Experimental
Reagents and materials
All chemicals used in this work were analytical reagent grade
and double-distilled water was used throughout. Carmine and
Triton X-100 were purchased from Merck Chemicals Company
(Darmstadt, Germany). A solution of nonionic surfactant (40%
w/v) Triton X-100 was prepared by dissolving accurately 40 g of
Triton X-100 in water and diluting to 100 mL in a volumetric flask.
Buffer solution pH 5 was prepared by adding 1.0 mol L1 of sodium hydroxide solution to acetic acid (0.1 mol L1) and adjusting the
pH to 5 using a pH meter. Edible drink and smarties samples were
purchased from local supermarkets in Khorramabad (Lorestan,
Iran).