Create: Purpelness of the tuber flesh color

[dcornet]

Submitter

Name	CORNET
Program	Cirad

Creation Request

Trait Name	Purpelness of the tuber flesh color
Definition	Measurement of the surface purpelness of the yam tuber flesh
Trait Class	Quality
Measurement Method	Tuber flesh purpleness computation from standardized image Lab* values. Compute the index based on the flesh surface color of tuber longitudinal section using image analysis with a color correction based on a custom color chart. Considering a stable light environement (i.e. similar L*), the Hue is used to discriminate purple yam (low value) and white or creamy yam (high value). Hue=atan(b*/a*)
Measurement Type	Unit
Measurement Unit	degrees

[aafolabi]

@dcornet What device are you using for this measurement?

[dcornet]

@aafolabi We can use any personal of professional camera as long as it is programmed to provide sRGB values (which are then turned into CIE Lab values allowing the computation of Hue). An SOP was written to describe every steps of this procedure: https://rtbfoods.cirad.fr/deliverables/scientific-cross-cutting-activities/laboratory-reports-standard-operating-procedures/2019