Este trabalho teve como objetivo realizar um estudo sobre a composição físico-química e, especialmente sobre a composição de ácidos graxos nos lipídios totais de cabeças de tilápias (Oreochromis niloticus), submetidas a diferentes tempos (0, 10, 20, 30 dias) de fornecimento de ração suplementada com óleo de linhaça (fonte do ácido a-linolênico, 18:3n-3 LNA), em substituição ao óleo de girassol. Não houveram diferenças (P>0,05) entre os teores de umidade, cinza, proteína e lipídios totais para os diferentes tratamentos (tempos de fornecimento). Os teores de lipídios totais das cabeças variaram de 8,41 a 10,13% e foi encontrado um total de 27 ácidos graxos nestes lipídios para todos os tratamentos. Os ácidos graxos majoritários foram 18:2n-6 (29,66 a 32,11%), 18:1n-9 (29,68 a 31,71%) e 16:0 (15,53 a 16,63%). Houve um aumento nos teores percentuais do ácido 18:3n-3, da somatória de ácidos graxos ômega-3 e uma diminuição da razão n-6/n-3, com diferenças (P<0,05) entre o tratamento A (tempo zero) e os demais tratamentos que receberam óleo de linhaça. Não houveram diferenças (P>0,05) entre os tratamentos para a razão entre ácidos graxos polinsaturados e saturados (AGPI/AGS).

The main of this study was to analyze the physical-chemical composition and, especially the fatty acids composition, in the total lipids of tilapia (Oreochromis niloticus) heads, submitted to different ration supply times (0, 10, 20, 30 days) with flaxseed oil (source of a-linolenic acid 18:3 n-3, LNA), in substitution to the sunflower oil. There were not significant differences among (P>0,05) the moisture, ash, protein, and total lipids values for the different treatments (times of supply). The values of total lipids found in the heads varied from 8.41 to 10.13%, and 27 fatty acids were found in these lipids in all treatments. The majority fatty acids were 18:2n-6, 18:1n-9 and 16:0. There was an increase in the LNA acid percentage values, in the omega-3 (n-3) sum, and a decrease of the n-6/n-3 reason, with significant differences among the treatment A (zero time) and other treatments that received flaxseed oil. There were not significant differences among the treatments in relation to polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA) rate.

Composición nutricional y estabilidad de la vitamina C en la pulpa de camu-camu (Myrciaria dubia) almacenada. El camu-camu (Myrciaria dubia), fruta nativa de la región Amazónica, es una de las fuentes mas ricas de vitamina C (de 2,4 hasta 3,0g/100g de pulpa) en Brasil. Este trabajo tuvo por objeto la caracterización físicoquímica de algunos nutrientes y la evaluación de la estabilidad de la vitamina C en la pulpa de camu-camu producida por el Instituto Agronómico de Paraná (IAPAR), Estación Experimental de Morretes (PR), Brasil. La determinación de vitamina C se realizó por titulación com iodato de potasio. La fruta cultivada en el estado de Paraná, presentó menor cantidad de vitamina C que la nativa de la región Amazónica, posiblemente, debido a las diferentes condiciones para el desarrollo de la planta y, consecuentemente de la fruta, así como la variación climática, humedad y características del suelo. Con relación a la estabilidad de la vitamina C en la pulpa almacenada en congelador a -18ºC, se pudo observar una disminución considerable (23%) en su concentración hasta el 28º dia (de 1,57 hasta 1,21g/100g), permaneciendo constante hasta el fin del experimento. Después de 335 dias de almacenaje, la cantidad encontrada fue de 1,16g/100g de pulpa, indicando una pérdida de 26%, siendo esta cantidad aún superior a la encontrada en la mayoría de las fuentes de esta vitamina.

Camu-camu (Myrciaria dubia), a native fruit of the Amazon region, is one of the richest sources of vitamin C (2.4 to 3.0g/100g in the pulp) found in Brazil. The purpose of this work was the physical-chemical characterization of some nutrients and the valuation of vitamin C stability in stored camu-camu pulp, produced by the Agronomic Institute of Paraná (IAPAR), Paraná State, Brazil. The vitamin C determination was made by titration with potassium iodate. The fruit produced in Paraná State, presented a lower content of vitamin C than the one native of the amazon region, possibly due to the different development conditions of the plant, and consequently of the fruit, as well as the climatic variation, the humidity and the characteristics of the soil. Regarding the vitamin C stability in stored (-18ºC) camu-camu pulp, a considerable decrease in its concentration until the 28th day was observed lost 23% (from 1.57 to 1.21g/100g), staying approximately the same until the end of the experiment. After 335 days of storage, the content found was of approximately 1.16g/100g of pulp, the ascorbic acid losses amounted to 26%. This content was still higher than the one found for most fruits that are good sources of this vitamin.