# Impact of UV‑C Light Treatment on the Vitamin D Content and Quality of Bread

## TL;DR

UV-C light can boost vitamin D in bread without harming its quality, offering a plant-based solution for dietary needs.

## Contribution

UV-C treatment is proposed as a novel method to enrich bread with vitamin D2 while maintaining sensory quality.

## Key findings

- UV-C treatment increased vitamin D2 content in bread without compromising quality under optimal conditions.
- A 14 g serving of UV-treated white bread met 27% of the vitamin D RDA.
- Optimal UV-C dose rate minimized negative effects on taste and odor.

## Abstract

Vitamin D deficiency is a global health concern linked
to various
chronic diseases. Although food fortification is a promising solution,
its implementation remains limited by processing losses, matrix inconsistency,
and clean-label trends. Certain foods, including mushrooms and yeast-containing
bakery products, naturally contain provitamin D2 (ergosterol),
which can be photoconverted into vitamin D2 by ultraviolet
(UV) light. While UV-based vitamin D2 enrichment has been
extensively studied in mushrooms, its application in bread remains
largely unexplored. This study investigated UV-C irradiation as a
biofortification strategy for white and whole wheat bread, evaluating
the effects of UV-C dose (0.50 and 2.00 kJ/m2) and dose
rate (0.03 and 0.13 kJ/m2·min) on vitamin D2 content and bread quality attributes. Optimized UV-C parameters
enabled a novel strategy to increase vitamin D2 content
in bread without compromising the quality. UV-C treatments resulted
in varying vitamin D2 levels in bread, depending on the
dose and dose rate, whereas control bread did not contain any detectable
vitamin D2. The highest vitamin D2 content was
obtained when the 2.00 kJ/m2 dose was applied at 0.03 kJ/m2·min dose rate, although this treatment altered odor
and taste. However, other treatments increased vitamin D2 without compromising the quality. The optimal treatment of 2.00
kJ/m2 dose at 0.13 kJ/m2·min dose rate
achieved the best balance between vitamin D2 enrichment
and sensory acceptability. Under the optimal conditions, a 14 g serving
of UV-C treated white bread and a 15.5 g serving of whole wheat bread
provided 27 and 37% of the recommended dietary allowance (RDA) for
vitamin D, respectively. Thus, UV-treated bread represents a valuable
and practical source of plant-based vitamin D for consumers, particularly
for vegetarians or vegans.