The apparent opacity (Yap) of the films was determined using a
colorimeter (BYK Gardner, USA) and was calculated based on theratio between the luminosity (L*) of the system (CIELab), which was
measured with a black background (L
B) and a white background
(L
W), and the thickness of the film (4). The results were expressed
on an arbitrary scale (0e100% mm1
) according to Equation (1):
Yap ¼ L
B=L
W
4
100 (1)
The opacity of the films intercalated with fresh pasta was
determined after 2 and 37 days of storage at 10 C.