Fishing sector activities generate significant fish waste daily, which strongly affects the environment
[1]. Seafood waste could be an exceptional source of innovative bioactive compounds, such as
omega-3 fatty acids and vitamin D3, that can be extracted and used in the formulation of nutraceutical
or pharmaceutical products. Therefore, the need for techniques to extract and repurpose these
compounds is essential. In this work, an innovative extraction approach using supercritical CO2 was
applied, and the resulting fish waste extract was loaded into spray-dried microparticles that are useful
as nutraceutical ingredients [2]. Fish waste from Sardina pilchardus species, collected by CNRIRBIM
in collaboration with fishing associations from the Mediterranean Sea (Adriatic Sea), was
homogenized and freeze-dried by ENEA. A sustainable supercritical fluid extraction (SFE) was
conducted to identify the optimal conditions using a two-variable experimental design (temperature
and pressure). The best conditions were replicated three times on a pilot scale, and the extract was
characterized for vitamin D3 and its precursor 7-dehydrocholesterol content (via HPLC-DAD) as well
as fatty acid profile (via GC-MS) [3]. Next, the extract was formulated with an aqueous solution
(maltodextrin, arabic gum, and pea protein hydrolysate) to produce a stable emulsion through stirring
(1100 rpm for 5 minutes), followed by ultrasound (US) treatment (constant power 219 Watts for 3
minutes, 75% amplitude). The emulsion was subsequently subjected to spray drying (Tin 160 °C,
aspirator 100%, atomizing pressure 1.75 bar, feed rate 9.6 g/min), and the resulting microparticles
were characterized for particle size distribution, flowability, residual moisture, and antioxidant
activity. SFE optimal conditions were 90 minutes, 350 bar, and 40 °C. The oil extraction yield on the
pilot scale was 18.1% w/w DM. The oil contained vitamin D3 (6.18 ± 0.54 μg/g EXT) and its
precursor (789.77 ± 95.02 μg/g EXT). Fatty acids were identified and quantified: ω3-polyunsaturated
fatty acids represented the largest proportion (> 43%), followed by saturated fatty acids (~29%) and
monounsaturated fatty acids (~19%). The ω3 DHA is the most abundant compound (19.5%). Finally,
sardine SFE oil served as the oily phase of the O/W emulsion used as feeding material to be treated
via spray drying. The oily droplets of the emulsion obtained after US were very small in size (< 10
μm). The spray drying yield was high (> 87%). The resulting microparticles exhibited good
flowability (angle of repose of 33 °), an average diameter of 18.75 μm, SPAN 2.30, 3.63% of residual
moisture, and antioxidant activity of 9.25 μg TE/mL.This work adds another building block to the
reuse of daily output from the fishing sector, serving as a source of high-value extracts rich in
bioactive compounds for pharmaceutical and nutraceutical applications.
This work is part of the project “VITADWASTE” - funded by Ministero dell’Istruzione
dell’Università e della Ricerca—PRIN 2022. Project code: 2022M9JL3T.