This study aims to research the effects of rosin acid (RA) and size of starch on the properties of Pickering emulsifier. Potato (PS, 10–100 µm), corn (CS, 5–25 µm), and rice (RS, 3–8 µm) starches are modified with RA, and their starch ester is used to prepare Pickering emulsions. The results of scanning electron microscopy, X‐ray diffraction, and nuclear magnetic resonance hydrogen spectrum analysis reveal that the structure of native starch is largely destroyed, and esterification occurs between starch and RA. The starch‐based Pickering emulsion, which is esterified by RA, has the uniform particle size and higher stability than native starch. With prolonged storage, the emulsion of large‐sized RA–starch (PS and CS) show a stable gel phenomenon, and the emulsion of small‐sized RA–starch (RS) is a Newton fluid. In addition, the results indicate that RA–starch displays high viscosity and emulsifying properties.

Lactobacillus rhamnosus GG (LGG) microcapsules prepared using the complex coacervation method were dried through spray and vacuum freeze drying. Physical properties, resistance to simulated gastrointestinal and bile salt conditions, and the stability of the LGG microcapsules during storage and heat treatment were estimated. Spray and vacuum freeze drying are suitable for LGG microcapsule preparation because of lower than 2.80% of the water content, and higher than 93.21% of the encapsulation efficiency. Under the simulated gastrointestinal condition, the survival rates of two kinds of microencapsulated LGG were over 96%. At 0.6% bile salt concentration, the survival rate of microencapsulated LGG subjected to spray drying was 110.89% higher than that of LGG subjected to vacuum freeze drying. In addition, the stability of the former was better than that of the latter during storage under low water activity condition (0.11). However, under high water activity condition (0.75), the two showed opposite results. The two kinds of microencapsulated LGG were completely inactivated after 4 weeks in 0.75 of water activity. The survival counts of microencapsulated LGG had no significant difference at −18 • C after 8 weeks. After 8 weeks at 25 • C and 4 • C, the survival loss of microencapsulated LGG through drying and vacuum freeze drying was approximately 2 and 1 log CFU/g, respectively.