Encapsulação de suco de maracujá por co-cristalização com sacarose: cinética de cristalização e propriedades físicas
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Data
2005-12-01
Autores
Astolfi-Filho, Zailer [UNESP]
Souza, Ana C. [UNESP]
Reipert, Érika C. D.
Telis, Vânia R. N. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Resumo
O processo de co-cristalização consiste na concentração de um xarope de sacarose até a supersaturação, quando então é adicionado o material a ser encapsulado. A partir daí, a mistura é submetida a uma intensa agitação que induz à nucleação e à aglomeração do produto. Neste trabalho, a encapsulação de suco concentrado de maracujá em sacarose por co-cristalização foi avaliada, determinandose o efeito da fração de suco adicionada e do pH do suco sobre a umidade, solubilidade, densidade aparente e ângulo de repouso do produto final e acompanhando-se a cinética de cristalização em um reo-reator, constituído de um cristalizador acoplado a um reômetro rotacional de cilindros concêntricos, cujo cilindro interno foi substituído por um agitador. A cinética de co-cristalização foi representada por um modelo empírico ajustado aos dados obtidos. A co-cristalização foi acelerada em função do aumento do pH e da redução da porcentagem de suco. Os produtos co-cristalizados apresentaram menor umidade e maior solubilidade em baixas concentrações de suco. A densidade aparente e o ângulo de repouso foram similares aos da matriz encapsulante e situaram-se na faixa em que se encontram a maioria dos pós alimentícios.
Co-crystallization is an encapsulation process where a second ingredient is incorporated in a porous conglomerate of sucrose microcrystals formed by spontaneous crystallization. The process is carried out by concentrating a sucrose syrup until supersaturation and, then, adding the core material, with the mixture being submitted to an intensive agitation that leads to nucleation and product agglomeration. In the present work, encapsulation of passion fruit concentrated juice by co-crystallization with sucrose was evaluated by determining the effects of added juice fraction and juice pH on moisture content, solubility, apparent density and repose angle of final product, as well as by following the co-crystallization kinetics in a rheo-reactor, constituted of a crystallizer adapted to a concentric cylinders rotational rheometer, in which an agitator substitutes for the internal cylinder. The cocrystallization kinetics was described by an empirical model fitted to experimental data and the crystallization rate was accelerated with increasing pH and decreasing added juice fraction. The co-crystallized products presented lower moisture content and higher solubility at lower juice fractions. Apparent density and repose angle were similar to those reported for the encapsulating matrix and were in the range of values reported for most of food powders.
Co-crystallization is an encapsulation process where a second ingredient is incorporated in a porous conglomerate of sucrose microcrystals formed by spontaneous crystallization. The process is carried out by concentrating a sucrose syrup until supersaturation and, then, adding the core material, with the mixture being submitted to an intensive agitation that leads to nucleation and product agglomeration. In the present work, encapsulation of passion fruit concentrated juice by co-crystallization with sucrose was evaluated by determining the effects of added juice fraction and juice pH on moisture content, solubility, apparent density and repose angle of final product, as well as by following the co-crystallization kinetics in a rheo-reactor, constituted of a crystallizer adapted to a concentric cylinders rotational rheometer, in which an agitator substitutes for the internal cylinder. The cocrystallization kinetics was described by an empirical model fitted to experimental data and the crystallization rate was accelerated with increasing pH and decreasing added juice fraction. The co-crystallized products presented lower moisture content and higher solubility at lower juice fractions. Apparent density and repose angle were similar to those reported for the encapsulating matrix and were in the range of values reported for most of food powders.
Descrição
Palavras-chave
microencapsulação, sucos de frutas, açúcar, pós, viscosidade aparente, microencapsulation, fruit juice, sugar, food powders, apparent viscosity
Como citar
Food Science and Technology (Campinas). Sociedade Brasileira de Ciência e Tecnologia de Alimentos, v. 25, n. 4, p. 795-801, 2005.