Effects of Onion (Allium cepa) and Lemongrass (Cymbopogon citratus) Extracts on Lipid Oxidation and Acceptability of Frozen Deboned Milkfish (Chanos chanos)

Abstract

This study was conducted to determine the effectiveness of red onion (Allium cepa) and lemongrass (Cymbopogon citratus) extracts on lipid oxidation and on its effect on acceptability of frozen deboned milkfish (Chanos chanos). The deboned milkfish fillets were immersed in 5% (v/v) aqueous solutios of onion and lemongrass extracts including the Vitamin C and stored up to 30 days in frozen storage (18°C). Chemical indices of lipid oxidation were analyzed by Peroxide Value Determination, pH and Free Fatty Acid Determination. Changes in the organoleptic properties particularly flavor, color and odor were also determined using a Sensory Descriptive Score sheet and General Acceptability was likewise assessed using a 5-point hedonic scale. Results of the study showed that among the treatments, onion extract-treated samples exhibited a significant decrease in Peroxide Value at R=0.941 with a final Peroxide Value of 0.75 meq/kg sample which did not exceed the USFDA standard at 7-8 meq/kg, not exceeding to 20 meq/kg and not more than ≤ 5.0 meq/kg sample. No significant difference, however, were observed in Free Fatty Acid Value between treatments throughout the 30-day study period which denotes that the extracts have no effect on lipid hydrolysis brought about by lipolytic activity enzyme. Sensory evaluation revealed that among the treatments the lemongrass extract treated samples yielded the highest general acceptability scores within the 30-day storage period. Statistical analysis however reveals that there is no significant difference between treatments at 5% level of significance.