# Utilization of Quinoa Post-Fermentation Waste as a Medium for Carotenoid Production by Yeast

## TL;DR

This study explores using quinoa fermentation waste to grow yeast that produces carotenoids, which are valuable natural pigments with antioxidant properties.

## Contribution

The novelty lies in repurposing quinoa post-fermentation waste as a medium for carotenoid-producing yeast, demonstrating its viability and bioactive potential.

## Key findings

- The highest total carotenoid fractions were obtained from strains R-1 and R-2 at 2.85 and 3.05 mg/g d.w., respectively.
- FTIR analysis confirmed the presence of β-carotene-like functional groups in the extracted carotenoid powders.
- The carotenoid powders showed strong antioxidant activity, with DPPH radical scavenging between 66.80–78.05%.

## Abstract

Carotenoids are a diverse group of isoprenoid compounds found in nature. As natural pigments and bioactive compounds, carotenoids are used in various industries as functional additives. The increasing knowledge about the disadvantages of synthetic carotenoid production has drawn attention to the potential of carotenogenic yeasts and the use of food industry waste. This study analyzed the potential of post-fermentation waste from fermented quinoa production as a culture medium. For this purpose, reference yeast strains and strains isolated from various environments were used. The C:N ratio in the waste used was determined, and then the yeast was cultured in waste medium with the isolated strains and in a mixed culture with L. plantarum, using three culture variants. In subsequent stages, carotenoid powder was produced, and the carotenoid content, antioxidant capacity, and FTIR spectrum distribution were determined. The studies confirmed the possibility of using plant ferments as culture media. The extraction of powder enabled the concentration of carotenoids, obtaining the highest total fraction of carotenoids (TFC) for strains R-1 (2.85 mg/g d.w.) and R-2 (3.05 mg/g d.w.). FTIR spectra confirmed the presence of functional groups found in β-carotene standards in the resulting powders. At the same time, the obtained formulate exhibited bioactive properties by binding DPPH oxygen free radicals at a level of 66.80–78.05%.