Evaluation of the Effects of Plasmolysis, Solvent, and Ultrasonication on Encapsulation of Lycopene in Saccharomyces cerevisiae Cells

Lycopene is one of the members of carotenoids and is used in various food formulations due to its outstanding effects on human health. However, the sensitivity of lycopene to oxygen, light, and heat is the main drawback in its utilization. Encapsulation can be applied to protect the bioactivity of lycopene. Yeast cells are suitable materials for encapsulation because they are biodegradable and safe carriers. In the current study, Saccharomyces cerevisiae was used for lycopene encapsulation, and various strategies, including plasmolysis, solvent, and ultrasonication, were tested to improve loading capacity. The amount of lycopene in the non-plasmolyzed cells was 111.18 µg lycopene/g yeast; however, it was determined as 14.67 µg lycopene/g yeast in the plasmolyzed capsules. The results showed that plasmolysis decreased the loading capacity. The best lycopene retention (324.95 µg lycopene/g yeast) after the encapsulation of non-plasmolyzed cells was achieved by applying both ultrasonication (120 W, 20 min) and solvent (ethyl acetate). Moreover, morphological and conformational characterizations were carried out for yeast samples, and the presence of lycopene within yeast cells was confirmed with Fourier transform infrared spectroscopy and differential scanning calorimetry analysis. Yeast cells, as a low-cost and convenient bio-vehicle, showed promising properties for the encapsulation of lycopene.