Investigação microscópica da estrutura do leite adicionado de polissacarídeos

Abstract

This study aimed to investigate and compare the effects of calcium and κ-carrageenan addition on microstructure and quality of model solutions using the technique of scanning electron microscopy. Four samples of milk with or without κ-carrageenan (0.025 %) and calcium chloride (4 mM) were heated (65 °C/30 minutes) and stored for 24 hours in a refrigerator at 4 °C. After 24 hours, the samples were frozen (-80 °C) and than lyophilizated during 72 hours. The addition of calcium ions did not decrease the size of the molecular aggregates after lyophilization as compared to aggregates formed only with milk. The presence of κ-carrageenan in milk after lyophilization formed a rigid structure characterized by interactions between κ-carrageenan and milk proteins. The fi lm formed by adding calcium ions and κ-carrageenan has the property of adsorbing crystals. Lyophilization was an important step on the preparation of the samples reducing time and costs in regard to samples’ water elimination protocol, well known and routinely applied before scanning electron microscopy.