Moisture sorption isotherms of fresh and blanched pumpkin (Cucurbita moschata)

Food Science and Technology (Campinas)

Lucídio Molina Filho¹  Ana Karla Rebes Gonçalves¹  Maria Aparecida Mauro¹  Elen Cristina Frascareli¹ 

[1] ,Sao Paulo State UniversitySão José do Rio Preto SP ,Brazil

关键词: blanching;    pumpkin;    desorption isotherms;    isosteric heat;    GAB model;    branqueamento;    abóbora;    isotermas de dessorção;    calor isostérico;    modelo de GAB;   

DOI  :  10.1590/S0101-20612011000300025

来源: SciELO

【 摘 要 】

Moisture desorption isotherms of fresh and heat blanched pumpkins (Cucurbita moschata) were determined at three temperatures (30, 50 and 70 °C), using the standard, static-gravimetric method. The GAB, Oswin, BET, Halsey, and Henderson models were tested and, with the exception of the Henderson model, showed satisfactory fits to the experimental data. The GAB model was used to analyze the fitting ability to describe the isotherm type. The shape of the desorption isotherms of fresh and blanched pumpkin at 30 and 50 °C was intermediate to types II and III, and at 70 °C it was of type II for the blanched pumpkin and close to type II for the fresh sample. The influence of blanching on the decrease in equilibrium moisture was very small compared to the fresh samples and it was related to the loss of soluble solids during the pre-treatment. The isosteric heat of sorption measures indicated that a larger amount of heat was required to remove the water from the fresh samples than from the blanched ones.

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