Elaboração de mix para bolo adicionado de farinha de carcaça de tilápia do Nilo (Oreochromis niloticus) e aplicação em bolo de chocolate

Abstract

Brazil has been increasing the pisciculture production and the major part is from nile tilapia. Fish processing residues are heads, scales, skins, viscera and carcasses (skeleton with meat attached), and depending on the fish species and the final product obtained can represent between 60 and 72% in the production of fillets without skin, which have high nutritional value, being rich in proteins and omega-3 fatty acids, a fact that motivates the creation of products for human consumption. Most of the use of residues from the industrialization of fish is destined to produce flour. This work aims to compare two nile tilapia flours, one made by lyophilization (a) and another from the conventional drying (b), adding them in cake mix and the application of the mix in chocolate cake. Two flours were prepared, the oven dried and lyophilized, then the cake mixes were prepared with different concentrations of the flours (0%, 10%, 20% and 30%), subsequently the chocolate cakes were prepared with the dry flour in greenhouse. The following analyzes were performed in both flours: moisture, ash, protein, lipids, fatty acids, lipid oxidation, ph, aw, color and grain size. In the mixes it was evaluated: moisture, ash, protein, lipids, ph, aw, color and water absorption index and for cakes: moisture, ashes, protein, lipids, aw, color, water loss, expansion index, volume acidity, texture, microbiological analysis, sensory analysis and acceptability index. The flours presented good nutritional values, however, the lyophilized flour had a higher lipid content and a lower ratio of fatty acids n-6/n-3. In addition, they presented low lipid oxidation index varying from 0,378 ± 0,007 to a 0,510 ± 0,004 and 0,172 ± 0,005 to 0,306 ± 0,007 mg of malonaldehyde.kg-1 for the lyophilized flour and oven dried, respectively, for 180 days of storage. The dry flour in greenhouse had low granulometry, better particle uniformity as compared to lyophilized. The use of lyophilized flour in the preparation of the mixes favored the lipid content, ashes and promoted a reduction of carbohydrates. The use of the greenhouse flour in the partial substitution of wheat flour in the chocolate cakes presented higher values of ashes, proteins, lipids and lower carbohydrate value, aw ranging from 0.91 ± 0.01 to 0.92 ± 0.01 and lighter color (l *) in the cakes, as well as the lower specific volume and lower softness, did not prevent the sensorial acceptance of the cakes, all had an index acceptability above 70% (80%, 84%, 78% and 74%). From the technological point of view can be added up to 30% of carcass flour in cake mix, improving the nutritional value. Mixes can be applied in chocolate cake without changing acceptable microbiological limits, increasing nutritional values and presenting good sensory acceptability.