Abstract
The effects of freezing and thawing, and of heating, furthermore, on the properties of yolks were studied in view of physical values and microscopical structures.
The following yolks were used : a) raw, b) frozen at-3--7°C for 24 hours, c) frozen at-3--7°C for 9 days, d) frozen at-24--29°C for 24 hours.
The results were as follows : 1. After thawing, b) and c) showed the same fluidity as a). But d) was gelatinized with higher physical values. As for heated ones, a) and b) were granular, and c) and d) were rubbery. Physical values increased after heating.
2. From microscopical observations, it was shown that a) consisted of polyangular granules. In b) and c), the structures disappeared with longer frozen time. The polyangular granules of d) were broken. The changes of structures by heating were not observed.
3. The property of yolk after heating was affected by the change of microscopical structure of yolk by freezing and thawing.
