Abstract. Grittiness of egg yolk is a major factor in consumer acceptance of salted duck egg
product. Commonly, the grittiness level is determined by the destructive method. Salted egg
industries need a grading system that can judge the grittiness accurately and nondestructively.
The purpose of this study was to develop a method for determining grittiness of salted duck eggs
nondestructively based on ultrasonic method. This study used 100 samples of salted duck eggs
with 7,10,14 and 21 days of salting age. Velocity and attenuation were measured by an ultrasonic
system at frequency 50 kHz, followed by physicochemical properties measurement (hardness of
egg yolks and salt content), and organoleptic test. Ultrasonic wave velocity in salted duck eggs
ranged from 620.6 m/s to 1334.6 m/s, while the coefficient of attenuation value ranged from –
0.76 dB/m to -0.51 dB/m. Yolk hardness was 2.68 N at 7 days to 5.54 N at 21 days of salting
age. Salt content was 1.81 % at 7 days to 5.71 % at 21 days of salting age. Highest scores of
organoleptic tests on salted duck eggs were 4.23 and 4.18 for 10 and 14 days of salting age,
respectively. Discriminant function using ultrasonic velocity variables in minor and major
diameter could predict grittiness with 95 % accuracy