Alba’s can and often do show yellow.With the yellow throat is this still alba?
The definition is correct, albeit the diagnosis is wrong: the plants, that cannot express anthocyanin are albinos.Alba’s can and often do show yellow.
reds, pinks, blue and purple are expressed by the pigment Anthocyanin. To be a true alba the flower lacks the ability to express Anthocyanin. I am sure others will have a more thorough explanation but that’s the essence.