Preparation, Characterization and Antioxidant Effects on Processed Sausages of Ultrafine Green Tea Powder Emulsions

The potential of ultrafine tea powder or its extracted crystalline substances as food-grade emulsified particles is attracting increasing attention because they are biobased, environmentally friendly and edible. This work explores the potential of ultrafine green tea powder (UGTP) as a stabilizer to produce stable emulsions. The UGTP microparticles were characterized using dynamic light scattering (DLS), laser Doppler velocimetry (LDV), and confocal laser scanning microscopy (CLSM), respectively. Furthermore, the effects of the microparticle concentration (1.0%-5.0%, w/v) and oil-water ratios (1:9-4:6) on the characteristics of the emulsions stabilized via UGTP were investigated. The results indicate that increasing the particle concentration and/or oil mass fraction was associated with improved emulsion stability. Emulsions prepared with 3% (w/v) UGTP and an oil-water ratio of 3:7 exhibited reduced creaming during storage. UGTP particles were observed to adsorb at the oil-water interface and to participate in the formation of a gel-like network structure within the emulsion. The UGTP-stabilized emulsions were subsequently incorporated into sausage formulations. Compared with the control sausages and those containing directly added tea powder, sausages containing UGTP emulsions showed lower lipid oxidation levels during storage, as reflected by reduced malondialdehyde (MDA) and peroxide value (POV). The incorporation of UGTP emulsions was also associated with changes in product color and sensory attributes, including tea aroma intensity, retention of meaty aroma, and textural characteristics. These findings suggest that UGTP can be used as a particulate stabilizer in food emulsions and may provide a feasible approach for the incorporation of green tea powder into meat products.