Rapipun Laohabanjong, Chutima Tantikitti, and Suthawat Benjakul

pp. 501 - 514

Abstract

Changes of chemical quality and physical properties of fish meal due to lipid oxidation under different storage conditions were studied using a 3-factor factorial design (2x2x4). Premium grade fish meal (72% protein) was divided into two portions, with and without ethoxyquin, each portion was then stored at either
ambient temperature or 4°C for 0, 1.5, 3 and 4.5 months. The results showed no interaction between 3 factors (supplemented with or without ethoxyquin, at 27-32°
C and 4° and storage time) on protein, lipid and ash of fish meal. Peroxide value (PV) and anisidine value (AnV) increased with storage time with the highest
value in the non-ethoxyquin sample stored at ambient temperature for 4.5 months. An increase of TBARS was found in non-ethoxyquin fish meal stored at both ambient temperature and 4°C with the highest value in the sample stored at 4°
C for 4.5 months. Storage conditions without ventilation/air circulation caused an
accumulation of malonaldehyde in the fish meal storage at 4°C for a long period. FFA content was highest in the ethoxyquin treated fish meal stored at ambient temperature for 3 months. At 4.5 months, the nonethoxyquin fish meal stored at ambient temperature showed higher FFA content than other samples. Levels of TVN of samples stored at ambient temperature decreased with time but those stored at 4°C changed in an opposite direction, which could be explained by the similar phenomenon as the changes of TBARS value. Parameters tested by feed microscopic and simple chemical techniques did not show any difference among
fish meal under studied conditions.