Oral Presentation 49th Nutrition Society of Australia Annual Scientific Meeting 2025

Vitamin D biofortification of shelf-stable salmon (Salmo salar) products using pulsed ultraviolet light (129645)

Eleanor Dunlop 1 2 , Alexis Wing Huen Chung 3 , Janet Howieson 3 , Belinda Neo 4 , Welma Stonehouse 1 , Paul Adorno 5 , Georgios Dabos 5 , Linda Portsmouth 2 , Lucinda J Black 1 2
  1. Institute for Physical Activity and Nutrition, Deakin University, Geelong, VIC, Australia
  2. Curtin School of Population Health, Curtin University, Bentley, WA, Australia
  3. Curtin School of Molecular and Life Sciences, Curtin University, Bentley, WA, Australia
  4. Curtin Medical School, Curtin University, Bentley, WA, Australia
  5. National Measurement Institute, Port Melbourne, VIC, Australia

 

Efficient use of ocean food resources is imperative for the sustainable production of nutritious foods; however, up to 60% of some fish, e.g., Atlantic salmon (Salmo salar), is discarded during processing(1). This includes offcuts that contain vitamin D and omega-3 long-chain polyunsaturated fatty acids (LCPUFAs), nutrients that are in low dietary supply. The worldwide prevalence of low vitamin D status (circulating 25-hydroxyvitamin D [25(OH)D] concentration < 50 nmol/L) has been estimated at nearly 50%(2), while many countries have a weighted mean Omega-3 Index (omega-3 LCPUFA biomarker) classification of low or very low(3). The vitamin D content of some fish has been shown to increase following treatment with ultraviolet (UV) light(4). Hence, we investigated whether the vitamin D content of shelf-stable snack products made from salmon offcuts (crispy salmon skin and salmon jerky) could be increased using pulsed UV light. A secondary aim was to assess omega-3 LCPUFA content. Crispy salmon skin was made by coating raw skin with corn starch, salt, and olive oil before baking. Salmon jerky was made by marinating minced salmon flesh in brine, adding a binding enzyme, and baking. Measurement of total fat (Soxhlet extraction) and vitamin D3, 25(OH)D3, vitamin D2 and 25(OH)D2 (liquid chromatography with triple quadrupole mass spectrometry) was conducted for all samples (three paired samples each of crispy salmon skin and salmon jerky) before and after pulsed UV light treatment (crispy salmon skin: 3 pulses skin side up, average dose per pulse 34.63 mJ/cm2, average peak 14.91 W/cm2; salmon jerky: 3 pulses each side, average dose per pulse 34.97 mJ/cm2, average peak 14.98 W/cm2). Fatty acid profiling was conducted after pulsed UV treatment using gas chromatography. Omega-3 LCPUFA content (g/100 g) was calculated from % total fatty acids and total fat using a factor of 0.9 to account for non-fat components of triglycerides in fatty fish. In crispy salmon skin and salmon jerky, the respective mean (SD) increases in vitamin D3 (µg/100 g) were: 48.7 (1.8), p < 0.0001; 1.7 (0.3), p = 0.0001. Crispy salmon skin and salmon jerky contained 1.1 (0.1) and 1.6 (0.02) g/100 g omega-3 LCPUFAs, respectively. Pulsed UV light significantly increased vitamin D3 in baked snack products made from salmon. Both products contained nutritionally useful amounts of omega-3 LCPUFAs, but at lower concentrations than may be expected, considering relative moisture content and reference values for grilled salmon fillet (2.4 g/100 g, Australian Food Composition Database). Future studies could include measurement of LCPUFAs before and after pulsed UV treatment to quantify any impact on concentration, and investigate whether any impact could be mitigated by using a lower UV light dose. Nutrient-dense, shelf-stable snack products could be made using salmon processing offcuts and pulsed UV light.

 

  1. AMEC (2003) https://p2infohouse.org/ref/42/41590.pdf
  2. Dunlop E, Pham NM, Hoang DV et al. (2025) J Public Health (Oxf), fdaf080
  3. Schuchardt JP, Beinhorn P, Hu XF et al. (2024) Prog Lipid Res 95, 101286
  4. Sun Y, Alessandroni L, Angeloni S et al. (2024) Food Chem X 22, 101373