Investigation of bioencapsulation possibilities of pithaya fruit extract with Saccharomyces cerevisiae yeast cells

Bioencapsulation is a technique that has been frequently studied in recent years, with the use of different yeast cells in encapsulation. The low cost, environmentally friendly, and non-toxic nature of yeast cells has enabled them to find applications as encapsulation agents in addition to their well-known uses in the food and fermentation industry. In this study, lyophilized powder extracts from pithaya fruits were encapsulated with plasmolyzed and non-plasmolyzed Saccharomyces cerevisiae yeast cells and bioactive tests, SEM, and FTIR analyses were performed. In addition, different concentrations of ethanol: water solvent media were tested for encapsulation. DPPH inhibition values of the capsules were found between 5.08% and 25.53% and the highest value was found in the encapsulation method performed with non-plasmolyzed cells in 80:20% ethanol medium. Similarly, ABTS inhibition values were determined as 1.91-6.13μg Trolox eq/g, and the highest value was found in the encapsulation method performed in 80:20% ethanol medium with non-plasmolyzed cells. Shrinkage and deformations in plasmolyzed cells were observed in SEM images and clearer images of capsules were obtained in non-plasmolyzed yeast cells. In the FTIR analysis of the fruit extract, the sharp peak obtained at approximately 2950 cm-1 indicated the presence of galacturonic acid and this band intensity decreased in encapsulated samples. Our study showed that yeast cells can be used in encapsulation for the preservation of low-stability components such as betacyanin and betanin in pithaya and more successful results were obtained in non-plasmolyzed yeast cells.