Water adsorption isotherms and isosteric sorption heat of spray-dried and freeze-dried dehydrated passion fruit pulp with additives and skimmed milk

Ciência e Agrotecnologia

Kelly Tafari Catelam²  Carmen Sílvia Fávaro Trindade¹  Javier Telis Romero² 

[1],Universidade Estadual Paulista Departamento de Engenharia e Tecnologia de Alimentos São José do Rio Preto SP ,Brasil

关键词: Maltodextrin;    gum arabic;    GAB model;    Maltodextrina;    goma arábica;    modelo de GAB;   

DOI  :  10.1590/S1413-70542011000600021

来源: SciELO

【 摘 要 】

Moisture equilibrium data of passion fruit pulp powders with maltodextrin and gum arabic were obtained by two different drying methods (spray drying and freeze drying) and determined at 20, 30, 40 and 50º C. Skimmed milk was used to substitute part of these additives in the samples. One formulation using passion fruit pulp/maltodextrin/skimmed milk (PMS) was prepared, and another using passion fruit pulp/gum arabic/skimmed milk (PGS). The behavior of curves was type III, according to Brunauer's classification. GAB models were fitted to experimental equilibrium data. The parameters obtained from GAB models was affected by the presence of additives. The behavior of the sorption isotherms for different temperatures are similar, noting only a small effect of temperature. There were little differences between both drying methods and additives used in relation to equilibrium moisture content. The parameters obtained with the addition of the skimmed milk were considered satisfactory (Xm values ranged from 0,04084 to 0,06488 in dry basis), demonstrating that it is an effective and cheap alternative for regular additives. A progressive increase in the heat of sorption in relation to decreasing moisture content was observed and the heat of sorption values of different samples are all similar, comparing the relative equilibrium moisture content.

【 授权许可】

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