Characterization of acid silage obtained from tilapia filleting wastes (Oreochromis niloticus) during storage

Abstract

The present study aimed to obtain acidic silages of different types of waste from tilapia (Oreochromis niloticus) and its characterization through chemical, physical and microbiological analysis over the storage time. To obtain the silage different residues were used, which were divided into five treatments: T1 100% guts, T2 - 100% head, T3 - 100% carcass, T4 - 30% head + 70% carcass and T5 - 15% guts + 20% head + 47% carcass + 15% leather + 3% scales. Each treatment was performed by adding 5% acetic acid and 0.1% p/p of BHT / Kg. Analyses were performed at days 0, 7, 14, 21, 28, 60 and 90. It was found that the texture of the ensiled biomass showed no visible immediate changes, prevailing caramel coloring. The first hydrolysis signals were seen from the 4th day of storage. T1 and T5 treatments had lower temperatures in the biomasses. The pH of the silages were less than 4.5. T1 obtained the highest values of malondialdehyde / kg. The results of microbiological analysis have not detected the presence of aerobic mesophilic microorganisms, yeasts and molds for all treatments of the silages. The use of acetic acid and BHT acted efficiently to preserve silage quality. Thus, it can be said that the silages in the process are of high quality, with applicability in food and feed, as well as commercially valuing the fish byproduct and reducing to almost zero waste generation.