《礼记·杂记下》
为国君的母亲和夫人守丧，其礼数比照兄弟。在守丧期间，凡是影响面部哀容之物，都不可饮食。
发诸颜色者，亦不饮食也。
Mourning for the king's mother and wife, the etiquette is the same as for brothers. During the mourning period, anything that affects the sadness of the face should not be eaten.