Desenvolvimento de um produto desidratado combinando pescado salgado com uma base proteica obtida de farinhas de soja e trigo

AUTOR(ES)
DATA DE PUBLICAÇÃO

1985

RESUMO

The present work was undertaken with the aim of developing a dehydrated product (fish-balls) by combining defatted soy flour, wheat flour and minced salted fish. Defatted soy flour and wheat flour were mixed at levels of 1.0 : 1.0 , 0.75 : 1.0 , 0.50 : 1.0 and 0.5 : 1.0 parts respectively, leavened with 6% of commercial yeast for 45 minutes, baked at 200-210°C for 15-25 minutes and dried at 65°C to yield protein mixtures of fibrous texture and functional properties similar to those of conventional texturised soya protein (TSP). The protein mixture 0.5 : 1.0 was considered the most adequate to be mixed with approximately 35%, 50% and 55% of salted fish, resulting in three different formulations (fish-balls) called 1, 2 and 3, These formulations, also containing egg white (10%) and spices (2,5%), were dried in the conditions stated previously for the protein mixtures. Hake (Merluccius hubbsi), the fish used in the experiment, was salted by using a mixed salting process, pressed and minced. The salted fish had 49.74% protein, 2.45% lipids, 39.36% NaCl and a moisture content of 53,34%. Protein contents of 34.02%, 31.96%, 28,70% and 24.10% were found for the protein mixtures 1.0 : 1.0 s 0.75 : 1.0 , 0.5 : 1.0 and 0.25 : 1.0 respectively. The increase in the amount of soy flour in the mixtures caused a decrease in the values of loaf volume, drying rate, water absorption capacity and rehydration ratio on the contrary, an improvement in the ability to resist disintegration in boiling water was observed. So far as these variables are concerned, a smaller degree of efficiency was noted when the yeast was replaced by chemical leavening agents. The addition of hydrogenated vegetable fat (5%) during the preparation of the protein mixtures did not cause relevant changes in the above mentioned variables. The addition of minced salted fish into the uncooked dough, and further baking and drying of the protein mixture, yielded very compact fish-balls of poor hydration capacity. However, the addition of the fish after cooking the dough yielded fish-balls of fibrous texture which were quickly and easily rehydrated. The drying of the fish-balls took approximately 6 hours, but no significant changes were observed in the drying rate of the different formulations. Protein contents of 36.20%, 38.50% and 39.10% and NaCl contents of 12.40%, 16.50% and 21.50% were found for formulations 1,2 and 3 respectively. Rehydration in excess of water for 10 minutes was effective in increasing the fish-ball volume, doubling its weight and desalting the product to acceptable level. The moisture content after hydration was found to vary between 56.5% and 59.4% and the NaCl content to be approximately 4.5%. The hydrated product had a firm, typical fish texture and could be readily prepared for consumption by frying. As regards the nutritional aspect, it was observed that the baking and drying of the protein mixture 0.5 : 1,0 caused losses of 37%, 8-5% and 15.6% of lysine, sulphur, containing aminoacids and tyrosine respectively. The content of other essential aminoacids did not undergo changes above 5%. The addition of salted fish to the mixture compensated the above mentioned losses and allowed formulations 1,2 and 3 to meet the FA0 requirements. After rehydratation, the available energy for formulations 1,2 and 3was 123.65 kcal , 129.87 kcal and 120.52 kcal, respectively. After frying, these values were found to be 220.55 kcal, 236.78 kcal and 220.91 kcal respectively for the afore-said formulations. Sensory evaluation was conducted with fried hydrated fish balls and fried hydrated fish-balls with tomato sauce. Significant differences at 1% level were revealed for the parameter Taste of the fried fish-balls. Significant differences at 5% level were also observed for the parameter Texture of the fried product with tomato sauce. The conclusion was that 35% of salted fish was enough to provide fried fish-balls with good texture and taste; 65% of salted fish would be necessary if tomato sauce was to be added to the product. Microbiological determinations showed that the processing conditions of the protein mixtures, salted fish and fish-balls were satisfactory and that all products met the obligatory counts required.

ASSUNTO(S)

trigo farinhas soja pescados

ACESSO AO ARTIGO

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