Effect of Palm or Coconut Solid Lipid Nanoparticles (SLNs) on Growth of Lactobacillus plantarum in Milk

This study was performed to investigate the effect of palm or coconut solid lipid nanoparticles (PO-SLNs or CO-SLNs) on growth of Lactobacillus plantarum (L. plantarum) in milk during storage period. The PO or CO (0.1% or 1.0%) was dispersed both in distilled water (DW) and ultra high temperature milk (UHTM), and subsequently emulsified with Tween^® 80 by ultrasonication (30% power, 2 min). Increase in particle size and encapsulation efficiency (EE%) in DW was observed with an increase in oil concentration, whereas a decrease in ζ-potential of SLNs was noted with an increment in oil concentration. Moreover, the CO-SLNs exhibited relatively smaller particle size and higher EE% than PO-SLNs. The CO-SLNs were found to be more stable than PO-SLNs. Higher lipid oxidation of PO or CO-SLNs in UHTM was observed during the storage test, when compared to PO or CO-SLNs in DW. However, there was no remarkable difference in lipid oxidation during storage period (p>0.05). In the growth test, the viability of L. plantarum in control (without PO or CO-SLNs in DW) exhibited a dramatic decrease with increasing storage period. In addition, viability of L. plantarum of PO or COSLNs in UHTM was higher than that of SLNs in DW. Based on the present study, production of SLNs containing PO or CO in UHTM is proposed, which can be used in lactobacilli fortified beverages in food industry.