Conference Abstract Book

Enhancing Yogurt Microstructure and Texture through the Use of Modified Whey Protein Nanoparticles T. Biza*, K. Zampouni, T. Moschakis Department of Food Science and Technology, School of Agriculture, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece Yogurt is a popular fermented dairy product valued for its nutritional and functional benefits. With the rising demand for additive-free foods, there has been a growing interest on developing yogurt with improved characteristics, including better texture, taste, and additional health benefits, to meet consumers' preference for more natural and functional ingredients [1]. In this context, the present study investigates the use of modified whey protein isolates (WPI) as a means of enhancing the microstructure and rheological properties of yogurt-type fermented products. WPI nanoparticles were fabricated through a combined ethanol (50%) and ultrasound treatment, aiming to induce partial denaturation and aggregation at the nanoscale, thereby improving protein functionality. The resulting nanoparticles were characterized using laser diffraction for particle size distribution (SALD) and Fourier-transform infrared spectroscopy (FT-IR) to evaluate alterations in secondary protein structure. Four experimental yogurt formulations were prepared: (i) a control sample with skimmed milk powder (SMP-Y), (ii) a full-fat sample with 4% cream (FAT-Y), (iii) a sample containing 1% untreated WPI (WPI-Y), and (iv) a sample containing 1% ethanol–ultrasound-modified WPI nanoparticles (P50-Y). Rheological measurements and microstructural assessments via microscopy were conducted to evaluate the impact of each treatment. The formation of nanoparticles led to a decrease in the presence of α-helical secondary structures, which contributed to the modification of the proteins' secondary structure. When incorporated into yogurt products, these nanoparticles significantly enhanced the water retention capacity, resulting in a smoother and more stable texture. Additionally, yogurts enriched with the modified nanoparticles displayed a more compacted microstructure, showing superior texture and consistency compared to all other treatments. Overall, the modification of WPI using ethanol and ultrasonication presents a promising, clean-label approach for improving the quality of fermented dairy products. It offers a viable strategy for producing low-fat or additive-free yogurts with enhanced textural and functional attributes, aligning with current consumer preferences and food industry demands. [1] Giacone, L., Siegrist, M., Stadelmann, A., & Hartmann, C. (2024). Consumers’ perceptions of healthiness and environmental friendliness of plant-based and dairy product concepts. Food and Humanity, 2, 100288.