Effect of microfluidization on the microstructure and physical properties of a novel yoghurt formulation

This study aims at development of a new method to form emulsion-based yoghurt like gels from, but not limited to hazelnut. For this purpose, hazelnut slurries with varying solid content were processed using a microfluidizer to obtain creamy structures possessing high consistency. Then, these slurries were processed into fermented hazelnut products (HNPs) by inoculating with lactic acid bacteria culture. Real time rheological measurements were conducted to monitor how moduli values changed during fermentation. For the sake of comparison conventional cow milk yoghurt (CMY) was also included in the study. Texture analysis experiment showed that microfluidization greatly improved physical properties of the HNPs with significant increase in firmness values. When moisture content of HNP was around 22.7%, the firmness value was close to that of CMY. Since the entire hazelnut was used in processing, the HNPs contained soluble (0.34-0.75 g/100 g) and insoluble fiber (1.58-4.12 g/100 g). Microfluidization treatment also resulted in markedly increased colloidal stability of the HNPs. Sensory evaluation studies revealed that some of the HNP formulations had comparable texture, flavor, and appearance properties with CMY.