Optimizing the shelf-life of minimally processed aquacultured tilapia (Oreochromis niloticus) stored under refrigeration.

Author(s)

Marcilene Camilo Heidmann Soccol

• Document type: Master's Dissertation
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2003-02-26

Examining board members

Marilia Oetterer; Jose Eurico Possebon Cyrino; Elisabete Maria Macedo Viegas

• Advisor: Marilia Oetterer
• Field of knowledge: Agronomical Sciences - Food Science and Technology
• Indexed in: Banco de Dados Bibliográficos da USP-DEDALUS; Biblioteca Digital de Teses e Dissertações - USP
• Location: Universidade de São Paulo. Biblioteca Central da Escola Superior de Agricultura Luiz de Queiroz; ESALQ-BC/t664.94028; S678o

Abstract

The effective aquaculture consolidation depends on the production sale, which in the other hand, depends on the demand. In order to increase Brazilian fish consumption, it is necessary to offer products with quality demanded by the consumers. The purpose of this research was to obtain a new convenience product - minimally processed tilapia. The shelf-life of the product were determining by monitoring physical-chemical components, sensory and microbiological analysis. With this intent, aquacultured Nile tilapia (Oreochromis niloticus) raised in farms located in the Jau region, Sao Paulo State, was depurated, gutted, filleted, packed in polyestirene trays and covered with ethylene-vinyl-alcohol (EVOH) plastic films (control). It was also made packing with modified atmosphere (MAP) 60%CO2+40%O2 and vacuum packing. Part of the fish was chemically treated by immersing in a 1% acetic acid solution. The packed samples were storage under a temperature which ranged from 1 ± 1 oC and had been analyzed at the 1st day of experiment and to the 7th , 13th and 20th days. No significant differences were verified among treatments for the centesimal composition, non-protein nitrogen (NPN), total volatile bases nitrogen (TVBN) and pH as well. The use of the MAP, whether associated with acetic acid or not, promoted the TBA (thiobarbituric acid) increasing. It was detected rancidity the team responsible for the sensory evaluation. The fillets treated with acetic acid were fainted colors and showed less firm texture, when compared to the non-treated ones. Salmonella, Clostridium sulfite-reducing and E. coli were not detected during the storage period. Treatments using MAP and vacuum packing, whether associated with acetic acid or not, inhibited the development of S. aureus, total coliforms and psychrotrophic, maintaining the shelf life to 20 days. However, the treatment combining vacuum packing and acetic acid maintained the physical-chemical, microbiological and sensory characteristics stabler until the end of the experiment. (AU)