A collaborative study was conducted to evaluate the interlaboratory performance of an LC method for lycopene in dietary supplements and the raw materials commonly used in their manufacture. Twelve laboratories from six countries agreed to participate in the study. Results from 10 laboratories were received and are reported. Five dietary supplements, including both tablets and a softgel capsule with a lycopene content ranging from 25 g to 25 mg per unit, and three raw materials, including gelatin-based beadlets, vegetarian beadlets, and a suspension in oil ranging from 5 to 20 lycopene, were analyzed as blind duplicates. In addition to the commercial products, two positive controls and a negative control were included in the study. For the raw materials studied, the repeatability relative standard deviations (RSDr) ranged from 1.49 to 5.13 for total lycopene, and the reproducibility relative standard deviations (RSDR) ranged from 3.84 to 9.21 with HorRat values from 1.23 to 3.24. For finished products, the RSDr ranged from 1.31 to 4.62, RSDR from 4.28 to 10.5, and HorRat values from 0.79 to 2.07. Corresponding values for all-trans-lycopene were significantly higher. It is recommended that the method be considered for Official First Action for all-trans- and total lycopene in finished products and raw materials.

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Food fortification is an effective approach to improve vitamin D (VD) concentrations in foods. Eggs are a useful food vehicle for enrichment with VD via its hydroxylated metabolite, 25-hydroxyvitamin D (25-D3), in hen feed. This study determined the impact of time of lay, storage conditions (ambient and refrigeration) and common cooking methods (boiling, frying, scrambling, poaching and microwaving) on the vitamin D metabolite concentration of eggs enriched with 25-D3. Processed samples were freeze-dried and analysed for D3 and 25-D3 using an HPLC-MS(/MS) method. The results indicated that storage and cooking practices influence VD metabolites, with 25-D3 showing true retention of 72–111% and concentrations of 0.67–0.96 µg/100 g of whole egg. Vitamin D3 showed true retention of 50–152% and concentrations of 0.11–0.61 µg/100 g of whole egg. Depending on the storage and method of cooking applied, the calculated total VD activity of enriched eggs ranged from 3.45 to 5.43 µg/100 g of whole egg and was 22–132% higher in comparison to standardised VD content for non-enriched British eggs. The study suggests that 25-D3 is a stable metabolite in eggs following storage and cooking, and that 25-D3-enriched eggs may serve as a potent dietary source of VD.