Ohmic heating treatment of fruit puree

• Autor(a) principal: Machado, L.
• Data de Publicação: 2007
• Outros Autores: Vicente, A. A., Teixeira, J. A., Miranda, F.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/6673

Ohmic heating is an alternative pasteurization process and is growing interest in industry. Understanding the influence of ohmic heating on the sensorial and microbiological quality of foods is a pertinent matter. This study concerns with the pasteurization effects of a pilot scale continuous ohmic heater on a strawberry puree containing fruit particles on relevant quality parameters of the product. The impact of pasteurization temperature (85 ºC, 90 ºC, 95 ºC) on the microbiological load, size distribution of strawberry particles (<0.3 g, 0.3 g to 0.7 g, 0.7 g to 1 g and >1 g), texture and microbial stability was studied. All treatments destroyed yeasts and moulds to values below 10 CFU/mL. The strawberry particles size distribution shows that the average size of particles decreased with increasing treatment temperature. A texture reduction, measured in terms of the force applied on a 5-blade Kramer cell, was observed when strawberry particles were collected before and after the thermal treatment: 20 %, 23 % and 25 % reduction at 85 ºC, 90 ºC and 95 ºC, respectively. The reduction for a scrapped surface heat-exchanger treatment at 95 ºC was of 31 %. In conclusion, ohmic heating reduces the product microbiological load and for parameters such as texture and size distribution of the strawberry particles the cooking effects are reduced when compared with a scrapped surface heat-exchanger treatment.