Characteristics of clouding substances in guava puree

This work investigates the composition and characteristics of cloud in guava puree prepared at various heating temperatures. The cloud content in guava puree was initially at 0.1% and increased greatly with increased heating temperature due to the polymerization of components (i.e., pectin and protein) in the puree. The cloud content in guava puree was significantly correlated with the change of its turbidity. Guava puree cloud was found to be composed of 43-45% protein, 25-26% carbohydrate, 5-8% pectin, 3-5% crude fiber, 6.5-9.3% ash, and 0.18% crude fat. The analyses of protein pattern and amino acid composition showed that the protein in cloud was of a low molecular weight, with a high isoelectric point and a compact structure; thus, it could combine with pectin and become suspended in the guava puree. The amount of divalent cation increased with increasing heating temperature, indicating that divalent cations could promote aggregation of components in puree. Phenolic compounds also contribute to the turbidity and sediment in puree.