Spray freeze-dried powders and layered double hydroxides (LDHs) are comparatively new materials in the pharmaceutical industry to produce value-added products. However, the food applications of these materials are yet to be thoroughly explored. Thus, this study deals with potential application of these materials in the food industry.Spray freeze-drying is the most suitable for heat sensitive products which need to be size control such as probiotics. Lactobacillus casei (IFO 15883) was spray freeze-dried to obtain fine probiotics powder with no heat damage. The survival rate of L. casei in the powder after spray freeze-drying (SFD) process was investigated using plate agar counting method. To improve the survival rate of L. casei during SFD process, the experimental conditions such as incubation growth media, freeze drying media composition and spraying conditions were optimized. The optimized conditions for growth media, freeze drying media composition and spraying conditions were Lactobacilli MRS broth with 1% mannose and 0.1%CaCO3, BPW (non protective agent) and 0.2 kPa air pressures, respectively. Scanning electron microscopy (SEM) was applied to estimate physical structure and properties of the particle. SFD probiotic particles had various sizes and shapes with porous structures at different SFD conditions. The decreasing viability rate of final SFD probiotics powder through the optimized conditions was 0.22 log CFU/ml. Layered double hydroxides (LDHs) were developed as nanocontainers for various therapeutic agents. However, LDHs have not been investigated from a nutritional point of view. Mg2+, Zn2+ and Cr3+ are involved in the mechanism of insulin action and in glucose metabolism. MgZnCrAl-LDHs were synthesized at various ratios Al3+/ Cr3+. Also, we intercalated pyridoxal-5-phosphate (PLP) into LDH nanoparticles by ion exchange method. According to the X-ray diffraction (XRD) patterns of PLP-LDH hybrids, the gallery height of LDHs was expanded from 3.8 � to 11.9 �, indicating that the PLP molecules were successfully intercalated into the interlayer space of LDHs. Fourier transform infrared (FT-IR) spectra also revealed that the PLP molecules were well stabilized in the LDHs through electrostatic interaction. In addition, the scanning electron microscopy (SEM) images showed that the LDHs had hexagonal, thin, plate-like shapes with homogeneous size distribution. To evaluate the light stability of PLP, free PLP and PLP-LDH hybrids were exposed to UV light. After 180 min of exposure, the PLP contents of free PLP and PLP-LDH hybrids decreased by 72.0 and 4.7 %, respectively.

Applications of spray freeze-drying method and layered double hydroxides for value-added food ingredients

248th National Meeting (2014)

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