Carotene pigment extracted from carrot by simple process. The pigment added by 3 and 7% to different biopolymers [poly(vinyl alcohol) (PVA), poly(methyl methacrylate) (PMMA), cellulose and starch]. Different tests are carried out such as differential scanning calorimeter (DSC), ultra-visible spectra and hardness. Ultra-visible spectra confirmed that there are physical interactions between carotene and biopolymers, thus the effects of the pigment are on the secondary bonds (engineering bonds) and not on the primary bonds. Also results show that carotene increases the hardness of the study polymers, thus it increase the glass transition temperature (T_g) of the PVA, PMMA and starch while lowering the T_g of cellulose, this is due to the high molecular weight of cellulose comparing with starch. The increasing of T_g of the biopolymers means carotene support the strength of the secondary bonds in these polymers by the delocalized π-electrons (carotene molecule has π-bonds can share it to the polymer to support their strength).