• Improved emulsion stability and modified nutrient release by structuring O/W emulsions using konjac glucomannan

      Lu, Wei; Zheng, Baodong; Miao, Song; National Natural Science Foundation of China; China Scholarship Council; 31628016; 201508300001 (Elsevier, 2018-02-22)
      Functional konjac glucomannan (KGM) was used to structure the water phase of O/W emulsions containing a lipophilic bioactive compound (β-carotene). KGM greatly increased the viscosity of the water phase and thus the viscosity of final emulsions. Results of Fourier-transform infrared spectroscopy (FT-IR) showed that there is no significant non-covalent interaction between KGM and whey proteins in the water phase. KGM significantly improved the creaming and pH stability of whey-protein-stabilized emulsions (p < 0.05), and significantly decreased the oiling-off of emulsions during freeze-thaw test. Emulsions with or without KGM all had good thermal stability at 80 °C. Microscopy observations indicated obvious aggregation of free proteins and oil droplets in gastric phase and an enzymatic-induced break-down of droplets, mainly in the intestinal phase of the simulated gastrointestinal tract (GIT) digestion. Emulsions with KGM-structured water phase showed a lower final release rate of encapsulated β-carotene than emulsion without KGM (p < 0.05), and the release rate decreased with the increasing KGM content. The findings of this study contribute to a better understanding of the influence of the water phase on the release of encapsulated compounds from emulsions, and make it possible to achieve controlled release of encapsulated compounds, and/or to deliver multiple health-beneficial nutrients at once by structuring emulsion-based carriers with functional natural biopolymers.
    • Preparation and characterization of lotus seed starch-fatty acid complexes formed by microfluidization

      Chen, Bingyan; Guo, Zebin; Miao, Song; Zeng, Shaoxiao; Jia, Xiangze; Zhang, Yi; Zheng, Baodong; National Natural Science Foundation of China; Scientific and Technological Innovation Team Support Plan of Institution of Higher Learning in Fujian Province; Construction Projects of Top University; et al. (Elsevier, 2018-05-22)
      Using dynamic high pressure microfluidization, we prepared starch-lipid complexes from lotus seed starch (LS) and six saturated fatty acids (FAs) of different carbon chain length and analyzed their semi-crystalline structure and digestibility. Iodine blue value analysis showed the highest complex index (86.3%) was observed between LS and octanoic acid (C8). X-ray diffraction analysis showed crystal structure changed from V6II to V6I type with decreasing FA chain length. Small angle x-ray scattering and differential scanning calorimetry analyses confirmed the presence of a strong V6I-type mass fractal structure with a Bragg distance of 12.3 nm in LS-C8, which can be considered to be a type-II complex with high melting temperature (Tp = 123.98 °C). Scanning electron microscopy results showed the complexes had more spherocrystals with decreasing FA chain length. Compared to other FAs, C8 significantly reduced the LS susceptibility to digestive enzymes, increased slowly digestion starch content (26.06%) and decreased digestion rate (3.59 × 10−2).