Physical, chemical and rheological properties of pitomba (Talisia esculenta) seed starch and its application as a thickener and stabilizer in ketchup

The present study aimed to characterize the physical, chemical and rheological properties of starch extracted from pitomba seeds and verify the influence of its addition on the syneresis and viscosity characteristics of ketchup during storage, compared to maize starch. Extraction was performed by grinding the seeds in sodium metabisulfite solution (0.2%) followed by drying at 50 ºC. ketchups were formulated with the addition of 0.5 and 1% pitomba starch, 0.5 and 1% maize starch and a control formulation. Starch showed low percentages of protein, ashes and lipid, starch purity of 77.78%, amylose of 19.25%, apparent density of 0.46 g/cm3 and compact density of 0.66 g/cm3. The starch pastes showed pseudoplastic behavior and imparted significant viscosity, usable in increasing the consistency of fluid foods. Ketchups formulated with addition of pitomba starch showed reduction of syneresis during storage, and the 1% starch concentration can slow down the syneresis process in ketchup at temperatures of 7 and 25 °C, similar to the stabilizing capacity of maize starch. Ketchup viscosity increased with the addition of pitomba and maize starches, but the highest apparent viscosities were obtained in ketchup with addition of pitomba starch during storage