Duck egg yolk pickled by salt attained more desirable characteristics, such as orange color, oil exudate, and grittiness, than salted chicken egg yolk. Salted duck egg yolk reached a hardening ratio of 90% in 28-days; 35 days were required for the salted chicken egg yolk to achieve the same hardening. Moisture content of egg yolk affected the quantity of extracted lipid, an index of oil exudation. The moisture content of duck egg yolk was 19%, and the extracted lipid was 30%. But less than 4% lipid was extracted when moisture content was >27.5%. Under scanning electron microscopy, yolk spheres dominated the yolk structure probably responsible for the gritty texture.

To elucidate the relationship between shyandan yolk formation and NaCl penetration degree, fresh duck eggs were brined in 26% NaCl and a prolonged brining test was conducted for up to 24 weeks. Shyandan yolk was obtained from brine-cured duck shell eggs in 26% NaCl for 4-6 weeks and subsequently heated at 85 degrees C for 90 min. Though NaCl contents for albumen and yolk increased to 14.8 and 8.9%, respectively, during the prolonged test for up to 24 weeks, the R values (NaCl/water x 100) were similar (increased from 0.6 to 21) throughout the brining process. The oil-off ratio of the yolk increased rapidly from 14 to 50% (0-6 weeks) and gradually decreased during the extended brining. Granulation and gelation of yolk appeared in the different stages of the brining process. This study demonstrates that the formation of shyandan yolk was determined by the degree of NaCl penetration.

Response surface methodology (RSM) was applied to determine the effects of monosodium glutamate (MSG) and sodium chloride (NaCl) concentrations on the hedonic score of nonspiced and spiced chicken broth. Sensory analysis indicated that both MSG and NaCl concentrations affected (P < 0.005) the hedonic score of the chicken broth. Estimated by the second order polynomial equation, the maximum hedonic score of nonspiced broth was 7.28 on a 9‐point hedonic scale with the combination of 0.33% MSG and 0.83% NaCl. In the presence of spice, the maximum hedonic score increased to 7.81 with the estimated levels of 0.38% MSG and 0.87% NaCl. the increase in the hedonic score of spiced chicken broth might indicate the contribution of spice to the palatability. the increase in levels of MSG and NaCl for the maximum hedonic score of spiced chicken broth was probably due to a masking effect of spices on the taste response of MSG and NaCl.