analyzed by gas chromatography with a flameionization de-
tector (GC-FID). Deep fried sardines maintained the lowest and apparently stable PV,
TBARS and FFAs. Proportions of saturated fatty acids and polyunsaturated fatty acids
decreased with time while that of monounsaturated fatty acids increased. Omega-3
fatty acids EPA, DPA and DHA decreased with increase in storage time. In 21 days of
storage, DHA was oxidized beyond detectable levels in all sardine products. Gradual
increase in FFAs in sun dried sardines was suggestive of lipid hydrolysis induced by
enzymes.
Description
Journal Article of Food Sci Nutr:1–8.
Keywords
Fatty acid profile, Lake Victoria, Omega-3 fatty acids, Rastrineobola argentea