RESUMEN
We investigated the effect of different levels of organic acids on the formation of biogenic amines in anchovy fish sauce. Fish sauce samples were prepared with fresh anchovies used immediately after being caught (F), and anchovies left at ambient temperature for 4 h (4 h), 18 h (18 h), or 24 h (24 h). Anchovies from each of the four groups were mixed with salt at a 4:1 ratio and then fermented at ambient temperature for varying periods of time. The F and 4 h anchovies contained higher levels of acetic acid, succinic acid, and lactic acid, and the levels increased during the fermentation process. The histamine content of the fish sauce samples prepared using F anchovies ranged from 44.0 to 9.2 mg/kg at 1 and 24 months of fermentation. The histamine content of fish sauce samples prepared using 4 h, 18 h, and 24 h anchovies was 111.5-37.0 mg/kg (4 h), 780.1-560.3 mg/kg (18 h), and 880.6-675.7 mg/kg (24 h). Our findings indicated that the histamine and other biogenic amine levels were closely associated with the degree of freshness of the raw anchovy material. These findings indicate that lower pH levels resulting from organic acids generated by the fresh raw material can effectively inhibit histamine formation.
RESUMEN
We analyzed the volatile basic nitrogen content, pH, total viable cell count, and biogenic amine contents in chub mackerel (Scomber japonicus) stored at 5 and 25°C to examine changes in freshness. Among the various parameters, we found the volatile basic nitrogen content had the highest correlation with cadaverine content (r2 = 0.72 to 0.88). We also tried to measure cadaverine contents at different times during storage by using near-infrared (NIR) spectroscopy. However, because of the high water content in the fish, we could not obtain meaningful results. Next, we prepared samples for NIR spectroscopy by dilution with 0.1 N HCl, ultrafiltration (3 or 10 kDa) with a glass filter, and dehydration. The samples prepared with the 3-kDa filter had peaks in the NIR spectra between 1,379.3 and 1,388.9 nm, and those prepared with the 10-kDa filter had peaks in the spectra between 1,897.3 and 1,898.6 nm. The correlation coefficient (r2) between the NIR spectroscopy and high-performance liquid chromatography with cadaverine results was 0.98 to 0.99. We concluded that the biogenic amine content could be used to evaluate freshness in fish products, and that NIR measurements could be used to rapidly and accurately determine freshness.