Abstract: [Objective]The particle size distribution of yogurt significantly affects its taste,stability,and digestibility,while the measurement results of laser particle size analyzers are susceptible to sample pretreatment conditions.[Method]This study systematically investigated the effects of different dilution ratios（1︰1~1︰20） and obscuration levels（0%~25%） on yogurt particle size measurement,aiming to establish a standardized detection method.[Result]The results showed that at a dilution ratio of 1︰10,the D50 average value was closest to the true value（20.766 μm）,with the smallest relative standard deviation（RSD=1.52%） and the most concentrated particle size distribution（D90/D10=2.28）.When the obscuration level was within 5%~10%,the measurement precision was optimal（RSD=1.50%）.Based on these findings,a standardized operation protocol is recommended,including sample homogenization by glass rod stirring,a 1︰10 dilution ratio,and an obscuration level of 5%~10%.[Conclusion]This study provided a reliable methodological reference for quality control in dairy enterprises and academic research.

Key words: yogurt, particle size measurement, dilution ratio, obscuration, laser particle size analyzer, standardized method