# From 7-dehydrocholesterol to vitamin D3: Optimization of UV conversion procedures toward the valorization of fish waste matrices

## TL;DR

This study shows how fish waste can be turned into a valuable source of vitamin D3 using optimized UV treatment, helping reduce environmental impact.

## Contribution

The paper introduces an optimized UV conversion method to transform 7-dehydrocholesterol in fish waste into vitamin D3.

## Key findings

- The optimized UV treatment increased vitamin D3 levels more than 10 times in fish species.
- Five different fish species were successfully treated to enhance their vitamin D3 content.
- Fish waste can be reused as a sustainable source of vitamin D3 for nutraceutical purposes.

## Abstract

Vitamin D, a fat-soluble steroid, has increasingly taken a central role due to its crucial role in human health. It is estimated that about 40% of worldwide population are vitamin D deficient. The fish industry produces significant quantities of waste daily, with consequent high environmental impact. The aim of this work is to place a first brick for the fish waste reuse as a source of vitamin D3 extracts to be used for nutraceutical purposes. For this purpose, an UV conversion method for transforming the 7-dehydrocholesterol, highly present in fish, in vitamin D3 has been optimized. The UV wavelength, exposure time, temperature, stirring, and UV intensity were optimized using a surface response design tool. The optimized treatment was applied to five fish species with different fat percentages and the results were very promising reaching vitamin D3 levels >10 times higher than the pre-treatment ones.

•Fish can be considered good sources of 7-dehydrocholesterol, the vitamin D3 precursor.•Optimization of 7-dehydrocholesterol to vitamin D3 UV conversion method.•The most performing UV treatment was applied to five different fish species.•The optimized method significantly increased the vitamin D3 content in the fishes.•Reuse of fish waste as vitamin D3 source reducing environmental impact.

Fish can be considered good sources of 7-dehydrocholesterol, the vitamin D3 precursor.

Optimization of 7-dehydrocholesterol to vitamin D3 UV conversion method.

The most performing UV treatment was applied to five different fish species.

The optimized method significantly increased the vitamin D3 content in the fishes.

Reuse of fish waste as vitamin D3 source reducing environmental impact.