Determination of β-Carotene in Commercial Foods: Interlaboratory Study

Abstract

Abstract Two sample preparation procedures for determination of total β-carotene and (all-)-β-carotene were tested in a collaborative study involving 14 laboratories and using 4 commercial products containing supplemented or natural β-carotene. One assay used classical sample preparation, consisting of saponification, extraction, washing, and drying ofthe extract and redissolution of residue for liquid chromatography (LC). The other assay used simple extraction without saponification. LC conditions were left for the analysts to decide as long as aclear separation of lycopene and ϑ-carotene from Bcarotene was achieved. Mean contents of test samples ranged from 0.3 to 18 mg/100 g for total β-carotene and from 0.2 to 16 mg/100 g for (all-)-β-carotene. Repeatability relative standard deviations (RSDr)for total B-carotene ranged from 2.9 to 5.6% and relative reproducibility standard deviation (RSDR) ranged from 6.5 to 15%. Corresponding values for(all-)-β-carotene were 3.3-5.1 % for RSDr and 8.4- 14% for RSDR. Excluding the (Z)-isomers from uantitation of β-carotene can result in significant underestimation of the effective β-carotene content especially if the LC systems used is high quality.