Rendimento, caracterização físico-química e composição de ácidos graxos de peixes siluriformes da Amazônia

Abstract

As an excellent quality food, fish presents in its corporeal constitution a series of nutrients essential to the development and maintenance of the human organism physiology. Therefore, the present work evaluated the meat and residual yield, physicochemical composition and fatty acid composition in muscle tissue and viscera of fourteen species of siluriform fish in different seasonal cycles of the Amazon Basin. It should be noted that species belonging to this order have low acceptance for consumption in Amazonas State, with most of their production destined for export. The fish were collected in two seasonal periods (flood and dry) of the Amazonian rivers, at the landing ports of the municipalities of Manaus and Careiro da Várzea. The species dourada (Brachyplatystoma rousseauxii), filhote (Brachyplatystoma filamentosum), piracatinga (Calophysus macropterus), jandiá (Leiarius marmoratus), piramutaba (Brachyplatystoma vaillantii), jaú (Zungaro zungaro), pirarara (Phractocephalus hemioliopterus), piranambú (Pinirampus pirinampus), surubim (Pseudoplatystoma fasciatum), caparari (Pseudoplastystoma tigrinum), mapará (Hypophthalmus edentatus), babão (Brachyplatystoma platynema), zebra (Brachyplatystoma juruense), mandubé (Ageneiosus inermis) were processed to determinate yield and centesimal composition in Laboratório de Tecnologia do Pescado da UFAM. The determination of the fatty acids was performed with falc chromatography in UEM-PR’s Chemistry Laboratory. The samples weighed on average 1820 ± 45g (flood) and 1067 ± 39g (dry season). The preferential cuts for clean body, fillet with skin and skinless fillet presented percentages of yield that oscillated between 49.49 ± 2.78% and 76.72 ± 1.43%; 47.87 ± 2.38% and 81.75 ± 1.41%; 22.83 ± 2.31% and 62.03 ± 3.70% (for flood season) and 21.95 ± 1.52% and 49.41 ± 2.51%; 19.48 ± 1.98% and 55.55 ± 2.88% and 24.66 ± 1.59% and 41.55 ± 2.56% (for dry season), respectively. Centesimal composition of meat for all species studied presented percentages ranging from 56.39 ± 0.11% to 80.30 ± 0.19% for humidity; from 0.86 ± 0.01% to 1.21 ± 0.01% for ash; from 0.70 ± 0.10% to 26.29 ± 0.14% for total lipids; from 16.85 ± 0.40% to 20.34 ± 0.15% for protein; and from 0.04 ± 0.02% to 2.73 ± 0.59%, for nifext in the flood season. For the same period viscera presented (55.29 ± 0.53% to 82.47 ± 0.93%); (0.78 ± 0.03% to 1.47 ± 0.13%); (3.11 ± 0.16% to 26.23 ± 1.49%); (10.23 ± 0.62% to 23.56 ± 0.23%); (0.054 ± 0.034% to 27.731 ± 01.69%), respectively. During the dry season percentages ranged from (66.91 ± 0.21% to 81.63 ± 0.56%) for humidity; from 0.70 ± 0.01% to 1.14 ± 0.03%, for ash; from 0.98 ± 0.04% to 14.45 ± 0.39%, for lipids; from 13.24 ± 0.48% to 18.10% ± 0.36%, for protein and from 0.04 ± 0.03% to 2.28 ± 0.22%, for Nifext. In viscera (64.65 ± 0.42 to 82.33 ± 0.36%); (0.90 ± 0.05% to 1.84 ± 0.05%); (3.52 ± 0.11% to 20.91 ± 0.28%); (9.06 ± 4.17% to 20.55 ± 0.96%); (0.08 ± 0.05% to 4.68 ± 0.64%). The most abundant saturated fatty acids in fillets and viscera throughout the study period were 16: 0 (palmitic), 18: 0 (stearic) and 14: 0 (myristic). The monounsaturated were 18: 1n-9 (Oleic), 18: 1n-7 (vacnic) and 16: 1n-7 (palmitoleic). 18: 2n-6 (linoleic), 20: 4n-6 (arachidonic) and 22: 6n-3 (docosahexaenoic) polyunsaturated fatty acids were also abundant throughout the study period. The yield analysis showed good results on catfish species for the preferential cuts for consumption and potential of by - products to be submitted to technological processes of exploitation. The physico-chemical characterization of the muscle and viscera was consistent with studies already carried out for Amazonian fish evidencing this group of fish as excellent sources of nutrients. The percentages of quantified saturated, monounsaturated and polyunsaturated fatty acids were also in line with studies already carried out with freshwater fish. The essential polyunsaturated of omega 3 and 6 families were characterized as significant in muscle tissue of all species when they showed an n-6 / n-3 ratio of up to 1/3. Due to the significant results in its nutritional aspects it is suggested this group of fish for consumption by regional population as important sources of nutrients essential to human physiology.