Abstract Loricariid catfish (Pterygoplichthys disjunctivus [Weber, 1991]) has invaded water catchments throughout the world, due to the lack of predators and high fecundity. An approach to control its population could be using its roe as food; however, more knowledge is needed. Thus, the present study aimed to evaluate the shelf-life of fresh loricariid catfish roe stored in ice, as an approach for possible food utilisation. Physicochemical characteristics (moisture content, aw, pH, hardness, and colour), protein electrophoresis (SDS-PAGE), amino and fatty acid contents, oxidative stability (TBARS) and microbiology of roe were analysed at 0, 2, 4, 6, 11, 15 and 21 days. Moisture content (58.5 ± 2.1 vs. 60.4 ± 1.2%), aw (0.89) and pH (5.87 ± 0.14 vs. 5.96 ± 0.03) were shelf-stable (initial vs. final day, respectively). SDS-PAGE showed minor hydrolysis of its protein. Ice storage increased roe free amino acid concentration, confirming proteolysis of its proteins/peptides with not impact on the fatty acid content and TBARS (2.4–3.3 mg malonadehyde/kg sample). Thus, ice storage of fresh loricariid catfish (P. disjunctivus [Weber, 1991]) roe, under the study conditions, proved to be an effective preservation method for its food utilisation, maintaining its physicochemical and microbiological characteristics for up to 20 days.

Abstract Enormous amounts of by-products and waste are generated during the processing of seafood, sometimes representing about 65% of the raw material employed. Seafood by-products (SB) include solid waste such as skin, head, viscera, trimmings, and bones; however, liquid wastes (effluents) derived from operations such as washing, thawing, cooking and the production of fishmeal are also produced. SB contain considerable amounts of protein and others biomolecules, which has been regularly processed as food ingredients for animal nutrition. But also, sometimes SB are used as fertilizers or discarded to environment without a previous treatment. Nowadays, there is an increasing interest in adding value to the protein material within SB by improving their properties through hydrolysis and thus releasing of peptides with bioactive properties. Thus, this review aims to present an overview of the potential of SB, focused on effluents, as a source of protein hydrolysates, summarizing their methods of production, bioactive property evaluation and structural characteristics.

ABSTRACT Navicula incerta is a benthic diatom with potential use in nutrition and health for humans and aquaculture. Therefore, it is important to know its optimal growth conditions and biochemical composition. In this study, the effects of nitrate and silicate concentration on the growth kinetics and biochemical composition of N. incerta under laboratory conditions were measured. F/2 media was used as the control, and different concentrations of nitrogen (N/4, N/8 and N/16) and silicates (Si/4, Si/8 and Si/16) were evaluated. We measured cell concentration, chlorophyll-a and conducted proximal chemical analyses. It was found that different concentrations of nutrients affected the diatom's growth kinetics and affected the concentrations of ash, chlorophyll, protein, lipids and carbohydrates. The highest concentration of lipids was obtained in the limiting treatment of nitrogen N/8 (27.09%), while the lowest value was found with silicate Si/8 media (16.97%). Carbohydrates increased compared to the control, with the N/16 treatment presenting the maximal concentration (23.31%). Treatments with reduced nitrate (N/8 and N/16) demonstrated the lowest concentrations of protein (18.75 and 12.44%, respectively), while in reduced silicate treatments, no statistical differences (P ≥ 0.05) were observed. Therefore, media limited nitrogen and silicates affected the growth kinetics and proximal chemical composition of N. incerta. The growth of this species using the N/8 medium is a suitable method for increasing lipid concentration in N. incerta.