Recrystallization Properties of High Hydrostatic Pressure Induced Gelatinized Tapioca Starch

Tapioca was selected as the raw material(C-type, 17% amylose) and formulated as a 30% starch using high hydrostatic pressure(HHP)-assisted at 600 MPa, dwell time 30 min pasting it. Treatment different times, different temperature on recrystallized structure of gelatinized tapioca starch. The appearance and particle size of the granules were studied by micro-polariscopy, scanning electron microscopy (SEM) and laser diffraction instrument. The X-ray diffraction, rapid viscosity analyzer, magnetic resonance imaging, Fourier infrared spectrum(FIRT) were employed to investigate the features of granular structure at the nanometer scale. The results showed that tapioca starch completely gelatinized in 600 MPa, tapioca starch recrystallization on the outside of the particle aggregation, the charge of particle size by 10 μm to 60 μm, particle structure consists of a layered structure becomes dense fibrous ring lines structure. From type C, 4℃ higher than the crystallinity numerical value of 25℃ when the 4℃ infrared short range order enough of the intermolecular hydrogen bond, the structure is more compact, it is determined at 4℃ gelatinized tapioca starch easier recrystallization. Recrystallized from tapioca starch properties: after recrystallization tapioca starch PV, TV, FV 4℃ bigger than 25℃. HHP gelatinized tapioca starch gel after recrystallization weak, with the extension of recrystallization time increases the rigidity of tapioca starch gels also increased, recrystallization 8 d, the curves cross phenomenon, tapioca from the typical weak gel system into a strong gel. With the extension of time of recrystallization, tapioca shear thinning phenomenon in 2, 4, 6 d shear stress is 0, when the recrystallization time reaches 8 d, only showing gelation, there is a certain shear stress, but with decreasing shear rate decreases, showing signs of shear thinning. After examining the nature of HHP recrystallization of cassava starch can be in paper making, textile, food and chemical industry and other fields have a wide development prospects. © 2019, Editorial Office of Journal of CIFST. All right reserved.