Passion Fruit Starch and Effect on Juice Viscosity

Starches in the juices of yellow passion fruit, Passiflora edulis f. flavicarpa , and purple passion fruit, P. edulis f. edulis , were isolated and characterized. Starch granule sizes for the yellow variety (7.8 μm) and purple variety (6.4 μm) were similar. Gelation temperature ranges for the yellow variety (58.5–67.0 ° c) and purple variety (58.5–66.5 ° C) were also similar. The amylose content was slightly higher in the yellow variety (8.7%) than in the purple variety (5.8%). Viscosity differences between juices of the two varieties after treatment with heat and α‐amylase were attributed to differences in pH and starch content between the yellow variety (pH 2.8, 0.06% starch) and the purple variety (pH 4.2, 0.74% starch). α‐amylase was effective in reducing the viscosity of passion fruit juice in which the starches are gelatinized.