Efecto del tiempo de refrigeración en la oxidación de lípidos y perfil de ácidos grasos del pez gato (Arius maculatus) comercializado en el Camerún

The effects of refrigeration at 4 °C during 9 days on the quality and stability of catfish oil were evaluated using a change in fatty acid composition by gas chromatography (GC), commonly used analytical indexes (acid and peroxide values), and analysis by Fourier transform infrared (FTIR) spectroscopy. The results revealed that lipid deterioration, hydrolysis and oxidation occurred throughout the cold storage (4 °C). Refrigeration induced the lipolysis of triglycerides by lipases and phospholipases. It also affected the fatty acids composition of the catfish. The progressive loss of unsaturation was monitored by the decrease in the absorbance band at 3012 cm-1 on FTIR spectra and the lowest value was observed in the catfish muscle at 9 days of refrigeration. Eicosapentaenoic C20:5ω3 (EPA) and docosahexaenoic C22:6ω3 (DHA) acids were the polyunsaturated fatty acids most affected during refrigeration. Refrigeration for less than 5 days was found to be the best conditions for the preservation of the catfish.El efecto de la refrigeración a 4 °C durante 9 días sobre la calidad y estabilidad del aceite de pez gato se evaluó mediante el cambio en la composición de ácidos grasos por cromatografía de gases (CG), los índices analíticos comúnmente utilizados (acidez y peróxidos) así como mediante análisis por espectroscopia de infrarrojo por transformada de Fourier (FTIR). Los resultados mostraron que el deterioro de los lípidos, la hidrólisis y la oxidación ocurrieron durante el almacenamiento en frío (4 °C). La refrigeración indujo a lipolisis de triglicéridos por lipasas y fosfolipasas. También se vio afectada la composición de ácidos grasos, la pérdida progresiva de insaturación se controló mediante la disminución de la banda de absorbancia a 301cm-1 en los espectros FTIR y el valor más bajo se observó en el músculo a los 9 días de refrigeración. Los ácidos eicosapentaenoico C20:5ω3 (EPA) y docosahexaenoico C22:6ω3 (DHA) fueron los ácidos grasos poliinsaturados más afectados durante la refrigeración. Se encontró que la refrigeración durante menos de 5 días era la mejor condición para la conservación del pez gato

The proximate composition of three marine pelagic fish: blue whiting (Micromesistius poutassou), boarfish (Capros aper) and Atlantic herring (Clupea harengus)

peer reviewedThis study presents data from an in-depth proximate compositional analysis of three marine fish species: blue whiting (Micromesistius poutassou), boarfish (Capros aper) and Atlantic herring (Clupea harengus). These fish contained significant amounts of protein (16–17%), lipids (4–11%) and minerals (2–6% ash). The proteins, particularly from boarfish, had close to optimum amino acid profiles for human and fish nutrition. They compared favourably with other fish species in terms of total lipids and relative concentration of the omega-3 fatty acids docosahexaenoic acid and eicosapentaenoic acid (11.8–13.3% and 5.9–8.1% in triacylglycerols [TG] and 24.6–35.4% and 5.8–12.0% in phospholipids [PL]). Atlantic herring had the highest lipid content among the three fish and was found to contain high levels of PL poly-unsaturated fatty acids, including omega-3 fatty acids. Minerals detected in the fish included calcium (272–1,520 mg/100 g), phosphorus (363–789 mg/100 g), iron (1.07–2.83 mg/100 g), magnesium (40.70–62.10 mg/100 g), potassium (112.00–267.00 mg/100 g), selenium (0.04–0.06 mg/100 g), sodium (218.00–282.00 mg/100 g) and zinc (1.29–5.57 mg/100 g). Boarfish had the highest ash fraction and also the highest levels of all the minerals, except potassium. Atlantic herring had considerably lower mineral content compared with the other two species and, levels detected were also lower than those reported in previously published studies. Heavy metals contents were quantified, and levels were significantly below the maximum allowable limits for all elements except arsenic, which ranged from 1.34 to 2.44 mg/kg in the three fish species. Data outlined here will be useful for guiding product development. Future studies would benefit from considering catch season, sex and developmental stage of the fish