Bioformulation of Yamadazyma mexicana LPa14: photoprotection, thermoprotection, physicochemical properties, and biocontrol efficacy against phytopathogens

The effectiveness of a microencapsulated Y. mexicana LPa14 bioformulation in avocado fruits has been demonstrated. However, to ensure the stability of the microencapsulated yeast during storage, improve its handling and application, and increase its potential for future commercial applications, it is fundamental to characterise the powder bioformulation. This study aimed to evaluate the effectiveness of microencapsulated Y. mexicana against postharvest fungi, evaluate its photostability, and characterise its physicochemical and thermal properties. The bioformulation of Y. mexicana reduced the incidence of Penicillium italicum in lemon, Penicillium digitatum in orange, and Botrytis cinerea in blueberry fruits by 100, 63, and 70%, respectively. The powder bioformulation fulfilled the appropriate physicochemical parameters for long-term storage, with low moisture (3.8%), aw (0.29), and hygroscopicity (7.3%). The thermal analysis demonstrated the thermoprotective effect of the microcapsules based on whey protein concentrate, sodium alginate, and arabic gum on the yeast. Besides, the high glass transition temperature (127°C) may contribute to maintaining the physical stability of the microcapsules during storage. The microcapsules protected the yeast from UV-B radiation with a 21% loss of viability after 15 days. The storage at 4°C preserved the yeast viability for 5 months. The research demonstrated that the bioformulation accomplishes the physicochemical quality parameters of a powder product, is suitable for field and postharvest application, and can be considered a commercially viable alternative for the management of fungal diseases in lemon, orange, blueberry, and avocado fruits.