Abstract #M115

# M115
Engineering innovative dairy emulsion droplets to mimic native milk fat globules.
H. Zheng*1, L. Ingram2, J. A. Ortiz Salazar3, J. Lu4, R. Fernando3, 1Dairy Innovation Institute, Department of Animal Science, California Polytechnic State University, San Luis Obispo, CA, 2Department of Biomedical Engineering, California Polytechnic State University, San Luis Obispo, CA, 3Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, CA, 4Dairy Processing group, Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China.

The impact of milk fat globule membrane (MFGM)-coated emulsion droplets on lipid digestion has become an interesting research topic. Efficiently manufacturing emulsion droplets coated by MFGM materials has been a technological challenge. The MFGM materials are enriched in buttermilk, and they may be further concentrated in buttermilk concentrate (BMC) using membrane filtration technology. In the current research, the emulsification capacity of in-house manufactured BMC was investigated. Response surface methodology (RSM) was used for optimizing the volumes and ratio between BMC as the emulsifier and milk fat as the oil phase, 1–15% of BMC (variable 1) and 1–15% anhydrous milk fat (AMF, variable 2) were combined at different ratios for manufacturing emulsion systems. Emulsions were manufactured by using homogenizer at 100MPa with 5 passages. All emulsions were heat-treated at 70°C for 30min for testing the physical stability after pasteurization. Both protein and fat contents are enriched in BMC comparing with original dried buttermilk (DBM) (P < 0.05). The lipidomics results showed that phosphatidylcholine is about 14% enriched in BMC powder comparing with original DBM. A 6-mo shelf life study showed that BMC is an efficient emulsifier. Particle size distribution (PSD) results showed that an emulsion system made from 8% BMC + 8% AMF (namely 8/8-BMC emulsion) had D4,3 as 3.9 ± 0.14 μm. Moreover, the sample PSD profile is similar to the PSD profile of raw milk. Confocal laser scanning microscopy images confirmed that both protein and MFGM phospholipids were loaded onto to the surface of BMC stabilized emulsion droplets. Using amplitude sweep technique, the rheological characterization confirmed that the 8/8-BMC emulsion was in liquid state at both 5°C and 25°C (loss tangent >1). Stress ramp test was performed for the construction of flow behavior Ostwald/de Waele model for “8/8-BMC emulsion.” All data points were covered in 95% prediction interval (95% PI) of the model. In conclusion, we developed a technology for manufacturing recombined emulsion droplets that mimic the structural assembly of native MFGs. These emulsion droplets may be applied in infant formula and in cheeses made from fully recombined milk.

Key Words: emulsion, buttermilk concentrate