Improvement in Storage Stability and Physicochemical Properties of Whole-Grain Highland Barley Pulp Prepared by a Novel Industry-Scale Microfluidizer System in Comparison with Colloid Milling

Abstract

The aim of this study was to assess the advantages of an industry-scale microfluidizer system (ISMS) to prepare whole-grain highland barley pulp (WHBP) compared with colloid milling. Storage stability was evaluated by particle size, gravity separation stability, and rheological properties, as well as the microstructure observation by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLMS). The results showed that colloid milling failed to effectively homogenize the material, while ISMS sample surfaces were compact and smooth at higher pressures according to visual observation and SEM. The Turbiscan stability index of WHBP by ISMS was much lower as a result of colloid milling, demonstrating ISMS can improve WHBP stability. WHBP by colloid milling displayed a three-peak particle size distribution pattern, while a single-peak pattern was evident after ISMS treatment. A higher shear rate decreased the apparent viscosity, suggesting that WHBP was a shear-thinning fluid. According to CLMS, ISMS can successfully improve homogenization by disrupting the structures of oil bodies, proteins, and starches. The WHBP prepared by ISMS exhibited a higher β-glucan level than that prepared by colloid milling, and showed a significant increase in β-glucan level with ISMS pressure. These findings indicate that using ISMS to produce WHBP is viable for enhancing its storage stability and nutritional value.