Effect of Pregelatinization and Retrogradation on Some Physicochemical Changes of Wheat-Potato Starches

Authors : Nesimi AKTAŞ, Kamil Emre GERÇEKASLAN

Pages : 281-289

Doi:10.15832/ankutbd.426252

View : 29 | Download : 7

Publication Date : 2019-09-05

Article Type : Research Paper

Abstract :The freezable insert ignore into journalissuearticles values(FW); and unfreezable water insert ignore into journalissuearticles values(UFW); contents of wheat and potato starches and their physically modified  forms [pregelatinized insert ignore into journalissuearticles values(PGS); and retrograded insert ignore into journalissuearticles values(RS);] were analyzed by Differential Scanning Calorimetry insert ignore into journalissuearticles values(DSC); at  various hydration levels insert ignore into journalissuearticles values(25, 35, 45, 55, 65, 75 and 85%);. In all the starch samples, the UFW content increased with  increasing hydration level. Potato starch samples insert ignore into journalissuearticles values(native, pregelatinized and retrograded); had higher UFW contents than  wheat starch samples at all hydration levels. Similarly, with the increase of hydration level in all starch samples, onset  insert ignore into journalissuearticles values(To);, peak insert ignore into journalissuearticles values(Tp); and endset insert ignore into journalissuearticles values(Te); temperatures of the peaks also increased. It was obtained that physical modifications in  starches had significant effects insert ignore into journalissuearticles values(P<0.05); on water absorption index insert ignore into journalissuearticles values(WAI); and water solubility index insert ignore into journalissuearticles values(WSI); of starch  samples. The highest WAI insert ignore into journalissuearticles values(10.51); and WSI insert ignore into journalissuearticles values(2.31); values were determined in pregelatinized potato starches. Rapid Visco  Analyzer insert ignore into journalissuearticles values(RVA); profiles revealed that physically modified starches had higher viscosity values than native starches. The  results clearly showed that pregelatinization and retrogradation had positive effects on the physicochemical properties  studied. 
Keywords : Unfreezable water, wheat potato starch, physical modifications, DSC, RVA