Extension of shelf life of chilled hake (Merluccius capensis) by high pressure

Abstract

Vacuum packed hake muscle subjected to 400 MPa (three 5-min cycles) at 7 °C proved to be more stable at chilled temperatures (2-3 °C), and sensorially acceptable, until 43 days of storage in comparison with the nine days for the non-pressurized hake. The lot pressurized at 400 MPa had the appearance of cooked muscle. The microbial load was initially reduced by two log units by pressurization at 400 MPa. Trimethylamine nitrogen (TMA-N) values were also very low. Pressurization had no effect on dimethylamine nitrogen (DMA-N) production. The lot pressurized at 400 MPa showed slower increase in drip loss from day 15 of storage. In the lot subjected to 200 MPa (three 5-min cycles) at 7 °C, which retained the appearance of raw fish, microorganisms were one log unit lower than in the non-pressurized sample and TMA-N was lower. In conclusion, the chilled shelf life was prolonged by about one week in the lot pressurized at 200 MPa and about two weeks in the lot pressurized at 400 MPa.