Effect of clove extract pretreatment and drying conditions on lipid oxidation and sensory discrimination of dried omena (Rastrineobola argentea) fish

Abstract

Summary Sun‐drying is a low‐cost, low‐technology fish preservation method frequently employed in developing areas. However, the process promotes lipid oxidation and its associated undesired flavours and odours. This study investigated low‐technology solutions for impact on lipid oxidation and sensory attributes of oven‐dried omena fish (Rastrineobola argentea). Two oven‐drying conditions and four doses of clove water extract ‘dip’ pretreatments were studied in a complete factorial design. Lipid oxidation in dried fish was assessed by TBARS, peroxide value and fatty acid analysis by GC‐FID. Results showed that soaking in 10 g L−1 clove water extract for 1 h and oven‐drying at 150 °C × 30 min significantly reduced TBARS and peroxide values in omena fish by 77% and 79%, respectively, and polyene index showed improved retention of long‐chain polyunsaturated fats, compared to original drying condition. Lastly, panellists of a triangle test were able to discriminate between biscuits made with the modified and original dried fish.

Effect of clove (Syzygium aromaticum) and seaweed (Kappaphycus alvarezii) water extracts pretreatment on lipid oxidation in sun‐dried sardines (Rastrineobola argentea) from Lake Victoria, Tanzania

“…This could be due to higher phenolic content in clove than seaweed extracts although there was no linear relationship between total phenolic content and DPPH in clove extracts suggesting compounds other than phenolics (e.g., flavonoids) contributed to the antioxidant activity of clove extract. The DPPH decreased from 95.59% to 94.34% in clove extract and from 51.56% to 29.67% in seaweed extract when the amounts of clove and seaweed extracted in one liter of hot water were increased from 10 to 20 g.This could be due to decreases in extraction efficiency of clove and seaweed phenolics in boiling water at concentration above 10 g/L as reported in another study (Slavin, Dong, & Gewa, ). Elsewhere, clove water extract has been found to contain substantial amounts of phenolic compounds and powerful antioxidant activity in linoleic acid emulsion (Gülçin, Şat, Beydemir, Elmastaş, & Küfrevioǧlu, ).…”

“…The use of spices like clove as natural antioxidant to protect lipids in meat and fish oil has been demonstrated (Falowo, Fayemi, & Muchenje, 2014;Shah, Bosco, & Mir, 2014). Improved retention of long-chain polyunsaturated fats and preservation of omega-3 fatty acids in oven dried sardine (R. argentae) pretreated with clove water extracts has also been shown (Slavin et al, 2016). Clove oil seems also a powerful antioxidant in the linoleic acid system with its inhibition potential TA B L E 4 Fatty acid profiles (% fatty acid of total fatty acids) of sun-dried sardine pretreated with different concentrations of clove and seaweed water extracts Note.…”

Protection against Oxidation of Omega-3 Fatty Acids with Natural Antioxidants in Clove (Szygium aromaticum) Water Extracts during Storage of Sun dried Sardines (Ratrineobola argentea)

“…flavonoids) might have contribution to free radical scavenging activity of clove extracts. The DPPH decreased from 95.59 to 94.34% when the amounts of clove extracted in one litre of hot water was increased from 10 to 20 g. This could be due to decrease in extraction efficiency of clove phenolics in boiling water at concentration above 10 g/L as reported in another study [28].…”

“…Use of spices like clove as a natural antioxidant to protect lipids against oxidation in meat and fish oil has been demonstrated. Protective effect of clove water extracts against oxidation of polyunsaturated omega-3 fatty acids during oven and sun drying of sardines has been reported [27,28]. Clove oil and clove water extracts are also known to have as strong peroxidation inhibitory effect as ethanol extract in linoleic acid emulsion [26].…”

“…Elsewhere, the clove water extract has been found to contain substantial amounts of phenolic compounds and powerful antioxidant activity in linoleic acid emulsion [26]. Clove water extracts are reported to result in improved retention of nutritionally valued long chain PUFAs DHA, EPA and DPA during open sun and oven drying of sardines [27,28]. The aim of the current study was to evaluate the efficacy of clove (Szygium aromaticum) water extracts in protecting omega-3 fatty acids during extended storage of sun dried sardines.…”