Morphological analysis of the second haze in concentrated apple juice

The morphological analysis and the turbidity measurement of the second haze in concentrated apple juice were carried out and the composition of the second haze in concentrated apple juice were determined preliminary in order to supply informations for fruit juice processing and preservation. Negatively stained(uranyl acetate) images of the particles in the second haze apple juice and post bottling haze apple juice were observed. The turbidity of apple juice was decreased by freezing(at -18℃, frozen for 8～10 h) but increased by boiling after freezing. Spherical particles of protein and chain polymers of phenolic compounds were detected by negatively stained with uranyl acetate through transmission electron microscopy. Sub-particles were accompanied aggregation into the macroscopic particles with each other or by themselves. The turbidity of post bottling haze was higher than that of the second haze in apple juice after 6 months storage.