Table 5.

Colour difference $(\mathsf{\Delta }\mathrm{E}$_ab*) values of biscuits.

Biscuit	Control	Rapeseed 2%	Rapeseed 5%	Rapeseed 10%	Phacelia 2%	Phacelia 5%	Phacelia 10%	Sunflower 2%	Sunflower 5%	Sunflower 10%
control		4.6	8.0	11.9	9.6	16.1	22.3	5.3	12.4	15.9
rapeseed 2%			3.6	7.5	6.7	12.9	19.0	2.1	8.1	11.8
rapeseed 5%				3.9	5.5	10.8	16.4	3.9	4.6	8.5
rapeseed 10%					6.4	9.2	13.9	7.6	1.7	5.6
phacelia 2%						6.5	12.7	8.3	8.0	11.9
phacelia 5%							6.3	14.3	10.7	13.5
phacelia 10%								20.2	15.1	16.7
sunflower 2%									7.8	11.1
sunflower 5%										4.2
sunflower 10%

0 < $\mathsf{\Delta }\mathrm{E}$_ab* < 1—observer does not notice the difference. 1 < $\mathsf{\Delta }\mathrm{E}$_ab* < 2—only an experienced observer can notice the difference. 2 < $\mathsf{\Delta }\mathrm{E}$_ab* < 3:5—an unexperienced observer also notices the difference. 3.5 < $\mathsf{\Delta }\mathrm{E}$_ab* < 5—clear difference in colour is noticed. 5 < $\mathsf{\Delta }\mathrm{E}$_ab*—observer notices two different colours [49].