Yield and chemical composition in Arapaima gigas fillets, reuse of by-products for flour make and quality of vegetable tannin-tanned leathers

Abstract

Objective: The aimed of this study was to evaluate the yield and chemical composition of paiche (Arapaima gigas) fillets and use of head and spine for elaboration of flour and quality of the skins tanned with vegetable tannin. Main Body: Therefore, different flours were developed and evaluated in terms of chemical composition, minerals, fatty acid and amino acid profile, pH, Aw, colorimetry, granulometry and microbiology. Paiche evaluated had 12.61 kg and 120.5 cm in total length, with a skinless fillet yield 44.56%, totaling 55.44% of filleting by-products. Among these, there was possibility of using the spine 16.17%, head 16.49% and skin 16.81%. The fillets had 71.41% moisture, 20.34% protein, 5.58% lipids and 1.05% minerals. Natural flour was obtained from spines and heads, with an average yield 15.48%, and the spine flour had better nutritional value, containing 54.42% of protein and 7.24% of lipids, in addition to lower Aw 0.27, despite head flours having higher levels of calcium and phosphorus. Spine flour showed a more reddish color and smaller granulometry, where the Mean Geometric Diameter (MGD) was 0.24%, making its inclusion in food products easier. Leathers have higher tensile strength 13.85 N mm-2 and elasticity 86% in transverse direction. The skins within the by-products generated can tanned with vegetable tannin, shown high quality resistance and being able to used for making clothes, bags and shoes, adding a substantially high economic value to products.