The Effects of Hot Air and Microwave Drying on the Structural and Physicochemical Properties of Soluble Dietary Fiber from Sugar Beet Pulp.

Abstract

Sugar beet pulp (SBP), a byproduct of the sugar industry, presents significant potential for enhancing economic benefits and promoting sustainable development through its comprehensive utilization. SBP is rich in fiber, with its soluble dietary fiber (SDF) constituting a high-value component. The initial step in the preparation of SDF involves the drying of fresh SBP. This study compares the effects of hot air and microwave drying on the composition, structure, and physicochemical properties of SDF in SBP. Technologies such as gel permeation chromatography, gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy, scanning electron microscopy, and Zeta potential analysis were employed. Results indicated that microwave drying enhanced sugar components in SDF, reduced polysaccharide molecular weight, and formed a uniform and porous microstructure. This resulted in a higher Zeta potential (-24.76 mV) and increased water holding capacity (5.01 g/g). Hot air-dried samples preserved a more intact cell wall network, exhibiting higher swelling capacity (5.18 mL/g). The study demonstrated how both drying methods differentially regulated SDF quality from sugar beet pulp, suggesting that drying process selection should be based on specific application needs.