Vitamin D Enhanced Foods Using Artificial UVB Development of Products and Quantification of Vitamin D

It is estimated that on annual basis 40 % of the European population is vitamin D insufficient/deficient. The recommended intake of vitamin D is between 10 and 20 μg/day; however the estimated intake is 3 to 7 μg/day. A way to increase the vitamin D intake is to fortify a broader range of foods or by increasing the natural vitamin D content in food sources that already contain vitamin D.

Like humans, hens and pigs can produce vitamin D when their skin is exposed to UVB. Preliminary investigations (ex vivo) showed that the optimal wavelenght for vitamin D production in skin was 296 nm; and that the vitamin D3 production depended on the dose and not the exposure time or total irradiance.

Hens and pigs were exposed to artificial UVB in order to increase the vitamin D content in eggs and pork, respectively. It was shown that the vitamin D content in eggs could be increased when the hens were exposed daily to ≥ 4000 J/m2 UVB (306.5 nm) from above, however due to erythemal change of the comb the trial was stopped after 7 days.

Based on existing published data a linear response between vitamin D3 in feed and vitamin D3 content in eggs was shown. It was concluded that feeding higher levels of vitamin D3 to laying hens is more efficient than UVB exposure to increase the vitamin D content in eggs as it only requires a change in the feed composition.

UVB emitting fluorescent tubes were installed in settings comparable to conventional pig farms. With a dose of 1 SED/day for 28 days (including 7 days adaption period) before slaughter the total vitamin D3 content in lean meat and subcutaneous fat was a factor 19 and 29 higher, respectively, compared to the control; while 25(OH)D3 was a factor 8 higher in both compared to the control.

It was shown possible to produce vitamin D enhanced pork rind and liquid egg products (whole eggs and yolk) by direct exposure to UVB. The vitamin D content of such products could be tailored by adjusting the dose of UVB. All methods presented still calls for further research and approval in the EU before it can be implemented in industry.

Continuous post-column infusion of vitamin D3-d6 was used to visualise ion suppression in the analysis of vitamin D3 as no blank matrix was available; by using this method it was possible to visualise the effect different eluent additives had on ion suppression in extracts of different food matrices.

With a sample preparation consisting of saponification, liquid-liquid extraction, SPE and derivatisation with PTAD an enormous amount of ion suppression of vitamin D3 was observed. Due to its earlier retention time vitamin D3-d6 could not fully eliminate matrix effects in most food matrices.