Hyperbaric storage of soup and comparison with refrigeration

• Autor(a) principal: Moreira, Sílvia Alexandra Monteiro
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/13737
• topic: Biotecnologia alimentar; Conservação dos alimentos - Alta pressão

The aim of this work was to investigate if hyperbaric storage, using high hydrostatic pressure, is effective in delaying ready-to-eat food products microbial and physicochemical spoilage allowing extending its shelf-life, with no need for refrigeration. Inicially, the hyperbaric storage of a ready-to-eat carrot soup was studied and compared to refrigeration. Soup was stored at diferente time (4 and 8 h), temperature (4, 25 and 30 ºC), and pressure (0.1, 100 and 150 MPa) conditions. In addition, were also performed tests in an industrial equipment with two real commercial products, Caldo verde and Bacalhau com natas that were stored for 12 h at different pressures (50, 100 and 150 MPa) at room temperature (~21 ºC). For both cases, microbial loads (total aerobic mesophiles, Enterobacteriaceae and yeast and moulds) and physicochemical parameters such as pH, titratable acidity, reducing sugars and colour, were compared with the controls at atmospheric pressure at the same temperature. Hyperbaric storage resulted in similar to better results when compared to refrigeration, since 100 MPa resulted in microbial growth inhibition, while for storage under 150 MPa microbial inactivation occured. Higher pressure (150 MPa) and a longer storage period (8 h for laboratorial scale, and 12 h for the tests in the industrial equipment) resulted in more pronounced microbial growth inactivation. Total aerobic mesophiles were found to be the less susceptible microorganisms to hyperbaric storage, compared to Enterobacteriaceae and yeast and moulds. Concerning the physycochemical parameters, storage under pressure, generally, was able to maintain the values similar to refrigeration. Therefore, hyperbaric storage with no need for temperature control seems to be a possible new preservation methodology, and an alternative to refrigeration.