Ảnh hưởng của ướp muối đến sự oxy hóa lipid và oxy hóa protein trong cơ thịt cá lóc (Channa striata) nuôi

Abstract

The study was carried out to investigate lipid oxidation and protein oxidation of snakehead fish meat by changing the salt concentration (0, 4, 8, 12, 16, 20% NaCl, w/v) and pH adjustment (4, 5, 6, 7, 8 and 9) of soaking solution. The magnitude of oxidative changes was monitored by: (i) lipoxygenase enzyme activity (LOX), peroxide value (PV) and TBRAS (thiobarbituric acid reactive substances) value, (ii) protease activity, sulfhydryl index, and (iii) whiteness index, water holding capacity and drip loss (physicochemical properties). The results showed that salting process has limited the activity of lipoxygenase and protease enzymes, while improving the quality of fish meat. Salted fish in 12% NaCl (w/v) for 3 hours had significantly lower (p < 0.05) lipoxygenase and protease activity, PV and TBARS value and a higher sulfhydryl value when compared with control sample (no salt immersion) and salted fishes in lower salt concentration (4, 8% NaCl, w/v). In addition, lipid oxidation and protein oxidation of the snakehead fish meat was delayed at neutral pH of salt solution, which was most effective at pH 8. The quality of snakehead fish meat at this condition was also improved with whiteness index (WI) of 81.17, water holding capacity 72.39%, and drip loss 11.78%.