A process of preparing symmetric C.sub.40 -carotenoids by reacting a C.sub.15 -triphenylphosphonium salt of the formula ##STR1## and a 2,5-bis(1,1-dialkoxy-2-propyl)-2,5-dihydrofuran to form a reaction product containing a diacetyl and a triphenylphosphonium salt, adding a strong base to the reaction product to convert the triphenylphosphonium salt to a carbenium ion, hydrolyzing the diacetyl to a dialdehyde, subjecting the dialdehyde and the carbenium ion to a Wittig reaction to prepare a Wittig reaction product, and converting the Wittig reaction product to the C.sub.40 -carotenoid by acid treatment.
A carotenoid composition derived from a natural source wherein at least 50% by weight of the carotenoid content of the composition is cis beta-carotene and preferably 9 cis beta-carotene. Typically, the beta-carotene content of the composition is predominantly 9 cis beta-carotene.
