Modifications in the physicochemical properties of flour “fractions” after Pulsed Electric Fields treatment of thermally processed oat

Changes in Starch In Vitro Digestibility and Properties of Cassava Flour Due to Pulsed Electric Field Processing

“…The conductivity increase after PEF treatment is mainly due to membrane electroporation and ion diffusion into the medium [ 38 ], but the cassava flour samples showed no or a smaller conductivity increase (0–9.97 μS/cm) compared to thermally processed oat flour (41–62 μS/cm) [ 21 ] and glutinous rice grain (40–140 μS/cm) [ 16 ] when treated at 2–4 kV/cm with 50–451 kJ/kg of SEI and at 3 kV/cm for 100–300 pulses, respectively. Presumably, the comminuted nature of cassava flour (pre-sieved in the miller at ϕ 0.25 mm) allows almost complete dispersion of ions when prepared as a suspension in the water prior to PEF treatment.…”

“…This aside, the shift to higher gelatinization temperatures indicates the loss of the less stable crystalline structures [ 51 ] during PEF, leaving more uniform and perfect crystallites. Other authors have also suggested that the granular aggregation and physical reorganization inside the granule provided stability during heating [ 52 ], thereby requiring higher temperatures to facilitate starch swelling [ 17 , 21 ]. Furthermore, this shift did not impose much difference between control and treated samples in terms of Tpeak.…”

“…This study was able to show that at constant EFS with sufficient SEI, gelatinization can progress. Additionally, a strong correlation was found between ΔH and EFS in japonica rice starch [ 41 ], as well as a positive relationship between ΔH and relative crystallinity in oat flour fractions [ 21 ].…”

“…Baseline of the generated spectra were corrected using the OPUS software (Version 8.1, Bruker Optik, Ettlingen, Germany). Then, the spectral region of 1200–875 cm −1 , associated with the short-range ordered structure of starch, was deconvoluted based on the second-order derivative peak identification [ 21 , 32 ] using the OMNIC software (Thermo Scientific Fisher Inc., Waltham, MA, USA). The ratio of the peak height of the absorbances around 1047 and 1022 cm −1 was used to quantify the ordered and amorphous structure of the flour’s starch [ 33 , 34 , 35 ], while the absorbance ratio of 1022/995 was used to measure the molecular order of starch double helices inside the crystallites [ 33 , 36 ].…”

“…In the case of ground material such as flour, the initial investigation of PEF use was for bacterial reduction in dark rye flour [ 20 ], but recent work revealed the opportunity to create novel starchy products with various properties. As an example, PEF-treated oat flour had increased pasting stability, producing a paste with reduced syneresis and hardness [ 17 ] and the probability of creating customized “oat fractions” with targeted physicochemical properties [ 21 ]. Naturally fermented sorghum flour after PEF treatment had increased porosity of the cellular membrane, thereby increasing the release of phenolics bound by the protein–carbohydrate matrix and enhanced the health properties of sorghum flour [ 22 ].…”