Conservação de fatias de manga utilizando tecnicas combinadas : desidratação osmotica e congelamento

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

Slices of Tommy Atkins mangoes, 5 mm thick, were submitted to osmotic pre-treatment in order to improve the freezing process characteristics. Mangoes at the initial stage of ripening (84,8 + OU - 1,9% water content; 12,9 + OU - 1,9 DEGREES Brix) were peeled and sectioned following the seed direction. The slices, without prior thermal treatment, were submitted to osmotic dehydration, at ambient temperature, using an excess of aqueous solutions of sucrose (40% and 50% by weight) and solutions of sucrose and glycerol (40%-10% and 50%-10%), at two time levels: 30 minutes and 60 minutes. The product was characterized by its final water content, by the loss of mass and gain of solids during the osmotic treatment, by the initial freezing temperature and by the freezing enthalpy. These data allowed for the calculation of the ice fraction formed during freezing. The freezing of the individually wrapped slices proceed by immersion in an ethanol bath (- 25 DEGREES C) with two freezing rates: slow (22 mm/h) and intermediate (228 mm/h). The qualification of the freezing process was ascertained by the mass of exsudated after thawing and confirmed that the osmotic pre-treatment works effectively as a celular mass loss reductor. The dripping loss as affected by the freezing rates only with slices higher water content... Note: The complete abstract is available with the full electronic digital thesis or dissertations.

ASSUNTO(S)

manga alimentos congelados alimentos - desidratação manga - secagem exsudação (botanica)

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