Effects of temperature and shear on the structural, thermal and pasting properties of different potato flour

Abstract

Background: The properties of potato flour will be different due to different processing parameters, which will affect their processing adaptability. In this paper, different potato flour were investigated to determine viscoelastic properties and structural transformation using thermodynamics, rheological and spectrum methods. Potato flour was prepared by drying at different temperature after soaking in citric acid, microwave and steamed respectively. The treated samples were dried by hot air and then compared with the freeze-dried potato flour. Four kinds of potato flour showed different properties after shearing at high temperature. Results: Differential scanning calorimetry (DSC) results revealed that potato flour with low gelatinization had lower enthalpy and faster melting process than freeze-dried potato powder. RVA and texture results showed that potato flour with low gelatinization had the best retrogradation property and the stable gel. X-ray diffraction (XRD) patterns revealed that the crystalline properties of different potato flour after shearing at high temperature were the same. In addition, low gelatinization potato flour presented a crystalline structure or strong internal order. Fourier-transform infrared spectroscopy (FTIR) spectra showed that high temperature and shearing mainly caused δ-deformation of O-H in intact potato granules. Conclusion: Freeze drying and hot air drying at low temperature made potato flour had better gel stability than microwave and steamed treatment. Hot air drying at low temperature made potato flour had good retrogradation after hot shearing, which was more conducive to the formation of hot-processed products.

An Insight into the Ultrastructural and Physiochemical Characterization of Potato Starch: a Review

“…Due to the limitations of optical microscopy and FTIR to parameters such as the temperature range and starch-water ratio, X-ray diffraction has been employed to study the transition of starch in a variety of moisture contents and temperature changes (Liu et al 2002). Comparison of XRD spectra of native potato starch with those of processed ones, such as heat-treated potato starch shows that crystallinity of the starch reduces after microwave and steam treatment (Zhang et al 2020). The extent of gelatinization also affects the physical properties of the starch; a lower degree of gelatinization of potato starch was associated with lower enthalpy, a faster rate of melting of the starch and formed a more stable gel.…”

“…This occurrence has been hypothesized to be a result of water molecules having a structural role in the starch molecules (Dankar et al 2018). Processing of potato starch utilizing high temperatures and shear has also been linked to the deformation of O-H bonds, which consequently affect its structural properties (Zhang et al 2020).…”

Physicochemical properties of rice analogs based on multi-level: influence of the interaction of extrusion parameters

“…The potato flour was prepared following the procedure by Zhang et al with some modifications. [22,23] Fresh potatoes were cleaned, peeled, and cut into slices (2.5 mm thick) with a fruit slicer. Then, the flakes were soaked in anti-browning agent containing 0.4% citric acid for 30 min to avoid enzymatic browning and dried by hot air in natural convection oven (DHG-9055A, Bluepard, China) for 12 hours.…”

“…Adjusted the water content of potato and rice flour to about 14% according to Zhang's method. [22,23] Potato or rice flour was placed in a sealed container under the conditions of 25°C and 70% relative humidity (RH) until its final moisture content was about 14%. The RA was prepared following the procedure by Zhang et al [24] 360 g rice flour, 240 g potato flour, and 150 g distilled water were mixed thoroughly and processed by twin-screw extruder (DS32-, Jinan Saixin Machinery CO LTD, China).…”

“…C., Australia) according to the method in reference. [22] The rotating speed of rotor was 160 r/min. The temperature raised from 50°C, rised to 95°C after 3 min 42 s and keep warm for 1.5 min, and then dropped to 50°C after 3 min 48 s and keep warm for 2 min at 50°C.…”