Effects of hydrothermal pretreatments on thermodynamic and technological properties of red bean starch

Abstract

The aim of this study was to investigate the effects of hydrothermal pretreatments (HPs) on the thermodynamic and technological properties of red bean starch. The HP chosen included cooking and autoclaving processes and were applied to beans and red bean starches. To obtain powdered starch, the starch pastes were dried at temperatures of 50, 60, and 70 C in an electric oven with 1,200 W. The diffusion model with boundary condition of the third type was fitted to the experimental data and the thermodynamic properties were calculated. The starches obtained were analyzed for extraction yield, color, and technological properties (apparent viscosity, X-ray Diffraction (XRD), and DSC). Effective diffusivity values ranged from 7.621 Â 10 À9 to 9.815 Â 10 À5 m 2 min À1 , which reduced drying time by up to 480 min. Starches submitted to HP showed a decrease in activation energy and an increase in Gibbs free energy. It was observed that for an extraction yield >30%, the highest values were found for the treatments submitted to 70 C, especially for the starch submitted to cooking (SC). Red bean starch presented type A crystalline structure, where its crystallinity index ranged from (27.32%-33.41%) and thermal properties were affected by the application of HPs. Using autoclave HP in starch, it is possible to reduce process costs by reducing drying time, as well as changing the crystal structure and thermal properties. Practical ApplicationsThe results obtained contribute to optimize the hydrothermal modification using autoclave and cooking in the grains and starch of several cereals. The HP technique influenced the drying time, consequently reducing the cost of the process. The rheological, thermal, and structural properties were affected, thus being considered a viable treatment for starch modification for large-scale application, due to the technique being easy to handle, low investment, and not using reagents harmful to the environment.

Non-Traditional Starches, Their Properties, and Applications

“…Pregelatinized starch originates when starch slurry is heated by steam [86]. It is a common ingredient in foods, as well as other industrial applications.…”

“…Phosphorylation and acetylation change the functional and physicochemical properties of starches. The hydroxypropylation of non-traditional starches enhances swelling capacity, viscosity, clarity, and freeze-thaw stability [86,106]. Also, a combination of physical and chemical modification was tested, e.g., ozone oxidation together with high-pressure homogenization [56] or high hydrostatic pressure and cationization [85].…”

Impact of pretreatments with ethanol and freezing on drying slice papaya: drying performance and kinetic of ultrasound‐assisted extraction of phenolics compounds

“…Santos et al 21 using the same model, obtained a diffusivity of 3.28 × 10 −10 m 2 s −1 for drying acuri slices without pretreatment at a temperature of 60 °C. According to Almeida et al 38 the use of this model can lead to significant errors, especially in the description of the initial moments of the process, as it uses only the first term of the equation that represents the analytical solution. For this reason, we also use model 2.…”

Impact of Treatment with Superheated Steam on the Structural, Thermal, and Functional Characteristics of Quinoa Starch

“…Previously studied different methods of starch modification, such as: pulsed electric field, [6,7] hydrothermal pretreatments, [8,9] high-intensity low-frequency ultrasound, [10,11] combination of hydrothermal pretreatments and 𝛼-amylase hydrolysis, [12,13] and heat-moisture treatment. [14,15] Modification with heat moisture allowed to obtain greater structural changes in the quinoa starch with 3 h of pretreatment.…”